DE390123C - Process for the production of potassium chloride from hard salt and sylvinite - Google Patents

Description

Process for the production of potassium chloride from hard salt and sylvinite. The production of potassium chlorine from hard: alz or sylvinite generally requires no evaporation systems; because the alkaline solutions that fall in the process are repeated over and over again Can be used and, under normal circumstances, they cannot be multiplied Experienced. This also applies if the manufacture of high percentage potassium chlorine it is necessary to cover the first product obtained in the crystallization power.

But they are growing in importance as a result of the manufacture of sulphates Lye quantities are supplied, which also contains magnesium chloride to be eliminated from the plant evaporation cannot be avoided. This is done appropriately by narrowing the lye as much as possible and crystallizing potassium chlorine, this corresponds to the same formation conditions for the representation of potassium chlorine from carnallite is just as low as there, while that from cooling obtained liquor is evaporated again and in addition to artificial carnallite final liquor supplies.

On the further processing of the potassium chlorine and carnallite obtained in this way the procedure: les main patent is to be applied.

For the further processing of the sodium chloride containing potassium chloride by It is irrelevant how. the table salt content is high, since the table salt, whether present in larger or smaller quantities, remains unsolved while from the Solution of pure potassium chloride is obtained. Therefore, it is also omitted during evaporation the need to use such methods as to separate the at allow the evaporation of deposited salt from the hot solution so that the Constriction in towers or in drums can take place in which the atomized liquor exposed to cold or hot air or fire gases. The evaporation can be carried out more economically, especially when using exhaust gases than what happens in vaporizers. The hot lye then comes without prior separation of the salt precipitated during the evaporation for complete Cooling and crystallization.

If a hot lye is fed to the cooling tower, the cooling effect takes place once through heat transfer from the hot liquid to the cold air, secondly, however, it increases with the temperature, intensity and dryness of the counteracting air flow also an evaporation of the lye, and the evaporation cold increases the cooling effect achieved through heat transfer.

Take a closer look at the processes - so surrendered a crystallization for the cooling of a caustic solution of about 11.3 percent by weight M-g CI1 of 9.78 percent of 77.9 percent potassium chlorine. The same lye separates during the Evaporation of 8.2 parts of water and 3.96 parts of potassium chlorine of 59.6 percent Cooling down another 9, t9 parts of 87.9 percent salt, a total of 13.15 1 eae 6Z5, t percent salt.

The content of the potassium chloride obtained in the crystallization of co-crystallized sodium chloride increases with the content of magnesium chlorine in the mother liquors. Likewise, the sodium chloride content rises in the salt with the chloromagnesium content obtained during evaporation from solutions saturated with chlorine and sodium chloride, but here to a greater extent, so that the salt obtained during evaporation of lye with 15 percent by weight to 25 percent by weight is below Reduction of the sodium content when covering pure potassium chloride can no longer be obtained. But even in the mixture with the crystallized higher-percentage salt, in all cases in which evaporation is necessary, the amounts of water necessary to dissolve the sodium chloride content of this salt component have to speak of a completely useless burden on the evaporation, possibly even as a result not to mention the reduction in yield that occurs. But even at low magnesium chlorine concentrations, the evaporation of saturated solutions causes an unjustified burden on the evaporation, if such is necessary at all. The observation made everywhere that in cooling systems with considerable use of the evaporative cold the quality of the salt obtained suffers, and that the apparent increase in the yield in the Dejkbottich converts into loss of substance under the load of the dam, is explained by these facts.

In contrast, the increase in yield is an actual one as soon as instead of the covering process, the dissolving process to remove what remains undissolved Rock salt and separation of pure potassium chloride is used in the cold. The amount of heat required for this dissolving process is low compared to the evaporation costs of the water introduced in the decking process.

The usual form of execution uses alkalis with a medium chlorine magnesium content the hard salt and Sylv initfabrikation or from ancillary businesses, z. B. Potash magnesia and Sulphate production, by evaporation to such a chlorine magnesium concentration concentrated so that when crystallizing, potassium chlorine is still free of carnallite is obtained, and the cooled liquor evaporation again under the otherwise subject to usual evaporation conditions. In general, the enrichment the caustic solutions of the potash magnesia and sulphate production with chlorine magnesium by cold Stir with carnallite and add these alkalis enriched in magnesium chloride preferred for evaporation, because so the sulfuric acid still in solution Salts can be made usable in the sulphate plant.

Another embodiment of the method would consist of that the evaporation of the lyes is driven to the point at which carnallite would begin to appear as a sediment at the vapor temperature. That at the Evaporation of the separated mixture of potassium chloride and sodium chloride would have to be recrystallized, while from the hot solution carnallite in addition to high-percentage chlorine magnesium lye is obtained.

The second claim relates to the extraction of potassium chlorine from stage salts falling during the evaporation of mother liquors. The one for this viable way was in »Kali« 192o, p.230, in the additional evaporation of final liquors, however, by increasing the evaporation costs. instructed. The limit of possibility To obtain potassium chlorine in pure form from the mixture with rock salt through blankets, is in the ratio of the simultaneously dissolved salt quantities of the cover liquor, for 25o ° given by the ratio K C1_ Na Cl = 35.5: 645, so that when covering of salt mixtures with a lower chlorine content, finally pure rock salt, With a higher potassium chlorine content, pure potassium chlorine is obtained. From salt mixtures any mixing ratio, including the potassium chloride obtained during evaporation containing mixtures, but can be dissolved by dissolving with water or from such solutions falling mother liquor completely removes the potassium chloride and in pure, rock salt-free Gain shape. Especially with this possibility of extracting potassium chloride from low-percentage Mixtures of salts can be avoided by using the usual evaporators for evaporation, which separates the salt deposited during evaporation from the hot Solution allow apart, and it can also be used during the cooling process without any damage Devices are brought into use, which an intensive evaporation of Have water in the wake. So the use of hot exhaust gases of any kind can take place, especially as you may be carried away with your subsequent redemption Fly ash can be easily removed. Also the procurement costs of evaporation drums or similar devices are considerably lower than those of the vaporizers.

Claims (1)

PATENT CLAIMS: i. Process for the extraction of high percentage potassium chlorine from the salts which work on hard salt and sylvinite during evaporation of caustic solutions from potassium chlorine production or their ancillary operations, e.g. B. sulphate production, are obtained, characterized in that the covering process by releasing the sodium chloride containing potassium chloride is replaced according to the main patent 388789. a. procedure according to claim i, characterized by the use of such chlorine potassium-chlorosodium mixtures, which would otherwise no longer be used for the covering process due to their high sodium chloride content are usable, -z. B. of stage salts. 3. The method according to claim i, characterized through the use of such salts, which are obtained from evaporation and cooling processes the separation of the salts precipitated during evaporation from those during cooling secluded do not allow.