DE1492916B2 - PROCESS FOR SEPARATING POTASSIUM FROM INDUSTRIAL BY-PRODUCTS - Google Patents

Description

The present invention relates to a method for reducing the potassium content of industrial by-products, such as yeast or distillation liquor, for the production of animal feed, a sulphate or sulfuric acid being added to the vinasse and the potassium sulphate formed by filtration or centrifugation.

A method is already known from US Pat. No. 1,886,045, with which a mixture of Potassium and organics that are a by-product in fermentation processes or in the sugar industry accrues, can be separated. In this known method, an aqueous solution of this mixture ■ Ammonium sulfate added, the solution concentrated, potassium sulfate and ammonium chloride precipitated and separated from the solution by means of ethyl alcohol. The potassium sulfate precipitate formed during separation consists of very small crystals that are very difficult to filter out or centrifuge out. The separation the potassium salts can only be done with an additional expenditure of energy, which in none Ratio to profit, d. H. to increase the market value of the product.

For the above reason are therefore generally the yeast or distillation vinasse that are highly enriched in nitrogenous organic matter and have large amounts of sodium and Contains potassium salts, used only for fertilization purposes.

Also known from the German patent specification 860 737 for the treatment of molasses liquor with hydrochloric acid and then with ammonia to excrete the potassium only leads to excretion of potassium in fine crystalline form. So here, too, is an expensive filtration process Separation necessary. The price to be paid for this is also out of proportion to that for the feed obtained in this way achievable market price.

ίο In this known method there is also no Separation of the thickened amount of stillage mixed with sulfuric acid or sulphate into two parts, which can be further processed in different ways and then brought together again.

Sulfuric acid or sulfates are added in such a way that the crystals precipitate immediately, and in fine crystalline form.

From the German patent specification 873 491 is also a method for removing the potassium content from industrial waste products is already known. Here the potassium from the molasses is removed by a suitable ion exchanger. To do this, the Molasses first diluted with 25 to 30% water and then in contact with a cation exchanger to be brought. The amount of water used must be removed later. After the ion exchange has taken place, whereby the potash salts of the molasses are converted into organic acids, must by a Acid replaces the potassium absorbed by the ion exchanger with hydrogen ions and so on the ion exchanger can be made usable for a new potassium removal. With this procedure is the ion exchange column is saturated very quickly, so that a very high outlay on equipment is necessary will. This also makes this process uneconomical.

The object of the present invention is to provide a with simple economic means Excretion of potassium salts, which are present in a dissolved state in liquid industrial by-products are to enable.

This is achieved in the method of the type mentioned at the beginning by the following procedural steps:

a) The stillage is concentrated to a content of approximately 45 g of K ₂ O per liter;

b) a sulphate or sulfuric acid is added to the concentrated stillage up to a ratio, in which no precipitate of potassium sulfate occurs;

c) a small amount of this solution is concentrated in a crystallizer to a content of 75 to 80 g K ₂ O per liter;

d) with continuation of the vacuum evaporation process, the other part of the Solution supplied;

e) the solution with the potassium sulfate crystals it contains is cooled to about 35 ° C;

f) the potassium sulfate crystals are separated from the solution by centrifugation in a known manner.

In this process, a small part of the concentrated stillage is first added Sulfuric acid or sulfate are added and further thickened in a further vacuum evaporation process becomes, with then continually the other part

3 4

is added to the solution, with a corresponding 2001 of this stillage treated in this way are im

Cooling causes the crystals to become larger, vacuum evaporated until the dry matter content

so that the thus obtained coarsely crystalline potassium is 750 g per liter, with potassium sulfate crystals

Form sulfate crystals easily by filtering.

or centrifugation. The 5 The rest of the stillage (3401) is added in such a way that

The separation process is thus simplified and that the concentration increases increasingly,

cheaper. At the end of the thickening process, the density is

In the case of yeast pulp, it is recommended that the mother liquor be about 1.4, which is a proportion of

the sulphation by adding ammonium sulphate corresponds to a dry matter of about 1075 g per liter,

to be carried out, since the addition of only sulfur io the amount of residue obtained in this way of 145 liters

acid an end product that is too acidic is produced. The cooled to about 35 ⁰ C over 12 hours. One

Addition of soda increases the sodium separation of the residue by centrifugation (without

content of the stillage freed from potassium, which is often washing) results in 125 1 of in its potassium content

With regard to the use of this secondary product - strongly reduced stillage and 40 kg of crystalline mass,

product is not wanted. 15 The stillage obtained in this way has a pH of

To produce large crystals that are slightly different from the 5.9 and show the following composition:

Solution can be separated, the Kristalli tv ₇ . , _o ,

ization in a non-continuously working dry matter 74.5 / ₀

Crystallizer carried out, the construction of which Γλ ° ο /

a good stirring of the mass during the crystalline 20 potassium (m K ₂ O) .......... 5.0 / ₀

sizing allowed ^of dry material

. Nitrogen, total 7.3%

^{ΰ exs} P ^{1 e l of} the dry material

Removing potassium from a yeast liquor ammonia nitrogen 2.5%

The stillage is first thickened so far that you 25 of ^the dry material

Dry matter component is 260 g per liter; ^ ,,. ",

the dry mass had the following composition: ^The crystalline mass shows the following composition:

Potassium (inK ₂ O) 15.8% ⁶ _{QOn0 /}

SuIfate (in SO ₂ ) 5.8% SSTSS SSw '

Total nitrogen 5.5 <> / ₀ 3o Kahurn (K ₂ O) 39.5%

Ammonia nitrogen 0.5% ^ ^at ?, ^(S ° S> ⁴ H J, ⁰

_{n TTW} . ,. ,. ^{/ 0} chlorides (C) 0.5%

The pH is 6.9. Sodium and Calcium (in Na ₂ O and

For 5401 stillage, 201 ammonia (density CaO) 6.5%

0.92), followed by 8 1 sulfuric acid (density 1.84) 35 nitrogen, total 3.0%

added. Ammonia nitrogen 1.0%

Claims (2)

Patent claims: 1. Process for reducing the potassium content of industrial by-products, such as Yeast or distillation vinasse, for the production of animal feed, whereby vinasse is a Sulphate or sulfuric acid added and the potassium sulphate formed by filtration or centrifugation disconnected, characterized by the following steps: a) The stillage is concentrated to a content of approximately 45 g of K ₂ O per liter; b) the concentrated stillage becomes a sulphate or sulfuric acid up to a ratio added at which no precipitate of potassium sulfate occurs; c) a small amount of this solution is concentrated in a crystallizer to a content of 75 to 80 g K ₂ O per liter; d) with continuation of the vacuum evaporation process the other part of the solution is continuously added; e) the solution with the potassium sulfate crystals contained therein is cooled to approximately 35 ° C; f) the potassium sulfate crystals are known in Way separated from the solution by centrifugation. 2. The method according to "claim 1, characterized in that that ammonium sulfate is used for the separation of the potassium.