Use of branched alcohols and alkoxylates thereof as secondary collectors

A collector composition comprising:

• a surface-active primary collector selected from the group consisting of fatty acids;
• sulfonates;
• alkyl phosphates;
• alkyl sulfates;
• compounds of the formula (II)
• wherein R1 is a hydrocarbyl group having 8-22 carbon atoms, A is an alkyleneoxy group having 2-4 carbon atoms, p is a number 0 or 1, q is a number from 0 to 5, R2 is a hydrocarbyl group having 1-4 carbon atoms or is the group
• wherein R1, A, p and q have the same meaning as above, Y− is selected from the group consisting of COO− and SO3−, n is a number 1 or 2, M is a cation, which may be monovalent or divalent, and inorganic or organic, and r is a number 1 or 2 or where the compound (II) is in its acidic protonated form without an external cation (Mr+) 1/r;
• compounds of formula (III)
• wherein R2 is a hydrocarbyl group with 8-22 carbon atoms, D is —CH2— or —CH2CH2—, k is a number from 0 to 4, and M is hydrogen or a cation, such as sodium or potassium;
• and compounds of formula (IV)
• wherein R is a hydrocarbyl group having from 7-23 carbon atoms, optionally substituted, R1 is H or CH3, R2 is H or a C1-C4 alkyl group, R3 is H or CH3, n is a number from 1 to 20;
• p is a number from 1 to 3, X is H+ or an organic or inorganic cation and m represents the valency of the cation and is a number from 1 to 2;
• and mixtures thereof;
• and
• a secondary collector that is selected from the group of branched fatty alcohol alkoxylates having 12-16 carbon atoms, a degree of branching of 1-3, and a degree of ethoxylation of up to 3 of the formula (I)
• R—O-(EO)yH (I)
• wherein R is an alkyl or alkenyl group having 12-16 carbon atoms, and wherein said alkyl or alkenyl group has a degree of branching of 1-3, EO is an ethyleneoxy unit, and y is a number from 0 to 3;
• wherein the weight ratio between the primary collector and the secondary collector is between 15:85 and 99:1.