【摘要】：電鍍行業(yè)的蓬勃發(fā)展產(chǎn)生了大量的電鍍污泥,而其中含有許多有價金屬,必須對其回收利用。對電鍍污泥的處理方法通常為強酸浸出,這不僅浪費大量的化學(xué)試劑,提取缺乏選擇性,浸出液中雜質(zhì)金屬含量高,而且對設(shè)備腐蝕嚴(yán)重。為了選擇性提取電鍍污泥中的有價金屬,降低酸耗和后續(xù)除雜過程的處理量,本文首先通過氯化焙燒對電鍍污泥中金屬元素進行選擇性氯化,然后對焙燒料進行弱酸浸出,最后采取逐步分離除雜的方法對浸出液進行凈化處理,實現(xiàn)有價金屬的高效回收。在氯化焙燒熱力學(xué)分析基礎(chǔ)上,確立了以氯化銨為氯化劑對電鍍污泥進行焙燒處理。實驗結(jié)果表明:氯化劑與物料質(zhì)量比為0.8、焙燒溫度673K、焙燒時間60min、物料粒度200目,主金屬氯化效果最好。對氯化焙燒后的電鍍污泥進行弱酸浸出,實驗結(jié)果表明:鹽酸濃度1mol/L,反應(yīng)時間30min,反應(yīng)溫度318K,液固比4:1的情況下,鎳、銅的浸出率分別達(dá)到97.48%和87.65%,而鉻、鐵的浸出率只有45.07%、26.83%,符合電鍍污泥氯化焙燒的熱力學(xué)分析結(jié)果。通過對原料、浸出渣、氯化焙燒料進行XRD物相分析研究電鍍污泥的氯化機理,結(jié)果表明一定條件的氯化焙燒處理有利于電鍍污泥有價金屬弱酸的選擇性浸出。電鍍污泥氯化焙燒-弱酸浸出液中含有鎳、銅、鐵、鉻、鈣、鎂等金屬離子,為了得到氯化鎳溶液,必須進行分步除雜。首先采用鐵粉置換法除銅,實驗結(jié)果表明鐵粉用量是除銅理論量摩爾數(shù)1.2倍、反應(yīng)溫度60℃、反應(yīng)時間15min為最佳工藝條件,銅去除率為99.17%,鎳損失率為1.58%,除銅渣物相分析結(jié)果顯示只有銅的物相,基本無其他元素物相。其次采用高溫中和水解法除鐵,實驗結(jié)果表明終點p H值為3.5、反應(yīng)時間6h、反應(yīng)溫度95℃為最佳工藝條件,鐵去除率為98.59%,鎳損失率為2.84%。采用磷酸鹽對除鐵后溶液除鉻,實驗結(jié)果表明初始p H值為2、磷酸鈉用量為除鉻理論摩爾數(shù)0.5倍、反應(yīng)時間50min、反應(yīng)溫度80℃為最佳工藝條件,鉻去除率為97.08%、鎳損失率為3.81%。最后采用氟化銨除鈣鎂,實驗結(jié)果表明反應(yīng)p H值為5.5、氟化銨用量為除鈣鎂理論摩爾數(shù)1.6倍、反應(yīng)溫度應(yīng)95℃、反應(yīng)時間2.5h為最佳工藝條件,鈣鎂去除率分別為92.39%、93.12%,鎳損失率為2.39%,除鈣鎂沉淀渣物相分析表明只有氟化鈣物相,基本元素?zé)o其他物相。通過對電鍍污泥的氯化焙燒-弱酸浸出工藝研究,實現(xiàn)了有價金屬選擇性提取,達(dá)到了富集有價金屬鎳的目的,對高效處理電鍍污泥二次資源具有重要的意義。
[Abstract]:The rapid development of electroplating industry has produced a large amount of electroplating sludge, which contains many valuable metals, which must be recycled. Electroplating sludge is usually treated by strong acid leaching, which not only wastes a large number of chemical reagents, lacks selectivity in extraction, but also corrodes the equipment seriously because of the high content of impurity metal in the leaching solution. In order to selectively extract valuable metals from electroplating sludge and reduce acid consumption and the treatment capacity of subsequent impurity removal process, the selective chlorination of metal elements in electroplating sludge was carried out by chlorination roasting, and then the roasting material was leached by weak acid. Finally, the leaching solution was purified by stepwise separation and impurity removal to realize the efficient recovery of valuable metals. On the basis of thermodynamic analysis of chlorination roasting, ammonium chloride was used as chlorination agent to treat electroplating sludge. The results showed that the chlorination effect was the best when the mass ratio of chlorination agent to material was 0.8, the calcination temperature was 673K, the calcination time was 60 min, the particle size was 200 mesh. The electroplating sludge after chlorination roasting was leached with weak acid. The results showed that the leaching rate of nickel and copper reached 97.48% and 87.65%, respectively, and chromium was obtained when the concentration of hydrochloric acid was 1 mol / L, the reaction time was 30 min, the reaction temperature was 318K, and the liquid-solid ratio was 4:1. The leaching rate of iron is only 45.07 and 26.83, which is in accordance with the thermodynamic analysis results of electroplating sludge chlorination roasting. The chlorination mechanism of electroplating sludge was studied by XRD phase analysis of raw material, leaching slag and chlorination roasting material. The results showed that chlorination roasting under certain conditions was beneficial to selective leaching of valuable metal weak acid in electroplating sludge. Electroplating sludge chlorination roasting-weak acid leachate contains nickel, copper, iron, chromium, calcium, magnesium and other metal ions. In order to obtain nickel chloride solution, it is necessary to carry out step by step removal of impurities. Firstly, copper removal was carried out by using iron powder replacement method. The experimental results showed that the optimum technological conditions were the amount of iron powder being 1.2 times the theoretical amount of copper removal, the reaction temperature 60 鈩，

本文編號：2162082