Patent GB-418289-A (GB)
Title: An improved process for the production of composite fertilisers
IPC: C05C3/00
Filed: 1933-01-18
Abstract: Fertilizers are obtained from magnesium salts and potassium salts containing magnesium salts, e.g. carnallite, by treating these salts in the solid state with ammonia and carbon dioxide, or with gaseous mixtures containing these substances, in excess and then evaporating off the ammonia or ammonium carbonate taken up in excess by the salts.  The excess may be evaporated by spreading out the ammoniated salts in the air, by heating the ammoniated salts or by treating them with a current of hot gas; it is stated that temperatures up to 100 DEG  C. may be employed.  Alternatively the excess ammonia and ammonium carbonate may be absorbed by mixing the ammoniated salts with ammonia combining substances, e.g. superphosphates or calcium or magnesium salts.  The treatment of the salts with ammonia and carbon dioxide may take place in two apparatus which are alternately used as absorption apparatus for the gaseous mixture used in excess and the excess ammonia and ammonium carbonate taken up in excess and evaporated and as the actual reaction apparatus.  The salts may be agitated during the ammoniating process and salts such as magnesium chloride which become caked and lumpy during the ammoniating process may be disintegrated before continuing the process.  Small quantities of water insufficient to dissolve the salt may be added before or during the process.  The reaction material may be cooled or heated as desired; a temperature of 50--75 DEG  C. during the whole course of the reaction is stated to be desirable.  When using potassium salts containing magnesium salts these salts may be mixed with superphosphates prior to ammoniation.ALSO:Fertilizers are obtained from magnesium salts and potassium salts containing magnesium salts, e.g. carnallite, by treating these salts in the solid state with ammonia and carbon dioxide, or with gaseous mixtures containing these substances, in excess and then evaporating off the ammonia or ammonium carbonate taken up in excess by the salts.  The excess may be evaporated by spreading out the ammoniated salts in the air, by heating the ammoniated salts or by treating them with a current of hot gas; it is stated that temperatures up to 100 DEG  C. may be employed.  Alternatively the excess ammonia and ammonium carbonate may be absorbed by mixing the ammoniated salts with ammonia combining substances, e.g. superphosphates or calcium or magnesium salts.  The treatment of the salts with ammonia and carbon dioxide may take place in two apparatus which are alternately used as absorption apparatus for the gaseous mixture used in excess and the ammonia and ammonium carbonate taken up in excess and evaporated and as the actual reaction apparatus.  The salts may be agitated during the ammoniating process and salts such as magnesium chloride which become caked and lumpy during the ammoniating process may be disintegrated before continuing the process.  Small quantities of water insufficient to dissolve the salt may be added before or during the process.  The reaction materials may be cooled or heated as desired; a temperature of 50-75 DEG  C. during the whole course of the reaction is stated to be desirable.  When using potassium salts containing magnesium salts these salts may be mixed with superphosphates prior to ammoniation.