砷污染治理及砷资源回收利用的清洁生产新技术研究

【作者】 牛秋雅；

【导师】 陈维平；

【作者基本信息】 湖南大学 ， 环境工程， 2001， 硕士

【摘要】 含砷废水和含砷尾矿是砷污染的两个重要来源，也是治理砷污染和回收利用砷资源的两个重要切入点。论文分析比较了砷污染治理和砷资源回收利用的相关技术，在此基础上研究开发了两种既能防治砷污染，同时又能回收利用砷资源的清洁生产新技术。 大量砷硫尾矿堆置造成砷污染和砷资源浪费。而现有的砷硫矿提炼、富集、加工利用技术，或工艺过程环境污染严重；或对于加工尾矿在经济上不合理；或产品纯度低，主含量达不到药用要求；或不能加工利用相对低品位的尾矿；或处理量有限，难以实现规模化工业生产。论文提出了“浮选—化学除杂—粉末冶金方法制块”利用雄（雌）黄尾矿制备块状药用雄（雌）黄的新工艺流程，并对其关键工艺“化学除杂”和“粉末冶金方法制块”进行了试验研究，制得了结构较致密、符合药用要求的块状雄（雌）黄，且制备过程无污染。该工艺流程具有砷资源利用率高、产品质量好、生产成本低、环境效益好等明显优点。从而实现了消除砷硫尾矿堆置造成的砷污染和避免砷资源浪费的目的。 现有的废水除砷方法，大多只考虑除砷的净化程度，没有考虑砷与其它元素的分离，形成的含砷废渣不能利用，易于造成二次砷污染和砷资源浪费。论文在对As₂S₃-H₂O系进行热力学分析的基础上，从理论上探讨了应用硫化沉淀法实现高选择性除砷的可行性；并以一种特殊的含砷溶液“铟冶金浸出液”为研究对象，试验研究了选择性硫化沉砷的工艺条件。理论分析及试验结果表明，工艺条件的控制，特别是酸度的调节是实现高选择性硫化沉砷的关键；在较佳的工艺条件下，砷去除率达99.1％；且除砷废渣纯度高（主要成分As₂S₃质量分数达95.40％），易于利用。从而避免了剧毒污染物AsH₃的产生和除砷渣堆置造成的二次砷污染，且回收了砷资源。该技术对于其它工业废水的除砷具有借鉴意义。 以砷污染防治为目标的清洁生产工艺流程和以砷资源回收利用为目标的清洁生产工艺流程主要工艺过程包括：含砷废水（液）的选择性硫化沉淀、含砷尾矿（除砷废渣）的综合利用、砷硫尾矿的浮选富集、浮选粉末的化学除杂、以及利用除杂后的粉末通过粉末冶金方法制备块状药用雄（雌）黄。应用上述工艺流程，既可以实现防治砷污染的目的，又可以实现回收利用砷资源的目的。且工艺过程基本实现了清洁生产。更多还原

【Abstract】 Arsenic-containing waste water and tailings are two main origins of arsenic pollution and also two important starting points of both treating arsenic pollution and recovering arsenic resource. In this paper, the relative technologies about the treatment of arsenic pollution and the recovery of arsenic resources were analyzed and compared, and based on which two new types of cleaner technologies for both preventing arsenic pollution and recovering arsenic resources were studied and exploited.The piling-up of As-S tailings resulted in arsenic pollution and arsenic resource waste, while the existing technologies for refining, enriching, or utilizing it are with the disadvantages that it can result in serious pollution, or it is uneconomical for utilizing tailings, or the product is with a low purity which can not meet with the medicinal requirements, or it can not utilize the tailings with low main content, or the processing quantity is limited which make it.difficult to realize large-scale production. In this paper, a new process flow "floating -eliminating impurity by chemical method-preparing block by powder metallurgical method "for preparing blocky medicinal realgar (orpiment) from the tailings was put forward; Furthermore, the key process " eliminating impurity by chemical method and preparing block by powder metallurgical method " were studied by experiments in which the compact blocky medicinal realgar (orpiment) were got while it bring about little pollution. The new process flo%v hold obvious advantages that it is with higher resources-utilizing ratio, better product quality, lower production cost, and higher benefit on environment, so that by applying such process, the objective of eliminating the arsenic pollution and avoiding the arsenic resources waste resulted by As-S tailings piling -up were achieved.Most of the existing methods for eliminating arsenic from waste water focus on the purifying efficiency, not on the separation of arsenic from the other elements, which make the dregs can’t be utilized, so that the methods tend to result in secondary pollution and resources waste. In this paper, based on the thermod>Tiamic analysis on As:S3-H:0 system, the feasibility of realizing selective arsenic removal by sulfurizaton-precipitation was theoreticallystudied; Furthermore, the process conditions for eliminating arsenic from a specific arsenic-containing solution "indium metallurgical solution" were studied through experiments. The results of both the theoretical analysis and the experiments indicate that the controlling of process conditions, especially the adjustment of acidity, is the key for realizing selective arsenic removal; that on better process conditions, the arsenic removal ratio can be up to 99.1%, and the purity of the arsenic -removal dreg is high with main content As;S3 mass fraction 95.4%, which make the dreg is liable to be utilized. Consequent!}’, the objectives of avoiding the generation of virulent pollutant AsH3, eliminating the secondary arsenic pollution resulted by the dreg piling-up, and recovering arsenic resources were achieved. The technology is instructive to the arsenic removal of other industrial wastewater.The main parts of the cleaner production process flow for preventing arsenic pollution and recovering arsenic resources are as follows: the selective sulfurization-precipitation of arsenic-containing waste water (solution), the comprehensive utilization of arsenic-containing tailings (arsenic removal dregs), the enrichment of As-S tailings by floatation, the purifying of the powder obtained by floatation, preparing blocky medicinal realgar (orpiment) from the purified powder by powder metallurgical methods. By applying such process flow, the objective of both preventing arsenic pollution and recovering arsenic resources can be realized. Moreover, the cleaner production can be realized.更多还原