DE621580C - Process for the production of ammonium chloride and ammonium sulphate - Google Patents

Description

Process for the production of ammonium chloride and ammonium sulfate In The technology often produces mixtures of chlorammon and ammonium sulfate. This is z. B. the case when using mixtures of magnesium chloride and magnesium sulfate Ammonium carbonate processed into magnesium carbonate. Such mixtures of the two ammonium salts are at most salable in the form of mixed fertilizers. Their separation is therefore desired.

It has been found that upon evaporation of solutions, both Contains dissolved salts, depending on the ratio of the two salts to one another, one of the same - chloride or sulfate - separates in pure form until one a solution saturated with both salts at a higher temperature is obtained. This delivers Remarkably, on cooling, high percentage ammonium chloride, if necessary in addition to small amounts of ammonium sulfate. These amounts of sulfate are so small that there is suffices to obtain pure ammonium chloride in any case, the solution before the To cool with a small amount of water, so that the ammonium sulfate ip solution remains (for the solution saturated at 80 ° about 5% water). Even better one proceeds in such a way that the cover liquors that arise when covering the ammonium chloride are removed used for this. Nevertheless, pure ammonium chloride is obtained by the process and the covering process merely displaces the adhering mother liquors to the Purpose, the amount of cover liquor produced is sufficient in any case, to ensure crystallization of pure ammonium chloride. It can of course also other solutions of other origin, cold or hot, saturated with ammonium chloride in the required or larger amount for this use, especially since this does not reduce the yield of crystals, and may even increase it will.

These can also be used when processing mixtures of the two salts be dissolved with water or cover liquor in such a way that in addition to one of the two salts in pure form, a solution which is hotly saturated with both salts is obtained, which is cooled as above with the addition of ammonium chloride cover liquor.

The mother liquors separated from the ammonium chloride obtained result in the case of evaporation until the beginning of a salt deposition, initially one in the heat solution saturated with ammonium sulphate, which precipitates ammonium sulphate is further evaporated until the above-mentioned, saturated with both salts solution again is obtained. The ammonium sulfate obtained during evaporation is pure when the evaporation is interrupted as soon as the saturation point is reached on both salts. the The solutions thus obtained are again as above with the separation of ammonium chloride brought to crystallization. The procedure allows the full Processing of alkalis containing both salts with alternating deposition of ammonium chloride and ammonium sulfate.

A method for the direct separation of ammonium chloride is known from mother liquors, which in the ammonium sulfate recovery from distillate gases attack. With these acidic mother liquors, which contain 5 to% free sulfuric acid contain, there are significantly different solubility ratios insofar as than in these also the solubility of acidic salts is taken into account. must find. In contrast The present invention relates only to the separation of the salts ammonium chloride and ammonium sulfate or the separate production of the same from both salts Solutions. . -Design example, ieI. ..

500 g of a salt mixture consisting of 38; z 6 "° / o (NH4) 1S04 and 61.84 '/, N H4 C1, are to be broken down into the individual salts. One at ordinary Temperature obtained solution of this salt mixture in about goo g of water is at 8o ° evaporates until the first crystals of ammonium chloride begin to separate, whereby the solution I is obtained. If you continue to vaporize until the moment in which ammonium sulfate crystals add to the separated ammonium chloride begin, with evaporation of 127.1 g of water, 83.6 g of the latter salt become and get solution II. When this solution cools to 25 °, rounds separate 115 g of ammonium chloride, which still contains 4.4% ammonium sulfate, -of which it passes through Ceilings can be easily freed with a little water. The mother liquor obtained III- is evaporated at 80 ° and separates with evaporation of. 197.7 g water 87.8 g Ammonium sulfate, which is obtained in pure form when the evaporation in the moment is interrupted, in which ammonium chloride also occurs as crystals. The -so solution IV obtained has the same composition as solution II and provides -Cool again ammonium chloride and solution III etc.

To obtain pure ammonium chloride as crystals, you can also Cool the solution 1I by adding a little water or ammonium chloride cover liquor. In the latter case, when 15 g of cover liquor are added, 9 g of pure ammonium chloride are obtained obtained and a mother liquor, the composition of which the solution III completely is equivalent to.

If one cools the solution II without additives to 0 ° with stirring, .so becomes the ammonium chloride also obtained free of ammonium sulfate. The yield is then 149.1 g.

As an example of processing mainly containing ammonium sulphate Solutions or salt mixtures, solution III according to the above example can be used, which is evaporated with ammonium sulphate separation and ammonium chloride on cooling delivers etc.

Finally, the salt mixture of the example can also be combined with so much hot water that solution II is obtained immediately, some of the ammonium chloride remaining undissolved; so the example according to 416.49 salt mixture with 406.4 g of water of 80 ° would provide 83.6 g of N H4 Cl and a solution II, which in the. Cooling gives 114.9 g of crystals consisting essentially of ammonium chloride. When this solution evaporates, 87.8 g of ammonium sulfate are deposited and a solution IV - solution II is obtained, and so on.

Or 302.51 g of a salt mixture corresponding to solution III are treated with 2o &; 7 g of water at 80 ° and yield 87.8 g of ammonium sulphate and solution IV -solution II, which separates out ammonium chloride when it crystallizes, and so on. (N H4) 2 S 0, N H4 Cl H, 0 Solution I 8o °. 39 0, 8 309.2 5335 . -.-83.6 127.1 crist. 83.6 NH4C1 Solution 11 80 0 1 90.8 225.6 4o6.4 5.1 1 0 9.8 - Cryst. 114.9 NH4Cl containing sulfate Solution 111 25 ° 186.7 - - 1X5.8 4o6.4 '. 87-, 8 197.7 crist. 87.8 (NH4) 2 S04 Solution IV 80 ° 97.9. 115.8 2o8.7

Claims (3)

'PATENT CLAIMS: i. Process for the production of ammonium chloride and Ammonium sulfate from mixtures or solutions containing these salts, characterized in that that first a solution containing these salts with deposition of one of the salts is evaporated in pure form until one of the two salts is at a higher temperature saturated solution is obtained, which is then used for the purpose of separating out a high-percentage ammonium chloride is cooled, and that thereupon the mother liquors separated from the ammonium chloride be evaporated with the separation of ammonium sulfate, until again one of the two Salting at a higher temperature creates a saturated solution, which in the same way is further treated. 2. Modification of the method according to claim i, characterized in that that in order to obtain a pure ammonium chloride the cooling of the two 'Salt at a higher temperature saturated solution only after the addition less Amounts of water or of cover liquors produced when covering the ammonium chloride he follows. 3. The method according to claim i, characterized in that mixtures of both Salts with such amounts of hot water or / and cover liquors, especially des Ammonium sulphate, treated «-erden that with the separation of one of the two salts obtained in pure form a solution saturated with both salts at a higher temperature which is further processed according to claim i.