Zinc ingots contain few impurities and are relatively pure. Zinc ingot has a wide range of applications, suitable for die-casting alloy, printing and dyeing industry, pharmaceutical industry, rubber industry, chemical industry, etc. Zinc ingot production methods include: electrolysis, vacuum distillation, regional melting, inert atmosphere distillation and heavy distillation method.
1. Electrolysis. This method is simple equipment, simple process conditions, so it is used more, the cost is relatively low, but because the cathode will absorb impurities, impurities will form oxide scum when melting. However, the purity of zinc used in electrolysis can reach more than 5N, so it is still useful.
2. In the inert atmosphere (N2), the purity of zinc obtained by distillation is higher than that obtained by electrochemical method, and the content of impurities Cu, A1, Bi, Ni, Fe, Sn and Sb is less than 100000wt%. This force method has low productivity and high overall purification cost. Higher purity and less impurity content were obtained by 2 - stage vacuum distillation.
3. Vacuum distillation, using the difference in steam pressure between the metal being distilled at the same temperature and the impurities contained in it to separate the metal.
4. The basic principle of heavy distillation is the same as that of crude zinc distillation, which is based on the different boiling points of zinc and various impurities. Impurity zinc after distillation, in addition to a little evaporation of Pb, can basically remove the high boiling point of impurities. Zinc steam condensation may produce high purity zinc containing Cd ingot.
5. The boiling points of Zn and rd are very close. A fractionation tank can be used to separate Zn from Cd. The zinc purified by distillation and electrolytic zinc is smelted in dozens of sub-regions. But zone melting is more expensive.
At present, the purity of zinc ingots has been purified to 6-7N. Pure zinc ingot containing more than 99.99 wt% zinc is called 4N, generally used as zinc die casting alloy products, the performance of zinc ingot with the increase of purity. Zinc ingots with an average zinc content greater than 99.999 wt% are called 5N. 5N zinc ingots are mainly used in semiconductor production. Zinc can be formed by a variety of deformation processing methods. Such as rolling, drawing, extrusion. Rolling is a common processing method, rolled zinc ingots can be used in many occasions. The raw material used for rolling is usually zinc ingot.