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

January 19, 2011

Refractory Bricks – Shapes and Sizes


There is no limit to which a refractory brick can have different shapes and sizes to suit a particular design or lining requirement. Production of refractory shapes depends upon the design and size of furnaces or other service constructions where such refractories are to be used. Numerous shapes and sizes of refractory bricks are produced to meet the specific lining requirements of straight walled, cylindrical, arched, dome and other special types of construction work besides the shapes like wedges, keys, sleeves, nozzles, burner blocks, tiles etc. For example, only an iron blast furnace requires refractory bricks of so many types, shapes and sizes. However, most of the lining works are made of certain standard refractory shapes and sizes which are always available in the market. Special refractory shapes are only produced to meet the specific lining requirements of each furnace or refractory structures like some typical coke oven shapes, stopper heads, arch tiles etc. The shapes which are universally accepted and used are listed below (see figure):
Refractory Bricks - Shapes and Sizes image
Fig: Refractory Shapes
Standard Refractory Shapes
1. Straight (Rectangular)                
2. Side Arch
3. End Arch
4. Wedge
5. Key
6. Flat Circle
7. Combined Arch and Wedge
8. Circle
9. Splits
10. Dome Brick
11. Skew (End / Side)
12. Bullnose or Jamb Brick
13. Soap or Closer
Refractory Bricks shapes and sizes image
Fig: Refractory Brick Shapes / Sizes 
Refractory Ladle Well Block image
Fig: Ladle Well Block
Refractory Lining | Steel Technology - Stopper Sleeve image
Fig: Stopper Sleeve
Stopper Pin image
Fig: Stopper Pin
Refractory Stopper Head image
Fig: Stopper Head
(For a short definition of each shape see the ‘Glossaries > Refractories’ in the menu navigation bar above)
Standardization and rationalization of refractory shapes becomes important as a host of refractory shapes needed for lining even a single part of a production unit involving very complex and complicated designs necessitates use of numerous kinds of opening and aperture details besides inter-chamber dimensions et. As such one can not imagine preparation of moulds either by mechanical pressing or by hand / pneumatic moulding to suit production of large number of shapes with different design details without involving a very high cost of production. So, it is always preferable to design a lining with commonly used refractory shapes as they facilitate easy availability, reduce cost (moulds / liners are generally available with manufacturer), and easy to repair.  
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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