1. Definition of refractory material:Inorganic non-metallic materials with a refractory degree greater than 1580 are called refractories.
2. Chemical composition of refractory materials:
3. Mineral composition of refractory materials
4. Main properties of refractory materials:
5. Damage mechanism of refractory materials used in cement kiln:
1) Mechanical damage: thermal expansion, ovality stress, dislocation of lining bricks, stress extrusion of lock iron.
2) Rapid cooling and rapid heating: overheating and thermal shock.
3) Chemical erosion: alkali erosion, chromium erosion, redox bursting, hydration phenomenon.
6. The temperature of each part of the cement kiln and the requirements for the material:
7. Requirements for refractory materials for firing in rotary kilns:
Good hanging kiln skin;Sufficient resistance to chemical attack;It has good thermal shock resistance;It has sufficient mechanical strength;It has sufficient refractoriness;It has a low rate of thermal expansion;environmental harmony, etc.
8. Types of refractory materials used:
1) Alkaline refractories.
The main varieties of alkaline refractory materials are: magnesia bricks, spinel bricks (magnesia aluminum bricks, magnesia chrome bricks), magnesia silica bricks, dolomite bricks, etc. Magnesia chrome bricks are divided into ordinary magnesia-chrome bricks, directly bonded magnesia-chrome bricks, and semi-directly bonded magnesia-chrome bricks.
2) Silicon-aluminum refractories.
The main varieties of aluminum-silicon refractories are: clay bricks, high-alumina bricks, and special high-alumina bricks, such as phosphate-bonded high-alumina bricks, phosphate-bonded high-alumina wear-resistant bricks, high-alumina bricks resistant to spalling and alkali-resistant semi-acid clay bricks.
3) Refractory castable.
There are many varieties of refractory castables, such as high-strength type, steel fiber reinforced type, low-cement type, ordinary type, alkali-resistant type, etc., which have different options depending on the use conditions. Such as low cement bonded castable, phosphate bonded castable, etc.
4) Thermal insulation.
Thermal insulation materials mainly include: calcium silicate board, aluminosilicate refractory fiber, diatomaceous earth brick, etc.
9. Refractory materials for various parts of the cement kiln:
1) Preheater, decomposition furnace:
Working layer - ordinary alkali-resistant bricks, alkali-resistant castables, high-alumina alkali-resistant castables;
Thermal insulation layer - CB thermal insulation bricks, diatomaceous earth bricks, hard calcium silicate boards.
2) Tertiary air duct:
Working layer - high-strength alkali-resistant bricks, high-strength alkali-resistant refractory castables;
Thermal insulation layer - CB thermal insulation bricks, diatomaceous earth bricks, hard calcium silicate type calcium silicate boards, thermal insulation castables.
3) After kiln mouth: steel fiber reinforced high-alumina castable, high-alumina alkali-resistant castable;
4) Front kiln mouth: steel fiber reinforced corundum castable, corundum refractory castable, high alumina alkali resistant castable, steel fiber reinforced high alumina castable.
5) Rotary kiln:
Firing zone - magnesia-chrome bricks, magnesia spinel bricks, magnesia-calcium bricks, etc.;
Transition zone - spinel bricks, magnesia-chrome bricks, spall-resistant high-alumina bricks, semi-direct bonded magnesia-chrome bricks, phosphate-bonded high-alumina bricks;
Decomposition zone - alkali-resistant insulating bricks, CB20, CB30 insulating bricks.
6) Kiln door cover:
Working layer - spall-resistant high-alumina bricks, high-alumina bricks, high-alumina alkali-resistant castables;
Thermal insulation layer - high-temperature resistant thermal insulation bricks, hard calcium silicate calcium silicate boards, lightweight thermal insulation castables.
7) Grate cooler:
Working layer - anti-spalling high-alumina bricks, silicon carbide composite bricks, phosphate-bonded high-alumina wear-resistant bricks, alkali-resistant castables, high-alumina alkali-resistant castables;
Thermal insulation layer - high temperature resistant thermal insulation bricks, diatomaceous earth bricks, hard calcium silicate type calcium silicate boards, thermal insulation castables.