Raw materials for refractory products

a.1- Low Grade DEAD BURNED MAGNESITE (DBM)

Dead Burnt Magnesite is produced in the Rotary Kiln by sintering raw magnesite at a controlled temperature of 1750 degree centigrade and its
chemically inactive. Dead Burnt Magnesite is consuming almost exclusively in the production of Refractory Field.

It is used in brick making and raw materials for producing unshaped refractories. The finished products are used for steelmaking, bottom of electric furnace and ramming lining.

a.2- Middle Grade Dead Burnt Magnesite

Middle Grade Dead Burned Magnesite is made from Caustic Calcined magnesite with MgO above 95% through processes of briquetting, sintering in shaft kilns at high temperature. Featured by good sintering level and dense structure.

It is an amorphous refractory material for producing magnesia branded bricks, medium-grade magnesia bricks, magnesia castables, etc. It is also a high-quality raw material for magnesia refractory products.

a.3- High Purity Dead Burnt Magnesite

High Purity Dead Burned Magnesite is made from finely selected super grade -A raw magnesite through processes of floatation concentration, calcinations, milling, briquetting, and sintering in ultra-high temperature oil shaft kilns. It is an ideal raw material for high-grade magnesia refractories such as magnesia bricks, magnesia soldering bricks, magnesia-carbon bricks, tamping materials for tundishes and magnesia castables.

Fused Magnesia

Fused magnesia (FM) is produced by smelting of calcined magnesia in electric arc furnaces at above 3000°C. Fused magnesia is considered to be one of the best thermal and electrical insulators with high density, high purity and large crystals. Kuma’s produces fused magnesia with capacity of 37.500 tons per year.

FM can be used in:

– High performance MgO-C refractory bricks for steel industry

– Fired refractory bricks for cement and glass industry

Fused Magnesia Grades

1-Calcined Alumina Powder

AW series of α-AL2O3 powder is the national project achievement and has passed the national technical appraisal, quality can be instead of Amati’s. It uses a unique process and possesses the characteristics of high activity, small grains and high conversion rate.

It is the main raw material for the high quality refractory products, as well as fine ceramics and polishing products. It is on the basis of establishing the control model of fine particle size, effectively controls and optimizes the particle size distribution. Meanwhile it makes phase change and surface modification to own small crystal grain size and crystal-like, spherical-like properties.

2-Tabular Alumina

Tabular alumina is a purely sintered α-corundum material that is a compact body rapidly sintered at temperatures above 1900 ° C without sintering aids. Tabular alumina has approximately 200 μm and well-developed hexagonal plate-like α-corundum crystals. Its excellent thermal volume stability and thermal shock resistance can be attributed to the following special microstructure of platy corundum: less open pores, large crystals, closed spherical pores due to recrystallization trap during rapid sintering. Tabular alumina has high heat resistance, mechanical strength, abrasion resistance, high chemical purity, excellent insulation properties, acid and alkali corrosion resistance.

3-White Fused Alumina

White fused alumina / White Corundum is a high grade refractory material, which is mainly made from industrial alumina powder by melting above 2000 ℃ in the electric arc furnace and cooling, classified into different parcel size. It has close texture and high hardness. Its particle is in sharp corners. It is suitable for kinds of advanced finalized refractories and amorphous refractories. It also can be used for high temperature, abrasion resistance and erosion resistance environment, such as steel ladle, sliding plate, nozzle, stopper rod, ventilated brick, iron ditch, kiln and coal spraying pipe.

4-Brown Fused Alumina

Our brown corundum is made of quality bauxite as raw material, anthracite and iron filings. It is made by arc smelting at 2000°C or higher temperature. It is crushed and plasticized by self-grinding machine, magnetically selected to remove iron, sieved into various sizes, and its texture is dense and hard. High, spherical pellets, suitable for the production of ceramic, high-resistance abrasive resin and grinding, polishing, sandblasting, precision casting, etc., can also be used to manufacture high-grade refractories.

The composition of Bauxite is very complex, and the general term of Hydrous Alumina Ore with different geological origin. Such as boehmite, diaspore and gibbsite (Al2O3 – 3H2O); some are diaspore and kaolinite (2SiO2 Al2O3 2H2O); some kaolinite, and with the increase of the content of kaolinite, which is generally the bauxite or kaolinite clay. Bauxite is usually formed by chemical weathering or exogamic action. There are few pure minerals and always contain some foreign minerals, which contain more or less clay minerals, iron minerals, titanium minerals and detrital heavy minerals.