DE1063092B - Process for the electrostatic processing of potash salts - Google Patents

Description

GERMAN

The success of the processing of salt minerals by separation in the electrostatic field depends on depends to a large extent on the provenance and history of the mineral. As the reasons for this different behavior are unknown, it can never be foreseen whether an electrostatic separation process, which has brought excellent separation results with a salt of certain provenance, will or will not have the same success with the same salt of a different provenance.

In previous investigations into the electrostatic processing of potash salts, a large number of substances were found which, when used as conditioning agents for potash salts, produce very good results in electrostatic separation. In the continuation of these experiments it has now been found that the class of organic acid anhydrides are very excellent conditioning agents for certain potash salts. For example, with the help of phthalic anhydride from a hard salt with 15.7% K ₂ O, from which with the conditioning agents found so far, at best, a concentrate with 43% K ₂ O with a K ₂ O yield of 79% and a residue with 4.3% K ₂ O could be obtained, a concentrate of 58% K ₂ O with a K ₂ O yield of 94.2%, a residue with only 1.2% K ₂ O being obtained. Other carboxylic acid anhydrides, but also organic sulfonic acid anhydrides and mixed anhydrides such as, for example, o-sulfobenzoic acid anhydride, act in an analogous manner with certain quantitative differences. Mixtures of anhydrides with one another or of anhydrides with known conditioning agents can often be used to great advantage.

The new process is structured as follows: 10 to 200 g, preferably 50 to 120 g, of the organic acid anhydride are applied to the potash salt, which has been ground to the particle size customary in electrostatic separation. The conditioning agent is expediently added in dissolved form in an apparatus which ensures good distribution of the conditioning agent on the material to be processed (eg mixer).
However, the conditioning agent can also be added to the salt in pure form, in liquid or molten form. Even conditioning of the salt with the anhydrides added in powder form is possible, provided that thorough mixing and sufficient fineness of the conditioning agent are ensured.

Another possibility of applying the conditioning agent uniformly to the salt surface of the crude salt mixture provided for the separation is given by the fact that the salt is carried out using the electrostatic method
Processing of potash salts

Applicant:
Potash Research Institute G. mb FL,
Hanover, Georgstr. 29

Dr.-Ing. Hans Autenrieth ₁ Hanover,
and Dr. rer. nat. Gerd Peuschel ₁ Benthe over Hanover, have been named as the inventor

agents present in vapor form are treated (e.g. in fluidized beds or in trickle towers).

If you have used a solvent, this must be removed before being applied to the electrostatic precipitator become, what in any known manner, most expediently by treatment of the conditioned salt can be done with a warm gas (air) stream. At the same time, the material to be processed is thereby heated to the most favorable separation temperature, which is generally between room temperature and 120 ° C. The most favorable separation temperature and amount of conditioning agent for a specific item to be processed can be determined by simple preliminary tests. The pretreated product is now in an electric separator of known design (e.g. roller or free-fall separator) at a field strength separated from 3 to 9 kV / cm.

Examples

The examples summarized in the table below are purely illustrative and do not restrict the process in any way. For comparison purposes, the amount of conditioning agent added was kept constant = 100 g / t and the temperature was also varied only slightly. The results of the table were obtained by spraying as much of a solution of the conditioning agent mentioned in column 4 on the processing material indicated in column 2, which had the K _{2 O content listed in column 3, in a mixer, up to 100 g of the conditioning agent per} Ton of salt were applied. The solvent was then evaporated in a stream of warm air and the material to be processed was heated to the separation temperature given in column 5. At this temperature, the material conditioned in this way was fed to a three-stage roller separator and two fractions were removed at the lower end of the separator.

909 607/65

Claims (4)

the residue and the pre-concentrate. The K2O content of the residue is listed in column 6, the K2O content of the pre-concentrate in column 7. The pre-concentrate was then passed through the electric separator again and two fractions were again removed, the post-concentrate and the medium (not listed). In continuous operation, the medium is returned to the preconcentration and there, generally together with the crude salt, is separated again. The K2O content of the secondary concentrate is listed in column 8, the K2O yield based on the K2O content of the crude salt, which was set = 100, in column 9. Processing goods Separation-Return-Before-AfterK2 O-Lfd. No. Salt type ProvenanceK »O- content ° / oConditioning agent per 100 g / tcempe- rature ° C level%> K2 O concentrate% K2 O concentrate% K2 O concentrate% / 01234567891 Hard salt I, a15.7 Phthalic anhydride801,239,058,094,22 Hard anhydride801,239,058,094,22Hard salt , 136,556,695.93 hard salt I, a15.7 maleic anhydride803,040,049,187.94 hard salt I, a15.7 succinic anhydride802,141,249,991.45 sylvinitol II13,4 phthalic anhydride801,639,651,691,86 mixed salt III (sylvinite anhydride )801,639,651,691,86 mixed salt III,56,57,4 anhydride salt8,3801,639,651,691,86 mixed salt III (sylvinite anhydride salt8,380,380,1 mixed salt III,57,4 anhydride salt14,380,360) IIIthalic anhydride salt14,43,453,240,040,049,187,94 hard salt I, a15,7,440,049,187,94 , 4butyric anhydride603,937,545,882,79 mixed salt III14,4 benzoic anhydride601,438,057,392,910 \ / {Λ C c \\ CQ 1 rT TTT14 4diphenic anhydride601,538,356,293.21 1 hard salt I, b15,4 in apninao salt 801,14,8, anic anhydride, III 801,400 , a15,7benzenesulfonic anhydride601,739,854,193,114hard salt I, b15,4p-toluenesulfonic anhydride801,637,655,093,615hard salt I, a15.7Nap hthalenedisulphonic anhydride802,236,352,891,516 hard salt I, a15.7 maleic anhydride + phthalic anhydride 1: 1801,538,854,794,117 hard salt I, a15.7 succinic anhydride + phthalic anhydride 1: 1801,337,953,295,514,7 mixed salt 1: 1801,337,953,295,019.4 mixed salt (III.1801,337,953,295,514.4) mixed salt III. 4Butyric anhydride + sulfonated fatty acid amide 1: 1601,740,454,692,020Sylvinit II13,4Tetrachlorophthalic anhydride601,438,952,492,921Sylvinit II13,4Tetrahydrophthalic anhydride601,339,253,293,4 The concentrates can be brought up to 60% more easily by further concentration. By varying the amount of conditioning agent added and possibly the separation temperature, the results of the examples listed under No. 3, 4, 7, 8 and 15 could be further improved. The invention makes it possible to electrostatically process even potassium salts, which stubbornly resisted the ability to be processed by the electrostatic process through conditioning with the conditioning agents found earlier, with in some cases excellent success. 65 patent claims 1. A method for the electrostatic separation of potash salts, characterized in that the Processing material with small quantities of organic 70 shear acid anhydrides conditioned and then known in an electrostatic precipitator Type of electrostatic separation is subjected. 2. The method according to claim 1, characterized in that as a conditioning agent Carboxylic anhydrides can be used. 3. The method according to claim 1, characterized in that the conditioning agent organic sulfonic anhydrides or mixed anhydrides, which are different from carboxylic acids and organic Derive sulfonic acids can be used. 4. The method according to claims 1 to 3, characterized in that mixtures of the in the Claims 2 and 3 mentioned anhydrides among themselves or mixtures of known conditioning agents with the anhydrides mentioned in the preceding claims as conditioning agents be used. & 909 607/65 8.59