氯盐体系电镀污泥中有价金属选择性提取工艺研究

发布时间：2018-08-03 14:47

【摘要】：电镀行业的蓬勃发展产生了大量的电镀污泥,而其中含有许多有价金属,必须对其回收利用。对电镀污泥的处理方法通常为强酸浸出,这不仅浪费大量的化学试剂,提取缺乏选择性,浸出液中杂质金属含量高,而且对设备腐蚀严重。为了选择性提取电镀污泥中的有价金属,降低酸耗和后续除杂过程的处理量,本文首先通过氯化焙烧对电镀污泥中金属元素进行选择性氯化,然后对焙烧料进行弱酸浸出,最后采取逐步分离除杂的方法对浸出液进行净化处理,实现有价金属的高效回收。在氯化焙烧热力学分析基础上,确立了以氯化铵为氯化剂对电镀污泥进行焙烧处理。实验结果表明:氯化剂与物料质量比为0.8、焙烧温度673K、焙烧时间60min、物料粒度200目,主金属氯化效果最好。对氯化焙烧后的电镀污泥进行弱酸浸出,实验结果表明:盐酸浓度1mol/L,反应时间30min,反应温度318K,液固比4:1的情况下,镍、铜的浸出率分别达到97.48%和87.65%,而铬、铁的浸出率只有45.07%、26.83%,符合电镀污泥氯化焙烧的热力学分析结果。通过对原料、浸出渣、氯化焙烧料进行XRD物相分析研究电镀污泥的氯化机理,结果表明一定条件的氯化焙烧处理有利于电镀污泥有价金属弱酸的选择性浸出。电镀污泥氯化焙烧-弱酸浸出液中含有镍、铜、铁、铬、钙、镁等金属离子,为了得到氯化镍溶液,必须进行分步除杂。首先采用铁粉置换法除铜,实验结果表明铁粉用量是除铜理论量摩尔数1.2倍、反应温度60℃、反应时间15min为最佳工艺条件,铜去除率为99.17%,镍损失率为1.58%,除铜渣物相分析结果显示只有铜的物相,基本无其他元素物相。其次采用高温中和水解法除铁,实验结果表明终点p H值为3.5、反应时间6h、反应温度95℃为最佳工艺条件,铁去除率为98.59%,镍损失率为2.84%。采用磷酸盐对除铁后溶液除铬,实验结果表明初始p H值为2、磷酸钠用量为除铬理论摩尔数0.5倍、反应时间50min、反应温度80℃为最佳工艺条件,铬去除率为97.08%、镍损失率为3.81%。最后采用氟化铵除钙镁,实验结果表明反应p H值为5.5、氟化铵用量为除钙镁理论摩尔数1.6倍、反应温度应95℃、反应时间2.5h为最佳工艺条件,钙镁去除率分别为92.39%、93.12%,镍损失率为2.39%,除钙镁沉淀渣物相分析表明只有氟化钙物相,基本元素无其他物相。通过对电镀污泥的氯化焙烧-弱酸浸出工艺研究,实现了有价金属选择性提取,达到了富集有价金属镍的目的,对高效处理电镀污泥二次资源具有重要的意义。
[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，

本文编号：2162082