GB186020A - Improved method of and apparatus for producing a solution of cyanamide from calcium cyanamide - Google Patents

Abstract

186,020. Wargons Aktiebolag, and Lidholm, J. H. Dec. 1, 1921, [Convention date]. Cyanamide.-In the production of solutions of free cyanamide by gradually adding calcium cyanamide to a circulating body of water or cyanamide solution into which carbon dioxide is admitted, the process is carried out in such a way that the quantity of liquid between the points where the calcium cyanamide and carbon dioxide respectively are supplied is constant and small compared with the total quantity of liquid notwithstanding the increase in bulk owing to the addition of the calcium cyanamide. The result is that each addition of calcium cyanamide is only a short time in the liquid before reaching the carbonic acid, and only a small proportion of the liquid is alkaline. Calcium oyanamide is fed from a hopper 2 by a valve 3 into a small tank 1, from which the liquor passes tod a pumping-device 5 containing a centrifugal wing wheel 11 and mixing-vanes 12. Carbonic acid is supplied by a pump 13 and is mixed with the liquid in the apparatus 5. The liquor then passes through a pipe 6 to a cooler 7 if necessary and thence by a pipe 8 to a large tank 9 which is capable of accommodating the increase in the bulk of the circulating liquor. From the tank 9 the liquor is passed by a valve 15 and pipe 10 to the tank 1. The pipe 8 is preferably tangential to the tank 9 so as to facilitate the escape of gas which is led off by a pipe 14. The finished solution is withdrawn at 16