Refractory Materials & Milestones achieved by Indian Refractory Industry

What are Refractories? / What are Refractory Materials?

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 1200^OC (+) 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 / Types of Refractory Materials

Refractories are classified into various categories (ref to the above Table). Refer to next article for details on Classification of Refractories.

Milestones and Developements achieved by Indian Refractory Industry:

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	Sillimanite Blocks for Glass Melting Furnace
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