Studies On Effect Of Cooling System On Leaching And Self-disintegrating Properties Of Calcium Aluminate Slag

Although the high iron bauxite in Guangxi province contain iron and aluminum,its storage is immense.At present,the resource of bauxite in our state is deficient,and possibly in the future,the exploration of it will alleviate the shortage situation of ore resources in aluminum industry and steel industry in our state.The Northeastern University put forward the process of "minerals sintering-blast furnace smelting-alumina leaching",aiming at the bauxite,which will solve the problem how to comprehensively utilize.Leaching alumina from calcium aluminate slag treating by alkaline solution which is rich in Na2CO3 is an important method to produce Al2O3.The method can process calcium aluminate slag left after iron-bearing bauxite is sintered.In the process,the procedure of minerals sintering and cooling technique which determine the phase composition of slag is important.The leaching and self-disintegrating properties of calcium aluminate slag which can be extracted alumina determine the whole process,so the paper proceeded systematic studies on the cooling system of calcium aluminate by measuring the alumina leaching property,the composition of slag and self-disintegrating property,which founded a better cooling system in slag sintering and synthesised the better slag with higher alumina leaching property for raising production capacity,obtained the results:The higher cooling rate of calcium aluminate slag in the cooling process is,the worse alumina leaching property and self-disintegrating property is.there are 2CaO·Al2O3·SiO2 and 3CaO·Al2O3 that have bad leaching property in the slag when the cooling rate is higher than 20℃/min.When cooling the slag by the rate 0.3℃/min in 1340℃-1330℃,the slag will have better alumina leaching property above 90%.The self-disintegrating property of calcium aluminate slag is determined by the amount of 2CaO·SiO2 in it.In practical production,there are various impurities which affect the self-disintegrating property of 2CaO·SiO2.The paper studied the effect of MgO,TiO2,and FeO on self-disintegrating property of 2CaO·SiO2.The self-disintegrating property of 2CaO·SiO2 have no evident change when adding MgO in its batching.MgO enter into the lattice of 2CaO·SiO2.When adding TiO2,in the powder there is CaTiO3 that enable self-disintegrating property of 2CaO·SiO2 to be decreased seriously.The self-disintegrating property of 2CaO·Si02 sintered when adding FeO under reducing atmosphere is worse than that sintered under oxidizing atmosphere.Under reducing atomosphere,FeO enable 2CaO·Si02 to appear many microparticles rather than powder, possibly the cause is that FeO enable the melting point of system to descend,and influence the phase transition of C2S,the crystal form of CaO and FeO is similar, FeO enter into the lattice of C2S and cause imputity defects.