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DOE Application by Compilation of Taguchi and RSM in
Optimization 135
DOE Application by Compilation of Taguchi and RSM
inOptimization-Case Study: Interaction Parameters
Flotation of Zinc Oxide Minerals
A. Hajati Department of Mining Engineering, Iran University of
Science and Technology,
Arak Branch, IranE-mail: [email protected] ,
[email protected]
ABSTRACT: One of the aims important to increase of quality is
design of methods for improved of quantity andquality production of
system. Statistical program tests are the base for this part
effectiveness. Today, Designs of Experiment (DOE) tests are used
engineering tools for control and optimization varies system. In
this research,
by compilation of design of experiment methods by taguchi and
RSM (Response Surface Method) used for optimization of Zinc oxide
minerals flotation system. Almost, most parts of benefit minerals
as ore in extractionmining are oxidized. Then, flotation of these
minerals will be difficult. The aim minerals of this dam
tailing(Irankuh Company in Iran) are Smithsonite, Sphalerite,
Galena, cerussite and Ferro oxide minerals. The grade of Zn, Pb and
Fe are 7.5%, 3.4% and 13% respectively. In this flotation tests,
oxine and dithizone are chelatingagent collectors and the surface
of particle is not sulfide. By study of interaction parameters and
optimization of them and analysis of results and use of DOE
methods, oxine is better than dithizone. In the optimum condition
of flotation test; the grade of Zn, Pb and Fe are 15.55%, 2.77% and
3.51% and recovery are 40.12%, 7.75% and10.11% respectively.
1. INTRODUCTION
Almost in the all systems, optimization andknowledge of action
parameters is very impor-
tant. One of the aim basic to increase of quality,is design of
methods for improve of quantity andquality production of systems.
Statistical
program tests are the base for this part effective-ness. Today,
Designs of Experiment (DOE) testsare used engineering tools for
control andoptimization of varies factors effective systems.
Design experiment by taguchi method is oneof the family
fractional factorials. It can used invaries condition of systems.
By using of thismethod, the stability of process and decrease of
variable around of results are aim. But someresults have a few
uncertain. It has tried that
decrease of distance between of X i (much of parameter test) and
X (average of results). Then,it possible that optimum condition
focused on theother point. It seems that, knowledge of interaction
parameters effect system by threedimensional is help to conceive of
complex
process. Compilation of the Response SurfaceMethodology (RSM)
and taguchi method is very
benefit method for solving of this problem. RSM
or surface knowledge is combination techniqueof mathematics and
statistics for modeling andsimulation of problems. By using of
twomethods, end results of tests will be uphold andcorrect.
Application of this method is verysuitable for analysis of any
systems of industrylaboratory, pilot plant and other tests.
Different technologies such as pyro-metallurgy, hydrometallurgy,
bioleaching andflotation have been employed to extract metalfrom
ore; however, with the new crisis inenvironmental issues, flotation
methods seemmore amenable [1]. Today, selecting collector for
flotation of zinc oxide is very important, andamong the collectors,
chelating agents are
promising ones. One of the most significantapplications of
chelating agents in flotation is inenrichment of low-grade ore
recovery. In thisresearch, by sampling of oxide dam tailing
atGoshfill Mine (Bama Co.) and use of DOE for analysis of results,
optimization of parameters act
by chelating agent (oxine) and non sulfidation of surface zinc
minerals [2].
mailto:[email protected]:[email protected]://opt/scribd/conversion/tmp/scratch5/[email protected]://opt/scribd/conversion/tmp/scratch5/[email protected]://opt/scribd/conversion/tmp/scratch5/[email protected]:[email protected]
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136 Mineral Processing Technology (MPT 2007)2. MATERIAL AND
METHODS
The material is provided by Bama Companyfrom Goshfil Mine
Tailing. The Tailing includethe 7.65% zinc (Smithsonite and
Sphalerite)3.5% lead (galena and cerusite) and 13% of iron(hematite
and goethite). One Kg of the samplewere crushed with jaw crusher.
The crushedsamples were ground with ball mill to fine sizesin
different time scales (0, 5, 10, 20, 30, 40, 50,60 min).The fine
particles then sieved withscreen size of (18, 50, 100, 200, 270,
325, 400mesh) and the accumulated weight of passing
particles were measured. After obtaining theselection of
appropriate time (10 minute wereselected for this study) for the
grinding, and thensamples were taken from each size on the
screen.The selection samples were fixed through theresin and
polished the surface of the minerals.The prepared sample was used
for themicroscopic analysis by the counting the number of minerals
and the percentage of liberated ones.The degree of liberation can
magnificentlyoptimize flotation processes. For these
specificminerals it can be concluded that all samplesshould grind
under 90 micron size in which 80-100% of smithsonite and 50-100% of
iron oxides(hematite + goethite) are liberated. The details
study of degree of liberation can be found [2]. Inorder to
reduce the iron contents of the samples,the prepared samples were
also passed through 2Tesla Magnetic field.
For the flotation test, an experimental cellsimilar to the
Halimound cell was used. Thedimension of the considering the
liberation of smithsonite, were selected in the range of
38-90micron. Oxine is a chelating agent and it wasused as a
collector. Oxine (C9H7NO) is a white
crystal with molecular weight of 145.16 g/mole.
Oxine is insoluble in water and mostly organicchemicals likely,
ethers, alcohols, aromatichydrocarbons acetone, acetic acid and
chloro-form are used as solvent. In this test acetone wasemployed
as solvent (Figure 1).
The oxine concentration was kept below 2%.This is because of
solubility of acetone in water may remove oxine from the system
Pine oil witha range of 120 g/ton was selected as frother.
Theconditioning time was 12 min. In this study themain parameters
which were used for flotationinclude pH, oxine concentration, corn
starch,sodium thiosulfate, sodium citrate, sodium
silicate and conditioning time. Preliminary testswere carried
out in order to evaluate theeffectiveness of oxine with various
concen-trations of oxine, corn starch, sodium tiosulfate,sodium
citrate and sodium silicate. during theexperiment.
Fig. 1: Chelating of Zinc by Oxine
To optimize the experimental parameters, theTaguchi experimental
design was employed.According to the method, an array of L 32
wassuggested and the data were analyzed byQualitek-4 software.
Table1 demonstrates themain parameters and their levels
investigated inthis research.
Table 1: Demonstrate the main parameters and their ranges
investigated
Parameters Levels of parameter Level 1 Level 2 Level 3 Level
4
1- pH 3 6 9 12
2- Oxine (g/ton) 20 60 180 5403- Corn Starch (g/ton) 500 1000
1500 20004- Sodium Thiosulfate (g/ton) 20 60 180 5405- Sodium
citrate(g/ton) 20 60 180 540
6- Sodium Silicate (g/ton) 20 60 180 5406- Time Condition (min)
5 10 15 30
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DOE Application by Compilation of Taguchi and RSM in
Optimization 137
3. RESULTS AND DISCUSSIONS
The results of mineralogical analysis throughXRF are tested.
Nearly 80% of zinc minerals aresmithsonite. The most gangue
minerals for theflotation process are including of iron and
leadmetals. For iron removal, it prepared sampleswere passed
through the wet-high magneticintensity field. The results of
magnetic separationtest caused that grade of Pb, Zn and Fe viruses
to3.01%, 7.85% and 5% and recovery in nonmagnetite part are 91.81%,
90.55 and 65.68%respectively.
The results of parameter optimizationtechnique using taguchi
method indicated that the
parameters which effect on the experimentalresults in 1 st
stage, are include corn starch withconcentration of 1400 g/ton,
sodium silicate 100g/ton and time conditioning 12 min. The
other
parameters which are variable include pH, oxine,sodium
thiosulfate and sodium citrate.
Table 2: Results of L9 array taguchi method
SeriesGread (%) Recovery (%)
Zn Fe Pb Zn Fe Pb
1 11.45 7 4 29.06 17.92 10.24
2 11.25 12 4 20.40 21.76 5.44
3 10.98 6 4 24.89 14.60 6.80
4 11.48 7 4 45.81 22.04 9.44
5 10.6 6 4 70.95 40.16 26.77
6 11.6 5 4 49.18 21.20 16.96
7 12.12 4 4 14.57 4.46 4.48
8 12.30 5 4 14.45 5.47 4.28
9 12.76 4 4 24.82 7.47 5.60
Thus, the above mentioned variable para-
meters were optimized. The results of L 9 taguchimethod is shown
in Table 2{Limit factors are: pH= (10, 12, 14), Oxine = (800, 1500,
2000 gr/t),sodium thiosulfate = (0, 1000, 2000 gr/t) andsodium
citrate = (0, 1000, 2000 gr/t) by L 9array}. As shown in Table 2,
pH is one of themost contribution factor which affect therecovery
of zinc. This is also demonstrated inFig. 2.
0
5
10
15
20
25
30
3540
45
500 1000 1500 2000 2500
Concentration of Oxine (gr/ton)
R e c o v e r y
( % )
Zn
Pb
Fe
Fig. 2: Recovery of zinc, Iron and Lead by Oxine
The results of the Taguchi for the interaction of
sodium citrate and sodium tio sulfate through theRSM (Response
Surface Method) for grade of zinc is shown in Figure 3.
Fig. 3: Interaction of Citrate-Thiosulfate on theRecovery of
zinc by RSM
As shown in Figure 3 for study interaction of sodium citrate
with sodium thiosulfate indicats,show that sodium citrate did not
affect on theincreasing recovery of zinc. Whereas, withelimination
of sodium citrate the optimizedcondition for the sodium tiosulfate
for therecovery of zinc was obtained at a few gather than 2000
gr/ton.
Finally, optimum condition was obtainedwhen fuel oil mixed with
oxine. In thiscondition the grade of zinc was obtained 15.89 %and
the recovery was 52.56%.
4. CONCLUSIONS ANDRECOMMENDATION
The feasibility of zinc recovery from mineresidue was shown by
this study. Oxine as achelating agent collector in the floatation
process
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138 Mineral Processing Technology (MPT 2007)exhibits potential
for selective recovery of
smithzonite minerals ore. Through the Taguchiexperimental design
the optimum condition wasobtained. The optimum condition for the
abovementioned parameter is as follows: Size range38-90 micron, pH
= 12.5, Sodium Citrate:Removed, Sodium Tiosulfate: 1000-1500
g/ton,Sodium Silicate: 100 g/ton, Corn Starch: 1400g/ton, Time
Condition: 12 min, High Tention of Magnetite separation: 2 Tesla,
Fuel Oil: Concentration Of Oxine, Frother (Pine Oil): 120g/ton,
Solid Percent: 10%. The results alsoindicate that pH was one of the
most important
parameter which affects the recover of zincoxide.
As the results of the study demonstrated, thedisturbing
parameters which affected the resultsof smithsonite recovery in the
tailing were highsurface oxidation all minerals including iron
leadand zinc.
REFERENCES
[1] Barbaro, M, Comparison of Pb-Zn SelectiveCollectors Using
Statistical Methods, MineralProcessing Institute, Roma, Italy,
1998.
[2] A. Hajati, et. al., determination of degree of liberation
zinc and iron oxide minerals inGoshfill mine, mining Eng.
conference, Iran,2004.
[3] Rinelli, G., Marabini, Selective separation of zinc and lead
from oxide ores through formationof organo-metallic compounds.
XIIth IMPC,Sao Paulo, Brazil, 1977.
[4] Quast, K.B.,"A review of Hematite FlotationUsing 12-Carbon
Chain Collectors", School of Geonce, University of South Australia,
Mawson
Lakes, Australia, 2000.[5] Song, S. (2002) Magnetic Separation
of Hematite and Hematite limonite Fine asHydrophobic flocs From
Iron Ores,[email protected]
[6] King, R.P. (1982) Flotation of Fine Particle, InPrinciples
of Flotation Ed. King, R.P., Afr.,Institute Mining Metallurgy
Johannesburg Chap.11.
mailto:[email protected]:[email protected]
