| Zinc hydrometallurgy process of atmospheric oxygen-rich direct leaching of zinc concentrate, its arsenic salt solution purification process calcium and magnesium content than the traditional process, solution of calcium and magnesium in the device crystallized, fine crystals wrapped in the purification process of zinc powder was added surface, increased cell voltage, the electrolyte turbidity, pipe blockage, excessive accumulation of anode mud, burning board and other issues during electrolysis, serious impact to the production process. Study of calcium and magnesium disordered crystal in leaching solution, mitigate the effects of calcium and magnesium crystals and provided effective open, it is the key to solve above problems, the research has important applications for zinc hydrometallurgy industry.Based on literature data and preliminary research work for zinc sulfate solution of zinc hydrometallurgy arsenic salt purification process, using controlled cooling process to remove calcium and magnesium. By industrial production data, the crystallization of calcium and magnesium mechanism, experimental study on condition control of crystallization process, get the temperature range of arsenic salt purification process during crystallization of calcium and magnesium, For this reason launched the cooling rate of the solution, seed species, seed amount and other factors which affecting the experimental study of the crystallization of calcium and magnesium.Calcium and magnesium removal mechanism of cooling process as well as experimental studies have shown that: reduce the temperature of the solution is the dominant factor in the crystallization of calcium and magnesium; magnesium ions in solution can be induced crystallization of the main metal element zinc precipitation; the reaction of calcium and magnesium ions compete under high salt role in the process of crystallization, calcium ion in solution at high temperature is easy to magnesium ions preferentially crystallized, magnesium ions in solution at low temperatures than the calcium ion is easy to crystallize.By controlling the cooling rate of zinc sulfate solution and seeding can achieve crystallization of calcium and magnesium, in the cooling rate of 4℃/min, after adding a mixed seed(4% of the two water calcium sulfate + 6% magnesium sulfate heptahydrate) cleaning fluid solution temperature is reduced from 62℃ to 46℃ the solution of calcium and magnesium can be reduced to a minimum level; adding 4% of both calcium sulfate seed control the cooling rate of 4-5℃/min for the new fluid temperature is reduced from 42℃ to 30℃ after solution of calcium precipitation can be achieved ensure the smooth progress of the electrolysis process.Cooling method can achieve zinc sulfate solution crystallization of calcium and magnesium, the research achievements open circuit of calcium and magnesium ions of zinc hydrometallurgy leaching solution to provide an economical and environmentally friendly removal method. |
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