08 Industrial Minerals (Pages 743-806)

8/10/2019 08 Industrial Minerals (Pages 743-806)

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Proceedings of 14th

International Mineral Processing SymposiumKuadas, Turkey, 2014

743

BENEFICIATION OF UKRANIAN KAOLINS FOR CERAMIC

INDUSTRY WITH FALCON GRAVITY SEPARATOR AND

HYDROCYCLONE

Utku Anl Bata1, Mustafa zer1, Ozan Kkkl1and Hayrnnisa Ateok1,a

1. I.T.U. Mineral Processing Engineering, Istanbul, Turkey

a. Corresponding author ([email protected])

ABSTRACT: In this study, kaolin sample which is belonging to Ukraine Vikninskaya

area is prepared for ceramic industry. First of all, after communition, kaolin sample has

scrubbed with Attrition Scrubber for separating over 0,5 mm sized quartz (SiO2) particles

from the system as quartz concentrate. After scrubbing, enrichment tests have done with C-

124 diffuse-type 50 mm Mozley Hydrocyclone and Falcon Gravity Concentrator and the

results were compared. In hydrocyclone tests, optimum mixing time and solid rates aredetermined and in Falcon tests the effect of the solid rates to the separation are optimised.

Also, in parallel, with the optimal conditions, the optimum capacity is calculated for

getting the best possible concentrate. The processing plants process flow chart has been

created and solid water balance has calculated with the optimum conditions.

1. INTRODUCTION:Kaolinite clay with formula

Si2Al2O5(OH)4, is the major mineral

component of kaolin, which may usuallycontain quartz and mica and also, less

frequently feldspar, illite, ilmenite,

anatase, heamatite, bauxite, zircon, rutile,

kyanite, silimanite, graphite, attapulgite,

montmorillonite, and halloysite [Varga

G.,2007].

Kaolin finds extensive applications in a

variety of industries such as paper, paint

rubber and especially in ceramics

[Murray etal, 1993]. The quality ofkaolins used in the ceramic industry is

very important so chemical and

mineralogical specifications of the

kaolins should meet the following

requirements; minimum 35% Al2O3

maximum 0,4 % Fe2O3and between 44-

64% SiO2 for marketing to ceramic

industry [Guven, 1998].

The preferred beneficiation methods of

kaolin minerals depend on the amount

and nature of the mineral impurities

associated to it. Although these methods

are quite useful in removing impurities,they are, at the same time, costly,

complicated and environmentally

hazardous [Rawlings D.E.,2004].

The size classification produces different

grades of kaolin with varying particle size

distribution. Increase in the finer fraction

can result in improved brightness due to

the increase in surface area and hence

more light scattering sites. During sizing,

coarser (quartz) and / or denser (ilmenite,rutile etc.) impurity minerals get

separated. Even small quantities of the

coloring impurities in the finer fractions

contaminate the clay and reduce its

brightness. Hence, these impurities can

be removed only by special techniques

such as froth flotation, magnetic

separation, oxidative/ reductive bleaching

etc.

Depending upon the nature and quantity

of impurities (Murray et al, 1993; Jepson,1988).


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2. EXPERIMENTALThe physical,chemical and mineralogical

properties were determined by standart

methods and the chemical composition of

the row ore has shown in the table. (Table1)

Table 1: The chemical composition of

row ore

ComponentWeight

(%)

LOI 9.06

SiO2 63.83

Al2O3 25.33

Fe2O3 0.51

TiO2 0.73

CaO 0.04

Na2O 0.16

K2O 0.26

For determining the particle size

distribution of the sample screen test

were done and particle size distribution

curve has and d50 and d80 parameters

were found as 10 and 23 mm.(Figure 1)

Figure 1:Particle size distribution of the

sample

2.1. Attrition Scrubbing TestsAttrition scrubbing tests were done in

Wemco attrition scrubber. The samples in

-20 mm and 10 mm particle sizes and%

50 slurry density were fed into the

scrubber and, 1200 and 900 rpm

velocities and 5, 10 and 15 min. times

were adjusted as the working conditions

of scrubber. And at the end of the testsoptimum scrubbing time and speed and

optimum particle size distributions were

optimised.

2.1.1. Scrubber Tests with -20 mm

SampleThe sample is crushed under 20 mm with

Jaw crusher and screening tests were

applied to the sample and particle size

distribution of the sample was

determined.(Figure 2) After that, attritionscrubbing tests were done for optimising

scrubbing time, scrubbing speed and

slurry density of the pulp. The results

were given in (Table 2).

Figure 2: Particle size distribution curve

of -20 mm sample

2.1.2. Tests with -10 mm sampleThe sample is crushed under 10 mm with

Jaw crusher and screening tests were

applied to the sample and particle size

distribution of the sample was

determined(Figure 3).After that, attrition

scrubbing tests were done for optimising

scrubbing time, scrubbing speed and

slurry density of the pulp.


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1200 rpm was found to be optimum after

the tests and the scrubbing tests were

done in these constant conditions: 1200

rpm and %50 slurry density.

The results of the scrubbing tests weregiven in (Table 3) and (Table 4).

Figure 3: Particle size distribution curveof -20 mm sample

Table 2: -20 mm sized sample attrition scrubbing test results for determining optimum

mixing time.

Time

(min)

Particle

Size(microns)

Amount

(%)

Content, (%) Distribution, (%)

SiO2 Al2O3 Fe2O3 SiO2 Al2O3 Fe2O3

5

+500 19,2 97,3 0,33 0,13 29,3 0,3 5,3

-500+106 13,6 91,3 4,67 0,28 19,5 2,6 8,1-106+38 6,8 62,8 24,51 0,68 6,7 6,7 9,8

-38 60,4 46,9 37,17 0,6 44,5 90,5 76,8

Total 100 63,7 24,87 0,47 100,0 100,0 100,0

10

+500 17 98,75 0,07 0,04 26,22 0,05 1,47

-500+106 12,6 95,20 2,62 0,19 18,73 1,34 5,18

-106+38 10 66,21 22,25 0,63 10,34 9,06 13,63

-38 60,4 47,40 36,41 0,61 44,71 89,55 79,72

Total 100 64,03 24,56 0,46 100,00 100,00 100,00

15

+500 18,7 99,45 0,05 0,03 29,94 0,04 1,21

-500+106 11,4 96,3 1,88 0,17 17,67 0,88 4,17

-106+38 9,4 55,3 21,52 0,62 8,37 8,27 12,55

-38 60,5 45,2 36,7 0,63 44,02 90,81 82,07

Total 100 62,12 24,45 0,46 100,00 100,00 100,00


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Table 3: -10 mm sized sample attrition scrubbing test results for determining optimum

mixing time.Time

(min)

Particle

Size

(microns)

Amount

(%)



5+500 20,8 98,1 0,33 0,13 31,9 0,3 5,9

-500+106 12,5 92,4 4,67 0,28 18,1 2,5 7,7

-106+38 8,4 65,32 24,51 0,68 8,6 8,7 12,5

-38 56,3 47,04 37,17 0,6 41,4 88,5 73,9

Total 100 63,9252 23,63794 0,45696 100,0 100,0 100,0

10

+500 18,8 99,05 0,26 0,07 28,8 0,2 2,8

-500+106 12,0 95,00 2,65 0,24 17,6 1,3 6,1

-106+38 9,0 64,45 21,65 0,77 9,0 7,8 14,7

-38 60,2 47,98 37,52 0,6 44,6 90,7 76,5

Total 100,00 64,70 24,90 0,47 100,00 100,00 100,00

15

+500 18,6 99,50 0,04 0,02 29,68 0,03 0,82

-500+106 12,3 96,10 1,86 0,18 18,96 0,94 4,85

-106+38 9,2 55,70 21,54 0,64 8,22 8,18 12,91-38 59,9 44,90 36,72 0,62 43,14 90,84 81,42

Total 100,00 62,35 24,21 0,46 100,00 100,00 100,00

Table 4: Attrition scrubbing test results for determining optimum mixing velocity.Velocity

rpm

Particle

Size

(microns)

Amount

(%)



1200 +500 19,20 97,30 0,33 0,13 29,30 0,30 5,30

-500+106 13,60 91,30 4,67 0,28 19,50 2,60 8,10

-106+38 6,80 62,80 24,51 0,68 6,70 6,70 9,80

-38 60,40 46,90 37,17 0,60 44,50 90,50 76,80Total 100,0 63,69 24,81 0,47 100,0 100,0 100,0

900

+500 26,10 97,65 1,19 0,07 39,20 1,30 4,50

-500+106 11,20 84,20 10,13 0,34 14,50 4,70 9,50

-106+38 4,40 63,80 24,22 0,65 4,30 4,30 7,20

-38 58,30 46,90 37,52 0,54 42,0 89,70 78,80

Total 100,0 65,06 24,38 0,40 100,0 100,0 100,0

2.2. Classification Tests:After -20 mm sample was screened from

0,5 mm sized screen classification tests

with hydrocyclone and Falcon Gravity

Concentrator were done for determining

optimum working conditions.

2.2.1. Hydrocyclone TestsAfter scrubbing and screening from 0,5

mm screen over 0,5 mm size particles

were taken as quartz concentrate. Under

0,5 mm sized sample was fed to the

hydrocyclone. The parameters slurry

density,feed pressure,apex and vortex

diameters were optimised for determining

optimum working conditions of

hydrocyclone.The flowsheet of

hydrocyclone tests were given in the

(Figure4). And the results of

hydrocyclone tests were given in (Table

5).


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Figure 4:Flowsheet of hydrocyclone tests

2.2.2. Beneficiation tests with Falcon

Gravity Concentrator:

After scrubbing and screening from 0,5

mm screen over 0,5 mm size particleswere taken as quartz concentrate. Under

0,5 mm sized sample was fed to the

Falcon Gravity Concentrator. The

parameters slurry densityand G force

were optimised for determining optimum

working conditions of Falcon Gravity

Concentrator.

The flowsheet of Falcon Gravity

Concentrator tests were given in the(Figure 5).And the results of Falcon

Gravity Concentrator tests were given in

(Table6). After these tests the final flow

sheet was determined as in the (Figure 6).

Table5: Hydrocyclone tests results

Products Amount

(%)



Kaolin 65,20 46,90 37,35 0,66 48,89 93,20 87,82

Middling 5,30 57,50 28,84 0,81 4,87 5,85 8,76

Quartz 29,50 98,08 0,85 0,09 46,26 0,96 5,42

Total 100,0 62,55 26,13 0,49 100,0 100,0 100,0

Figure 5: Flowsheet of Falcon GravityConcentrator tests.


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Table 6: Falcon Gravity Concentrator test results

3. RESULTS AND DISCUSSION1) From the chemical and mineralogical

analysis of the row sample it can be seen

that the quartz content of the sample is

higher for the needs of the ceramic

industry.

2) After screen tests row ores d80= 23

mm and d50= 10 mm has determined.3) As the results of the scrubbing tests the

optimum conditions for enrichment were

found like that: %50 slurry density, 1200

r.p.m. attrition speed, -20mm particle size

and 5 minutes scrubbing time.

4) After attrition scrubbing +0,5 mm can

be separated from the system as quartz

concentrate.

5) The optimum conditions for

hydrocyclone tests slurry density10%; 3,2

mm and 2,2 mm apex radius aredetermined.

6) From Falcon gravity separator tests it

has been found that the ideal slurry

density10 %.

7) It can be clearly said that the content

of the quartz concentrate that is obtained

from Falcon gravity concentrator is not

as well as the hydrocyclone tests.The

efficiency of the Falcon is not enough to

get a good quality of quartz concentrate

but good quality of kaolin concentrate

can be obtained.

4. CONCLUSION:

As the results of the attrition scrubbing

tests, optimum scrubbing time 5 min.,

%50 solid ratio and 1200 rpm scrubbing

velocity were found. From hydrocyclonetests %46,90 SiO2, %37,50 Al2O3 ve %

0,66 Fe2O3 content kaolin concentrate;

%98,08 SiO2, %0,85 Al2O3 ve % 0,09

Fe2O3 content quartz concentrate were

obtained. From the Falcon gravity

concentrator tests the content of kaolin

concentrate were found %46,90 SiO2,

%37,50 Al2O3and % 0,66 Fe2O3 and

content of quartz concentrate %98,08

SiO2, %0,85 Al2O3and % 0,09 Fe2O3

were obtained.Also according to the results of the

process flow chart 1,78 m3 water must be

feed per ton ore to the process plant.

Saolid

Ratio, %

Products Amount

(%)



10

Kaolin 20,80 98,10 0,33 0,13 31,90 0,30 5,90

Middling 12,50 92,40 4,67 0,28 18,10 2,50 7,70

Quartz 8,40 65,32 24,51 0,68 8,60 8,70 12,50

Total 100,00 63,90 23,60 0,45 100,00 100,00 100,00

20

Kaolin 20,80 98,10 0,33 0,13 31,90 0,30 5,90

Middling 12,50 92,40 4,67 0,28 18,10 2,50 7,70

Quartz 8,40 65,32 24,51 0,68 8,60 8,70 12,50

Total 100,00 64,70 24,90 0,47 100,00 100,00 100,00

30

Kaolin 20,80 98,10 0,33 0,13 31,90 0,30 5,90

Middling 12,50 92,40 4,67 0,28 18,10 2,50 7,70

Quartz 8,40 65,32 24,51 0,68 8,60 8,70 12,50

Total 100,00 62,35 24,21 0,46 100,00 100,00 100,00


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Figure 6: Flowsheet of the process plant.

Acknowledgements: Authors present

their special gratefulness to EczacbaEsan to reproduce chemical analysis of

the samples.

REFERENCESGuven, C., 1998, Investigation of beneficiation

possibility of Istanbul-Sile region clays for

ceramics industry, Graduation Thesis, I.U.

Mining Eng. Dept.

Jepson, W.B., 1998,Structural iron in kaolinites in

associated ancillary Minerals, Iron in soilsand clay minerals. NATO Advanced Science

Institutes Series, pp. 467-536.

Murray, K.J., and Keller, W.D.,1993. Kaolins,

Kaolins and Kaolins in Kaolin Genesis and

Utilisation. Special publications by the Clay

Mineral Society, Colorado, US pp 1-24.

Rawlings, D.E., 2004. Microbially assisted

dissolution of minerals and its use in the

mining industry.

Varga, G., 2007. The structure of kaolinite and

metakaolinite. Epitoanyag, 59, 4-8.


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751

INVESTIGATION OF USAGE OF ZONGULDAK ALACAAZI

SANDSTONE IN CASTING INDUSTRY

Gndz Ateok1,a, Feridun Boylu1, Mustafa zer1, Frat Burat1and Hseyin

Batrkc1

Istanbul Technical University Mining Faculty, Mineral Processing Engineering Department,

Maslak-stanbul, Turkeya. Corresponding author ([email protected])

ABSTRACT: In 2013 demand of silica sand, which has a usage area in glass, casting,

construction, metallurgy, electronic, and ceramic industries with silicon-ferrosilicon

production, is over 4 million tons in Turkey. This demand cannot be met with running out

of reserves of coastal sand and it resulted in production gap. Therefore, quartzite reserves

of 6.3 billion tons, which exists in Zonguldak, Antalya, Adana, Kastamonu, Yozgat, and

Denizli provinces of Turkey, have increased in importance.

In this research, technological tests were performed on Zonguldak Alacaaz sandstone,which have 700 million tons of reserves. In order to investigate the possibility of usage of

this sandstone in casting industry, at first, physical and chemical properties of the sample

was determined. Particle size was reduced with jaw and cone crushers. Then, scrubbing

was performed on Alacaaz sandstone sample, which has 96.8% SiO2and 0.6% Fe2O3.After classification into size fractions, it was seen that a clay product could be obtained

with 4.40% Fe2O3content, while the sandstone contained 0.36% Fe2O3.

On the other hand, the scrubbed sandstone was tested in high intensity wet magnetic

separation and flotation. According to the results, flotation method gave more positive

results than magnetic separation did. 96% amount of Alacaaz sandstone was obtainedwith 0.24 Fe2O3. At the end of the tests, process flow sheets for both of the samples were

generated.

1. INTRODUCTIONQuartz naturally occurs as colorless or

light-white colored and fine-grained

structure. It has a hardness of 7 on the

Mohs scale with 2.65 specific gravity and

17850

C melting temperature [pekolu,1999].

While pure quartz crystals can be used in

optic and electronic industry, quartz has

areas of usage in chemistry, electric,

glass, detergent, paint, ceramic, abrasive,and metallurgy industries [SPO, 2001].

On the other hand, quartz ores contain

impurities, especially iron. Unless irons

minerals are removed, transmission of

optic fibers are obstructed, discolorationin ceramic products occurs and melting

point of refractory materials is decreased

[Taxiarchou et al.1997].

In order to remove iron minerals, various

physical, chemical and physico-chemical

methods can be applied. As simpleprocesses of crushing, grinding and

sieving can respond, sometimes magnetic

separation and/or flotation processed can

be necessary [Akl et al., 2007].However when the iron minerals are not

able to be liberated, then, acid leachingmethod becomes an alternative method to

obtain high-purity quartz [Loritsch ve

James, 1991].


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Figure 2: XRD pattern of the non magnetic product

Figure 3: XRD pattern of the magnetic product


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3. RESULTS

3.1 Scrubbing TestsThese tests aimed abrasion of the sample

by scrubbing rather than grinding. Thus,formation of fine sizes could be

prevented. Under the conditions of 60%

solid ratio by weight and 700 rpm

rotational speed, different scrubbing

durations were tested. After scrubbing,

the sample was decantated in three stages

and clay was separated. Scrubbing testsresults are given in (Table 1).

Scrubbing+decantation tests showed that

4.9-5.1% of clay material could be

separated, which provided a mechanicalabrasion.

Table 1: Scrubbing+decantation

Particle Size

Fraction, mm

Scrubbing

5 min 10 min 15 min

+1.41 100.0 100.0 100.0

-1.41+1.00 98.5 98.4 98.5

-1.00+0.710 96.5 96.6 96.8

-0.710+0.500 93.4 93.6 94.0

-0.500+0.355 84.3 86.3 87.4

-0.355+0.212 62.7 68.3 66.4

-0.212+0.180 20.9 27.8 27.6

-0.180+0.125 10.1 12.5 13.1

-0.125+0.090 6.7 7.7 8.0

-0.090+0.063 3.7 4.7 4.7

-0.063 2.0 2.8 2.4

Weight accordng

to feed, %95.1 95.1 94.9

-0.125+0.106 100.0 100.0 100.0

-0.106+0.090 99.8 100.0 100.0

-0.090+0.074 99.7 100.0 100.0

-0.074+0.063 99.7 100.0 100.0

-0.063+0.045 99.6 99.7 99.9

-0.045 98.1 99.1 99.7

Weight accordng

to feed, %4.9 4.9 5.1

Chemical analyses of the products are

shown in (Table 2a and 2b). Loss on

ignitions was nearly 0.1%. The SiO2

content of the raw ore sample, which was

96.8%, increased above 99%. On the

other hand, Fe2O3 content of the raw

sample known as 0.72% decreased to0.39%.

Table 2a: Chemical analyses of

Scrubbing+decantation tests

Scrubbing

Duration,

min

SiO2,

%

Al2O3

%

Fe2O3

%

TiO2

%

5 99.00 0.38 0.42 0.035

10 99.09 0.26 0.41 0.036

20 99.11 0.25 0.39 0.033

When the results were evaluated, in order

to decrease the iron content further,

flotation was decided to be performed

following 10 min scrubbing and

decantation.

Table 2b: Chemical analyses of

Scrubbing+decantation tests

Scrubbing

Duration,min

CaO

%

MgO

%

Na2O

%

K2O

%

5 0.01 0.00 0.00 0.05

10 0.01 0.00 0.00 0.04

20 0.01 0.00 0.00 0.04

3.2 Flotation Tests

In the flotation tests, collectors of R801

and R825 were used with the amounts of

varying between 100-400 kg/t. Since the

collectors have frother property, therewas no need to use any frother. The

collectors used in a ratio of R801/R825 :

2/1. pH value was kept constant between

2.5-3.0. Collector amount, multiple stage

collector addition and solid ratios were

tried in the flotation tests. The results

were given in (Table 3).

400 g/t collector addition in multiple

stages to the scrubbed pulp of which can

be adjusted above 30% solid ratios was


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determined as the optimum flotation

condition.

0.72% of Fe2O3 content in the raw ore

sample was decreased to 0.4% with

scrubbing and decantation. After flotationtests, this value was decreased to 0.24%

Fe2O3. Besides, 99.46% SiO2content was

able to be obtained.

3.3 Wet High Intensity Magnetic

Separation TestsScrubbed and decantated pulp, which

contained 0.4% Fe2O3, was fed to Jones

magnetic separator at 20% solid ratioswith a constant feed rate. During the test,

strength of current was adjusted to

different values of 1, 3 and 6.8 A.

Table 3: Scrubbing+decantation+flotation test resultsSolidRatio

Collector Weight SiO2 Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O

% Amount, g/t Add. % % % % % % % % %

20 150 150 99.2 99.33 0.23 0.27 0.028 0.01 0.01 - 0.04

20 200 200 98.8 99.31 0.23 0.29 0.027 0.01 0.01 - 0.04

20 250 250 96.6 99.36 0.24 0.26 0.022 0.01 0.01 - 0.04

20 360 360 94.9 99.43 0.23 0.23 0.022 - 0.01 - 0.04

28 250 250 96.6 99.46 0.19 0.26 0.022 - - - 0.03

40 250 250 96.6 99.40 0.22 0.25 0.025 - - - 0.04

28 250125+62.5+62.5

97.6 99.44 0.18 0.27 0.026 - 0.01 - 0.03

20 150 150 98.8 99.20 0.22 0.32 0.03 - 0.01 - 0.04

20 200 200 96.2 99.24 0.22 0.29 0.025 - - - 0.04

20 250 250 93.7 99.31 0.23 0.25 0.024 - 0.01 0.04

20 360 360 84.5 99.28 0.23 0.29 0.023 - 0.01 0.01 0.04

28 200 200 96.3 99.21 0.24 0.32 0.034 - 0.01 - 0.04

36 200 200 96.6 99.29 0.23 0.29 0.023 - 0.01 - 0.04

28 400

67.5 +67.5 +67.5 +

67.5+130

95.8 99.40 0.19 0.24 0.025 - - - 0.03

While the results of the magnetic

separation can be seen in (Table 4), the

distributed metal balances are given in

(Table 5).

According to the results, Jones magnetic

separator provided a decrease in Fe2O3

content, which was found as 0.3%. Under

these conditions, 99.45% SiO2 was able

to be obtained.

When the weights and contents of the

products were evaluated, it can be

concluded that there was not suitable

magnetic type iron minerals, which could

be removed with wet high intensity

magnetic separator.


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Table 4: Jones Magnetic Separation

Results

ProductsWeight, Fe2O3, %

% Content Distr.

NonMagnetic

68.2 0.30 59.4

Middling 8.9 0.31 8.0

Magnetic

Product-313.0 0.34 13.0

Magnetic

Product-26.6 0.51 9.7

Magnetic

Product-13.4 0.99 9.9

Feed 100 0.35 100

Table 5: Jones Magnetic Separation

Results (Distributed)

ProductsWeight, Fe2O3

% Content Distr.

Non

magnetic90.0 0.30 80.4

Middling 6.6 0.51 9.7

Magnetic 3.4 0.99 9.9

Feed 100 0.35 100

4. CONCLUSIONPrimary and secondary crushing units

were decided as jaw and cone crushers

respectively. Since sandstone ores

excavated from open pit mines can have

some extent of moisture, hammer

crushers are not be suitable for this

process.

Using flotation method, 0.24% Fe2O3was

able to be obtained with 96% efficiencyfrom the sandstone sample, which

contained 0.7% Fe2O3.

With wet high intensity magnetic

separation using Jones separator, 0.30%

Fe2O3was able to be obtained with 90%

efficiency from the sandstone sample,

which contained 0.7% Fe2O3.

Either flotation or magnetic separation

processes provided acceptable Fe2O3

contents. However when these processes

were compared, in terms of the silica

sand weight and lower Fe2O3 content

obtained, flotation method was thought to

be better.

REFERENCESAkl, A., Tuncuk, A, Deveci, H., 2007. An

Overview of Chemical Methods Used in the

Purification of Quartz. Madencilik, Vol.46,

No.4, pp 3-10.

pekolu, B., 1999. Quartz,Quartzite, Quartzsand. Association of stanbul MineExportersi, Inventory of Industrial Mineralsof Turkey, pp. 102-106.

Loritsch, K.B. and James, R.D., 1991. Purified

Quartz and Process for Purifying Quartz.

United States Patent, Patent Number:

4,983,370.Specialization Commission of Mining Reports of

Development Plan-8th

, 2001. Sub-

commission of Industrial Raw Materials,

Sand Industry Raw Materials- III (Quartz

sand, Quartizte, Quartz). State Planning

Organization.

Taxiarchou, M., Panias, D., Douni, I., Paspaliaris,I. ve Kontopoulos, A., 1997. Removal of Iron

from Silica Sand by Leaching with Oxalic

Acid. Hydrometallurgy, 46, 215-227.


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LEACHING OF A COMMERCIAL VERMICULITE IN H2SO4

SOLUTIONS

.Ehsani1, E.Turianicov2, M.Bal2and A.Obut1,a

1. Hacettepe University, Mining Engineering Department, Ankara, Turkey

2. Institute of Geotechnics, Slovak Academy of Sciences, Koice, Slovakiaa. Corresponding author ([email protected])

ABSTRACT:In this study, the leaching behaviour of a commercial vermiculite sample, in

natural and heated forms, in 1 M aqueous sulphuric acid solutions at 20C and 90C wasinvestigated using chemical and X-ray diffraction analyses, Fourier transform infrared

spectroscopy and nitrogen adsorption measurements. Although small changes occurred in

the chemical compositions and surface area values following leaching at 20C, greatreductions in the amounts of structural components, i.e. Al2O3, Fe2O3, MgO, and dramatic

increases in the surface area values were observed after leaching of both samples at 90C,indicating quantitative, but not total, dissolution of the samples. Similarly, acid leaching of

natural and heated vermiculite samples at 20C resulted only small changes in the X-raydiffraction patterns and infrared spectra, but with the increase of leaching temperature to

90C, significant changes, i.e. the dissolution of vermiculite structures and the formation ofhydrous amorphous silica phase, were observed.

1. INTRODUCTIONSwelling clay minerals, such as smectites

and vermiculites, exhibit differences in

their layer charges, adsorptive properties,

cation exchange capacities, particle sizes

etc. Because of these differences, they

can be used in different areas such as

foundry, construction, agriculture or

chemical industries either directly or after

the application of different modification

processes. Leaching by inorganic acids,

i.e. sulphuric or hydrochloric acid, is one

of the useful modification processes for

these clay minerals and due to the

enhanced surface and catalytic behaviourfollowing acid leaching, they can be used

as bleaching earths, as catalysts or

catalyst supports, in the production of

carbonless copying paper or in the

preparation of pillared clays and

organoclays [Komadel et al., 1990;Suquet et al., 1991; Mokaya and Jones,

1995; Breen et al., 1997; Ravichandran

and Sivasankar, 1997; Londo et al., 2001;

Gates et al., 2002; Jozefaciuk and

Bowanko, 2002; nal et al., 2002; Kooli,2009; Steudel et al., 2009a].

In contrast to numerous studies related

with acid leaching of smectites, the

number of studies investigating the

leaching behaviour of commercial

vermiculites in inorganic or organic acids

is low. Therefore, in this study, leaching

behaviour of a commercial vermiculite, in

natural and heated forms, in sulphuric

acid solutions was investigated and

comparative data were collected for

future studies. To identify the changes

caused by acid leaching, X-ray diffraction

(XRD), Fourier transform infrared (FT-

IR) and chemical analyses together with

nitrogen adsorption measurements wereperformed on the natural, heated and

leached vermiculite samples.

2. MATERIALS AND METHODSThe natural sample used in this work is

commercial micron grade Palabora(South Africa) vermiculite. According to

the data supplied by the producer, 80% of

the natural sample is in the size range of

-0.710+0.250 mm and the fraction of

-0.180 mm is maximum 10%. The naturalsample contains 85-95% vermiculite,


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and phlogopite, apatite, diopside with

trace amounts of dolomite and quartz are

the impurities. Chemical composition of

the natural sample was given in Table 1.

Table 1: Chemical composition (%) of the

natural vermiculite sample.

SiO2 Al2O3 Fe2O3 MgO

41.02 8.90 8.36 19.91

CaO Na2O K2O TiO2

6.27 0.07 4.63 0.97

P2O5 MnO Cr2O3 L.O.I

2.41 0.06 0.05 6.97

In the leaching studies, natural and heated

(at 900C, according to Turianicovet al.[2014]) vermiculite samples were used.

Because surface area is one of the most

important parameters in leaching studies,

in this study, heated vermiculite was

compared with the natural vermiculite

due to its higher surface area. Sulphuric

acid was selected as the leaching reagent

due to its reported efficiency ondissolution [Steudel et al., 2009a]. In a

representative experiment, 50 grams of

natural (NV) or heated (HV) vermiculite

was leached in 500 mL, 1 M aqueous

H2SO4solution either at 20C or 90C for60 minutes under constant rate of stirring.

Following leaching, the solid residues

were separated by filtration, washed and

finally dried at 105C. The chemicalcompositions, XRD patterns (Rigaku

with CuK radiation, followingequilibration under room atmosphere),

FT-IR spectra (Bruker, by KBr pellet

method), and B.E.T. surface area values

(Quantachrome Instruments, by nitrogen

adsorption following degas for two hours

at 105C) of the natural, heated andleached vermiculites were determined in

order to observe the changes caused by

acid leaching. The pore size distribution

of a selected leach residue was alsodetermined.

3. RESULTS AND DISCUSSION

3.1. Chemical Analyses, Surface Area

Measurements and Porous PropertiesSome of the main chemical components

and surface area values of the natural andheated samples together with their

corresponding leached counterparts were

presented in Table 2 and Table 3,

respectively.

Table 2: Main chemical components (%)

of the natural, heated and leached

vermiculites.

Sample SiO2 Al2O3 Fe2O3 MgO K2O

NV 41.02 8.90 8.36 19.91 4.63NV-20 44.22 9.32 8.77 20.21 4.65

NV-90 64.81 4.32 5.08 10.95 2.58

HV 44.39 10.09 9.31 21.69 5.20

HV-20 45.59 9.56 9.08 21.18 4.89

HV-90 62.10 4.94 5.54 13.18 3.03

Table 3: Surface area values (m2/g) of the

natural, heated and leached vermiculites.

NV NV-20 NV-90

3.322 5.632 251.844

HV HV-20 HV-90

13.963 15.429 97.950

(Table 2) showed that when the natural

and heated samples were leached at 20C(NV-20 and HV-20, respectively), there

were only small changes in the values of

main chemical components, indicatinginsignificant dissolution from the clay

samples. Due to the low amounts of

dissolution of the structural components,

i.e. Mg, Fe and Al, the increases in the

surface area values of the leached

vermiculites were also low (Table 3).

On the other hand, when leaching process

was performed at 90C (samples NV-90and HV-90), the amounts of magnesium,

iron and aluminum in the leach residuesbecame approximately half of their initial


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values, which indicated quantitative, but

not total, dissolution of the clay structures

in both samples. Although surface area of

the heated sample is higher than the

natural one, the amount of residualstructural components in its leach

residues were higher in comparison to the

residues of the natural sample probably

due to the presence of dehydrated and

collapsed clay structures in the heated

sample [Okada et al., 2006; Steudel et al.,

2009a,b].

In the studies where micron grade South

African vermiculite was used; Okada et

al. [2006] were increased the surface areafrom 1 to 265 m2/g by leaching the

natural sample in 1 M H2SO4solution at

70C for 60 minutes; Temuujin et al.[2003] were increased the surface area

from 1.4 to 407 m2/g by leaching the

natural sample in 1 M HCl solution at

80C for 60 minutes and to 553 m2/g byleaching under same conditions for 120

minutes; and Temuujin et al. [2008] were

increased the surface area again from 1.4to 547 m2/g by leaching the heated (at

600C) sample in 2 M HCl solution at80C for 120 minutes. In this study, thesurface area of the natural (3.322 m2/g)

and heated (at 900C, 13.963 m2/g)micron grade South African vermiculite

samples were increased to 5.632 m2/g and

15.429 m2/g by low temperature (20C),and to 251.844 m2/g and 97.950 m2/g for

high temperature (90C) leaching in 1 M

H2SO4 solution for 60 minutes,respectively (Table 3).

The adsorption-desorption isotherms and

pore size distribution of the leach residue

HV-90 were given in Figures 1 and 2,

respectively. As can be seen from Figure

1, there is a hysteresis loop which

suggests the presence of mesopores in the

sample. There are no micropores present

in the sample. Due to the shape of the

isotherm in the region of higher relativepressures, it can be said that there could

be some small amount of macropores

present in the sample. The total pore

volume of HV-90 was 0.1326 cm3g-1.

The presence of mesopores wasconfirmed by the pore size distribution

study. As can be seen from Figure 2, the

structure contains almost no other type of

pores than mesopores with radii between

1.5 and 10 nm (the diameters between 3

and 20 nm). The measurement from

adsorption isotherm confirmed the

presence of so-called tensile strength

effect, because the peak with maximum

around 2 nm present in case of pore size

distribution calculated from thedesorption isotherm does not present.

Figure 1: Nitrogen adsorption/desorption

isotherm for HV-90.

Figure 2: Pore size distribution for HV-

90.


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760

3.2. XRD AnalysesXRD patterns of the natural and heated

samples together with their leached

counterparts were given in Figures 3 and

4, respectively.

Figure 3: XRD patterns of the natural

vermiculite and its leach residues.

Figure 4: XRD patterns of the heated


XRD pattern of the natural sample (NV

in Figure 3) shows diffraction peaks at

6.22, 7.18 and 7.48, indicating thepresence of both two- and one-water-

layer hydration states and interstratified

phases [Ruiz-Conde et al., 1996; Marcos

et al., 2009; Muiambo et al., 2010]. High

content of potassium (see Table 1) in the

natural sample in comparison to truevermiculites also indicated the presence

of interstratification [Muiambo and

Focke, 2012]. Very small intensity peak

at 8.80 was attributed to mica impurity[Muiambo et al., 2010]. The main and

single basal peak at 8.86 in XRD patternof the heated sample indicated the

existence of dehydrated and collapsed

clay structures.

Leaching of the natural and heatedsamples at 20C in 1 M H2SO4 solutioncaused small changes and only

insignificant differences in the peak

intensities of clay structures were

observed, in accord with the chemical

analyses results. On the other hand,

leaching of the natural sample at 90Ccaused major dissolution of the

vermiculite structures as observed by the

disappearance of peak at 6.22 (compareNV or NV-20 with NV-90 in Figure 3).

The intensities of the basal peaks were

also greatly reduced and background of

the pattern was increased, both

suggesting amorphization by dissolution

of the clay structures.

Heating of the natural sample at 900Cproduced dehydrated and collapsed clay

structures, which resemble micas, as

observed by the main peak at 8.86 (seepattern HV in Figure 4). Although thechanges caused by acid leaching in the

natural sample were easily observable by

the analyses of XRD peaks in the related

patterns, almost no changes were

observed in case of the heated samples.

Only very small increase was observed in

the background intensity in XRD pattern

of the leach residue obtained by leaching

of heated vermiculite sample in 1 M

H2SO4 for 60 minutes (see HV-90 inFigure 4).

2()

NV

NV-20

NV-90

2()

HV

HV-20

HV-90


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761

3.2. FT-IR AnalysesFT-IR spectra of the natural and heated

samples together with their corresponding

leached counterparts were given in

Figures 5 and 6, respectively.

Figure 5: FT-IR spectra of natural


Figure 6: FT-IR spectra of heated


FT-IR spectrum of the natural sample

shows a broad and very strong intensity

absorption band at 999 cm-1belonging to

Si-O-Si and Si-O-Al vibrations. The

strong intensity band (with a shoulder)centered at 457 cm-1 may be associated

with Si-O-Si and Si-O-Mg. The medium

intensity absorption at 1632 cm-1 is

attributed to the OH bend deformation of

water. The medium band observed at 687

cm-1may be related with R-O-Si, where

R=Mg, Al or Fe. The weak bands at 602,

729 and 818 cm-1 may be assigned to

mixed Al-O/Si-O and hydroxyl groups

[Suquet et al., 1991; Ravichandran and

Sivasankar, 1997; da Fonseca et al., 2006;Steudel et al., 2009a; Chmielarz et al.,

2010; Muiambo et al., 2010; Hongo et al.,

2012; Muiambo and Focke, 2012].

In accord with the results of XRD

analyses, low temperature acid leaching

caused only small changes in the FT-IR

spectra of both the natural and heated

vermiculites. But, high temperature acid

leaching changed the corresponding IRspectra dramatically, because of the

sensitivity of FT-IR spectroscopy for

detecting the possible changes (or

destruction) in the crystalline structure of

clay minerals following any modification

process [Suquet et al., 1991]. By high

temperature leaching of the natural

sample, bands at 602, 687, 729 and 818

cm-1 disappeared and new absorption

peaks of Si-O at 1088 (with shoulder

~1200 cm

-1

), 800 and 461 cm

-1

, andSiOH at 968 cm-1 belonging to hydrous

amorphous silica phase were revealed

[Plkov et al., 2003; Wypych et al.,2005; Yu et al., 2012]. This indicates the

formation of hydrous amorphous silica

phase by acid dissolution of the structural

components from the natural and heated

vermiculites. Similar changes were also

observed by high temperature acid

leaching of heated vermiculite sample but

the effect of acid leaching is somewhatlower when compared to the natural

HV

HV-90

HV-20

Wavenumber (cm-1

)

NV

NV-90

NV-20

Wavenumber (cm-1

)


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762

sample. The absorption band at 1007 cm-1

belonging to the heated sample also

indicated the higher resistance of

collapsed mica like layers against acid

attack, which is consistent with theresults obtained by chemical and XRD

analyses.

4. CONCLUSIONSIn this work, the leaching behaviours of a

natural and a heated vermiculite sample

in 1 M H2SO4solution at 20C and 90Cfor 60 minutes were investigated using

different analyses methods. Although no

or small changes occurred in chemical

compositions, in XRD/FT-IR patterns andsurface area values of the leach residues

obtained by low temperature (20C) acidleaching, significant reductions in the

amounts of structural components,

important changes in XRD and especially

in FT-IR patterns and great increases in

surface area values of the leach residues

obtained by high temperture (90C) acidleaching of the natural and heated

vermiculites were observed. All results ofthe analyses methods indicated that

hydrous amorphous silica phase was

formed following high temperature acid

leaching of the natural and heated

vermiculites due to the dissolution of

structural components from the clay

structures. Under any leaching condition

studied, the heated vermiculite showed

higher resistance against acid leaching

probably due to the presence of collapsed

mica like layers. According to the datacollected in this work, a new leaching

study was initiated for determining the

high temperature (90C) acid leachingbehaviour of the vermiculite samples at

different sulphuric acid concentrations

and for the preparation of higher surface

area and purer hydrous amorphous silica

phases suitable for various applications.

Acknowledgements:The authors wish to

acknowledge Mike Darling (PalaboraEurope Ltd.) for the supply of natural

vermiculite sample. Two of the authors

(E.T. and M.B.) thanks the Slovak Grant

Agency VEGA (project 2/0064/14) and

the Agency for Science and Development

(APVV-0189-10) for the partial support.

REFERENCESBreen, C., Watson, R., Madejov, J., Komadel, P.

and Klapyta, Z., 1997. Acid-activatedorganoclays: Preparation, characterization

and catalytic activity of acid-treated

tetraalkylammonium-exchanged smectites,

Langmuir, 13, 6473.

Chmielarz, L., Kowalczyk, A., Michalik, M.,

Dudek, B., Piwowarska, Z. and Matusiewicz,

A., 2010. Acid-activated vermiculites and

phlogopites as catalysts for the DeNOx

process, Applied Clay Science, 49, 156.

da Fonseca, M.G.,Wanderley, A.F., Sousa, K.,

Araraki, L.N.H. and Espinola, J.G.P., 2006.

Interaction of aliphatic diamines with

vermiculite in aqueous solution, Applied Clay

Science, 32, 94.

Gates, W.P., Anderson, J.S., Raven, M.D. and

Churchman, G.J., 2002. Mineralogy of a

bentonite from Miles, Queensland, Australia

and characterisation of its acid activation

products, Applied Clay Science, 20, 189.

Hongo, T., Yoshino, S., Yamazaki, A., Yamasaki,

A. and Satokawa, S., 2012.

Mechanochemical treatment of vermiculite invibration milling and its effect on lead(II)

adsorption ability, Applied Clay Science, 70,

74.

Jozefaciuk, G. and Bowanko, G., 2002. Effect of

acid and alkali treatments on surface areas

and adsorption energies of selected minerals,Clays and Clay Minerals, 50, 771.

Komadel, P., Schmidt, D., Madejova, J. and iel,B., 1990. Alteration of smectites by

treatments with hydrochloric acid and sodium

carbonate solutions, Applied Clay Science, 5,

113.Kooli, F., 2009. Exfoliation properties of acid-

activated montmorillonites and their resulting

organoclays, Langmuir, 25, 724.

Londo, M.G., Yang, X. and Young, R.H., 2001.

Mesoporous silicoaluminate pigments for use

in inkjet and carbonless paper coatings, US

Patent 6274226B1.

Marcos, C., Arango, Y.C. and Rodriguez, I., 2009.

X-ray diffraction studies of the thermal

behaviour of commercial vermiculites,

Applied Clay Science, 42, 368.Mokaya, R. and Jones, W., 1995. Pillared clays

and pillared acid-activated clays: Acomparative study of physical, acidic, and


23/66

Proceedings of 14th


763

catalytic properties, Journal of Catalysis, 153,

76.

Muiambo, H.F. and Focke, W.W., 2012. Ion

exchanged vermiculites with lower expansion

onset temperatures, Molecular Crystals and

Liquid Crystals, 555, 65.Muiambo, H.F., Focke, W.W., Atanasova, M., van

der Westhuizen, I. and Tiedt, L.R., 2010.Thermal properties of sodium-exchanged

Palabora vermiculite, Applied Clay Science,

50, 51.

Okada, K., Arimitsu, N., Kameshima, Y.,

Nakajima, A. and MacKenzie, K.J.D., 2006.

Solid acidity of 2:1 type clay minerals

activated by selective leaching, Applied Clay

Science, 31, 185.

nal, M., Sarkaya, Y., Alemdarolu, T. andBozdoan, ., 2002. The effect of acid

activation on some physicochemicalproperties of a bentonite, Turkish Journal of

Chemistry, 26, 409.

Plkov, H., Madejov, J. and Righi, D., 2003.Acid dissolution of reduced-charge Li- and

Ni-montmorillonites, Clays and Clay

Minerals, 51, 133.Ravichandran, J. and Sivasankar, B., 1997.

Properties and catalytic activity of acid-

modified montmorillonite and vermiculite,

Clays and Clay Minerals, 45, 854.

Ruiz-Conde, A., Ruiz-Amil, A., Prez-Rodrguez,J.L. and Snchez-Soto, P.J., 1996.

Dehydration-rehydration in magnesiumvermiculite: conversion from two-one and

one-two water layer hydration states through

the formation of interstratified phases,Journal of Materials Chemistry, 6, 1557.

Steudel, A., Batenburg, L.F., Fischer, H.R.,

Weidler, P.G. and Emmerich, K., 2009a.

Alteration of swelling clay minerals by acid

activation, Applied Clay Science, 44, 105.

Steudel, A., Batenburg, L.F., Fischer, H.R.,

Weidler, P.G. and Emmerich, K., 2009b.

Alteration of non-swelling clay minerals and

magadiite by acid activation, Applied Clay

Science, 44, 95.Suquet, H., Chevalier, S., Marcilly, C. and

Barthomeuf, D., 1991. Preparation of porous

materials by chemical activation of the Llanovermiculite, Clay Minerals, 26, 49.

Temuujin, J., Minjigmaa, A., Jadambaa, Ts.,

Tsend-Ayush, S. and MacKenzie, K.J.D.,

2008. Porous properties of silica prepared by

selective acid leaching of heat-treatedvermiculite, Chemistry for Sustainable

Development, 16, 221.

Temuujin, J., Okada, K. and MacKenzie, K.J.D.,

2003. Preparation of porous silica from

vermiculite by selective leaching, AppliedClay Science, 22, 187.

Turianicov, E., Obut, A., Tuek, ., Zorkovsk,A., Girgin, ., Bal, P., Nmeth, Z., Matik,M. and Kupka, D., 2014. Interaction of

natural and thermally processed vermiculites

with gaseous carbon dioxide during

mechanical activation, Applied Clay Science,88&89, 86.

Wypych, F., Adad, L.B., Mattoso, N., Marangon,A.A.S. and Schreiner, W.H., 2005. Synthesis

and characterization of disordered layered

silica obtained by selective leaching of

octahedral sheets from chrysotile and

phlogopite structures, Journal of Colloid and

Interface Science, 283, 107.

Yu, X.-b., Wei, C.-h., Ke, L., Wu, H.-z., Chai, X.-

s. and Hu, Y., 2012. Preparation of

trimethylchlorosilane-modified acid

vermiculites for removing diethyl phthalate

from water, Journal of Colloid and InterfaceScience, 369, 344.


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MECHANICALLY INDUCED CHANGES ON CRYSTAL

STRUCTURE AND THERMAL BEHAVIOUR OF INDUSTRIAL

MINERALS: CASE STUDIES FOR COLEMANITE, PYROPHYLLITE

AND QUARTZT. Uysal1,a, M. ener1, H. Topta1, . S. Karamaz1, S. Yazc1, Y. Erolu1and

M. Erdemolu1

1. nn University Department of Mining Engineering, 44280 Malatya, Turkeya. Corresponding author ([email protected])

ABSTRACT: Some advanced engineering materials like B4C, CaB6, SiC, Si3N4, Si or

Al2O3are obtained by thermal treatment methods as calcination roasting or carbothermic

reduction. In this study, intensive planetary ball milling was employed to mechanically

activate selected minerals such as colemanite (Ca2B6O11.5H2O), pyrophllite

(Al2Si4O10(OH)2) and quartz (SiO2) in order to alter their thermal behaviour in the high

temperature processes. Unmilled and milled mineral samples were then roasted to

determine high temperature phases of the minerals. Minerals were also analysed using

thermogravimetry. By comparing the crystal structures and thermal behaviors of the

minerals investigated, the footprints of the mechanical activation were investigated. It was

concluded that mechanical activation of these industrial minerals can provide more useful

outputs in the production of the advanced materials at low costs.

1. INTRODUCTION

Mechanical activation (MA) is a pre-treatment method applied to increase the

reactivity of mineral in metallurgical

processes like roasting, carbothermic

reduction or leaching, and performed in

the new generation grinding mills where

the mechanical energy is intensively

transformed into mineral treated. During

MA, size of the mineral particles gets

finer and the formation of defects in the

crystal structure occurs due to mainly the

mechanical energy density [Bal andEbert, 1991]. Decreasing the reaction

temperatures, increasing the reaction rate,

preparation of water soluble compounds,

necessity for less expensive reactors and

shorter reaction times are some

advantages of MA [Erdemolu, 2009].

Various enginering ceramics are

manufactured generally by thermal

treatment of naturally occurring minerals.

Of these, colemanite (Ca2B6O11.5H2O),pyrophllite (Al2Si4O10(OH)2) and quartz

(SiO2) minerals are used as the primary

raw material in the production of severaladvanced materials.

Colemanite is the most occurring type of

the boron minerals. Advanced materials

such as silicon (Si), boron nitride, (BN),

titanium diboride (TiB2), boron carbide

(B4C) and calcium hegzaboride (CaB6)

are some of the examples that have

applications in the boron industry [Tekin,

1990; ekerci, 2000; stn, 2002]. For

instance, CaB6 is used in a variety ofindustrial applications, where it is known

as an abrasive and deoxydation material

because of its hardness and electronic

properties. CaB6 was reported by Yldzet al. (2005) to be produced from

colemanite. However, direct use of

colemanite is so problematic that

transporting raw colemanite and

removing impurities and crystal water

later is expensive and energy inefficient.

Thus colemanite must then undergo heattreatment before use. These compounds


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766

are used in most of today's high-tech

materials and are sold to 10-20 times the

cost. In our country, some of these

products espacially used in a variety of

cutting and etching materials areimported at very high prices.

Pyrophyllite is an aluminum silicate

mineral with Al2Si4O10(OH)2 formula.

Regarding the usage, it belongs to family

of high alumina clays like kyanite,

andalusite and diaspore [Cornish, 1983].

These alumina containing materials

exhibit very good thermal shock

resistance at high temperatures. Largely

depending on this, they are used in thefabrication of alumina refractories.

Investigations on pyrophyllite based

refractories and ceramics have revealed

some unique advantages, leading to high

corrosion resistance to molten iron, steel

and the slag in iron-steel works; good

thermal shock resistance, low

deformation under load, and good

mechanical resistance in the production

of ceramics. Thus, thermal treatment isvery important mainly mullite

(3Al2O3.2SiO2) requiring processes.

Silicon is one of the most found elements

in the Earths crust.But it is not availablein the element form. It is found as

compounds with oxygen in the form of

quartz or silicates. One of the most

important use of Si is in the solar cells.

Photovoltaic cell manufacturers mostly

use silicon, which can convert sunlightdirectly into electricity. 98% of the solar

cells are from silicon. Metallurgical grade

silicon is primaryly produced by high

temperature treatment of high grade silica

sand with a carbon source.

In this present study, effects of intensive

planetary ball milling on the crystal

structure and thermal behaviour of

selected minerals of colemanite

(Ca2B6O11.5H2O), pyrophllite(Al2Si4O10(OH)2) and quartz (SiO2) were

examined to determine whether the

milling resulted in an mechanical

activation or not.

2. MATERIALS and METHODSColemanite (Ca2B6O11.5H2O) of a high

grade colemanite concentrate, pyrophllite

(Al2Si4O10(OH)2) hand picked from the

mine and quartz (SiO2) from high grade

silica sand were used. All mineral

samples were dry milled in air by a

planetary ball mill. 250 cm3 tungsten

carbide bowl and 10 mm balls of the

same material were used. Colemanite and

pyrophyllite samples were milled alone,

whereas silica sand was milled togetherwith coke.

To define the crystal structure of the

unmilled but gently powdered for particle

size reduction, and intensively milled

mineral samples were analysed using

Rigaku RadB model X-ray diffractometer

(XRD). Thermal behavior of all samples

were determined using Setaram

Labsys1600 Model TGA/DTA

instrument operates in argon atmosphere

and up to 1600C.

3. RESULTS and DISCUSSIONFor determining the effects of intensive

milling on the structure of crystal

colemenite, it was milled and the milled

products were analysed by using XRD.

Milled colemanite samples were then

roasted to determine the solid phases

remained. (Figure 1) shows XRD patternsof unmilled and milled, and then roasted

colemanite. In the original colemanite

(K00) sample, there are some calcite

(CaCO3) and gypsum (CaSO4.2H2O). All

other peaks belog to colemanite. As also

seen from the Figure 1, intensive milling

for 45 min (Sample K4-45), not

completely but partially, altered the

crystal structure of colemenite. At the

examples subjected to mechanical

activation, colemanite crystal peakintensities decreased with milling.


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Proceedings of 14th


767

Accordingly, mechanical activation

caused disruption of the crystal structure

of this borate mineral. However, this

disorder is not very clear and maybe

gradual. When these samples wereroasted up to 500C it was found thatcolemanites peaks disappeared and

almost amorphous structure occurred. It

can be proposed that colemanite begin to

transform into dehydrated form, maybe

just calcium borate. When the

temperature was increased to 800C, newXRD peaks occurs, depending on the

recrystallisation of anhydrous colemanite.

Figure 1: Comparison of XRD patterns for unmilled (K00) and 45 min milled (K4-45)

colemanite samples, and of roasted at 425, 500 and 800 C (Symbols: , calcite; gypsum).

Seen in (Figure 2) are TG curves for

unmilled and 45 min milled colemanite

samples. Thermal decomposition

depending on initially loss of crystal water

begins nearly but not very significantly at

337 C and continues up to 700 C for

unmilled colemanite. At 363 C, otherstrong hydrogen bonds of water moleculesare broken and then borate structure is

began to decompose. When the

temperature is at between of 393-400 C,decomposition rate reaches to maximum

depending on the final release of water

molecules in the pores. This phenomenon

causes sudden crash of the samples, known

as decrepitation [Uzunolu, 1992; elik etal., 1994; ener and zbayolu, 1995].

After 700 C, colemanite converts tosintered colemanite. It was also

demonstrated by Yldz (2004) thatcolemanite loses its crystal water through

endothermic reactions at 300-460 C andthat decrepitation and decomposition of

colemanite to amorphous B2O3 and CaO

takes place at temperatures lower than 600

C, and finally CaB2O4 and Ca2B6O11appear as new crystalline boroncompounds at 800 C. When compared toTG curve of unmilled colemanite, 45 min

milled colemanite losses its water at very

low temperatures. Since the interval

between onset and offset temperatures

appears within very big interval,

decrepitation of milled colemanite does not

occur. In addition, decrepitation of the

milled colemanite was not observed during

atmospheric roasting experimentsperformed at isothermal conditions.


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768

Figure 2: Comparison of TG curves

obtained for unmilled and 45 min milled

colemanite samples.

(Figure 3) collectively shows XRD

patterns for pyrophyllite samples which

unmilled (P0, just gently milled), 45 min

milled (P45), and then roasted at various

temperatures. Major minerals determined

in pyrophyllite samples are pyrophyllite

(Al2Si4O10(OH)2), quartz (SiO2), kaolinite

(Al2Si2O5(OH)4) and dickite

(Al2Si2O5(OH)4). It was found that milling

for 45 min significantly results in decrease

mainly at the peak intensities ofpyrophyllite, kaolinite and dickite. Peaks

which remain after 45 min of milling fully

belong to quartz.

It is reported that when the milling time

increases, dry milled pyrophyllite losses its

original crystal structure depending on the

creep of tetrahedral-octahedral layers

[Prez- Rodriguez et al., 1988]. Erdemoluand Sarkaya (2002) was also reported thatcollectorless flotation recovery of

pyrophyllite decreases with prolonged

milling due to structural deformationoccurred during the milling.

In order to determine the effects of heat

treatment on the thermal behaviour

unmilled and milled pyrophyllite samples

were roasted at different temperatures and

the raosted samples were also analysed for

their crystal structure.

As seen in (Figure 3), peaks of

pyrophyllite and kaolinite are disappearedin the unmilled sample roasted at 800C,whereas they are not present in the milled

sample even at roasting temperatures as

low as 400C. Peaks of kaolinite found inthe unmilled sample disappeared at 800C,whereas 700C was enough fordecomposition of kaolinite present in the

milled pyrophyllite sample. Morover, new

peaks occurred at high temperatures

belonging to mullite with a nominal

composition of 3Al2O3.2SiO2 are very

common in the milled pyrophyllite samples

roasted at temperatures as low as 400C,when compared to those of unmilled

samples.


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Proceedings of 14th


769

Figure 3: Comparison of XRD patterns for unmilled (P0), 45 min milled (P45) and then

roasted phyrophyllite samples.

Thermograms obtained by roasting of

unmilled and milled pyrophyllite at

isothermal heating conditions are shown inFigure 4. It seems that pyrophyllite losses

its bound water without any structural

changes at temperatures between 400 and700C. At temperatures near to 800C,

pyrophyllite converts into a mullite-like

aluminium silicate form and stays steady

up to 1000C. After this temperature,mullite-phase conversions begin and free

quartz present converts into the

crystobalite which is a high-

temperature polymorph of quartz. It wasfound that intensive milling significantly

changes the thermal behaviour of

pyrophylite. Mass loss in 20 min of milled

pyrophyllite sample begins at 400C,whereas it is almost 500C for unmilledsample. Besides, mass loss of unmilled

pyrophyllite at 700C was calculated as2.5%, whereas it is 3.8% pyrophyllite

sample which was milled for 60 min.

Consequently, conversion of pyrophyllite

into mullite shifted to low temperatures,suggesting the mechanical activation. In

the literature, it was reported that

transformation in the pyrophyllite begins

with the milling; milling longer than 7 minchanges the thermal behaviour; according

to TG curves, onset temperature at which

mass loss begins decreases and

endothermic reaction region shifts to occur

at low temperatures [Prez-Rodriguez andSnchez-Soto, 1991].

Figure 4: TG curves for unmilled and

milled (20, 45 and 60 min) pyrophyllite as

obtained by isothermal roasting tests.


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770

Silicon carbide is manufactured by

charbothermic roasting of high purity silica

in the presence of coke:

SiO2+ 3C SiC + 2CO

Metallurgical-grade silicon used for many

purposes including photovoltaics is

obtained from the reduction of silicon in

the presence of carbon at high

temperatures:

SiO2 + 2C Si + 2CO

In order to determine the effect of intensive

milling on the carbothermic roasting and

reduction of quartz, high purity silica sandwas mixed with metallurgical grade coke;

milled for long periods and finally the

milled mixtures roasted at 1200 C for halfa day. Unmilled, milled and roasted

materials were characterised using XRD

and TGA.

As seen from Figure 5, XRD patterns of

unmilled mixture are very simple. Since

silica sand is very pure, one and only the

crystal mineral phase seems as quartz. All

the peaks on the patterns are belongs to

quartz. Since coke is in the amorphous

phase, it was not determined by XRD

analysis. However, intensities of the quartz

XRD peaks decreased and peak areas

enlarged gradually with prolonged miling.

Milling 5 h resulted in the amorphisation

of quartz in the silica sand-coke mixture.

Since the presence of coke in the mixture

behaved as grinding additive, 10 h ofmilling gave a complete amouphous

material.

XRD patterns for unmilled and 10 h milled

silica sand-coke mixtures both which were

roasted at 1200C for 12 h werecollectively shown in Figure 6. Seen on the

XRD pattern of unmilled and then roasted

silica sand-coke mixture is quartz with a

little bit high peak intensities due to heat

treatment. But, the materials includingquartz in the 10 h milled mixture were

completely amorphous, roasting of milled

mixture at 1200 C gave also rise toappearance of crystal quartz. But in this

case, quartz is in crystobalite phase. All of

the peaks reappeared belong to crystobalite

quartz. It is known that quartz is in

trydimite phase after 870C and incrystobalite phase after 1470 C. Since thecrystobalite phase is obtained just at 1200

C, this result solely suggests mechanicalactivation which provides phase

transformation of quartz to occur at low

temperatures.

Figure 5: XRD patterns of unmilled and milled (1, 5, 10 h) silica sand-coke mixtures.


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Proceedings of 14th


771

Figure 6: Comparison of the XRD patterns for the unmilled and 45 min milled silica sand and

coke mixtures roasted at 1200C for 12 hours in the air.

Figure 7: TG curves for unmilled silica

sand only, unmilled and milled (1, 5 and

10 h) silica sand-coke mixtures as obtained

by non-isothermal analysis in argon.

Shown in (Figure 7) are TG curves for

original silica sand only, unmilled and 1, 5

and 10 h milled silica sand-coke mixtures,

as obtained by thermal analysis performed

up to 1400 C. On TG curve of theunmilled original silica sand only, mass

loss onset temperature is about 1300C,whereas it is about 1050 C for theunmilled silica sand-coke mixture. It seems

that milling considerably changed the mass

loss starting temperature which decreaseswith milling time be longed from 1 to 5 h.

This may not be resulted from gasification

of carbon using O2originated from the air

to form COx gases, since TG analysis was

performed in argon atmosphere. According

to Sahajwalla et al. (2003), the reactionbetween SiO2 and C in powdery mixtures

has significant rates from about 1400Conwards in vacuum or in stream of argon.The reaction can be seen as a combination

of two basic reactions:

SiO2(s, l)+ C(s)SiO (g)+ CO(g)

SiO(g)+ 2C(s)SiC(s)+ CO(g)

The reactions taking place at the carbon

surface are also reported to play a role in

controlling reaction kinetics. Thus it was

suggested that the mass loss occurred inthe 1 and 5 h milled mixtures is due to

early reactions of silica and carbon to form

SiO gas and to release CO. But, TG curve

of the mixture milled for 10 is very

different. TG pattern is similar to others up

to 900-1000C, then the materialdramatically starts to gain mass up to

1350C and to loose its mass again withthe increasing temperature up to the end of

analysis limit. The mechanism causing this

thermal behaviour needs further study. Butwhat the observed is the clear effect of


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intensive milling on the charbothermic

reactions of quartz.

4. CONCLUSIONSIn this study, structural and thermal

alterations resulted from intensive millingof selected minerals such as colemanite,

pyrophyllite and quartz were investigated,

which are processed generally at very high

temperatures in their metallurgy.

For each of the minerals examined in this

study, it was typically found by XRD

analysis that intensive milling appearently

alter or deform the crystal structure of the

minerals, as leading to become XRD

amourphous as a final point. There was aremarkable result so that quartz present in

the pyrophyllite sample resists to the action

of intensive milling while the quartz in the

silica sand-coke mixture easily goes to

become amorphous.

Studies performed either at non-isothermal

or isothermal heating conditions showed

that, as compared to their unmilled

counterparts, thermal behaviour of the

intensively milled minerals significantly

was altered to release their volatile content

at low temperatures, mainly due to

mechanical activation.

Finally, it was concluded that mechanical

activation may be one of the keys to

develop existing technologies for

manufacturing many of the high

temperature processed engineering

materials like oxides (Al2O3, ZrO2),nitrides (AlN, BN), borides (CaB6, TiB2),

carbides (SiC, TiC, WC, B4C) at low-costs.

Acknowledgement: Financial supports of

nn University (BAPB Project Numbers:2012/108 and 2012/14) is gratefully

acknowledged.

REFERENCESBal P., Ebert I., 1991. Oxidative leaching of

mechanically activated sphalerite,

Hydrometallurgy, 27, 141-150.

elik, M.S., Uzunolu, H.A., Arslan, F., 1994.Decrepitation properties of some boron

minerals, Powder Technology ,79,167172.Cornish, B.E. 1983. Pyrophyllite. Industrial

Minerals and Rocks, SJ.Lefond (Ed.) SME

Publications, s.1085-1108, New York.

Erdemolu M., Carbothermic reduction ofmechanically activated celestite, Int. J. Miner.Process. 92, 144152, (2009).

Erdemolu, M., Sarkaya, M., 2002. The effect ofgrinding on pyrophylliye flotaion, MineralsEngineering, 15, 723-725.

Prez-Rodriguez, J.L., Madrid Sanchez Del Villar,L., Snchez-Soto, P.J. 1988. Effects of drygrinding on pyrophyllite. Clay Minerals. 23,399.

Prez-Rodriguez, J.L., Snchez-Soto, P.J. 1991.The Influence of the Dry Grinding on the

Thermal Behavior of Pyrophyllite. Journal of

ThermalAnalysis. 37:1401.

Sahajwalla, V., Wu, C., Khanna, R., SahaChaudhury, N., Spink, J., 2003. Kinetic study of

factors affecting in Situ reduction of silica in

carbon-silica mixtures for refractories. ISIJ

International, 43(9), 13091315.ekerci Y., 2002. Calcium hegzaboride production.

BSc Thesis. Afyon Kocatepe University,

Ceramics Engineering Department, Afyon.

ener, S., zbayolu, G., 1995. Separation ofulexite from colemanite by calcination,Minerals Engineering, 6, 697-704.

Tekin A., 1990. High technology ceramics and

developments in Turkey. Proceedings of 4th Int.

Ceramics Congress, p317, stanbul.stn, R., 2002. Titanium diboride production.Afyon Kocatepe University, Ceramics

Engineering Department, in Turkish, Afyon.

Uzunoglu, A., 1992. Decrepitation properties of the

boron minerals colemanite and ulexite. Master

of Science Thesis, Technical University of

Istanbul, in Turkish, 1992.

Yldz, ., 2004. The effect of heat treatment oncolemanite processing: a ceramics application,

Powder Technology, 142, 7-12.

Yldz, ., Telle, R., Schmalzried, C., Kaiser, A.,2005. Phase transformation of transient B4C to

CaB6 during production of CaB6 fromcolemanite. Journal of the European Ceramic

Society, 25, 3375-3381.


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Proceedings of 14thInternational Mineral Processing SymposiumKuadas, Turkey, 2014

773

OPTIMUM USE OF ZEOLITE IN THE PRODUCTION OF BLENDED

CEMENT

Melis Toker Derdiyok1and Hasan Ergin1,a

1. Istanbul Technical University, Mining Engineering Department, Istanbul, Turkey

a. Corresponding author ([email protected])

ABSTRACT:Cement industry is an energy-intensive process and results in large amount of CO2

emissions. This study is aimed at reducing energy consumption and the emissions by using

zeolite as a substitute of clinker. Firstly, the physical, chemical and mineralogical

characterization of zeolite was determined and the grinding properties of zeolite and

clinker were performed in laboratory ball mill. Then, the ground zeolite which has the

fineness of 5% residue on 32 micrometer sieve was substituted for clinker by 10% and

20%. The physical, chemical and mechanical analyses were conducted on produced

blended cements in accordance with standards. The use of zeolite has resulted in an

increase in the compressive strength at 90 days and also increase in setting time. It has also

been observed that the zeolite has much easier grindability than clinker. Therefore, the use

of zeolite reduces the grinding energy consumption and also emissions due to the use of

less amount of clinker usage without causing any degradation of cement properties. The

full results are illustrated in this article.

1. INTRODUCTIONCement is the biggest man-made and

used material in the world with its 3.6billion tons of annual production at 2013[Republic of Turkey Ministry of Economy, 2014].Production of cement is an expensive

process and has adverse ecological

effects. CO2, NOx, and SOx are among

the hazardous emissions generated in

relatively high volumes in the

conventional Portland cement process.

Zeolites are a group of crystalline

hydrated alumino silicates with uniquephysico-chemical properties resulting

from their specific structure in which

cavities or pores with strictly defined

nanodimensions occur [Mozgawa et al.,

2009]. The microporous crystalline

structure of zeolites is able to adsorb

species that have diameters that fit

through surface entry channels, while

larger species are excluded, giving rise to

molecular sieving properties that are

exploited in a wide range of commercialapplications. These include the use of

natural zeolites in water and air filtration,

pollution, and odour control, animal

hygiene, aqua-culture, pond filtration,soil amendment, and as an industrial filler

and dietary supplement in animal feeds

[Ortega et al., 2000]. Zeolite types that have

been tested so far are those most common

in the sedimentary zeolite (tuff) deposits

widespread all over the world, namely,

clinoptilolite, mordenite, phillipsite and

chabazite [Caputo et al., 2008].

Zeolite as natural pozzolan, which are

materials exhibiting cementitionsproperties, have been widely used as

substitutes for Portland cement clinker in

many applications because of reductions

in the production cost and CO2emission

[Kurudirek et al., 2010]. In a recent study,

Uzal et al. [2012] reported that the

clinoptilolite minerals of zeolite

possesses a lime reactivity which is

comparable to silica fume and higher than

fly ash and a non-zeolitic natural

pozzolan. They also concluded that thehigh reactivity of the clinoptilolite is


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774

attributable to its specific surface area for

certain grinding method and duration as

well as its reactive SiO2content.

In another study, the use of zeolitesamples, where collected from zmir-Foa, Balkesir-Bigadi and Manisa-Grdes, were investigated in ceramicindustry, in paper industry as filler and

coater and in the cement industry as

additive [Ulusoy & Albayrak, 2009].

Canpolat et al. [2004] investigated the

effects of zeolite, coal bottom ash and fly

ash as Portland cement replacement

materials. The results shown thatinclusion of zeolite up to the level of 15%

resulted in an increase in compressive

strength at early ages, but resulted in a

decrease in compressive strength when

used in combination with fly ash.

Karakurt & Topu [2012] reported thataccording to the results of accelerated

corrosion test; concretes produced with

zeolite, fly ash and ground granulatedblast furnace slag in ternary composition,

the corrosion were significantly reduced.

In this study, the usage of zeolite was

studied as clinker replacement material.

The zeolite was taken from Ktahya-Gediz. The experiments were carried out

at Nuh Cement Plant in Turkey.

2. MATERIALS & METHODOLOGY

2.1. MaterialsClinker, zeolite (Z) and gypsum were

used in this study. The chemical

compositions of these materials

determined by XRF. The results are given

in Table 1. The mineralogical analysis of

clinker and zeolite were also determined

by DTA as the results are presented in

Table 2.

Table 1: Chemical characteristics ofmaterials used (wt. %).

Clinker Gypsum Zeolite

CaO 65.91 32.4 5.81

SiO2 21.55 1.1 62.27

Al2O3 4.80 0.4 12.46

Fe2O3 3.29 0.1 1.51

MgO 1.34 0.1 5.81

SO3 0.48 44.50 0.16

K2O 0.78 0.05 3.65

Na2O 0.20 0.04 0.06

Loss on

ignition0.28 21.50 10.60

The specific gravity was determined by

Gas Pycnometer and the specific surface

area was measured by Blaine equipment.

Specific gravity of zeolite was found 2.24

g/cm3. Specific surface area of zeolite

was measured as 7969 cm2/g.

Table 2: Mineralogical characteristic of

clinker and zeolite.

Clinker (wt. %) Zeolite

C3S (58.48) Clinoptilolite

Illite mica

Opal-CT

Feldspar

SmectiteQuartz

C2S (47.69)

C3A (7.17)

C4AF (10.00)

C: CaO, S: SiO2, A: Al2O3, F: Fe2O3

The other authors were determined

morphology of zeolite by Scanning

Electron Microscope (SEM). As shown

in Figure 1, the particles are typically

euhedral plate prism, monoclinic and its

crystal size is 5-10 micrometer [Esenli &

Gltekin, 2011].


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775

Figure 1: SEM image of zeolite.

2.1. MethodologyFigure 2 shows the experimental design

of investigating the usability of the

zeolite as a substitute of clinker in

production of blended cement. Firstly;

the crushing and grinding test were

performed in order to compare the

grindability of the zeolite and clinker.

The zeolite was crushed in a laboratory

jaw crusher under the size 5 mm.

Then, the comparative test for grindingproperties of clinker and zeolite were

carried out in a laboratory ball mill. The

ball mill is 52 cm in length and 42 cm in

diameter as it has a rotational speeds of

46 rev/min. The ball sizes ranging from

60 to 15 mm are in total of 215 balls. Its

total weight is 58.58 kg.

The particle size distributions were

determined by Laser particle size

analyzer. Average particle size of groundclinker was 13.70 micrometer after 60

minutes of grinding. Average particle size

of ground zeolite was 7.85 micrometer

after 45 minutes. Thus, it has been found

as a result of grinding test, zeolites can be

ground easier than clinker.

In the final stage, the features of

reference cement was determined that

contains 95% clinker and 5% gypsum,

called Portland cement (R) that is CEM I

called as reference cement. After that, the

ground powders of zeolite, which has the

fineness of 5% residue on 32 micron

sieve, were added by 10% and 20% to the

ground clinker and gypsum.

Figure 2: Experimental processes to

investigate the usability of zeolite.

In experimental studies; the physical,

chemical, and mechanical analysis

(setting time, volume expansion,

compressive strength, fineness, Blaine)

were conducted on produced Blendedcements in accordance with Turkish

Standards that comply with European

Standards. TS EN 196-3 is for setting

time and volume expansion, TS EN 196-

6 is for Blaine and fineness, TS EN 196-1

is for compressive strength (Turkish

Standard, 2000, 2002, 2009). Chemical

analysis of the samples was performed

using X-ray spectrometer. Setting time

was determined by the Automatic Vicat

apparatus.

Determination of expansion of the

Blended cements was carried out by the

Le Chateliers. Fineness of Blendedcements was found by using both Blaine

apparatus and Air Jet Sieve. Compressive

strength of Blended cements was

determined in samples having dimensions

of 40 mm x 40 mm x 160 mm with

prismatic shape at the ages of 2, 7, 28,and 90 days.


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776

3. RESULTS AND DISCUSSIONBlended cements recipes were labelled

according to the amount of zeolite

additions. The cement mix recipes are

given Table 3.

Table 3. Mix proportions of the cements

(% mass).

Clinker Zeolite Gypsum

R 95 - 5

Z10 85 10 5

Z20 75 20 5

The physical properties of reference

cement and the cements containing

zeolite called blended cements are

presented in Table 4. The specific gravity

values were determined as the average of

four measurements. The fineness of

blended cements was determined using

sieves of 32 micrometer and 90

micrometer.

The specific gravity of the blendedcements was reduced while the specific

surface area was increased by the

addition of zeolite. Initial and final

setting times of blended cements were

longer than that of reference cement R.

The volume expansion, the fineness and

the compressive strength were within the

specified value in the standards. The

compressive strength values of R, Z10

and Z20 are presented in Figure 3.

Table 4: Physical characteristics of R and

the cement containing zeolite (% mass).

R Z10 Z20

Specific gravity

(g/cm3)3.15 2.98 2.88

Specific surface

(cm2/g)3343 5213 6063

Fineness

(32 micrometer) 27.2 23.7 23.0

Fineness

(90 micrometer)7.4 2.8 2.8

Initial setting

time

(minute)

124 173 174

Final setting

time

(minute)

157 227 260

Volume

expansion

(mm)

10 10 9

Figure 3: Compressive strength test results of reference cement and blended cements.


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777

4. CONCLUSIONSBlended cement produced by the addition

of zeolite was analyzed and their

compressive strength development was

compared at 2, 7, 28 and 90 days withreference cement R. The produced

blended cements comply with the

standards. Zeolite can be used as

substitute till 20% without any quality

degradation. Moreover, the use of zeolite

also contributes to the compressive

strength of the final product. Since the

grinding energy consumption of zeolite is

much less than clinker so that the usage

of the zeolite provides some economic

advantages as well.

Acknowledgements: This research has

been done in Nuh Cement Plant and was

supported by Turkish Cement

Manufacturers Association.

REFERENCESCanpolat, F., Ylmaz, K., Kse, M.M., Smer, M.,

yurdusev, M.A., 2004. Use of zeolite, coal

bottom ash and fly ash as replacement

materials in cement production, Cement andConcrete Research, Volume (34), pp. 731-

735.

Caputo, D., Liguori, B., Colella, C., 2008. Some

advances in understanding the pozzolanic

activity of zeolites: The effectof zeolite

structure, Cement and Concrete Composites,

Volume (30), pp. 455-462.

Esenli, F., Gltekin, A.H., 2011. SANTEKMining CompanyGediz (Ktahya) AreaZeolite (Clinoptilolite) Material

Characteristics, Internal Report, Istanbul

Technical University, Mining FacultyDepartment of Geological Engineering.

Hewlett, P.C. (ed), 2004. Leas chemistry ofcement and concrete, 4th edn, Oxford:

Elsevier Butterworth-Heinmann, Oxford.

Karakurt, C., Topu, I.B., 2012. Effect of blendedcements with natural zeolite and industrial

by-products on rebar corrosion and high

temperature resistance of concrete,Construction and Building Materiaals,

Volume (35), pp. 906-911.

Kurudirek, M., zdemir, Y., Trkmen, I., Levet,A., 2010. A study of chemical composition

and radiation attenuation properties in

clinoptilolite-rich natural zeolite from

Turkey, Radiation Physics and Chemistry,

Volume (79), pp. 1120-1126.

Mozgawa, W., Krol, M., Pichor, W., 2009. Use of

clinoptilolite for the immobilization of heavy

metal ions and preparation of autoclaved

building composites, Journal of Hazardous

Materials, Volume (168), pp. 1482-1489.

Ortega, E.A., Chris, C., Knight, J., Loizdou, M.,

(2000). Properties of alkali-activated

clinoptilolite, Cement and Concrete

Research, Volume (30), pp. 1641-1646.

Toker, M., 2013. Enerji tketimi ve emisyonlarndrlmesi amacyla imento retimindemineral katklarn kullanmnnoptimizasyonu, Optimization of the use

mineral additives in cement production forreduce to energy comsumption and

emissions. M.Sc. Thesis, Istanbul TechnicalUniversity, Graduate School of Science,

Engineering and Technology (in Turkish).

Trkiye Cumhuriyeti Ekonomi Bakanl, 2014.imento Raporu, Sektr Raporlar, hracatGenel Mdrl, Kimya rnleri ve zelhracat Daire Bakanl, Ankara (inTurkish).

Trk Standard, 2000. imento deney metotlar-blm 6: incelik tayini, TS EN 196-6, Trk

Standardlar Enstits, Ankara(in Turkish).Trk Standard, 2002. imento-deney metotlar-

blm 3: priz sresi ve genleme tayini, TSEN 196-3, Trk Standardlar Enstits,Ankara (in Turkish).

Trk Standard, 2009. imento deney metotlar-blm 1: dayanm tayini, TS EN 196-1, TrkStandardlar Enstits, Ankara (in Turkish).

Ulusoy, G. & Albayrak, M. 2009. Foa (Izmir) -Bigadic (Balkesir) ve Grdes (Manisa)Yresi Zeolitlerinin Mineralojik veTeknolojik Ozellikleri, MTA Dergisi,

Volume (139), pp. 61-74 (in Turkish).

Uzal, B., & Turanl, L. 2012. Blended cementscontaining high volume of natural zeolites:

Properties, hydration and paste

microstructure, Cement & Concrete

Composites, Volume (34), pp. 101-109.

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