The Zinc Hydrometallurgy Poor Cadmium Solution In Addition To Cobalt Purification Process

In2008, China issued new hazardous waste lists which comprised the waste residue derived from the process of zinc hydrometallurgy to remove Cu, Cd, Co, Ni, Sb and so on in leaching solution by using the purification method including zinc-xanthate reagent, arsenic salt, reversed antimony salt, lead-antimony alloy, its transport, storage, use or disposal is managed according to the dangerous wastes. Therefore, it is of vital and practical significance that how to effectively use the purification slag from zinc hydrometallurgy and to recycle the valuable metals, which is also one of the important conditions to measure the integrated competition strength of modern enterprise.The low-cadmium solution is obtained by the purification slag, derived from the purification process of zinc hydrometallurgy, which is leached by the acid and after the removal of Cu, Cd at the same time. One of the crucial technologies in the purification process of traditional zinc hydrometallurgy is how to remove Co from the zinc sulfate solution, but many zinc hydrometallurgy enterprises are always puzzled by the issue of closed-circuit circulation of Co in the low-cadmium solution.On the basis of the previous research associated with k-agent, its application to remove Co, Ni from the zinc sulfate leaching solution is studied, a new purification craft for zinc hydrometallurgy through a large number of laboratory experiments is developed which is carried out half-industrial test containing the whole process of purification, electrowinning and the removal of high Co, Ni from the low-cadmium solution by k-agent, the effect is good. In this paper, the craft to remove Co from the low-cadmium solution produced in a domestic zinc hydrometallurgy is particularly researched.In this research, the test of small-scale, half-industrial and industrial trial production are all systematically carried out. In the small-scale test, firstly, engaging in condition tests about the using amount of k-agent and the auxiliary precipitating reagent to remove Co from high or low concentration of that in pure zinc sulfate system, the conclusion is obtained that the concentration of Co2+between32.4mg/L-106mg/L in the zinc sulfate solution can be removed to lmg/L or so when the using amount of the auxiliary precipitating reagent and k-agent are respectively1.17times and15times than the quality of cobalt. Then, carrying out the small-scale qualification tests to remove Co from the low-cadmium solution such as the reaction time, the reaction temperature, the using amount of the auxiliary precipitating reagent and k reagent and the influence of Cd, the result is testified that the concentration of Co in the low-cadmium solution can be removed to lmg/L or so in the conditions of follows:reaction temperature is85-90℃, reaction time is1h, the concentration of Cd is less than100mg/L and the reagent usage is identical with the pure zinc sulfate system. Under the optimum conditions which derive from the small-scale tests, this craft engages in the half-industrial test and the industrial trial production, the concentration of Co is removed to1mg/L or so, which verify the feasibility and generalization of this craft. The content of Co in the once purified comprehensive samples slag derived from industrial trial production is between9%-12.8%, while the content of Co in1#purified comprehensive samples slag after roasted at650℃in the muffle furnace is34.80%, therefore, the Co slag has the very good value of using and recycling. The research results have been applied to the practical production which resolves the issues of Co closed-circuit circulation in the process of zinc hydrometallurgy, with better promotion value.