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硫化镍闪速熔炼终渣中铁主要以含镁橄榄石型硅酸盐为主,致使其后续资源利用中提取困难。本研究从提铁角度出发,通过适当调整熔炼初始渣系组分,利用Fact Sage热力学软件计算了FeO-SiO_2-CaO-MgO渣系在特定温度下的热力学条件、相平衡及物相组成,并用实验验证,以期找到最有利于后续还原提铁的渣组成。结果表明,在500~1 400℃间,该渣系主要存在物相以橄榄石以及钙镁硅酸盐为主,并伴有少量Fe_3O_4、MgO(方镁石)和Ca_3MgSi_2O_8。渣中CaO及Fe/SiO_2比增加,MgO含量降低(13%降为7%),均会降低渣系熔点。随着CaO含量从5%增加到20%,体系中铁镁橄榄石和铁橄榄石物相含量降低显著,FeMgSiO_4相对含量从34%降低到6%左右,Fe2SiO_4相对含量从39%降低到小于6%。该渣组分非常有利于渣后期还原提铁。
Nickel sulphide flash smelting final slag iron mainly forsterite type silicate, resulting in its subsequent use of resources difficult to extract. In this study, the thermodynamic conditions, phase equilibrium and phase composition of the FeO-SiO_2-CaO-MgO slag system at specific temperature were calculated by Fact Sage thermodynamic software, Experimental verification, in order to find the most conducive to follow-up reduction of iron slag composition. The results show that olivine and calcium magnesium silicate are the main phases of the slag system at 500-1 400 ℃, accompanied by a small amount of Fe 3 O 4, MgO (periclase) and Ca 3 MgSi 2 O 8. Slag CaO and Fe / SiO_2 ratio increased, MgO content decreased (13% down to 7%), will reduce the melting point of the slag system. With the increase of CaO content from 5% to 20%, the phase content of Fe-F olite and forsterite decreased significantly, the relative content of FeMgSiO 4 decreased from 34% to 6% and the relative content of Fe 2 SiO 4 decreased from 39% to less than 6%. The slag component is very conducive to the late slag lifting extraction.