用氢氧化铝处理浮选循环水同时脱除钙离子和硫酸根离子

Comparative study on simultaneous removal of calcium and sulfate ions from flotation recycling water by aluminum hydroxide

由于环境政策和经济因素,复杂硫化物矿的一些浮选作业用水循环使用,导致某些离子的浓度逐渐升高,影响到相关矿物的浮选。在此背景下,对含有高浓度钙和硫酸盐离子的合成溶液的处理进行实验研究和热力学分析。重点评估两种铝化合物对于Ca^(2+)和SO_(4)^(2-)以钙矾石形式析出过程的作用。结果发现,非晶态氢氧化铝比晶态氢氧化铝更为有效,可脱除高达83%的钙和91%的硫酸盐。对所得固体样品的XRD分析表明,因为吸收了大气中的二氧化碳,主要反应产物为钙矾石,伴随着少量的方解石。化学处理后的最终溶液中残留钙和硫酸盐的浓度低于200 mg/L。动力学研究发现,钙脱除过程对于钙浓度为二级反应,表观活化能为53.48 kJ/mol,表明钙矾石析出过程可能受化学反应控制。

Due to the environmental policies and economic reasons,the water used in some flotation operations of complex sulfide ores is recirculated,causing the ion concentration of some species to increase over time,affecting the flotation of the minerals of interest.In this work,an experimental and thermodynamic analysis of the synthetic solutions was presented with a high content of calcium and sulfate ions.The study focused on evaluating the use of two aluminum compounds for the precipitation of Ca^(2+)and SO_(4)^(2−)in the form of ettringite.The amorphous aluminum hydroxide was found to be more efficient than the crystalline one,giving rise to 83%calcium and 91%sulfate removal.The XRD analysis of the solids showed the main reaction product of ettringite,accompanied by small amounts of calcite,due to the absorption of atmospheric carbon dioxide.The final solution after the chemical treatment showed residual calcium and sulfate concentrations below 200 mg/L.Finally,the kinetics of calcium removal appeared to correspond to a second order reaction with respect to calcium concentration,with an apparent activation energy of 53.48 kJ/mol,which may suggest that the ettringite precipitation process is governed by the chemical reaction.