GB314819A - Improvements in or relating to the decomposition of calcium carbonate and to the manufacture of calcium carbide - Google Patents

Abstract

314,819. Patart, G., and Nielsen, H. Dec. 30, 1927. Calcium carbide.-In forming calcium carbide by decomposing calcium carbonate admixed with carbonaceous materials in a hot stream of gas and passing the resulting mixture of calcium oxide and carbon into an electric furnace, the stream of gas contains less carbon dioxide than is present in combustion gases whereby calcium carbonate may be decomposed at a lower temperature than usual (below 700‹ C.). Carbonaceous material such as bituminous or brown coal, and chalk or limestone are fed from hoppers A, B to a rotary mixer C, and by a screw-conveyer d to a rotary inclined retort D from which the mixture falls through a combustion chamber E into an electric furnace F. A controlled volume of air is admitted to the chamber E through a pipe G together with some of the carbon monoxide evolved from the electric furnace and admitted by a pipe f and some of the gases drawn from the retort D by a fan J and stripped by passage through a seal h and a condensing plant and admitted through a seal k<1> and a pipe k<3>. The temperature in the retort D may be varied to drive off more or less of the volatile matters, and the distillation may be carried out as described in Specifications 276,407, 287,037, and 287,381, [all in Class 55 (i), Coking &c.], to obtain a coke free from graphitic carbon in the mixture which passes into the electric furnace.