Some of the earliest experiments for the preparation of cyanamide compounds were those of Marguerette and Sourdeval in 1860 in connection with the preparation of barium cyanide, Ba(CN)2, by heating a mixture of carbon and barium carbonate in air. The first technical application was used by the Badische Company in 1896, who obtained a mixture of the cyanide and cyanamide, BaNCN, by heating the mixture at 1500° C. in an atmosphere of nitrogen.
The use of barium carbide instead of the mixture of carbonate and carbon was introduced by Frank and Caro in 1898, who found that if the carbide is used in large lumps, barium cyanide is almost exclusively produced, whereas a yield of 70 per cent, of barium cyanamide is obtained if small granules of carbide are used.
The technical manufacture of alkali cyanides for gold extraction by fusion of the mixture of cyanide and cyanamide with alkali chlorides was made use of by the Gold und Silber Scheidenanstalt of Frankfurt. |