Foaming agent and method for floatation of insoluble components of raw salts

1. A method for separating off insoluble components from sylvinite comprising the steps of suspending the sylvinite in saturated salt lye, adding a flocculant to the suspension, and subsequently adding a frother to the resultant suspension composition, wherein the frother comprises at least one polypropylene glycol and at least one ether or ester, wherein

a) the at least one ether corresponds to formula 1

R—O—R′  (1)

wherein R is linear or branched alkyl or alkenyl groups having 2 to 30 carbon atoms and R′ is linear or branched alkyl or alkenyl groups having 1 to 30 carbon atoms,

b) the at least one ester is derived from monobasic or polybasic carboxylic acids having 2 to 30 carbon atoms and monohydric or polyhydric alcohols having 1 to 30 carbon atoms, or

c) the at least one ether or ester are cyclic, wherein the ring size is from 6 to 30 carbon atoms.

2. The method as claimed in claim 1 , wherein the at least one polypropylene glycol has a number-average molecular weight of 100 to 5000 g/mol.

3. The method as claimed in claim 1 , wherein the radicals R and/or the acid radical comprise 4 to 22 carbon atoms and the radicals R′ and/or the alcohol radical comprise 2 to 22 carbon atoms.

4. The method as claimed in claim 1 , where R and R′ or the acid radical and the alcohol radical form a ring having 8 to 22 ring members.

5. The method as claimed in claim 1 , where the at least one ether or ester are selected from the group consisting of dihexyl ether, dioctyl ether, di-(2-ethylhexyl)ether, oleic acid eicosyl ester, 2-ethylhexyl stearate, 2-ethylhexylic acid butyrate, octanoic acid ethyl ester, hexanoic acid ethyl ester, 2-ethylhexylic acid butyl ester, 2-ethylhexyl butyrate and 2-ethylhexylic acid 2-ethylhexyl ester, adipic acid di(2-ethylhexyl ester), 2-ethylhexane-(1,3)-diol mono-n-butyrate, and 2-ethylhexane-(1,3)-diol di-n-butyrate.

6. The method as claimed in claim 1 , wherein the frother further comprises at least one alcohol which has a hydrocarbon radical of 6 to 16 carbon atoms.

7. The method as claimed in claim 6 , wherein the alcohol is a monohydric or dihydric alcohol.

8. The method as claimed in claim 1 , wherein the mixing ratio of ester/ether and optionally alcohol to polypropylene glycol is between 1:10 and 10:1 by weight.

9. The method as claimed in claim 1 , wherein MS is used, and where MS corresponds to the composition

Concentration range

Component

(% by wt)

Di-2-ethylhexyl ether

10-25

2-Ethylhexylic acid 2-ethylhexyl ester

10-25

C 16 -Lactones

 4-20

2-Ethylhexyl butyrate

 3-10

2-Ethylhexane-(1,3)-diol mono-n-butyrate

 5-15

2-Ethylhexanol

 4-10

C 4 - to C 6 acetates

 2-10

2-Ethylhexane-(1,3)-diol

2-5

Ethers and esters > C 20

 0-20.

10. The method as claimed in claim 1 , wherein the flocculant is selected from the group consisting of acrylamide polymers.

11. The method as claimed in claim 1 , wherein the frother is applied in an amount of 0.4 to 150 g/ton of crude salt.

12. The method as claimed in claim 1 , wherein the flocculant is applied in an amount of 0.1 to 100 g/ton of crude salt.

13. The method for the flotation of sylvinite, which comprises the steps of

A) separating off insoluble components from sylvinite as claimed in claim 1 , and

B) flotation of the sylvine by adding a collector and frother for the sylvinite flotation.