Patent GB-137034-A (GB)
Title: Improved manufacture of ammonium perchlorate
IPC: C01B11/18
Filed: 1919-11-21
Abstract: In the production of ammonium perchlorate by double decomposition of ammonium sulphate and sodium perchlorate, an initial solution saturated with ammonium perchlorate and sodium sulphate at a temperature below 33 DEG  C. is heated to a temperature above 33 DEG C., and ammonium sulphate and sodium perchlorate are added, preferably in equivalent quantities so as to cause precipitation of sodium sulphate and saturation with ammonium perchlorate, the higher temperature being such that the ratio dissolved of sodium sulphate to water in the hot solution is the same as the ratio of sodium sulphate to water in the solution at starting.  The precipitated sodium sulphate is removed and the solution is cooled to the starting temperature, when an equivalent amount of ammonium perchlorate separates, and the mother-liquid may be used again.  It is not necessary for the starting solution to be wholly saturated with sodium sulphate, so long as the ratios above mentioned are equal, nor for the final solution to be wholly saturated with ammonium perchlorate, but these conditions give the greatest efficiency.  In carrying out the process, the initial salts may be wholly or partly dissolved in separate portions of the initial solution, which portions are then mixed.  The Specification as open to inspection under Sect. 91 (3) (a) states that the process is applicable generally when one reaction product has a solubility increasing with the temperature and the other a solubility increasing to a maximum and then diminishing. An indifferent substance such as a small excess of one of the initial salts, or sulphuric acid, may be added once for all to the reaction mixture.  This subjec-matter does not appear in the Specification as accepted.ALSO:In the production of ammonium perchlorate by double decomposition of ammonium sulphate and sodium perchlorate, an initial solution saturated with ammonium perchlorate and sodium sulphate at a temperature below 33 DEG  C. is heated to a temperature above 33 DEG  C. and ammonium sulphate and sodium perchlorate are added preferably in equivalent quantities so as to cause precipitation of sodium sulphate and saturation with ammonium perchlorate, the higher temperature being such that the ratio dissolved of sodium sulphate to water in the hot solution is the same as the ratio of sodium sulphate to water in the solution at starting. The precipitated sodium sulphate is removed and the as a small excess of one of the initial salts, or solution is cooled to the starting temperature, when the equivalent amount of ammonium perchlorate separates, and the mother-liquor may be used again.  It is not necessary for the starting solution to be wholly saturated with sodium sulphate, so long as the ratios above mentioned are equal, nor for the final solution to be wholly saturated with ammonium perchlorate, but these conditions give the greatest efficiency.  In carrying out the process, the initial salts may be wholly or partly dissolved in separate portions of the initial solution, which portions are then mixed.  The Specification as open to inspection under Sect. 91 (3) (a) states that the process is applicable generally when one reaction product has a solubility increasing with temperature and the other a solubility increasing to a maximum and then diminishing.  An indifferent substance such sulphuric acid, may be added once for all to the reaction mixture.  This subject-matter does not appear in the Specification as accepted.