Chemical Industry and Chemical Engineering Quarterly (Jan 2014)
The possibilities of obtaining metallic calcium from Serbian carbonate mineral raw materials
Abstract
The experimental investigations defined both the technological scheme of the calcium production from limestone by aluminothermic process and the basic operating parameters of the particular technological phases. The limestone with high content of Mg, Na and K was used in the paper. X-ray analysis reveals that the samples contain mainly calcite with small amount of dolomite. At first, the influence of temperature, time and granulometry on the calcium carbonate calcination was examined. The dissociation process was completed in 10-15 min at 1200°C, and dissociation rate increases with decreasing of particle size up to 5 mm. Afterwards, the aluminothermic reduction process of calcium oxide was investigated. At the temperature 1200°C, and vacuum of at least 3 kPa, the reduction process completed within 2 hours. The chemical composition of calcium oxide and calcium showed increased content of magnesium oxide and alkaline oxides (especially sodium).[Projekat Ministartsva nauke Republike Srbije, br. TR34002 i br. TR34023]
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