碳化沉淀法从中和渣浸出除杂液中分离回收锌和镁

Separation and recovery of zinc and magnesium in the leaching solution of neutralization residue by carbonization precipitation method

基于碳酸锌和碳酸镁溶度积的差异,本文开展了碳化沉淀法分离回收锌、镁的研究,在理论计算的基础上,借助电感耦合等离子体发射光谱仪(ICP-OES)、X射线衍射仪(XRD)等表征手段,考察了碳酸盐种类及用量、温度等因素对锌、镁分离效果的影响规律,查明了中和渣浸出除杂液中锌、镁分离的调控方法。理论计算表明,以碳酸盐作为沉淀剂时,锌优先沉淀,且在镁离子沉淀之前,锌已沉淀完全。实验结果表明,相对Na_(2)CO_(3)、NaHCO_(3)、NH_(4)HCO_(3)等碳酸盐,以MgCO_(3)为沉淀剂进行镁、锌分离的效果更佳。实验所得的较优工艺条件为反应温度90℃,碳酸镁过量系数1.20,反应时间90 min,加料速度2.10 g/min。在该条件下,锌沉淀率达99.99%以上,镁沉淀率低于0.10%,实现了镁、锌的有效分离。所得沉锌渣为碱式碳酸锌,纯度较高,可达到工业碱式碳酸锌合格品(HG/T 2523—93)的技术指标。该方法简单易行,锌、镁分离效果好,且锌、镁均可资源化利用。

Based on the difference in the solubility product of zinc carbonate and magnesium carbonate,a study on the separation and recovery of zinc and magnesium by carbonization precipitation method was proposed and conducted.On the basis of the theoretical calculations,the influence of the type,dosage,temperature and other factors of carbonate on the separation effect of zinc and magnesium was investigated and the control method for the separation of zinc and magnesium in the leaching solution of neutralization slag obtained with the help of an inductively coupled plasma emission spectrometer(ICP-OES),X-ray diffractometer(XRD)and other characterization methods.It is shown by theoretical calculations that when carbonate is used as the precipitant,zinc is preferentially precipitated and the zinc has been completely precipitated before the precipitation of magnesium ions.It is shown in the experimental results that the separation of magnesium and zinc with MgCO_(3) as a precipitant is better compared to carbonates such as Na_(2)CO_(3),NaHCO_(3),NH_(4)HCO_(3).The best process conditions obtained in the experiment are a reaction temperature of 90℃,the magnesium carbonate excess coefficient of 1.20,the reaction time of 90 min and the feeding speed of 2.10 g/min.Under these conditions,the zinc precipitation rate can reach over 99.99%and the magnesium precipitation rate is less than 0.10%,realizing the effective separation of magnesium and zinc.The obtained zinc slag is alkali zinc carbonate with high purity,reaching the technical index of industrial alkali zinc carbonate qualified product(HG/T2523—93).The method is simple and easy to implement,with a good separation effect of zinc and magnesium,which can both be utilized as resources.