General characteristic

Zinc (Zn) is an element of second group of side subgroup, fourth period, of the chemical system of D. Mendeleev. Its atomic weight is 30. Under normal conditions it is a bluish-white metal (duller in the air, covered by a very thin layer of oxide ZnO). Specific weight is 7.133 ^g/cm3. Melting point 419.6°С, boiling point 906.2°С. The name "zinc" was suggested by Paracelsus in the 16th century. Zinc is an iron with a hexagonal lattice. When cast at room temperature, it is very malleable, but its plasticity increases substantially at temperatures between 100 and 150°C, which makes it possible to work under pressure.

History

Zinc alloys have been used by mankind since time immemorial. For example, brass - an alloy of copper and zinc - was known in ancient Egypt, China and India. For many years it was impossible to extract pure zinc. In 1746 Margrave B developed a method of production of this metal by calcination of ZnO oxide mixture with coal in refractory clay retorts without air with condensation of zinc vapors in special refrigerators. The smelting of this metal started at the end of the 17th century.

Geology

Over 60 minerals contain zinc: sphalerite, zincite, willemite, smithsonite, calamine, franklinite, etc. The most common mineral among them is zinc cladding or sphalerite, whose main component is the sulfide ZnS. Different additives may give this mineral different colors. It is called a dross because of the difficulty of its identification. Zinc oxide is considered to be the primary mineral, from which other minerals are formed: ZnO zinc oxide, _ZnCO3 smithsonite and _{2ZnO-SiO2 H2} O calamine.

Production

Zinc does not occur in nature in native form. This element is extracted from polymetallic ores, which contain in the form of sulfide 1-4% Zn, as well as Pb, Cu, Ag, Cd, Au and Bi. From polymetallic ores concentrates containing from 50 to 60% of Zn plus copper, lead and other elements are obtained through selective flotation. Zinc concentrates are roasted in fluidized bed furnaces, converting sulphide into zinc oxide. The sulphur dioxide from the roasting process is used in the production of sulphuric acid. From ZnO oxide the purified metal is obtained by two methods. 1) Pyrometallurgical (distillation) method - has been used for a long time. 2) Hydrometallurgical (electrolytic) method - has been introduced relatively recently.

Applications of

Metallic zinc is used to recover noble metals such as gold and silver by underground leaching. In addition, it is used to extract gold, silver and other less active metals from rough lead in the form of zinc intermetallides, with gold and silver - "silver foam", which is further processed by conventional refining method.

Buy, price

Evek GmbH sells non-ferrous metals at an optimal price. It is formed taking into account the LME (London metal exchange) rates and depends on the technological peculiarities of production without additional costs. We supply a wide range of zinc and zinc-alloy products. All batches are certified. With us you can buy in bulk everything you need for large-scale productions. The wide choice of goods, exhaustive consulting of managers, reasonable prices and prompt delivery determine the face of our company. Delivery time is minimal. The price depends on the order volume and additional delivery terms. Wholesale customers receive discounts.