Method for the removal and recovery of metals and precious metals from substrates

Abstract

A method for removing metal and/or precious metal-containing depositions from substrates, wherein said substrate is subjected to treatment with an organo amine protectant component P and an inorganic active component A. Component P may be formed in situ by reaction with component R. Component P is an organic amine and/or organic amine hydrochloride (preferably diisopropylamine hydrochloride), component A is an inorganic compound (preferably inorganic acid or a mixture thereof) and component R is an organic compound that can be split along the C—N bond by the component A into an organic amine (preferably dimethylformamide or N-methyl pyrrolidone). The metals in the form of organo-metallic complexes can be isolated and/or separated by means of different chemical reactions (preferably reduction reactions) and/or biosorption (preferably with seaweed or yeast).

1 . A method for removing metal and/or precious metal-containing depositions from substrates, wherein said substrate is subjected to treatment with an organo amine protectant component “P”/complexing component “C” and an inorganic active component “A”, wherein said component “P”/“C” is selected from the group including mono-, di- and tri-substituted amine hydrochlorides, wherein each substituent is independently an alkyl having 1 to 18 carbon atoms or a cycloalkyl having 3 to 8 carbon atoms, and wherein said component “A” is an inorganic acid or its salt or a mixture thereof. 
     
     
         2 . The method of  claim 1 , wherein said organo amine protectant is prepared in situ by reaction of organic amine and hydrochloric acid. 
     
     
         3 . The method of  claim 1 , wherein said component “P” is selected from triethylamine hydrochloride, diethylamine hydrochloride, ethylamine hydrochloride, dicyclohexylamine hydrochloride, N,N-dimethylcyclohexylamine hydrochloride, diisopropylamine hydrochloride, N-ethylcyclohexylamine hydrochloride and N-methylcyclohexylamine hydrochloride. 
     
     
         4 . The method of  claim 1 , wherein said component “P” is selected from trimethylamine hydrochloride, dimethylamine hydrochloride and methylamine hydrochloride. 
     
     
         5 . The method of  claim 1 , wherein said component “P”/“C” is formed in situ by reaction of said component “A” with a reactive component “R”. 
     
     
         6 . The method of  claim 5 , wherein said component “R” is selected from the group of organic amides and/or organic lactams. 
     
     
         7 . The method of  claim 6 , wherein said component “R” is selected from dimethylformamide and N-methyl pyrrolidone. 
     
     
         8 . The method of  claim 1 , wherein said component “A” is aqua regia. 
     
     
         9 . The method of  claim 1 , wherein said component A is selected from the group including nitric acid, hydrofluoric acid, hydrochloric acid, phosphoric acid, hexafluorosilicic acid, ammonium peroxydisulfate and sulfuric acid and mixtures thereof. 
     
     
         10 . The method of  claim 1 , wherein said deposition comprises at least one selected from the group including Be, Mg, Ca, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Tl, C, Si, Sn, N, P, As, S, Se, Te, and their mixtures, and/or their chemical compounds. 
     
     
         11 . The method of  claim 1 , wherein said substrate comprises at least one selected from the group including aluminum, copper, steel, stainless steel, glass, titanium, their alloys, graphite, carbon fibre, ceramic, fused silica, quartz, blasting media (such as corundum, sand, corn cob, plastic abrasives, silicon carbide, pumice, steel grit, steel shot, walnut shells, soda, and glass beads), polymers and ores. 
     
     
         12 . The method of  claim 1 , wherein said metal(s) is (are) recovered from the organo-metallic complex(es) in the solution resulting from said treatment. 
     
     
         13 . The method of  claim 12 , wherein said recovery is carried out by means of a biosorbant. 
     
     
         14 . The method of  claim 13 , wherein said biosorbant is selected from seaweed and yeast. 
     
     
         15 . The method of  claim 14 , wherein the biosorbant is Spirulina platensis. 
     
     
         16 . The method of  claim 15 , wherein the biosorbant is  Saccharomyces cerevisiae.    
     
     
         17 . A process for obtaining gold and/or platinum from a solution resulting from treatment of a substrate with depositions of gold, platinum and optionally other metals by the method of  claim 1 , said process comprising the following steps: (a) subjecting the solution resulting from said treatment, which contains organo-metallic complexes of the respective metals, to a reduction and refinement process to separate the gold from the complexes and/or other chemical compounds of the other metal(s), (b) adding yeast to the remaining solution in order to selectively biosorb the organo-platinum complex, (c) isolating the resulting yeast/organo-platinum complex by filtration and burning it to obtain platinum oxide, and (d) reducing the platinum oxide to platinum metal. 
     
     
         18 . The method of  claim 17 , wherein the substrate comprises at least one selected from the group including aluminum, copper, steel, stainless steel, glass, titanium, their alloys, graphite, carbon fibre, ceramic, fused silica, quartz, blasting media (such as corundum, sand, corn cob, plastic abrasives, silicon carbide, pumice, steel grit, steel shot, walnut shells, soda, glass beads, polymers and ores.