Refractory

About Refractory

GANESHAS is a certified vendor of once-over REFRACTORIES,

The materials whose usage is applied at a temperature of >6000C are considered as refractories.

According to ASTM(American Society For Testing And Materials) C71 the definition of refractories is:

Non-metallic materials having those chemical and physical properties that made them applicable for structures, or as components of systems, that are exposed to environments above 10000F(800K,5000C)

General Properties

  • These type of materials are stable at high temperatures and also they retain their strength at same
  • As their operating environment are different, they need to be thermal resistant ,they must be
    chemically inert
  • Also they must be having a specific range of thermal conductivity and coefficient of thermal
    expansion depending upon their working conditions
  • Generally the materials used in manufacturing of refractories are oxides of alumina, silica,
    magnesia etc.
  • Oxides of calcium(lime) are also one of the general refractories found. Fire clays are also used in the manufacturing of refractories
  • The highest referring melting pt. refractory is hafnium carbide with a melting point of 39000C(approx.)

Characteristics Of Good Refractory

  • Resistance against heat
  • Resistance against corrosion
  • Should have high fusing temperature
  • Ability to withstand high load
  • Should be chemically inert
  • Should not undergo deformation
  • Uniform expansion and contraction

Based on Chemical Composition

ACIDIC REFRACTORIES: The main element in this type of refractory is silica which reacts with bases such as alkalies, lime, basic oxides etc

Also alumina(Al2O3) is the main component along with silica

Mostly these are used in places where the atmosphere is acidic and these type of refractories are stable to acid attacks but the converse is not true

The major use of these type of refractories is done in steel and iron industries

BASIC REFRACTORIES: The key material used in this type of refractory is magnesia(MgO) or dolomite(MgCO3+CaCO3) or chrome-magnesia(Cr2O3+MgO)

This type of refractory is used in work place which has basic atmosphere(involving basic chemicals)

These are stable to basic attacks but they are affected by acidic attacks

NEUTRAL REFRACTORIES: These refractories are used in areas where slag and atmosphere is not fixed i.e. sometimes acidic and sometimes basic

Examples of these kind of materials are alumina(Al2O3),chrome(Cr2O3) and carbon

To avoid reaction between acidic bricks and basic bricks we use the neutral bricks. The neutral bricks are made up of graphite and chromites

Based on Fusion Temperature

Based on Fusion temperature refractories are classified in following:

NORMAL REFRACTORY: Fusion temperature=1580-17800C(ex: fire clay)

HIGH REFRACTORY: Fusion temperature=1780-20000C(ex: chromite)

SUPER REFRACTORY: Fusion temperature>20000C(ex: zirconia)

Refractory Anchorage

Anchorage systems are must for all refractories. Anchorage systems such as wire formed anchors, ceramic tiles etc.support the refractory lining

The commonly used anchorage systems have a rectangular or circular cross-section

The rectangular cross section can bear higher weight and it is used for high thickness refractory whereas the circular cross section can bear low weight and is used for low thickness refractory

Refractories used for roofs demand the ability to support the weight of refractory even at the
elevated temperatures and operating conditions

The amount of anchors used in the refractory is dependent on the working conditions of the
refractory

The preference of anchors shape, materials,size and numbers has significant impact on the quality and life of refractory

Refractory Heat-Up

Now after making of a new refractory lined furnace or equipment the next step is to initiate its working by heating it up in a controlled manner

It is done in order to stop spalling(the method in which the flakes of a material are broken from a
large body by projectile impact, corrosion, cavitations etc.) or shortening of the materials predicted lifetime

The technology which is used of heating up the refractory must contain following features:

1.Thermal homogeneity within all the equipment

2.Thermal stability of the heat source

3.Safety of operation

4.Reproducibility(ability to reproduce)

BLOCK DIAGRAM FOR REFRACTORY MANUFACTURING

Item FIRE CLAY BRICK HIGH ALUMINA BRICK
Grade SK30 SK32 SK34 SK35 SK36 SK37 SK38 SK40
Al2O3 ,% 30 35 ≥42 ≥48 ≥55 ≥65 ≥75 ≥80
Fe2O3, % 2.5 2.5 ≤2 ≤2 ≤2 ≤2 ≤2 ≤2
Apparent Porosity 22-26 20-24 ≤26 ≤22 ≤22 ≤23 ≤23 ≤21
Bulk Density g/cm3 1.9 – 2.0 1.95-

2.1

2.25-

2.35

2.25-

2.35

2.25-

2.35

2.25-

2.35

2.25-

2.35

2.25-2.35
Cold Crushing Streng  th Mpa 20 25 ≥20 ≥40 ≥44 ≥49 ≥54 ≥65
0.2Mpa Refractorine  ss Under Load T0.2

,min

1250 1300 ≥1300 ≥1420 ≥1470 ≥1500 ≥1520 ≥1530
Permanent Linear Ch  ange On Reheating 0.1 0.1 -0.3 0.1~-

0.5%

0.1~-

0.4%

0.1~-

0.4%

0.1~-

0.4%

0.1~-

0.4%

0.1~-

0.4%

%1500X2h

Properties

Primer:
A hot melt type acid-proof cement resist oxidizing and non-oxidizing chemicals up to certain limits. Best jointing cement for acid proof Brick/ Tile lining work in battery charging rooms & electro plating plants. It resist Temperature upto 90 °C.

Mastic
A Hot melt typr corrosion resistant cement in slab shape Resists dilute acids, alkalies, salts etc. Best for heavy dutyindustrial flooring and Brick/ Tile inter – liner material. Effective Laying system for floors/ elevated floors of chemicalstorage tank-pads in refinery, gase and oil base projects.

Bricks and Tiles:
Since the corrosion technology found, Acid Proof Bricks & Tiles are Prime and most effective material amongst all other anti-corrosive systems.The major Corrosion problems in all types of industrial plants are solved by laying & fixing of Acid Proof Bricks, Tiles or Mandana Stones.
The standard sizes : 10mm, 12mm, 15mm, 20mm, 25mm, 38mm, & 75mm thick Acid Proof Tiles and Bricks arealways available with us.

K-Silicate
A pure, buff white powder and crystal clear solution of k-Silicate Mortar is generally used as a bedding mortar in all types of brick, tile and stone lining work.It is highly recommended where concentrated Sulphuric and Nitric Acids are used. It is most identical cement mortar for the Acid Proof and refractory brick lining work into the RCC CHIMNEYS & TOWERS since it has an unique nature of Acid and Heat Resistance. It may resist temperature upto 900 °C

Phenolic:
A very limited used 2 component Acid Proof PHENOLIC Mortar has very specific usages. Excellent resistant againstSulphuric (H2SO4) Acid upto 93% has made this material most identical for frtilizer, S.S.P., and other phosphates plants.

EPoxy:
Epoxy is a most widely applicable and versatile material in Corrosion TechnologyEPOXY used as coating, Screeding, bedding & Jointing materila for Brick, Tile and Mandana Stone liningwork in all industrial plants i.e. : Agro, Foods, Dairies, Pharmacuticals, Bulk Drugs, Hospitals, Bravery &Breweries plants gives an excellent perfomance upto many years.

Colourful & Jont less Screeding or Coating with EPOXIES is highly recommended in all above lantswhich provides cost free, very high strength and excellent aesthetic view.

Epoxies due to its very high compressive & bonding strength is very versatile material for grouting work in all types of RCC Structures, Foundations of D.G Sets and Heavy Compressors, Bridges, Chimneys andSkyscraper buildings etc.

Epoxies and special grouting with high pressure shall fill up any deep craks into all above RCC base structures and provide the additional strength to RCC structures.

Furane:
A prime 2 Component ( Resin & powder ) Acid / Alkali / Solvent resistant Furnae : resin – Mortar is used a Bedding Joint Filling or Bedding & Jointing Materials for Acid proof bricks, tiles & Mandana Stone lining work. In all fertilizer, petrochemicals, termal power, pulp & paper, zinc & other precious metal treatment, oil refineries,….Plants.
Furane materials is always recommended in all above plants due to its high strength, excellent bonding& Acid/ Alkali / Solvent resistant Nature.

Sulphur:
A hot melt type acid-proof cement resist oxidizing and non-0xidizing chemicals upto certain limits. BestJointing cement for acid proof Brick/Tile lining work in battery charging rooms & electro plating plants.It resist Temperature upto 90°C.

×