The alkaline brick which uses dolomite as the main raw material is called dolomite brick. The advantages of dolomite brick are good performance and low cost. The main disadvantages of dolomite brick are hard to sintering and easy to hydrate in tide. If the sintering is not dense, the crystallization of CaO in dolomite sand is not complete, and there will be many open pores in the sand. In this way, the atmosphere of H2O gas or kiln gas CO2, SO2 and other acid gases will drill into the material, and easy to occur hydration CaO reaction, resulting in rapid damage to the material. Therefore, in order to improve the hydration resistance, corrosion resistance of CO2, SO2 and other acidic gases and high temperature volume stability of magnesium-calcium refractory materials, it is particularly required to use magnesium-calcium or dolomite sand with high purity, dense and low porosity, which is sintered well, as raw materials for brick making.

How to improve the hydration resistance of dolomite?

1. Sintering method includes activated sintering method (two-step calcination and digestion); Adding admixture sintering method, the method also includes: the generation of liquid phase additives, such as Al2O3, Fe2O3, SiO2, TiO2, CuO oxides and nitrites, boron carbide, metal boron, aluminum and other non-oxides and metals; Additives to form solid solutions, such as CeO2, La2O3, ZrO2, Y2O3, Cr2O3 and other oxides; Introduce cleaning additive options such as Ca(OH)2 or CaCO3 or calcium fluoride as additives; Stable compounds such as CaZrO3, CaTiO3, Ca2SiO4, Ca3SiO5 and CaAl12O19 are generated.

2, surface treatment method includes: organic matter surface coated organic solvent, such as tar, asphalt, paraffin, fatty alcohols and various resins, organic silicide, organic acid-organic acid salt complex (such as glycolic acid - aluminum lactic acid, citric acid - aluminum lactic acid); Inorganic material surface coating, the commonly used gas phase coating CaO+CO2→CaCO3 film; Liquid phase coated solution, such as phosphoric acid, sodium phosphate, sodium silicate, aluminum dihydrogen phosphate, oxalic acid, etc. These solutions react with free CaO on the surface of magnesia-calcium plastics to form insoluble or slightly soluble compounds that adhere to the clinker surface.

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