机械力化学法制备高岭石/碳酸盐复合材料及其抑制黄铁矿氧化的研究

Preparation of Kaolinite and Carbonate Composites by Mechanochemical Method and Its Inhibition of Pyrite Oxidation

黄铁矿氧化产生的酸性矿山废水引起的矿山环境问题一直是环境治理领域的难题,从源头控制黄铁矿氧化是治理酸性矿山废水的根本途径。以廉价黏土矿物和碳酸盐为原料,采用机械力化学法制备复合材料,实现了对黄铁矿氧化的高效钝化抑制。研究结果表明,以高岭石和碳酸钙为原料,两者摩尔比为1∶2,经转速为600 r/min球磨1 h后获得的钝化材料对黄铁矿的氧化抑制效果最佳,14 d后溶液pH值稳定在7以上,且SO_(4)^(2−)质量浓度仅为600 mg/L。研磨过程使高岭石晶体结构被破坏并趋于无序化,碳酸盐结合到高岭石中发生固相合成反应,生成非晶态物质。钝化材料溶解释放的硅、铝等活性组分与黄铁矿表面的氢氧化铁层结合形成稳定钝化层,阻止黄铁矿与氧气和水分接触,从而抑制黄铁矿的化学氧化。本研究制备工艺简单环保、原料廉价易得、钝化材料无环境污染风险,为酸性矿山废水的源头治理提供了新的研究思路。

The environmental problems of mines caused by acidic mine drainage from pyrite oxidation have been a challenge in the field of environmental management,controlling pyrite oxidation is the primary way to treat acid mine drainage at its source.The composite material prepared by mechanochemical method with cheap clay minerals and carbonate as raw materials realized efficient passivating inhibition of pyrite oxidation.The results showed that the passivation material prepared by ball milling with the molar ratio of kaolinite to calcium carbonate at 1∶2 and rotating speed at 600 r/min for 1 h significantly inhibited the oxidation of pyrite.After 14 days,the pH value was stable above 7 and the SO_(4)^(2−) concentration was only 600 mg/L.The crystal structure of kaolinite was destroyed and disordered by mechanochemical process,and the carbonate was combined with kaolinite to form amorphous substance.The active components such as silicon and aluminum released from the passivation material combined with the iron hydroxide layer on the pyrite surface to form a stable passivation layer,which can prevent the pyrite from contacting with oxygen and water,thus inhibiting the chemical oxidation of pyrite.The preparation process is simple and environmentally friendly,the raw materials are cheap and easy to obtain,and the passivation materials have no risk of environmental pollution.providing a new idea for the source treatment of acid mine drainage.