Showing posts with label Refractory material. Show all posts
Showing posts with label Refractory material. Show all posts

October 5, 2008

Refractory Material & Milestones of its Development in India

What are Refractories ?

Refractory items according to any standard dictionary are those materials which are hard to melt, fuse or work even under high pressure. Technically speaking Refractories are a large family of industrial lining and construction materials having melting point around 1200OC (+) and capable to withstand chemical & mechanical erosion, corrosion even under high temperature & pressure. For all high temperature operations, whether metallurgical viz. Steel, Aluminium, Copper, Zinc etc. or non-metallurgical viz. Glass, Fertilizer, Hydrocarbon, Chemicals, Paper, Cement etc. a refractory lining is necessarily required for their continuation with retention of heat in the furnace. For the above reasons refractories find their applications in lining construction of wall of all types of high temperature furnaces, kilns, reactors and other vessels wherever such operations are carried out. So directly or indirectly, virtually each of us is being constantly benefitted from refractories in our daily life.

Refractories used are of both types-

1. Those found as naturally occurring e.g. Basalt, Sillimanite, Carbon etc. and

2. Synthetic i.e. processed with natural or synthetic raw materials.

SHAPED
UNSHAPED
1. Alumino Silicates
  • High Alumina
  • Low Alumina
2. Silica
3. Basic
  • Magnesite
  • Mag-Chrome
  • Mag-Carbon
  • Forsterite
  • Dolomite
4. Carbon
5. Zirconia
  • Zircon (Acidic)
  • Zirconia (Neutral)
6. Carbides/Nitrides
  • Silicon Carbide
  • Silicon Nitride
  • Boron Carbide
  • Boron Nitride
7. Pure Oxides
  • Ferrites
  • Hofnium Oxides

1. Mortars
2. Castables
  • LCC
  • ULCC
  • NCC
  • SFC
3. Gunning Mass
4. Ramming Mass
5. Filling Mass
6. Fetling Mass
7. Spraying Compound
8. Patching/Coating Mass


Types of Refractories

Refractories are classified into various categories (ref to the above Table). Refer to another article for details on Classification of Refractories.
Milestones in the Development of Refractories in India:
India has an ancient history of ‘Potter’s Wheel’ which has, although remote, a definite link with the usage of refractory. Today India is producing and supplying almost all type of refractories (Shaped & Unshaped) equivalent to the International standard and quality. It took more than a century for India to attain this level by achieving milestones one after another. One such list of major developments (Milestones) which have taken place in the field of refractories in India is represented chronologically hereunder(ref to the Table below)


Year
Milestones Achieved
1874
  • Fireclay Bricks
1947
  • Magnesite Bricks
1949
  • Silica Bricks for Coke Oven
1955
1960
  • Bauxite based High Alumina Bricks for Steel & Cement Industries
  • Mullite Bricks for Glass Industries
1969
  • High Grog Fireclay Bricks for Steel Ladles
1977
  • AZS Electrocast Blocks
1983
  • Magnesia-Carbon Bricks
  • Magnesia based Slide Gate Plates
1984
  • High Alumina Slide Gate Plates
1985
  • Low Cement Castables (LCC) / Monolithics
  • Ceramic Fibres
  • High alumina Bauxite based Ladle Refractories
1986
  • BRN 62 / Similar Blast Furnace Hearth Bricks
  • Bubble Alumina based Insulating Refractory Bricks
1988
  • Dense Silica shapes for Tall Coke Ovens
1990
  • Direct Bonded Mag-Chrome Bricks (DBMC)
  • Unidirectional Gas Purging elements
  • Alumina-Carbon Slide Gate Refractories
  • Alumina-Carbon Torpedo Ladle Refractories
1991
  • Dense Silica shapes for Blast Furnace stoves
1993
  • Mullite Bricks for Blast Furnace stoves
  • Alumina-Carbon continuous casting refractories
  • Dry Basic Ramming Mass
  • Gunning materials for Converters
  • Tundish Spraying Mass
1994
  • Ultra Low Cement Castables (ULCC) / Monolithics
  • Pitch-Bonded tempered Dolomite Bricks
  • Multidirectional (Indicative) Gas Purging Plug
  • Cordierite & Silicon Carbide based Kiln Furniture
1995
  • Spinel based Monolithics for Ladle Lining
  • Alumina-Silicon Carbide-Carbon (ASC) Trough Mass for Blast Furnace
1998
  • Magnesia-Alumina-Zircon Bricks for Cement Rotary Kiln
  • Pumpable Refractories for Petrochemical Industries
  • Alumina-Zirconia / Zircon-Mullite Slide Gate & Continuous Casting Refractories