From Recovery Of Gallium, Indium, Germanium, Zinc Smelting Industrial Waste

The distributing of gallium, indium and germanium and their main application in the high-tech field were briefly narrated in the paper. The method, technics and evolvement of recovering gallium, indium and germanium from zinc residues were compared. The shortage, for example poison, flammability, high losing rates and high production cost to use full extraction, low recovery rates to deposit germanium using tannin and its color affecting on using of zinc and cadmium, existed in present technics of recovering gallium, indium and germanium from zinc residues. A new technology of recovery and new process flow, which can efficiently recover gallium, indium and germanium from zinc residues and don't affect the quality of seven water zinc sulfate, were advanced.In this paper, two key technical problem of extracting indium from acid lixivium of zinc residues were resolved. One problem was not to affect recovery of gallium and germanium when indium was extracted, another was not to disturb extraction of indium when the metallic ion, for example iron, cadmium, copper etal, existed in the lixivium of zinc residues. The separation and extraction of indium were performed from the concomitant solution of gallium, indium and germanium by different conditions of extraction and anti-extraction using p204 as extractant. The affect of different factor, for example acidity, time and thickness of Fe3+ on indium's extraction rate and anti-extraction rate by using p204 was researched. The disturbance of concomitant element was effectively eliminated and the recovery rate of indium was over 95%. Then, the germanium and gallium were extracted by using tannin-kaojiao from lixivium of zinc residues. On some condition, tannin and gallium can form chelate complex, which is stable and can be adsorbed by solid sorbent, e.g. active carbon. The new method, which broke through extraction, multi-neutralization to recover gallium from zinc residues, was advanced to recover gallium by tannin and active carbon. The separation, enrichment and recovery of gallium were first performed from acid lixivium of zinc residues and the recovery rate was over 91%. Secondly, the traditional method of depositing germanium by using tannin and kaojiaowas fully researched in this paper. The essence of depositing germanium by using tannin is that the anti-soluble chelate complex was formed. The key factor of affecting germanium's recovery rate is acidity. The germanium's recovery rate was increased from 60% to 86%.The germanium and gallium were recovered and separated from acid lixivium of zinc residues by using tannin and kaojiao on the base of individual extraction of germanium and gallium. The tannin and germanium formed anti-soluble deposit, which was filtrated to get germanium. But the tannin and gallium formed soluble chelate complex, which can be adsorbed by active carbon. According to different character of two chelate complex, germanium and gallium were recovered and separated. The recovery rate of gallium is over 91% and the recovery rate of germanium is over 86%.Through the study on individual recovery of gallium, indium and germanium, a new process flow of general recovery of gallium, indium and germanium was advanced. In the new process flow, gallium and germanium were recovered by chelation using innoxious tannin except that indium was recovered by extraction. After the germanium was separated, the surplus tannin can be used to separate gallium. Every metallic element was effectively separated. Working procedure was simplified and was propitious to realize clean production. The color of tannin was adsorbed by using active carbon in order to avoid effect on back technics. The quality of seven water zinc sulfate reached the standard II of industrial product. The quantity of residual residues was decreased over 93% and the remainder, which is only 7% of original zinc residues, was mostly mud and sand which need be innocuously disposed. So the disposal cost of environment was evidently reduced.