GB771310A - Process for the manufacture of crude calcium cyanamide - Google Patents

Abstract

In the production of fine granular calcium cyanamide from calcium carbide and gaseous nitrogen in a fluidized bed, the bed is maintained at a substantially constant temperature above 800 DEG C., but below the fusion temperature of calcium cyanamide, e.g. 1000 DEG C., and the concentration of calcium carbide in the bed is maintained at below 30 per cent by weight of the bed to prevent sintering. Solid catalyst, e.g. calcium fluoride or chloride, may be included in the bed, which otherwise comprises calcium cyanamide, calcium oxide and carbon, but it is preferred, instead of solid catalyst, to add a small amount, say 0.3 per cent, chlorine to the nitrogen stream. It is stated that at the high temperatures used, the reactant particles become coated with a film of fused material, presumably calcium cyanide, which increases reaction velocities. The product from the fluidized bed is desirably further treated with N2 in a fixed bed. It is suitable to divide the reaction zone into several fluidized beds, through which reaction materials pass successively, to conserve heat, and apparatus is described having two superposed fluidized beds, or three adjacent fluidized beds separated by radial partitions. Specifications 688,188 and 690,949 are referred to.