Study On The Treatment Process Of High Fluorine Chlorine Oxide

This article mainly study on secondary zinc oxide with high fluorine and chlorine as raw materials. In the first stage removal of chlorine through neutral washing by water, To recover of cadmium and thallium from dechlorinated solution by zinc dust precipitation, Then, zinc was deposited by lime precipitation; In the second stage, using sulfuric acid leaching dechlorinated secondary zinc oxide, and through adjusting pH indium enriched from Leaching Solution. Finally, studying on fluoride removal by lead salt and fluorine-removal agent. The separation of fluorine and chlorine from raw materials was achieved in this process. It is significant for improving the ratio of comprehensive utilization of secondary zinc oxide. The optimum parameters were obtained after systematic research in the experiments, which can provide the basis for practical industrial application.The results show that under the optimum condition of such as mass ratio of liquid to solid being 5,reaction temperature 70℃,reaction time 60 min, and terminal pH 5.5, The removal rate of chlorine was reached 80% in the high fluorine and chlorine secondary zinc oxide. During application of zinc dust precipitation the cadmium and thallium from dechlorinated solution process, under the most optimum conditions for this process are time 60min, at temperature of 50 ℃, the quantity of zinc power about the quantity of theory counting 2.0 times, the cadmium and thallium recovery over 98%, and meanwhile using lime milk adjust pH to 8.0, The zinc precipitation rate was over 99%, Zinc slag awaiting recycle use sulfuric acid leaching in the second stage.During using sulfuric acid leaching dechlorinated secondary zinc oxide process, the optimum parameters is obtained by experiment:liquid to solid ratio 3:1, temperature 30℃, the initial of sulfuric acid concentration is 210g/L, the terminal concentration is 5 g/L,that the terminal pH of 1.0, and the leaching time was 30min. Under those conditions, The total recovery of zinc is about 87.25%, the fluorine extracting rate close to maximum value 80%,and the chlorine extracting rate not more than 5.5%, the chlorine concentration is less than 200mg/L. Experiment use the first stage zinc slag to adjust pH to 4.8, under the conditions of temperature 60℃,and the reaction time 30min, According to the rate of residue calculation predicts that indium enriched more than ten times, In this process, The removal rate of fluorine was reached 43%. On the Basis of fluoride removal from pure zinc sulfate solution, The optimum conditions to removing fluorine are:temperature 70 ℃,time 60 min, pH 4.75 and the quantity of lead-based compound fluorine-removal reagent Aadding amount should be kept with the mass ratio of reagent to fluorine was 16:1, the results show that fluoride-removal reagent efficiency of defluoridation can be get 65.9%, The fluorine concentration dropped to 312.77mg/L,it need second time the deeper removal of fluorine by fluorine-removal agent B. Removing of fluoride the mass concentration of fluoride in solution could decrease under 40.22mg/L,at the conditions of fluoride-removal reagent B of 20g/L, reaction time of 80 minutes, reaction temperature of 50℃ and pH of 4.5,Its able to meet the requirements of zinc electrowinning. In addition, The sulfuric acid leaching residue was 37.41%,it could be used for recovery of lead.This process realized successfully for dechlorination and defluoridation at low cost from secondary zinc oxide with high fluorine and chlorine in zinc hydrometallurgy, with which the valuable and recoverable metals can be comprehensive recycled. It has broad prospects for industrial application.