REFRACTORY BRICKS MAKING PROCESS | FULL INFORMATION ABOUT REFRACTORY MATERIALS

FULL INFORMATION ABOUT POROSITY :-    • POROSITY TESTING IN IRON ORE PELLETS/...  

Refractory lining
The purpose of the refractory lining is to insulate the steel shell from the high temperatures inside the kiln, and to protect it from the corrosive properties of the process material. It may consist of refractory bricks or cast refractory concrete, or may be absent in zones of the kiln that are below approximately 250 °C. The refractory selected depends upon the temperature inside the kiln and the chemical nature of the material being processed. In some processes, such as cement, the refractory life is prolonged by maintaining a coating of the processed material on the refractory surface. The thickness of the lining is generally in the range 80 to 300 mm. A typical refractory will be capable of maintaining a temperature drop of 1000 °C or more between its hot and cold faces. The shell temperature needs to be maintained below around 350 °C to protect the steel from damage, and continuous infrared scanners are used to give early warning of "hot-spots" indicative of refractory failure.

Based on fusion temperature, (melting point) refractory materials are classified into three types.
Normal refractory: fusion temperature of 1580 ~ 1780 °C (e.g. Fire clay)
High refractory: fusion temperature of 1780 ~ 2000 °C (e.g. Chromite)
Super refractory: fusion temperature of more than 2000 °C (e.g. Zirconia)

Furnace bricks material, also called refractory bricks or fire bricks, which are manufactured with raw materials, additive and binding agent through molding, drying and firing in the high temperature. Furnace Fire brick can be used in the metallurgical industry.

Principal raw materials for firebrick include fireclays, mainly hydrated aluminum silicates; minerals of high aluminum oxide content, such as bauxite, diaspore, and kyanite; sources of silica, including sand and quartzite; magnesia minerals, magnesite, dolomite, forsterite, and olivine; chromite.

Acidic refractory usually refers to refractory material with more than 93% SiO2 content. The main characteristic of acidic refractory is to resist the erosion of acid slag at high temperature, but it is likely to react with alkaline slag.

Basic Refractory is refractory material contains magnesium oxide and calcium oxide. Basic refractory has high refractoriness and strong alkaline slag resistance. The most commonly used basic refractory brick is magnesite brick with the strong resistance to alkaline slag and iron slag.

Neutral refractory materials contain alumina, chromium oxide, and carbon. Corundum products, chrome bricks, and carbon refractory materials are common types of such materials. Corundum refractory materials are high-quality refractory materials, which contain alumina more than 95%.

Neutral refractories :- Neutral refractories are chemically stable to both acids and bases and are used in areas where slag and atmosphere are either acidic or basic. The common examples of these refractories materials are carbon graphite most inert, chromite refractories, and alumina refractories.

Pyrometric cone equivalent
PCE is a quality control method that detects variations in batch chemistry. Pyrometric cone equivalent is the ability to withstand exposure to elevated temperature without undergoing notable deformation. Due to their chemical complexity, refractories melt over a range of temperatures. In this test, ceramic specimens of known softening behavior are compared with the cone of the refractory after firing. This ensures consistency and measures refractoriness.

#REFRACTORY BRICKS #REFRACTORY MATERIALS #INDUSTRIAL PROCESS #SUBHAJIT MONDAL