發(fā)布時間：2018-01-31 03:51

  本文關鍵詞： 污酸 硫化沉淀法除砷 氟 氯　出處：《昆明理工大學》2015年碩士論文　論文類型：學位論文

【摘要】：重有色金屬冶金在現(xiàn)代工業(yè)中占有重要地位,而污酸是重有色金屬冶煉廠產生的主要污染物之一。其中重有色冶煉廠所產的污酸中砷及重金屬雜質含量較高,污酸酸度較低,難以直接循環(huán)利用。傳統(tǒng)直接中和的污酸處理方法,不僅不能使污酸達標排放,而且會產生大量含砷及重金屬的硫酸鈣渣,造成了嚴重的環(huán)境污染并占用了大面積的土地。因此污酸的除雜和再生循環(huán)的利用是冶金行業(yè)的難題之一。鑒于此,本課題針對高砷污酸的處理方法進行探索研究,結合理論分析開發(fā)出了新的污酸凈化工藝：第一種方法,硫化沉淀法除砷-濃縮法除氟氯；第二種方法,硫化沉淀法除砷-亞銅鹽法除氯-電解沉積除殘余銅。硫化沉淀法除砷-濃縮除氟氯工藝不僅可使污酸溶液達到較好的除雜效果,還解決了大量渣堆積和廢酸循環(huán)利用問題。本課題主要研究了硫化沉淀法除砷-濃縮除氟氯過程,得到較高濃度的硫酸。首先,對已有的硫化除砷方法進行改進,在除去污酸中大部分砷的同時,也把銅、鉛、鎘等雜質除至較低濃度。針對酸度為183.2g/L、砷含量為4.281g/L的實驗污酸溶液進行條件試驗,確定了最佳工藝條件為：硫化鈉用量為理論除砷用量的2倍,反應溫度為55℃,反應時間為20min,該條件處理后的實驗污酸砷含量降至l00mg/L、鉛12mg/L、銅含量和鎘含量為0mg/L,酸度降低至153.02g/L;其次,由于采用硫化鈉除砷及重金屬過程存在著會使溶液中殘留大量的鈉離子雜質和酸度降低的問題,所以將硫化鈉除砷改進為硫化氫除砷,并對此實驗設備及工藝做了初步的探究,硫化氫除砷可將溶液中的砷除到20mg/L以下；最后,對除砷后液進行蒸發(fā)濃縮除氟氯,通過實驗驗證證實污酸中的F、C1離子以HF、HCl的形態(tài)與蒸發(fā)出的水蒸氣結合揮發(fā)出溶液,氟氯的去除率達到98%以上,而溶液的含酸量可達60%以上。污酸通過上述方法進行處理后,得到了可以使污酸循環(huán)利用的簡易工藝。但上述方法有能耗高、設備易腐蝕等缺點。為了解決上述方法殘存問題,需探索另一種實驗方法,初步探索試驗為：首先,除砷過程與硫化沉淀法除砷-濃縮除氟氯過程相同,除砷后液用亞銅鹽法除氯。針對污酸的除砷后液進行條件試驗,由此確定亞銅鹽法除氯最佳工藝條件為：銅粉為理論除氯用量的1.6倍,硫酸銅用量為理論除除氯用量的1.4倍,反應溫度為55℃,反應時間為1h,該條件處理后的除砷后液可將氯離子除到100mg/L以下,除氯率達到98%以上；其次,借鑒成熟的電解沉積工藝參數(shù)對殘余銅離子的除氯后液進行電解沉積除銅,實驗的電流效率達到92%以上,除銅率達到97%。本研究所提出的硫化沉淀法除砷-濃縮除氟氯工藝,實現(xiàn)了體系閉路循環(huán),無“三廢”產生,成功實現(xiàn)了污酸的凈化,具有較好工業(yè)應用前景。
[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，

本文編號：1478115