Electric Furnace Zinc Powder In Organic Matter On The Effects Of Zinc Electrowinning

Zinc electrowinning is an important procedure in zinc hydrometallurgy, and zinc electrowinning has a significant impact on the manufacturing cost and product quality. Zinc electrolyte always contains impurities, which will bring harmful effect on zinc electrodeposition. Many scientific researchers have studied the behavior of impurities metallic ions on zinc electrodeposition from sulfate solutions. However, in domestic and abroad there are seldom studies on effects of organic impurities on zinc electrodeposition. Therefore, the effect of organics on zinc electrowinning was investigated to providing instructive suggestions for enterprise and industrial application value.This work dip-boiled 50 kilograms industrial zinc power with distilled water at 75±2℃to obtain upper floater, then filtered it and 2L solution A was obtained. Potassium chromate method was applied to determining the chemical oxygen demand (COD) of solution A. Results show that the content of organics should be more than 0.508mg per kilogram zinc power. Chromatograph-mass spectrometry (GC-MS) showed that a certain amount of organic compounds exist in industrial zinc power indeedly. Organic compounds contain ethyl benzene, xylene and 1, 3-dimethyl-benzene, etc. Meanwhile the effects of organic on cell voltage, power consumption, current efficiency and deposit morphology from the sulfate electrolyte were investigated. The electrowinning experiments were keeping current density on 450 A/m2 and ongoing for 2 hours at 40±1℃from the electrolyte contain 58 g/L Zn2+ and 165 g/L H2SO4, respectively. It was found that with the concentration of organic increased, the cell voltage and power consumption increased significantly, while the current efficiency decreased remarkably. But if controlled the concentration of organics not more than 2 mg/L, the cell voltage could be 2.84～2.86V, the power consumption of per ton Zn could be 2491-2600kWh and the current efficiency of 93.8～90%could obtained. The surface morphology of deposits obtained at different conditions were examined by scanning electron microscopy (SEM). It revealed that the presence of organics would lead rough, dull and bigger crystal size of zinc deposits.The effect of organics on zinc electrodeposition from sulfate solution was studied by cyclic voltammetry and cathodic polarization curves. Electrochemical methods results lead to the conclusion that organics have a pronounced inhibit Zn2+ from being electroreducted. This would lead higher cell voltage and higher power consumption.