Chrome brick is a shaped refractory product with chromium oxide and alumina as the main raw materials, or with a small amount of zirconia introduced, and the content of chromium oxide is not less than 75%, and the content of chromium oxide, alumina and zirconia is not less than 98%. Its refractory material with a chromium oxide content greater than 30%. In order to improve the high temperature performance of brick, more than 10% magnesia is generally added into the material. Chrome brick manufacturing in general industrial pure chrome green as the main raw materials to produce chromium oxide products.
It has excellent corrosion resistance, high temperature compressive strength, high temperature strength, excellent wear resistance, high refractoriness, excellent thermal shock resistance, high temperature volume stability and so on. Widely used in coal gasifier lining material and coal water slurry pressurized gasifier face lining. Chrome brick manufacturing belongs to neutral brick, its function with acid and alkaline refractories is very weak at high temperature, its softening temperature under load and heat shock resistance are lower than magnesia chrome brick. Mainly used in high temperature acid and alkaline refractory isolation layer, also used in the non-ferrous smelting furnace lining, but should not be used in direct contact with molten iron and atmosphere change frequently.
This series of firebrick was first used in nonferrous metallurgy furnace and gas slagging furnace. It has excellent corrosion resistance to outside steelmaking slag, non-ferrous smelting slag, coal gasification slag and all kinds of glass liquid. In recent 10 years, chrome brick began to get application in glass furnace, but limited to dark bottles glass furnace or non- alkali fiberglass furnace, and is mainly used in glass furnace high temperature parts, such as the upper wall, small oven, discharge hole, loading port, etc., because it can significantly extend the age of kiln, thus caused the attention of the glass industry.
The erosion rate of chrome brick manufacturing increases almost linearly with the increase of erosion temperature. The reason is that with the increase of temperature, the proportion of small group and silica complex anion increases, which accelerates the dissolution rate in the glass. As the temperature increases, the viscosity and free volume of liquid glass decrease, the average free path of motion increases, the diffusion rate increases, and the erosion of chrome brick by liquid glass is accelerated. When the temperature rises to 1550 ° C, oxidation occurs at the gas-solid/liquid-phase interface, resulting in a rapid increase in erosion rate, as evidenced by the appearance of yellow-green opaque glass at the interface.
With the increase of temperature, the apparent porosity and volume density of chrome refractory brick decreased, and carbon burial significantly reduced the firing temperature and improved the microstructure of chrome brick. Porosity microthinning may be an important way to improve the anti-permeability of chrome brick, which can prevent or reduce the penetration of slag to a great extent, so as to minimize the structural peeling of chrome brick and effectively extend its service life.
