Effect of magnesite tailings powder on properties of MgO-SiO2 castables
In order to improve the sintering performance of MgO-SiO2 castables,shorten the sintering time and reduce the production cost,MgO-SiO2 castables were prepared using fused magnesia,silica mi-cropowder,tabular corundum powder,silicon carbide powder,and magnesite tailings powder as the main raw materials.The effects of the magnesite tailings powder addition(0,2％,4％,6％and 8％,by mass,re-spectively)on the fluidity,microstructure and mechanical properties of the castables were studied.The re-sults show that:1)the in-situ reaction between highly active MgO generated by the decomposition of mag-nesite tailings powder and silica micropowder promotes the formation of forsterite neck connection,and the in-situ reaction between magnesia and corundum powder in raw materials promotes the formation of spinel neck connection;2)impurities such as CaO and SiO2 in magnesite tailings react with MgO at high tempera-tures to form a low melting point calcium magnesium olivine phase,which exists as a liquid phase at 1 500 ℃,promoting the sintering of the sample;3)when 4％magnesite tailings powder is added,the com-prehensive performance of the castable is the best.
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