磷酸盐类化合物重金属稳定化的机理与应用

Discussion on Phosphate Compounds Stabilization Mechanism for Heavy Metals and its Application

磷酸盐类化合物作为典型的重金属稳定化药剂,能够有效降低污染体系中重金属类污染物的毒性及生物危害性,稳定后的产物具有很高的地球化学稳定性。介绍了磷酸盐类化合物重金属稳定化的机理及实际应用,并认为:①磷酸盐类化合物可在一定的pH条件下与重金属反应并生成稳定的重金属矿物盐;②磷酸类矿物盐对它们的去除主要是表面吸附机理和络合反应;③某些金属阳离子可与羟基磷灰石晶格中的钙离子发生交换反应而进入晶格,形成含重金属的羟基磷灰石。磷酸盐类药剂在浙江省某矿山进行应用,对场地堆置中和渣进行了稳定化处理,重金属浸出结果满足《国家危险废物鉴别标准》(GB 5085.3—2007)。

As a kind of typical heavy metal stabilization agent,phosphate compounds can effectively reduce the toxicity of heavy metal pollutants and biological hazards and the final product is less toxic with high geochemical stability.This article describes the stabilization mechanism of the phosphate compounds used for heavy metals contaminants and related application.The results show that:①phosphate compounds can react with heavy metal under certain conditions of pH and produce stable compounds aftermath;②the removal of heavy metals by phosphate mineral salts is mainly based on surface adsorption and complexation mechanism of reaction;③some heavy metal ions can exchange with calcium ions inside hydroxyapatite crystal lattice to form new hydroxyapatite compounds containing heavy metals.A case study of phosphate treatment used in a mining site in Zhejiang province is also reported and the results show that final products meet the'National Hazardous Waste Identification Standard'(GB 5085.3—2007).