Abstract: A process for the preparation of calcium cyanamide by nitrification of calcium carbide composition in a rotary furnace. Ground carbide composition, composed of calcium carbide to which, if appropriate, calcium cyanamide and/or calcium fluoride have been added, is compacted to a density of from about 1.3 to 2.0 g/cm.sup.3 before introduction to the rotary furnace. In this manner the severe caking on the rotary furnace wall which normally takes place in the course of nitrification is prevented and the nitrification yield is unexpectedly increased.

Abstract: In a process for the production of calcium carbide in a shaft furnace, a plasma arc (plasma torch) is generated by the introduction of electric energy with the help of a plasma burner device penetrating the upper cover of the shaft furnace. A counter electrode is provided in the bottom part of the shaft furnace. About the plasma arc or torch, a burden mixture of calcium-oxide and carbon-containing substances is concentrically introduced so as to form a protective mound of solid burden components on the inner wall of the furnace. In order to provide an operationally safe process by using plasma burners, with which both coarse and fine-grain burden components may be employed and with which calcium carbide is obtained in higher yields with an improved utilization of the energy consumed, the burden mixture is used separately as a coarse-grain fraction and as a fine-grain fraction.