Saturday, March 15, 2008

The history of zinc

Centuries before zinc was discovered in the metallic form, its ores were used for making brass and zinc compounds, its ores were used for healing wounds and sore eyes. It is believed that the Romans first made brass in the time of Augustus (20 B.C. – 14 A.D.). In the 13th century Marco Polo described the manufacture of zinc oxide in Persia.
By 1374, zinc was recognized in India as a new metal – the 8th metal known to man at that time. At Zawar, India, both zinc metal and zinc oxide were produced from the 12th to the 16th century. Zinc metal was used to make brass and zinc oxide served medical purposes.
From India, zinc manufacturing moved to China in the 17th century where it developed as an industry to supply the needs of the brass industry.

Zinc was recognized in Europe as a separate metal in the 16th century when Agricola (1490 – 1555) observed that a metal called “zincum” was produced in Slesia and Paracelsus (1493 – 1541) stated clearly that “zincum” was a new metal. In 1743, the first European zinc smelter was established in Bristol in the United Kingdom using a vertical retort procedure. A major technological improvement was achieved with the development of the horizontal retort process in Germany which led to the erection of smelting works in Slesia, Liege, Belgium and Aachen, the Rhineland and the Ruhr areas in Germany. In 1836 hot-dip galvanizing, the oldest anti-corrosion process, was introduced in France. Zinc production in the United States started in 1850.

For about 500 years zinc was produced from its oxide ores before the more abundant sulfides became the major source of supply. On the technological side there was a drastic change in 1916 when the electrolytic process was introduced on a large scale replacing the pyrometallurgical process as the dominating production method.