Method of obtaining zinc

In 1738, the English metallurgist W. Champion defended the industrial method of obtaining zinc condensation from hot vapors. And he built a factory in Bristol. Before the launch of this plant, England imported the necessary zinc from the East. But was Champion a real inventor of the new method? This question is shed by the unexpected light of a note by the English scientist P. Creedoc.

In 1738, the English metallurgist W. Champion defended the industrial method of obtaining zinc

According to him, the first rumors about the rational method of obtaining zinc were brought by British merchants from India as early as the beginning of the 17th century. Then samples of metal were delivered to England, after which the owners of the metallurgical plants began sending their spies to India. And after a while there was also a Champion's patent. Its main secret in the formulation of fluxes, consisting of sodium chloride, borax, dolomite and vegetable oils. After the Champion plant achieved high productivity, obtaining zinc in India itself, conquered by the colonizers, quickly declined. And only now, after the excavations of Indian archeologists, the scale of the existing production has become clear. It was found that the receipt of zinc near the city of Zavar in the north-west of India began long before our era. By the beginning of the 14th century, hundreds of thousands of tons of ore had already been processed here. But the main discovery of Indian archaeologists is that they established the priority of ancient Indian metallurgists, who first in the world (around the 4th century BC) mastered the method of obtaining zinc and established on its basis the production of brass.

Today, for the production of zinc metal, a hydro- and pyrometallurgical process is used. When processing zinc ores as a result of their enrichment, zinc concentrate is obtained, which is subjected to firing: 2ZnS + 3O2 = 2ZnO + 2SO2, then zinc oxide is produced in two ways.

Pyrometallurgical process. Zinc oxide is alloyed with coke at a temperature of 1250-13500 C in refractory retorts: ZnO + C = Zn + CO; the zinc vapor condenses.

Hydrometallurgical process. Zinc oxide is dissolved in sulfuric acid: ZnO + H2SO4 = ZnSO4 + H2O; the resulting zinc sulfate solution is subjected to electrolysis, zinc is released at the cathode: 2ZnSO4 + 2H22 + 2H2SO4. To obtain high purity zinc, distillation is used in an inert atmosphere or in a vacuum.