| The raw material of the research is an cobalt ore with high As. In this study, the leaching methods of the sulfuric acid leaching, roasting-sulfuric acid leaching, sulfuric acid leaching under the action of sodium chlorate, sulfuric acid and nitric acid leaching and after magnetic separation sulfuric acid and nitric acid leaching, were discussed and compared. Then sulfate cobalt was prepared after removing impurity.The main phase in the ore is Fe3O4.The concentration of cobalt, iron, arsenic are 1.62%,33.35%,23.26% respective. The cobalt is mainly cobalt sulfide.Using the methods of sulfuric acid solution leaching, roasting-sulfuric acid leaching, sulfuric acid leaching under the action of sodium chlorate, the leaching rate of Co are 16.86%,67.48%,49.91% respective.In the process of nitric acid oxidation leaching with sulfuric acid, the leaching rate of Co is 96.35% when nitric acid and sulfuric acid addition volume are 56mL and 39mL in 100g cobalt ores, reaction time is 4h, reaction temperature is 60℃, the ratio of liquid to solid is 3:1. The cost can be reduced using the method of magnetic separation and mixed acid leaching.When the reaction time is 6h, the reaction temperature is 93℃, the solution pH is 2.0, the dosage of sodium sulfate is theoretical dosage, the iron removal rate reached 99% with the method of amarillite.When the reaction time is 1h, the solution pH is 9.0, the cobalt deposition rate arrived 99% with the method of precipitatation. When the reaction time is 2h, the reaction temperature is 90℃, liquid to solid ratio is 9:1,18.4g sodium hydroxide is added into 5g dry cobalt hydroxide, the zinc and arsenic removal rate reach 99%. The cobalt content in the obtained cobalt hydroxide is 64.8%. Cobalt sulfate products obtained through sulfuric acid dissolution, evaporation, cooling crystallization, drying, the cobalt content in the cobalt sulfate reached 25.69%.After cobalt hydroxide dissolved by sulfuric acid solution, using the neutralization method to remove Fe and As at the conditions of solution pH 4.0-5.0, reaction temperature 60℃, reaction time 1.5h, in the obtained cobalt sulfate solution the concentration of Co, Fe, As were 22.250g·L-1,0.009 g·L-1,0.041 g·L-1. Ammonium fluoride solution used to remove Ca, Mg, when the dosage of ammonium fluoride is 1.8 times the theoretical amount, the reaction temperature is 60℃, the removal rates of Ca, Mg were 98.51%, 96.62%.Removing Zn through solvent extraction by P204, when the pH value of the water phase is 3.5, volume fraction of P204 is 20%, the saponification rate is 60%, volume fraction of synergistic extractant(TBP) is 4%, mixing time is 10min, extraction temperature is room temperature, volume ratio of organic phase to water phase is 1:1, the extraction rate of Zn, Mn are 99.39%,49.02%, and the direct recovery of Co is 99.5%.Removing manganese through solvent extraction by P204, when the pH value of the water phase is 2.5, volume fraction of P204 is 10%, and the other conditions were the same as removing Zn, the extraction rate of Mn is 78.16%and the direct recovery of Co is 99.5%. Through three-stage extraction by P204, the direct recovery of cobalt can up to 96.23%, the removal rate of Mn is 96.5%,and the concentration of Mn is only 0.023 g·L-1.Separating nickel and cobalt through solvent extraction by P507, when the pH value of the water phase is 4.0, volume fraction of P507 is 10%, the saponification rate is 70%, mixing time is 5min, extraction temperature is room temperature, organic phase to water phase volume ratio is 1:1, the extraction rate of Co and Ni are 78.86% and 3.93%.Through three-stage counter current solvent extraction by P507, the direct recovery of cobalt can up to 96.23%, the removal rate of Ni is 98.7%, and the concentration of Co and Ni are 0.041 g·L-1 and 0.382 g·L-1 in the extraction raffinate.In the experimental process the quality of cobalt sulfate obtained outclass the requirements of chemical purity of HG/T 2613-2005. |
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