H_(2)S作用下锡铁精矿中锡的挥发脱除机制

Volatilization Mechanism of Sn from Sn-bearing Iron Concentrates Using H_(2)S Gas

采用H_(2)S(g)对含锡铁精矿进行还原硫化焙烧,可实现物料中锡的有效脱除。以热力学分析为基础,对含锡铁精矿中铁、锡物相的转变规律及脱锡机理进行了研究。结果表明,H_(2)S(g)通过自身热分解反应生成H_(2)(g)和S_(2)(g)后,S_(2)(g)优先与Fe_(3)O_(4)发生还原硫化反应生成Fe_(7)S_(8),H_(2)(g)则与SnO_(2)优先发生还原反应生成Sn(l)。在焙烧系统中引入CO(g)可促进SnO_(2)的还原和硫化。在混合气体(60vol%CO(g)+40vol%H_(2)S(g))流量70 mL/min、焙烧温度1000℃、焙烧时间20 min、以及锡铁精矿粒度-74μm的条件下,含锡铁精矿中Sn脱除率可以达到95.34%。

Sn could be effectively removed from Sn-bearing iron concentrates through its reduction and sulfurization under H_(2)S atmosphere.Based on the results of thermodynamic analysis,the phase transformation of Sn and Fe and the mechanism of separating Sn in the Sn-bearing iron concentrates were investigated.The results show that H_(2)S(g)will be translated into S_(2)(g)and H_(2)(g)through self-decomposition.Formed S_(2)(g)will preferentially reduce and sulfurize Fe_(3)O_(4) to Fe_(7)S_(8),while H_(2)(g)reduces SnO_(2) to Sn(l).The addition of CO can promote the reduction and sulfidation of SnO_(2) in the roasting system.Sn volatilization ratio can reach 95.34%under the optimum conditions including mixed gases(60vol%CO(g)+40vol%H_(2)S(g))flow rate of 70 mL/min,roasting temperature of 1000℃,roasting time of 20 min,and particle size of -74μm.