Precious metal and mercury recovery from aq. solns. - with polymeric thio-ureide(s) prepd. by reacting polyethyleneimine or polyvinyl amine with isothiocyanate

摘要

New polymeric thioureides are of formula -(-CH(-NHCSNHR1)-CH2-)a- (-CH2-CHNR2-)b- (I) (where R1 is alkyl or aryl, R2 is H, alkyl or aryl, the ratio a:b is 1:0 to 1:10 and a plus b is at least 30) and -(-CH2-CH2-NCSNHR1-)a- (-CH2-CH2-NR2-)b- (II) (where R1 is alkyl or aryl, R2 is H or -CH2-CH2-NH2, ratio a:b is 2:1 to 1:10 and a plus b is at least 30). Au, Pt, Hg, Pd, Rh, Ru, Os and Ir complexes of (I) and (II) and their specified derivs. are also claimed. (I) and (II) are used in hydrometallurgy for selectively sepg. and enriching Au, Pt metals or Hg from aq.solns., e.g. from over- flooded mines contg. no less than 1 ppb Au. Cpds. (I) and (II) have high water-solubility, metal-loading capacity, e.g. 1g polymer can bond 0.05-2 g precious metal, and selectivity. In an example, 98% Au is recovered from a soln. contg. 1 ppm Au salt. After precious metal sepn., the polymer complex-former can be re-used.