Use of nonionic surfactants in obtaining metals.

Procedure for obtaining metals from materials containing these metals, comprising the following process steps: (a) provision of a material containing metal, optionally grinding; (B) providing an aqueous composition containing cyanide, which contains at least one nonionic surfactant, wherein the nonionic surfactant in an aqueous solution adjusted to a pH of 9.8 to 10.2 with NaOH in a concentration of 0.01 to 0.2% by weight at 23 ° C, leads to a reduction of the contact angle on glass after 1 second of at least 20 °, and that the nonionic surfactant is selected from the group consisting of alcohol alkoxylates of the general formula (I) with the meaning R 1 R 2 R 5 R 8 R 1 -O- (CH2-CHR 5 -O-) r (CH2-CH2-O-) n (CH2-CHR 6 -O-) s (CH 2 CHR 2 -O-) m H (I) alkyl or alkylphenol with 4-22 carbon atoms branched at least once, alkyl having 3-4 carbon atoms, alkyl having 1-4 carbon atoms carbon, methyl or ethyl, n average value of 1 to 50 m average value of 0 to 20, r mean value of 0 to 50, s average value of 0 to 50, with the meaning R 3 R 4 wherein m is at least 0.5 if R 5 is methyl oe linden, or has the value 0, or the general formula (II) R 3 -O- (CH2-CH2-O) p (CH2-CHR 4 -O-) q H (II) alkyl or alkylphenol with 4-22 atoms of branched or unbranched alkyl, alkyl with 3-4 carbon atoms, p average value of 1 to 50, q average value of 0.5 to 20, or of the general formula (III) where a is ethyleneoxy C5H11CH (C3H7 ) CH2O (B) p (A) n (B) m (A) qH (III) B in each case independently alkyleneoxy having 3 to 10 carbon atoms, or mixtures thereof, introducing groups A and B in block in the order indicated, p number from 0 to 10, appearing in mixture n greater than 0 to 20 number, m is greater than 0 to 20 number q greater than 0 to 10 number, p + n + m + q at least 1, 70 to 99% by weight of alkoxylates A1, in which C5H11 has the meaning n-C5H11, and 1 to 30% by weight of alkoxylates A2, which C5H11 has the meaning C2H5CH (CH3) CH2 and / or CH3CH (CH3) CH2CH2, or group of isotridecanol alkoxylates of the general formula (V) in which R denotes a radical iso -tridecilo, RO- (CmH2mO) x- (CnH2nO) y H (V), m represents the number 2, and simultaneously n represents the number 3 or 4, m represents the number 3 or 4, and simultaneously n represents the number 2, x and y independently are numbers from 1 to 20, wherein the variable x greater than or equal and in the case m = 2 / n = 3 or 4; (C) contacting metalliferous material in the presence of an oxidizing agent with the composition according to b), obtaining a mother liquor enriched with metal complexes cyanide, in an application amount of 1 to 30 ppm of nonionic surfactant per tonne of starting material.