AT34873B - Process for the preparation of high-percentage potash from still coal or the like. - Google Patents

Description

  

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  Process for the preparation of high-percentage potash from still coal or the like.
 EMI1.1
 of at least 40 Bé. and a temperature of about 40-50 C is treated with carbonic acid, possibly under pressure, with potassium bicarbonate precipitating from the appropriately cooled liquid.
 EMI1.2
   The lye that remains is then evaporated accordingly, the sodium bicarbonate is converted into carbonate by heating and the remaining solution is recently treated with carbonic acid, with another part of the potassium precipitating as bicarbonate. With the known solubility ratios of sodium and potassium bicarbonate in water,

   If a potassium sodium carbonate solution is treated with carbonic acid, precipitation of sodium bicarbonate rather than potassium bicarbonate would be expected. In the case of the lye that comes under consideration, produced from coal stillage, however, the solubility ratios of the bicarbonates are significantly influenced by the presence of chlorides and sulphates; Temperature and duration of the introduction of carbonic acid brought about a state in which the solution is never saturated with sodium bicarbonate, so that precipitation of this malt is avoided. The detailed implementation of the procedure is clear from the example given.

   The starting product is, for example, a lye with the following composition of salt content:
 EMI1.3
   In the caustic solution, heated to about 45 ° C., carbonic acid is then introduced under pressure (0.2-1-5 atm.) In suitable apparatus. As a result of the heat of reaction that occurs, cooling to a temperature of 25-45 ° C. is necessary During this operation, a high-purity potassium bicarbonate precipitates and the salt content of the solution drops. When it reaches 39 Bé., the introduction of carbonic acid is interrupted and the precipitated salt is sucked off.



   The same can be used as such (bicarbonate) or as carbonate after previous calcination.
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 EMI2.1
 the sparingly soluble potassium bicarbonate separates out when this solution cools down. At a temperature of around 70 C, COg has recently been introduced until the concentration of the lye 39-41 Be. has reached. In doing so, 30-38% of the dry matter of the original liquor is recovered as high-percentage potash.



   Composition of the excretion:
 EMI2.2
   The residual mother liquor comes to renewed partial sulfate, chloride. Soda separation and can then be used again for carbonation.



   Composition of the residual liquor dry substance:
 EMI2.3
 The above method thus carbonates the same twice
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   Lime-kiln carbonic acid, fermentation carbonic acid (which is offered by a new technical utilization), furthermore the carbonic acid obtainable during the calcination of the bicarbonate can serve as carbonic acid sources.

 

Claims (1)

PATENT CLAIM: Process for the preparation of high-percentage potash as sehlempekohle or similar stolon, characterized in that after previous partial elimination of the by-products at a concentration of at least 400 Bé. and a temperature of about 40-50 "C, carbonic acid, possibly under pressure, whereby potassium bicarbonate precipitates from the appropriately cooled liquid, whereupon the introduction of carbonic acid is interrupted at a concentration of the base of at least 370 Bé., the remaining base concentrated, Sodium bicarbonate is converted into carbonate by heating and another part of the potassium salt still in solution is excreted by introducing carbonic acid again.