The History of Zinc
Centuries before zinc was discovered in the metallic form, ores used for making brass and zinc compounds were used for healing wounds and sore eyes. Brass was produced by the Romans in the time of Augustus (20 B.C.-14 A.D.). By 1374, zinc was recognised in India as a new metal and at Zawar, India, both zinc metal and zinc oxide were produced from the 12th to the 16th century. From India, zinc manufacture moved to China in the 17th century. Zinc was recognised as a separate metal in Europe in 1546. In 1743, the first European zinc smelter was established at Bristol in the United Kingdom
The solid zinc oxide (ZnO, Calcine) is separated from the gaseous sulphur dioxide (SO2) utilising various techniques. The collected zinc oxide is sent to the Leaching Plant and the sulphur dioxide goes to the Sulphuric Acid Plant via the Gas Cleaning Plant.
Zinc, like all metals, is a natural component of the earth's crust and an inherent part of our environment. Zinc is present not only in rock and soil, but also in air, water and the biosphere (plants, animals and humans). Zinc is constantly being transported by nature, a process called 'natural cycling' Rain, snow, ice, sun and wind erode zinc-containing rocks and soil. Wind and water carry minute amounts of zinc to lakes, rivers and the sea, where it collects as sediment or is transported further. Natural phenomena such as volcanic eruptions, forest fires, dust storms and sea spray all contribute to the continuous movement of zinc through nature.
Zinc's most remarkable quality is its natural capacity to protect. Zinc coatings protect steel against corrosion, extending the life of steel by up to five times. Thus car manufacturers can provide no-corrosion guarantees of 12 years or more and zinc helps to protect the value of a typical family investment. Zinc protects human health too. It is now known that zinc is essential for human health in general and the functioning of the human immune system in particular. Zinc-based creams and lotions are widely used to protect the skin against the harmful effects of the sun. Zinc is used in water purification systems and zinc supplements are added to soil to protect crop yields.
The key provision of sustainability is to fulfill present needs without compromising the ability of future generations to meet their needs too. Thus sustainability focuses on economic growth, environmental protection and social progress. Zinc makes a significant contribution to sustainable development. In its role as a steel protector, zinc is an essential material for public and private infrastructure development, prolonging the useful life of steel goods and structures and reducing the cost of their maintenance. As a natural essential element, zinc is part of every ecosystem. Zinc is completely recyclable, providing a sustainable resource for future generations. Zinc contributes to social progress too, by providing affordable shelter, promoting good health and contributing to the durability of the infrastructure and transport systems on which a modern society depends.
All life on earth has evolved, over hundreds of millions of years, in the presence of zinc. Zinc is used by nature for a host of biological processes. For this reason, zinc is referred to as an "essential element", meaning that it is essential for the health of living organisms. Plants, animals and humans all regulate their zinc intake from nature. The possibility that emissions from industrial activity during the last two hundred years might be leading to increased levels of zinc in the environment became an issue. Since the 1970s, however, progressive emission control at refineries and industrial installations have reduced these emissions considerably. At the same time, general pollution control has greatly reduced the acidity of the air in most industrialised countries, with the result that zinc coatings on steel exposed outdoors now last longer and longer. The amount of zinc in the environment today is close to natural background levels. In other words, man's activities are no longer disturbing the natural balance of zinc in the environment.