BE372062A - - Google Patents

Description

       

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  "Process for the manufacture of potassium nitrate"
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 A method COJVt1, -lLe. The preparation of potassium nitrate is the decomposition of potassium sulphate by calcium nitrate.
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 K2S04 + Ca (id03) 2 = Kli03 + CaBo 4
The gypsum formed is separated from the potassium nitrate solution by decanting or filtering and the resulting potassium nitrate solution is evaporated.



   This method of making potas- siam nitrate appears very simple and full of promise, but it has serious drawbacks.



   In the first place, the reaction does not take place in such a simple way as one supposes from the above equation, because not only gypsum is formed, but also co ..double exposures of potassium and calciam with sulfuric acid, like syngeri-
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 te (KSS04. CaS04. H20) and potassium sulphate ss illm

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 ponta calcium salfate (K2SO4.5 CaSO4.H2O). This leads to losses of potash, which increase the cost of the process and make it less advantageous or loss-making.



   Another drawback is that the potassium sulfate itself is too expensive a brate material for the manufacture of. potassium nitrate, especially when this potassium nitrate is to be used as a fertilizer.



   The present invention relates to a process which makes it possible to employ the above reaction for the manufacture of potassium saltpeter, without the mentioned drawbacks occurring,
According to this invention, no potassium salpate, only potassium chlorura, a raw material is employed. It represents a closed loop process, in which potassium chloride, nitric acid, carbonic acid, and ammonia are used as raw materials and potassium nitrate and ammonium chloride represent the products. finished.



   The process is carried out as follows:
In an ammonium chloride solution containing ammonium sulphate, a quantity of potassium chloride equivalent to ammonium salfate is stirred and ammonia is directed therein. Potassium sulphate is formed as a precipitate in ammonia solution of ammonium chloride. The potassium salfate is separated from the mother liquors and mixed with the calcium carbonate obtained from the process and the nitric acid, it then forms gypsum containing sulphate of po-

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   tassiam and a solution of potassium nitrate. These are separated by decanting or filtering and the solution is evaporated to obtain solid potassium nitrate.



   Instead of evaporating the solution of potassium nitrate, it can be cooled to separate the large part of the potassium nitrate, and use the mother liquors to dissolve the new quantities of potassium sulfate obtained afterwards.



   The potassium salfate mothers are then cooled to separate some of the ammonium chloride and after separating this, they are saturated with carbonic acid to form ammonium carbonate.



   In this solution of ammonium-chlorine ammonium carbonate, the gypsum containing de-patassiam salfate obtained in the preparation of potassium nitrate is brewed, which decomposes it into ammonium sulphate and calciam carbonate. This solation is that mentioned at the beginning as a solution of ammonium chlorare containing ammonium sulphate in which the potassium chlorare is separated by stirring by passing it through ammonia, which leads to the formation of new quantities of potassium sulphate.



   It is not necessary to separate the calcium carbonate from the ammonium chloride solution containing ammonium sulfate, because the potassium salfate must be mixed with the calciam carbonate before its decomposition by the 'nitric acid.


    

Claims (1)

CLAIMS 1. Process for the manufacture of potassium nitrate, characterized in that a solution of ammonium carbonate-ammonium chloride obtained by the process is brewed with a solution containing gypsum and calcium carbonate also obtained by the process and potassium chloride with ammonia, and the solid mixture of potassium sulphate and calcium carbonate thus obtained and separated is treated with nitric acid, which gives gypsum and a solution of potassium nitrate. The ammoniacal solution of ammonium chloride separated from the mixture of potassium salfate-calcium carbonate is treated with carbonic acid and cooled to separate part of its ammonium chloride and form ammonium carbonate, then the gypsum containing potassium sulphate obtained by preparing potassium nitrate is stirred into this solution of ammonium carbonate-ammonium chlorare. 2. Process according to claim 1, characterized in that the greater part of the potassium nitrate is separated from the solution of potassium nitrate in the solid form by cooling it, and the mother liquors are used to dissolve new quantities. - quantities of potassium sulphate for decomposition by nitric acid and calcium carbonate.