Study On Mechanism Of Pyrite Magnetization Composite Roasting Tin-iron Ore Under Non-carbon Condition

A method of roasting of tin-bearing iron ore using sulfur-bearing stone coal could transform the cassiterite to volatile tin sulphide(SnS(g)).However the magnetic susceptibility of hematite is relatively low.It was noteworthy that the ferrous sulfate with carbon and pyrite play important role in the process of reduction roasting of tin-bearing iron ore using sulfur-bearing stone coal.Hence,two novel methods for reduction roasting of tin-bearing iron ore using ferrous sulfate with carbon and pyrite without carbon are proposed,and the effect of pyrite is deeply analyzed.Thermodynamic simulation results of reduction roasting of tin-bearing iron ore using ferrous sulfate with carbon is studied,and the result shows the Fe-Sn spinel formated in the roasting process,which resulted in the tin removal rate and magnetic susceptibility of hematite are relatively low.The simulation results of reduction roasting of tin-bearing iron ore using pyrite without carbon suggested that hematite in tin-bearing iron is reduced to magnetite and cassiterite is transformed to volatile tin sulphide completely.Experimental research of reduction roasting of tin-bearing iron ore using pyrite without carbon is studied,and the results shows that magnetic susceptibility of hematite and removal rate of tin are increase with the roasting temperature,pyrite amounts and residence time.When pyrite amounts exceed 5.00 wt.%,some of the produced magnetite will be sulfurated to FeS(1),which decrease the magnetic susceptibility of hematite and obstruct the evaporation of SnS(g).The optimum parameters are established as follows:roasting temperature,1473.0 K;roasting time,60min;pyrite amounts,5.00 wt.%;particle size,<0.075mm.After roasted,the hematite in tin-bearing iron ore can be reduced to magnetite completely,meanwhile,the tin content is decreased to 0.07 wt.%.