铁矾渣还原焙烧自硫化研究

Research of Reduction Roasting and Sulfidation of Jarosite Residue

为解决铁矾渣大量堆存带来的资源浪费和重金属污染,及传统焙烧回收处理工艺会产生SO_2等二次污染的问题,同时实现铁矾渣中主要有价金属的回收利用,提出了铁矾渣还原焙烧固硫的预处理方法。以铁矾渣热分解过程和热力学计算为基础,通过考察焙烧条件对铁矾渣中主要有价金属锌的硫化率、硫的固定率及物相转变的影响,对铁矾渣还原焙烧自硫化过程进行了研究。结果表明:在焙烧温度为900℃,碳粉添加量为18%,碳酸钠添加量为5%,焙烧时间为90min的条件下,锌的硫化率和硫固化率分别可达93.47%和87.69%。焙烧产物主要以硫化物形式存在,可通过浮选等方式富集。铁矾渣还原焙烧可以实现Zn等主要有价金属的综合回收预处理并避免焙烧过程中SO_2的排放。该研究对其它重金属硫酸盐的清洁处理具有重要的指导意义。

In order to solve the problems such as the waste of resources and the heavy metal pollution caused by large-scale storage of jarosite residues,and the SO2 emissions caused by traditional roasting and recycling process,at the same time,to realize the recycling and utilization of the main metal in the jarosite residues,the pretreatment method for the reduction roasting and sulfur fixation of jarosite residues was put forward.Based on the thermodynamics calculation and the research of the thermal decomposition process of jarosite residues,the process of reduction roasting self-sulfidation of jarosite residues were studied,in which the effects of roasting condition on the sulfurfidation degree of zinc,the fixation extent of sulfur and the change of the phase were investigated.The results show that the sulfidation extent of Zinc and the fixation extent of S reaches up to 93.47%and 87.69%,respectively,under the following optimum conditions,which the roasting temperature is 900℃,carbon powder addition is 18%,the amount of sodium carbonate is 5%,and the calcination time is 90 min.The roasting product mainly exists in the form of sulfide and can be separated by flotation.The reduction roasting of jarosite residues can achieve the comprehensive recovery of Zn and other valuable metals and avoid the emission of SO2 in the roasting process.This study is of great significance for the cleaning treatment of other heavy metal sulfates.