为实现锡铁矿的资源化利用,采用硫化焙烧法对其进行处理。以热力学分析为基础,结合实验研究对锡铁矿的硫化焙烧反应特征进行了探索。结果表明,较高焙烧温度下,锡硫化挥发物相主要是SnS和SnO,Sn和SnO2的挥发作用相对较小,同等条件下SnO比SnO2和Sn硫化反应趋势大。焙烧过程控制CO浓度低于22%且温度高于873 K时,SnO2可选择性还原成SnO;过程中,FeS2可分解为FeS和S2,S2的硫化作用大于FeS。锡铁矿硫化反应受S2、SO2及SnS的扩散速率控制,界面化学反应不起决定性作用。焙烧后铁物相由赤铁矿相转变成磁铁矿相,可采用磁选法回收其中铁资源,为高效回收锡铁矿中铁资源提供了一种新思路。
Sulfidation roasting process was used to treat tin-bearing iron ore for resource utilization.According to the results of thermodynamics analysis,the sulfidation roasting reaction of tin-bearing iron ore was studied with experiment.The results showed main volatilization phases of tin as SnS and SnO and less volatilization of Sn and SnO2.The sulfidation reaction of SnO was stronger than SnO2 and Sn under the same reaction conditions.When the concentration of CO was lower than 22% and temperature was higher than 873 K in the roasting process,SnO2could be reduced to SnO selectively.FeS2 would be decomposed into FeS and S2 during the roasting process,and the sulfidation of S2 was stronger than FeS.The sulfidation reaction rate of tin-bearing iron ore was controlled by the diffusion of S2,SO2and SnS,and interfacial chemical reaction did not play a decisive role.After roasting,the iron phases of raw ore changed into magnetite,and then the iron could be recovered through magnetic separation.It provides a new method for the recovery of iron from tin-bearing iron ore.