GB339562A - Improvements in and relating to the production of mixtures comprising ammonium nitrate and calcium carbonate - Google Patents

Abstract

339,562. Odda Smelteverk Aktieselskabet, and Johnson, E. March 4, 1929, [Convention datel. Manures.-A mixture of ammonium nitrate and calcium carbonate is produced by treating a solution of calcium nitrate, which may be previously concentrated in vacuo, with ammonia and carbon dioxide, or ammonium carbonate or bicarbonate, and removing water, preferably in vacuo, to obtain a granular product, which may also contain calcium nitrate. Excess carbon dioxide may be used. The calcium nitrate solutiun may be obtained by the process of Specification 339,340, or by neutralizing nitric acid with limestone, carbon dioxide evolved being employed as above. Other sources of carbon dioxide are specified. The heat required may be obtained by heating the reaction gases. The process is preferably carried out by passing the reacting gas in countercurrent to the well-stirred solution, in revolving drums. The operation may be conducted in two stages, so that in the first, mainly the chemical reaction occurs, and in the second, water is evaporated. The presence of one or a mixture of the reacting gases, preferably carbon dioxide, in the second stage avoids a reversal of the reaction. Ground limestone may be added to the product at any convenient stage.