Refractory on Cement industry

Refractory on Cement industry

Refractory bricks are widely used in various industrial sectors and high-temperature technical fields. They are an indispensable production material for cement companies in the clinker calcination process. Alkali-based and silica-alumina-based refractory bricks are mostly used in cement companies. In the past, magnesia-chrome bricks were the most widely used in the firing zone of rotary kilns, but the hidden danger of water-soluble hexavalent chromium in magnesia-chrome bricks has become an important issue that needs to be solved urgently in the application of refractory bricks. With the improvement of environmental protection awareness, some industrialized countries (such as Germany, the United States, etc.) have passed legislation to restrict the use of magnesia chrome bricks. Our country also has corresponding regulations on this. At present, chromium-free refractory materials have been fully implemented in the cement industry. Magnesia iron and magnesia-calcium bricks can be used in the firing zone to replace the original magnesia-chrome bricks.

Different parts of the clinker calcination and cooling system of cement enterprises have different performance requirements for refractory bricks, and different types of refractory bricks are used. The refractory bricks commonly used by cement companies are: high alumina bricks, Baiyunshan bricks, magnesia chrome bricks, spinel bricks, anti-stripping bricks, silicon-mold bricks, etc.

High alumina brick

Mainly suitable for preheater, decomposition furnace, tertiary air duct, decomposition zone of rotary kiln, grate cooler lining, etc.

Dolomite Brick

Dolomite bricks are often used in high-temperature sintering parts of rotary kilns. Due to the inherent hydration of dolomite, it will absorb moisture and hydrate during the shutdown of the kiln, causing the brick body to crack and peel off, so dolomite bricks are suitable for use in rotary kilns with long operating cycles. Used in the calcining belt of the rotary kiln, the service life is longer than the original magnesia chrome brick.

Magnesia Chrome Brick

The appearance of magnesia-chrome bricks in the 1950s has greatly improved the life of furnace linings, making magnesia-chrome bricks a dominant position in refractories for cement rotary kilns. In the 1960s, the emergence of large cement rotary kilns made magnesia spinel bricks replace the position of magnesia chrome bricks in the transition zone.

In order to reduce the environmental pollution of hexavalent chromium, low chromium magnesia chrome bricks and chromium-free alkaline refractories have been manufactured to replace magnesia chrome bricks. If environmental pollution is not considered, magnesia chrome brick is a very cost-effective refractory material. At present, in the cement industry, magnesia-iron and magnesia-calcium bricks have been used in the firing zone to replace the original magnesia-chrome bricks and implement chromium-free refractories.

Magnesia alumina spinel brick

There is no chromium in spinel bricks. It is an environmentally friendly product and is mostly used in the front and back transition zones of rotary kilns.

Magnesium iron spinel brick

It does not contain chromium and is suitable for the entire alkaline area (firing zone, transition zone) of the rotary kiln, and has excellent kiln leather making ability;

Anti-stripping brick

Anti-stripping bricks are zirconium-containing high-alumina bricks, which are acid bricks and are ideal materials for the transition zone and decomposition zone of rotary kilns in cement enterprises. It can also be used in the kiln door cover, cooler and other parts of the rotary kiln.

Silica brick

The "silicon" in the silicon-moulded brick refers to silicon carbide, and the "mo" refers to mullite. Essentially, the silica brick is a high alumina brick with silicon carbide added. Suitable for upper and lower transition belts and safety belts of rotary kilns. The practice of many companies has proved that the use of silicon-molded red bricks or silicon-molded bricks in the transition zone of the precalcining kiln with a capacity of 5 000t/d can achieve a service life of more than 12 months.