DALMIA REFRACTORIES LTDWELCOMES THE DELEGATES

AF COMPATIBLE & ENERGY SAVING ALUMINA REFRACTORIES

FOR CEMENT PYRO PROCESS

Contents

❖ Raw materials for Alumina bricks

❖ Impact of pet coke and suitable bricks

❖ Impact of alternate fuel and suitable bricks

❖ Special problem solving Alumina bricks

Crystal phases of Alumina-Silica refractories

Al O Range Common Phases Major Raw Material2 3

Less than 40%

Al O

Mullite and glass (can

contain "free SiO )Fireclay (Chamotte)

50% Al O or

60% Al O

Major phase - Mullite

Minor phase - Glass

Calcined Bauxite,

Sillimanite,

Andalusite & Fireclay

70% Al O

Major phase - Mullite

Minor phase - Corundum

and Glass

Calcined Alumina,

Andalusite,

Sillimanite, Fused

Alumina

80% and 85%

Al O

Major phase - Corundum

Minor phase - Mullite and

Glass

Calcined

Bauxite,Fused

Alumina

90% and 99%

Al O

Major phase - Corundum

With trace amount of

Mullite and Glass

Tabular Alumina,

Fused Alumina

2 3 2

2 3

2 3

2 3

2 3

2 3

Raw materials characterization in Alumina-Silica Refractories

Raw Material Al2O3(%) Charactersics

Chamotte (Calcined fireclay) 35-45 - Alkali resistance

Andalusite 55-60 - Shock resistance

Bauxite 80-90 - Abrasion resistance

Corrundum (Alumina) 99 - High refractoriness

Synthetic mullite (Calcined Bauxitic Clay) 60-70

- Strength,Thermal elasticity

Silicon carbide (SiC) - Coating resistance

Major Raw Materials

Synthetic Natural Calcined

Brown Fused Alumina Andalusite Calcined Bauxite

White Fused Alumina Sillimanite Lumps Fire clay

White Tabular Alumina Sillimanite Sand

Fused Mullite Raw Kyanite

Sintered Mullite Clays

Calcined Mullite Bauxite

Petcoke Firing - Advantages Vs Challenges

▪ High Calorific Value

▪ Low Ash Content

▪ More Stable in Storing &

transportation

▪ Less chance of

spontaneous combustion

▪ Less moisture absorption

▪ Low cost

▪ Increase in Sulphur - Require optimization

of clinker chemistry & monitoring A/S

ratio

▪ Hard to grind - Increases maintenance

cost on coal mill rollers, ducts, liners etc.

▪ Unstable coating conditions in kiln -

Lesser refractory life

▪ Build up Formation towards kiln inlet &

preheater - direct damage from build up

removal

Advantages Challenges

Refractory Requirement - Petcoke Firing

✓ High Thermal load bearing capability.

✓ Dense brick with less porosity/permeability

✓ Coating friendliness

✓ Chemical attack resistance

✓ Abrasion resistance.

Special Alumina bricks - DALBURN & DALSINT

PROPERTIES UNIT DALSINT A DALBURN

PCE Ort/OC Min 38/1850 Min 36/1820

RUL taOC Min 1520 Min 1600

RTE @ 1000OC % 0.60 0.60

PLC @ 1500/2 hrs % Max + 2.0 Max +1.0

Spalling Resistance at 1000OC AIR QUENCH

Cycles Min 80 Min 100

ALKALI PENETRATION @1100°C/5hrs

mm < 3.0 < 3.0

Thermal Conductivity w/mK ~1.9 2.20

A.P % Max 15 Max 17

B.D g/cc Avg. 2.70 Avg 2.70

CCS kg/cm2 Min 600 Min 700

Al2O3 % Min 70 Min 70

Fe2O3 % Max 2.0 Max 2.0

DALSINT - Major benefits

Excellent Spalling Resistance

➢ High grade raw materials and well engineered granulometry

➢ Air quenching (1000°C to Air) : + 80 cycles (Typical ~120)

➢ The Refractoriness under load (RUL) ofDALSINT A is >1520°C.

➢ This high thermal value will give youhigh thermal load bearing capability.

High Refractoriness under Load

➢ Resistance to Temperature Fluctuations.

➢ Resistance to hot face cracking

➢ Resistance to high flame temperature.

➢ High thermal elastic properties

DALSINT - Major benefits

High Cemical purity

➢ Manufactured from high pure Raw materials

➢ Very low Fe2O3 (2.0% Max) & lowalkalis (1.0 Max)

➢ Resistance to redox reactions

➢ Resistance to chemical corrosion

➢ Low porosity means low permeability& high strength

Very Low porosity

➢ Resistance to alkali penetration

➢ High abrasion resistance

➢ Low handling breakages

DALBURN - Major benefits

Excellent Spalling Resistance

➢ High grade raw materials and well engineered granulometry

➢ Air quenching (1000°C to Air) : + 100 cycles (Typical ~120)

➢ Resistance to Temperature Fluctuations.

➢ Resistance to hot face cracking

➢ The Refractoriness under load (RUL) ofDALBURN is >1670°C.

➢ This high thermal value will give youhigh thermal load bearing capability.

High Refractoriness under Load

➢ Resistance to high flame temperature.

➢ High thermal elastic properties

DALBURN - Major benefits

High Cemical purity

➢ Manufactured from high pure Raw materials

➢ Very low Fe2O3 (2.0% Max) & lowalkalis (1.0 Max)

➢ Resistance to redox reactions

➢ Resistance to chemical corrosion

➢ Low porosity means low permeability& high strength

Very Low porosity

➢ Resistance to alkali penetration

➢ High abrasion resistance

➢ Low handling breakages

➢ High heat transfer resistance

➢ Thermal conductivity @ 1000°C - ~2.2W/mK

Low thermal Conductivity

➢ Low Kiln Shell temperature

DALSINT & DALBURN - Other benefits

➢Supplied in ISO & VDZ shapes

➢Stringent dimensional tolerances - +/-1mm or 1% whichever greater

➢When compared to basic bricks

✓ Better inventory control – Indefinite shelf life

✓ Less supply time - 4 to 6 weeks

✓ Less Refractory load.

✓ Low shell temperature

Alternate Fuel - Main Challenges

➢ Excessive build-up or clogging (kiln inlet or gas riser )

➢ Build-up of abnormal kiln rings, resulting from unbalanced sulfate modulus

➢ Variations in oxygen potential - redox cycles

➢ Direct action of alkali chlorides and sulfates

➢ Fluctuations in flame length & Thermal wash-out

➢ Destabilization & stripping of clinker coating

➢ Abrasive clinker in outlet causing refractory outlet issue

Sulphate Alkali Ratio & Build-up

(SO3/80)Q (ASR) = ------------------------------------------

{(Na2O/62) + (K2O/94) + (Cl/71)} When Q = 1 Alkalis Salts are in balanced condition in environment

When Q > 1 Environment contains Alkali salts with Free SO3

When Q < 1 Environment contains Salts with Free Alkali Oxides

Impacts of Sulphur & Alkali

The most adverse effect of alternate fuel has been thedestructive forces of sulfur / alkali.

✓ Alkali penetration,

✓ Expansive refractory reactions and

✓ Brick spalling,

✓ Un-wanted Buildups

✓ Direct damage from buildup removals.

Refractory Requirements - AF firing

✓ Low lining porosity & high hot strength

✓ Wear resistance.

✓ Chemical attack resistance.

✓ Coating repellence.

✓ High resistance to thermal shock.

Coating Repellent Refractories

DRL has developed a range of SiC containing bricks, with rawmaterials ranging from fireclay, Andalusite, Mullite and Bauxite.

✓ Very High Chemical Resistance

✓ Minimize coating or ring build-up

✓ High hot strength

✓ Long service life

✓ Extreme abrasion resistance

DAL CR - 50

5 - 7% SiC

DAL CR - 60

13 - 17% SiC

DAL CR - 70

23 - 27% SiC

Phases Present & Abrasion Loss

Quality

XRD Phases Abrasion Loss**

(gm/cm2)Major Phases Minor Phases

DAL CR-70Silicon carbide,

Mullite, CorundumAndalusite, Cristobalite

0.05

DAL CR - 60Mullite,

Silicon carbide, CorundumAndalusite, Cristobalite

0.11

DAL CR - 50 Mullite, Silicon carbide Andalusite, Cristobalite 0.13

LF-70 - 20 Mullite, Corundum Cristobalite, Sillimanite 0.98

LF-60 -20 Mullite, Cristobalite, Sillimanite 1.09

LF-45 -25 Mullite, Cristobalite, Sillimanite 1.20

** By DIN 52108 (Bohme Disk Abrader) with 70mm cube.

DAL CR Bricks Technical details

PROPERTIES UNIT DAL CR50 DAL CR60 DAL CR70

Al2O3% 45 46 45

Fe2O3% 1.5 1.2 1.2

SiC 5.0 – 7.0 13.0 – 17.0 23.0 – 27.0

AP (Max) % 15.0 15.0 15.0

BD (Min) gm/cc 2.35 2.50 2.65

CCS (Min) Kg/cm2 600 500 600

PLC at 14500C % +0.6 +0.6 +1.0

RUL ta O C 1450 1550 1580

Thermal Conductivity @ 10000C

(Kcal/m/hr/0C

2.0 2.5 2.68

SPALLING @ 1000 O C [AQ ]

CYCLES + 100 +100 +150

AREA OF APPLICATION CZ/IZ SZ LTZ/SZ

DAL CR Bricks Application Area

➢ Cement production is highly energy Intensive process.

➢ Energy consumes 25-30% of the total cost.

➢ Out of the total energy 75% is the thermal energy.

➢ Around 20% of the total thermal energy goes as waste even after

implementing & practicing the energy efficient measures.

➢ Heat transfer mechanism is complicated as it includes conduction,

convection and Radiation

➢ Highest heat loss occurs through kiln shell

Energy Saving Solutions

SPECIAL FEATURES

➢ VERY LOW THERMAL CONDUCTIVITY

➢ LOW DENSITY

➢ GOOD STRENGTH

➢ RESISTANT TO ALKALI / SULPHUR ATTACK

ADVANTAGES

➢ REDUCTION IN RADIATION LOSSES

[ SHELL TEMPERATURE REDUCTION UPTO 750C ]

➢ REDUCTION IN REFRACTORY LOAD ON THE KILN

APPLICATION AREA

➢ KILN INLET ZONE

ALITE

TYPE : High strength Energy Saving Brick

APPLICATION : Calcination Zone of cement rotary kiln and other areas where radiation losses are to be minimized.

CHEMICAL COMPOSITION Al2O3 % Min. 20.00

Fe2O3 % Max. 2.50

PHYSICAL PROPERTIES

Apparent Porosity % Min. 30.0 Bulk Density g/cc Max. 1.75

Cold Crushing Strength kg/cm2 Min. 200

THERMAL PROPERTIES

R.U.L. ta C Min. 1300 P.L.C at 1200 C /2 hrs. % + 0.6

ALITE

ALITE - SOLUTION TO ENERGY SAVING

Residual thickness 190 to 200mm

ALITE after 10 months service

Rotary Kiln with Alumina bricks Lining

THANK YOU