复杂微生物浸出液生物成矾法净化除铁的研究

针对低品位矿石生物浸出液中铁含量高而有价金属含量低的特点,研究低温、低pH条件下微生物成矾除铁方法,考察了温度、pH值、菌液接种量、时间等主要因素对微生物氧化及铁矾形成的影响规律,并采用正交实验对微生物成矾除铁规律进行多因素影响分析。结果表明:在生物氧化过程中,亚铁含量为9.46 g·L-1的料液,在pH范围为1.4～2.0,温度范围为30～40℃时,36 h细菌将亚铁氧化完全,细菌氧化亚铁的效果较好;在生物成矾除铁过程中,当pH为2,温度为45℃,菌液接种量为15%,反应时间为10 d时,除铁率达到99.97%,除铁后料液含铁0.015 g·L-1;通过正交实验,确定了影响生物成矾法除铁的主次因素顺序分别为反应时间、接种量、总铁浓度,最优水平组合为:总铁浓度50 g·L-1,接种量20%,反应时间10 d,在此最优组合条件下,沉淀除铁率高达99.95%,实现了低温、低pH条件下微生物成矾除铁,为微生物浸出液的低成本、高效净化除铁提供了一条新途径。

Iron Purification by Formation of Jarosite in Complex Bioleaching Solution

The characteristic of bioleaching solution with high concentration of Fe and low concentration of valuable metals,the separation of Fe by the formation of jarosite with bacteria at low temperature and low pH were studied.The factors,such as pH,temperature,inoculate quantity and time,which affected the separation of Fe from solvent system consisting of sulphate were investigated.And the factors that affected the formation of jarosite were studied by the orthogonal test.The experimental results showed that,in the biological oxidation process,for the solution containing ferrous Fe 9.46 g · L-1,in the pH range of 1.4~2.0,temperature range of 30~40 ℃,the oxidation of ferrous iron by bacteria was completed after 36 h,and the effect of bacterial oxidation of ferrous iron was better.In the process of iron removal by the formation of jarosite with bacteria,at pH of 2,temperature of 45 ℃,inoculate quantity of 15%,time of 10 d,the iron removal rate was 99.97% with low residual iron concentration of 0.015 g · L-1.Through orthogonal test,the primary and secondary factors that effected the jarosite precipitation were confirmed as time,inoculate quantity and the concentration of iron.The optimal combination of factors was total Fe concentration of 50 g · L-1,inoculate quantity of 20%,time of 10 d.With these optimal factors,the iron removal rate was 99.95%.It was realized to remove iron by biological purification under the conditions of low temperature and low pH values,providing a new way to purify complex biological leaching solution.