CHEMISTRY GLOSSARY

limestone    →   vapnenac

Limestone is a sedimentary rock composed primarily of calcium carbonate in the form of the mineral calcite.. Some 10 % to 15 % of all sedimentary rocks are limestones. Limestone is usually organic, but it may also be inorganic. Calcium carbonate may have been directly precipitated from the sea-water or by the lithification of coral reefs, marine organism shells, or marine organism skeletons.

basic Bessemer process    →   bazni Bessemerov proces

Basic Bessemer process is the process of steelmaking in a way that steel, melted iron and limestone are put in the blast-furnace after which the metal oxygen is released in gushes in order to oxidise the impurities.

blast furnace    →   visoka peć

Blast furnace is a furnace for smelting of iron from iron oxide ores (hematite, Fe₂O₃ or magnetite, Fe₃O₄). Coke, limestone and iron ore are poured in the top, which would normally burn only on the surface. The hot air blast to the furnace burns the coke and maintains the very high temperatures that are needed to reduce the ore to iron. The reaction between air and the fuel generates carbon monoxide. This gas reduces the iron(III) oxide in the ore to iron.

Because the furnace temperature is in the region of 1500 °C, the metal is produced in a molten state and this runs down to the base of the furnace.

The production of iron in a blast furnace is a continuous process. The furnace is heated constantly and is re-charged with raw materials from the top while it is being tapped from the bottom. Iron making in the furnace usually continues for about ten years before the furnace linings have to be renewed.

calcium    →   kalcij

Calcium was discovered by Sir Humphry Davy (England) in 1808. The origin of the name comes from the Latin word calix meaning lime. It is fairly hard, silvery-white metal. Exposed surfaces form oxides and nitrides. Reacts with water and oxygen. Occurs only in compounds. Calcium is obtained from minerals like chalk, limestone and marble. Pure metal is produced by replacing the calcium in lime (CaCO₃) with aluminium in hot, low pressure retorts. Used by many forms of life to make shells and bones. Virtually no use for the pure metal, however two of its compounds are, lime (CaO) and gypsum (CaSO₄), are in great demand by a number of industries.