重有色金属冶炼厂污酸处理工艺研究

发布时间：2018-01-31 03:51

  本文关键词： 污酸 硫化沉淀法除砷 氟 氯　出处：《昆明理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：重有色金属冶金在现代工业中占有重要地位,而污酸是重有色金属冶炼厂产生的主要污染物之一。其中重有色冶炼厂所产的污酸中砷及重金属杂质含量较高,污酸酸度较低,难以直接循环利用。传统直接中和的污酸处理方法,不仅不能使污酸达标排放,而且会产生大量含砷及重金属的硫酸钙渣,造成了严重的环境污染并占用了大面积的土地。因此污酸的除杂和再生循环的利用是冶金行业的难题之一。鉴于此,本课题针对高砷污酸的处理方法进行探索研究,结合理论分析开发出了新的污酸净化工艺：第一种方法,硫化沉淀法除砷-浓缩法除氟氯；第二种方法,硫化沉淀法除砷-亚铜盐法除氯-电解沉积除残余铜。硫化沉淀法除砷-浓缩除氟氯工艺不仅可使污酸溶液达到较好的除杂效果,还解决了大量渣堆积和废酸循环利用问题。本课题主要研究了硫化沉淀法除砷-浓缩除氟氯过程,得到较高浓度的硫酸。首先,对已有的硫化除砷方法进行改进,在除去污酸中大部分砷的同时,也把铜、铅、镉等杂质除至较低浓度。针对酸度为183.2g/L、砷含量为4.281g/L的实验污酸溶液进行条件试验,确定了最佳工艺条件为：硫化钠用量为理论除砷用量的2倍,反应温度为55℃,反应时间为20min,该条件处理后的实验污酸砷含量降至l00mg/L、铅12mg/L、铜含量和镉含量为0mg/L,酸度降低至153.02g/L;其次,由于采用硫化钠除砷及重金属过程存在着会使溶液中残留大量的钠离子杂质和酸度降低的问题,所以将硫化钠除砷改进为硫化氢除砷,并对此实验设备及工艺做了初步的探究,硫化氢除砷可将溶液中的砷除到20mg/L以下；最后,对除砷后液进行蒸发浓缩除氟氯,通过实验验证证实污酸中的F、C1离子以HF、HCl的形态与蒸发出的水蒸气结合挥发出溶液,氟氯的去除率达到98%以上,而溶液的含酸量可达60%以上。污酸通过上述方法进行处理后,得到了可以使污酸循环利用的简易工艺。但上述方法有能耗高、设备易腐蚀等缺点。为了解决上述方法残存问题,需探索另一种实验方法,初步探索试验为：首先,除砷过程与硫化沉淀法除砷-浓缩除氟氯过程相同,除砷后液用亚铜盐法除氯。针对污酸的除砷后液进行条件试验,由此确定亚铜盐法除氯最佳工艺条件为：铜粉为理论除氯用量的1.6倍,硫酸铜用量为理论除除氯用量的1.4倍,反应温度为55℃,反应时间为1h,该条件处理后的除砷后液可将氯离子除到100mg/L以下,除氯率达到98%以上；其次,借鉴成熟的电解沉积工艺参数对残余铜离子的除氯后液进行电解沉积除铜,实验的电流效率达到92%以上,除铜率达到97%。本研究所提出的硫化沉淀法除砷-浓缩除氟氯工艺,实现了体系闭路循环,无“三废”产生,成功实现了污酸的净化,具有较好工业应用前景。
[Abstract]:Heavy non-ferrous metals metallurgy plays an important role in modern industry, and sewage acid is one of the main pollutants produced by heavy non-ferrous metal smelters, in which the heavy non-ferrous metals smelters produce high arsenic and heavy metal impurities. Sewage acid degree is low and it is difficult to recycle directly. The traditional direct neutralization method not only can not make the waste acid discharge, but also produce a large amount of arsenic and heavy metal calcium sulfate slag. It has caused serious environmental pollution and occupied a large area of land. Therefore, the removal of pollutants and the utilization of recycling is one of the problems in metallurgical industry. In this paper, the treatment method of high arsenic polluted acid is explored and studied, and a new purification process of polluted acid is developed based on theoretical analysis: first, defluorination and chlorine removal by sulfide precipitation method; The second method is to remove residual copper by sulfurization precipitation method with cuprous salt method and electrolytic deposition method. The process of removing arsenic and concentrated fluoride and chlorine by sulfide precipitation method can not only make the polluted acid solution achieve better impurity removal effect. The problems of residue accumulation and recycling of waste acid were also solved. The process of arsenic removal and concentrated defluorination by sulphide precipitation was studied to obtain high concentration of sulfuric acid. The existing sulphide arsenic removal method has been improved. In addition to removing most of arsenic in the polluted acid, impurities such as copper, lead and cadmium are also removed to a lower concentration. The acidity is 183.2 g / L. The optimum technological conditions were determined as follows: the amount of sodium sulfide was twice as much as the theoretical amount of arsenic removal, and the reaction temperature was 55 鈩，

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