铁矾渣微波硫酸化焙烧水浸液的深度除铁

Deep removal of iron from jarosite residue after acid mixing,microwave roasting and water leaching

采用微波低温硫酸化焙烧-水浸和针铁矿除铁方法将Zn、Cu等富集到浸出液中,Pb和Ag富集到浸出渣中,使有价金属得到清洁的回收利用.研究了上述工艺中浸出液除铁的优化工艺条件,探究了反应体系的p H值、浸出液单次滴加量、浸出液的铁含量等因素对除铁效果的影响,并采用X射线衍射分析、扫描电子显微镜观察等手段对得到的沉淀渣进行了表征.研究获得的优化实验条件为:以200 m L的0.01 mol·L-1Zn SO4溶液为底液,晶种添加量为20 g·L-1,除铁体系p H值控制在3左右,温度90℃,每隔5 min滴加3 m L水浸液(保持反应体系中铁的浓度<1 g·L-1).在此条件下,除铁后溶液残铁量仅为0.065 g·L-1,去除率可达99.3%,达到了深度除铁效果.除铁过程中,Zn的损失率仅为4.1%.

A method combining microwave sulphation low-temperature roasting-water immersion and goethite processes was used to gain clean and valuable metals, such as Zn and Cu enriching to the leach liquor and Pb and Ag enriching to the leach residue. The process conditions to remove iron by using water immersion were optimized, and the iron removal effect was investigated when the pH value, the added amount of the leach liquor every time and the iron concentration in the leach liquor changed. X-ray diffraction and scanning electron microscopy were used to characterize the iron precipitates. It is found that with 200 mL of 0. 01 mol·L^-1 ZnSO4 solu-tion as a base solution, the iron removal rate can be reach to 99. 3% and the residual iron concentration in the solution is about 0. 065 g·L^-1 under the optimum conditions that the dosage of the goethite crystal seed is 20 g·L^-1 , the pH value is 3, the temperature is 90℃ and 3 mL leach solution is added per 5 min （ to keep the iron concentration in the solution 〈1 g·L^-1 ） . In the iron removal process, the loss rate of Zn is only 4. 1%.