Abstract: A process for digestion of fine iridium includes (a) alkaline oxidative digestion of 1 part by weight fine iridium and 3 to 20 parts by weight of a combination comprising 40 to 70 parts by weight sodium hydroxide, 15 to 30 parts by weight sodium nitrate, and 10 to 40 parts by weight sodium peroxide in the melt, whereby the sum of the weight fractions equals 100 parts by weight; (b) cooling the digestion material formed in step (a) to 20 to 70° C.; (c) dissolving the acid-soluble fractions of the cooled digestion material in water/halogen hydracid until an acidic aqueous solution with a pH value of ?1 to +1 is obtained; and (d) boiling the acidic aqueous solution obtained in step (c) until the formation of nitrous gases is completed. Insoluble ingredients can be separated from the acidic aqueous solution before or after step (d), if needed.

Abstract: Process for removing precious metal from precious metal-containing catalyst form bodies comprising form bodies and precious metal, whereby the precious metal to be removed is at least one precious metal selected from the group consisting of Au, Ag, Pd, Pt, Ir, Rh, Ru, Os, and Re, comprising the steps of: (a) producing a mixture of precious metal-containing catalyst form bodies in at least one mineral acid that is at least 1N; (b) supplying inert or oxidizing gas into the mixture containing noble metal-containing catalyst form bodies and mineral acid; (c) introducing at least one oxidation agent, in solid or liquid form, into the mixture containing noble metal-containing catalyst form body and mineral acid; and (d) separating the form bodies from the liquid.

Abstract: Process for digestion of fine iridium, comprising the steps of: (a) alkaline oxidative digestion of 1 part by weight fine iridium and 3 to 20 parts by weight of a combination comprising 40 to 70 parts by weight sodium hydroxide, 15 to 30 parts by weight sodium nitrate, and 10 to 40 parts by weight sodium peroxide in the melt, whereby the sum of the weight fractions adds up to 100 parts by weight; (b) cooling the digestion material formed in step (a) to 20 to 70° C.; (c) dissolving the acid-soluble fractions of the cooled digestion material in water/halogen hydracid until an acidic aqueous solution with a pH value in the range of ?1 to +1 is obtained; and (d) boiling the acidic aqueous solution obtained in step (c) until the formation of nitrous gases is completed; whereby a step (e) of separating insoluble ingredients from the acidic aqueous solution can take place before or after step (d), if needed.

Abstract: Process for removing precious metal from precious metal-containing catalyst form bodies comprising form bodies and precious metal, whereby the precious metal to be removed is at least one precious metal selected from the group consisting of Au, Ag, Pd, Pt, Ir, Rh, Ru, Os, and Re, comprising the steps of: (a) producing a mixture of precious metal-containing catalyst form bodies in at least one mineral acid that is at least 1N; (b) supplying inert or oxidising gas into the mixture containing noble metal-containing catalyst form bodies and mineral acid; (c) introducing at least one oxidation agent, in solid or liquid form, into the mixture containing noble metal-containing catalyst form body and mineral acid; and (d) separating the form bodies from the liquid.

Abstract: A method recovers noble metals from noble metal-containing compositions and includes steps of (i) providing a noble metal-containing composition containing an adsorption agent that is based on an inorganic material and is functionalized by organic groups and has at least one noble metal adsorbed to it, and (ii) ashing of the noble metal-containing composition provided in step (i) in order to adjust a residual carbon content of at most 10% by weight, relative to the total weight of the noble metal-containing composition after ashing, to obtain an ashed composition.

Abstract: A method recovers noble metals from noble metal-containing compositions and includes steps of (i) providing a noble metal-containing composition containing an adsorption agent that is based on an inorganic material and is functionalized by organic groups and has at least one noble metal adsorbed to it, and (ii) ashing of the noble metal-containing composition provided in step (i) in order to adjust a residual carbon content of at most 10% by weight, relative to the total weight of the noble metal-containing composition after ashing, to obtain an ashed composition.