Abstract: The invention relates to analytical chemistry and technology for processing clay-salt waste (slurries) of potassium-processing factories. The inventive method is based on the analysis of the totality of tested material and consists in annealing the nanoparticles of precious metal (Au, Pt, Pd) organic compounds at a temperature ranging from 600 to 950° C. in the presence of a chloride agent in the form of potassium chlorides (KCl) or sodium chlorides (NaCl) and in producing the acid-soluble compounds of said metals. The sample is exposed to the entire cycle of technological conversion: 1) chloridising roasting; 2) leaching with weak mineral acid solutions; 3) sorption of precious metal compounds on the industrial sorbent AM-2B 4 from the solution obtained after leaching and 4) desorption. A tradeable solution obtained at the end of said cycle is analysed for precious metal content.