铅锌冶炼废水脱钙软化工程设计  

Design of decalcification and softening engineering for lead-zinc smelting wastewater

作　　者：夏传 卢丽 李绪忠[1] 王杰 XIA Chuan;LU Li;LI Xuzhong;WANG Jie(CINF Engineering Co.,Ltd.,Changsha 410019,China;CHINALCO Environmental Protection and Energy Conservation Technology(Hunan)Co.,Ltd.,Changsha 410014,China)

机构地区：[1]长沙有色冶金设计研究院有限公司,湖南长沙410019 [2]中铝环保节能科技(湖南)有限公司,湖南长沙410014

出　　处：《工业水处理》2022年第8期170-173,共4页Industrial Water Treatment

基　　金：国家重点研发计划(2018YFC1901606);中铝环保节能科技(湖南)有限公司科研(业务)建设项目。

摘　　要：以云南某铅锌冶炼厂废水脱钙软化工程为例,分别从废水特点、工艺流程、设计参数及运行效果等方面阐述了CO_(2)+NaOH的脱钙软化工艺。高盐高硬度的铅锌冶炼废水经调节池均质均量后,加压输送至溶气罐,同时从顶部通入CO_(2)气体,形成溶气水并进入反应槽降压释放,同步投加NaOH溶液以维持反应pH,控制溶气压力为0.3~0.5 MPa、反应槽pH为10.5,实现废水的脱钙软化。软化废水经絮凝沉淀、过滤澄清及硫酸回调pH后,直接回用或深度处理后回用。加压溶气形成的CO_(2)饱和溶气水可提高溶气效率并节约CO_(2)用量,生成的碳酸钙渣返回原废水处理站用作中和剂,不产生固废。系统产水水质可达到设计要求,进水总硬度为993~1062 mg/L时,出水总硬度为40~100 mg/L,去除率达到90%~96%。该工程投入使用以来运行稳定,扣减收益后运行费用为4.89元/m3,可为铅锌冶炼废水的脱钙软化提供一种有效方案,解决废水浓缩结垢问题。Taking a wastewater decalcification and softening project of a lead-zinc smelting plant in Yunnan as an example,the decalcification and softening process of CO_(2)+NaOH was described in terms of wastewater characteristics,process flow,design parameters and operation effect,respectively.The lead-zinc smelting wastewater with high salt and high hardness was homogenized in regulating tank,and then transported to the dissolving-air tank under pressure,while CO_(2) gas was injected from the top to form dissolved water and released into reaction tank for release.NaOH solution was added synchronously to maintain the reaction pH.The dissolved gas pressure was controlled to be 0.3-0.5 MPa,pH of the reaction tank was 10.5 to realize the decalcification and softening of the wastewater.The softened wastewater was reused directly or deeply treated after flocculation and precipitation,filtration and clarification and pH adjustment by sulfuric acid.CO_(2) saturated dissolved gas water formed by pressurized dissolved-CO_(2) improved the efficiency of gas dissolution and save CO_(2) dosage.The generated calcium carbonate slag was returned to original wastewater treatment station as neutralizer without generating solid waste.The water quality of the system met the design requirements.When the total hardness of influent water was 993-1062 mg/L,the total hardness of effluent water was 40-100 mg/L,with a removal rate of 90%-96%.The project has been operating stably since it was put into operation.The operating cost was RMB 4.89/m3 after deducting the revenue,which could provide an effective solution for the decalcification and softening of lead and zinc smelting wastewater,and solve the problem of wastewater concentration and scaling.

关 键 词：铅锌冶炼废水 脱钙软化 加压溶气 

分 类 号：X703[环境科学与工程—环境工程] TU992.3[建筑科学—市政工程]