铝电解废阴极中氟化物浸提实验研究

Leaching Experimental Research on Fluorides in SPL of Aluminium Electrolysis

废阴极(SPL)由于长期受到电解质的侵蚀而含有大量的氟化物被认为是铝电解工业中排放的主要污染物之一。本文采用EDS能谱对废阴极的化学元素进行了分析,分别采用水、NaOH、HCl作介质对废阴极进行了浸提。结果表明,三种介质都能从废阴极中浸出一定数量的氟化物;按氟化物浸提率高低存在如下趋势:酸浸浸出率>碱浸浸出率>水浸浸出率(超声波)>水浸浸出率(恒温振荡器),酸浸浸出率约为79.51%,另外对酸浸及碱、酸联合浸提后的废阴极进行EDS能谱分析,分析表明残渣中氟元素含量分别为3.01%及0%;同时结合XRD衍射分析,反映出废阴极中氟的赋存形态主要以难溶性氟化物存在。

Spent pot lining is a hazardous waste product obtained during smelting of aluminum, mainly because it contains significant amounts of fluorides due to be subjected to infiltration and attack by molten electrolyte components. The elemental analysis was characterized using EDS, and the paper studied the conditions of SPL＇s leaching by H2O,NaOH,HCl. The results show that the quantity of fluorides can be leached by the different medium, and the sequence of leaching ability of different solvents is as follows： acid leaching fluoride 〉 alkaline leaching fluoride 〉 water leaching fluoride; acid leaching is 79.51%, in addition, fluorine element content in SPL after acid and alkali associated with acid leaching is 3.01% and 0% respectively using ESD; the fluorides existing form is as fluoride-bearing minerals in SPL combined with XRD.