Differential-Scanning Calorimetry of Anthracite, Graphite, and Calcium Salts

Resumo

It was established that a shift of equilibrium in the graphite–calcium oxide system toward the formation of calcium carbide can be observed at a temperature of 900°C due to the formation of a volatile substance—carbon monoxide. Upon the addition of anthracite, a maximum of calcium carbonate decomposition decreased from 813 to 780°C, and the endothermic effect of the formation of calcium carbide manifested itself at 1350°C. In a mixture of calcium chloride with anthracite or graphite in stoichiometric amounts, the formation of calcium carbide and carbon tetrachloride was observed at 1100°C. The formation of calcium carbide was confirmed by chemical reactions of pyrolysis products with water (the release of acetylene) and by calculations of weight losses from thermogravimetric curves.