摘要：

为降低闭坑煤矿老窑水对水环境的危害，开展钙矾石〔Ca₆［Al（OH）₆］₂（SO₄）₃·26H₂O〕沉淀法去除老窑水中高浓度SO₄ ^2-、Fe³⁺和Mn²⁺的工艺优化研究。采用单因素实验系统分析了初始pH、n（Al³⁺）/n（SO₄ ^2-）和n（Ca²⁺）/n（SO₄ ^2-）对SO₄ ^2-去除效果及Ca²⁺和Al³⁺残留质量浓度的影响，结果表明，当初始pH=11.5，n（Al³⁺）/n（SO₄ ^2-）=0.8，n（Ca²⁺）/n（SO₄ ^2-）=1.5，反应时间为1 h时，SO₄ ^2-去除率达到最大（81.85%），Fe³⁺、Mn²⁺去除率均保持较高水平，Ca²⁺和Al³⁺平均残留质量浓度分别为18.05 mg/L和29.96 mg/L。采用Box-Behnken响应面法对工艺条件进行优化，结果显示最优工艺条件为初始pH=11.557，n（Al³⁺）/n（SO₄ ^2-）=0.858，n（Ca²⁺）/n（SO₄ ^2-）=1.705，此条件下SO₄ ^2-实际去除率为85.470%，Al³⁺、Ca²⁺平均残留质量浓度分别为2.32 mg/L和29.64 mg/L，二次污染低。

关键词: 闭坑煤矿, 老窑水, 钙矾石, 硫酸根去除, 响应面

Abstract:

In order to reduce the harm of old kiln water in closed pit coalmine, an optimization study on the removal conditions of high concentration SO₄ ^2-, Fe³⁺ and Mn²⁺ in the old kiln water by sedimentation method of ettringite〔Ca₆[Al(OH)₆]₂(SO₄)₃·26H₂O〕 was carried out. The effects of initial pH, n(Al³⁺)/n(SO₄ ^2-), n(Ca²⁺)/n(SO₄ ^2-) on SO₄ ^2- removal and the residues of Ca²⁺ and Al³⁺ were systematically analyzed by single factor test. The results showed that, under the conditions of initial pH=11.5, n(Al³⁺)/n(SO₄ ^2-)=0.8, n(Ca²⁺)/n(SO₄ ^2-)=1.5, reaction time of 1 h, the SO₄ ^2- removal rate reached the highest of 81.85%, the romoval rates of Fe³⁺ and Mn²⁺ remained at a high level, and the residual concentrations of Ca²⁺ and Al³⁺ were 18.05 mg/L and 29.96 mg/L, respectively. The Box-Behnken response surface method was used to optimize the process conditions. The model showed that the optimal process conditions were initial pH=11.557, n(Al³⁺)/n(SO₄ ^2-)=0.858 and n(Ca²⁺)/n(SO₄ ^2-)=1.705. Under these conditions, the actual removal rate of SO₄ ^2- was 85.470%. Meanwhile,the average residual concentration of Al³⁺ and Ca²⁺ was 2.32 mg/L and 29.64 mg/L, respectively.

Key words: closed pit coal mine, old kiln water, ettringite, sulfate removal, response surface

中图分类号: 

• X523