【作者】 殷皓； 石瑶； 芦柏年； 王琳玲； 陈静； 娄伟； 卢琦；

【Author】 Yin Hao;Shi Yao;Lu Bonian;Wang Linling;Chen Jing;Lou Wei;Lu Qi;School of Environmental Science and Engineering,Huazhong University of Science and Technology;Hunan Provincial Engineering Research Center for Resource Recovery and Safe Disposal of Industrial Solid Waste Hunan Heqing Environmental Technology Co.,Ltd.;Daye branch of Huangshi Ecological Environment Bureau;

【机构】 华中科技大学环境科学与工程学院； 湖南省工业固废资源化与安全处置工程技术研发中心湖南省和清环境科技有限公司； 黄石市生态环境局大冶市分局；

【摘要】 硫酸厂生产过程中产生的含砷（As）污泥中As浸出毒性高,属于危险废弃物。现常用钙系材料提供Ca源稳定As后进行安全填埋,但由于污泥中三价砷（As（Ⅲ））与Ca反应生成的Ca-As（Ⅲ）的溶解度较高,导致As（Ⅲ）含量较高的污泥在稳定化处理后As的浸出浓度仍难以满足GB 18598—2019《危险废物填埋污染控制标准》的限值（1.2 mg/L）。本研究以电石渣（主要成分为Ca（OH）₂）为稳定化药剂,以漂白粉为氧化剂,以期将As（Ⅲ）氧化为As（Ⅴ）并与Ca形成稳定的Ca-As（Ⅴ）沉淀,实现污泥中As的稳定化。研究结果表明,当污泥中As（Ⅴ）浸出率超过69.1%时,单独添加电石渣即可通过形成CaHAsO₄·2H₂O等Ca-As（Ⅴ）沉淀使As浸出浓度最低降至1.15 mg/L;当污泥中As（Ⅲ）浸出率超过65.8%时,先添加适量漂白粉,将As（Ⅲ）氧化成As（Ⅴ）后,再添加电石渣通过形成CaHAsO₄·H₂O等Ca-As（Ⅴ）沉淀使As浸出浓度最低降至0.89 mg/L,达到（GB 18598—2019）《危险废物填埋污染控制标准》的限值标准,实现了含砷污泥的安全无害化处置。更多还原

【Abstract】 The arsenic-containing sludge produced in the production process of a sulphuric acid plant has high leaching toxicity and belongs to hazardous waste.Commonly used calcium materials provide Ca source to stabilize As for safe landfill.However,due to the high solubility of Ca-As（Ⅲ） generated by the reaction of As（Ⅲ） with Ca in sludge,the leaching concentration of As in sludge with high As（Ⅲ） content after stabilization treatment was still difficult to meet the limit value（1.2 mg/L） of the Hazardous Waste Landfill Pollution Control Standard（GB 18598—2019）.In this research,calcium carbide slag（main composed of Ca（OH）₂） was used as stabilizing agent,and bleaching powder was used as oxidant to oxidize As（Ⅲ） to As（Ⅴ） and form a stable Ca-As（Ⅴ） precipitation with Ca to realize the stabilization of As in sludge.The results showed that when the leaching rate of As（V） in sludge exceeded 69.1%,adding carbide slag alone could reduce the leaching concentration of As to 1.15 mg/L by forming Ca-As（Ⅴ） precipitation such as CaHAsO₄·2H₂O;when the leaching rate of As（Ⅲ） in sludge exceeded 65.8%,an appropriate amount of bleaching powder was added first,and As（Ⅲ） was oxidized to As（Ⅴ）.Then calcium carbide slag was added to form Ca-As（Ⅴ） precipitation such as CaHAsO₄·H₂O,so that the leaching concentration of As was reduced to 0.89 mg/L,reaching the limit standard of Hazardous Waste Landfill Pollution Control Standard（GB 18598—2019）,and the safe and harmless disposal of arsenic-containing sludge was realized.更多还原