低品位铜矿浸出液除铁及纳滤浓缩铜的研究

Iron removal and copper concentrate by nanofiltration for bioleaching solution of low grade copper mine

针对某铜矿湿法炼铜中目前生物浸出液Cu^2＋质量浓度低、Fe^3＋质量浓度高导致后续萃取和电积效率降低的问题,采用中和水解法及超滤、纳滤处理工艺对其生物浸出液进行除铁和铜富集。通过实验考察除铁温度和p H对铜损率、除铁率、纳滤操作压力、温度以及浓缩倍数对膜通量和铜离子截留率的影响。研究结果表明：中和水解除铁最佳条件是温度为30℃,p H为3.0-3.2;纳滤较佳操作条件是运行压力为15×10^5 Pa,温度为30℃,流量为18 L/min;在此条件下,对某铜矿堆浸厂生物浸出液进行中和水解除铁和超滤、纳滤处理后,Cu^2＋质量浓度由187 mg/L提高到542 mg/L,铜铁质量浓度比由原来的1：4提高到1：1;该工艺具有操作简单、能耗低、环保等优点,对于湿法炼铜中减少萃取乳化现象及提高电积效率均有重要意义。

Due to low mass concentration of copper and high mass concentration of iron in the bioleaching solution that decrease the efficiencies of solution extraction and electrowinning during copper hydrometallurgy in a copper mine, iron removal and copper enrichment on bioleaching solution of the copper mine were carried out by neutralizing hydrolysis, ultrafiltration and nanofiltration. The effects of temperature and p H on copper loss rate and iron removal rate as well as effects of nanofiltration operating pressure, temperature and concentration times on flux and rejection rate of Cu^2＋ were studied. The results show that the optimum conditions of iron removal include temperature 30 ℃, p H between 3.0 and 3.2 and the optimum conditions of nanofiltration include pressure 15×10^5 Pa, temperature 30 ℃, flow rate 18 L/min. After treatment on bioleaching solution in a copper heap leaching plant under these conditions, the mass concentration of Cu^2＋ is enhanced from 187 mg/L to 542 mg/L with the ratio of mass concentration of copper and iron increases from 1：4 to 1：1.The process of operating simplicity, low energy consumption and environmental protection have great significance on reducing emulsifications in solution extraction and enhancing efficiency of electrowinning.