초록 ▼

This invention relates to a process for the separation and purification of platinum group metals and particularly platinum, rhodium and iridium. Essentially the platinum group metals are present as salts dissolved in an aqueous solution and the process for separating and purifying the platinum group

This invention relates to a process for the separation and purification of platinum group metals and particularly platinum, rhodium and iridium. Essentially the platinum group metals are present as salts dissolved in an aqueous solution and the process for separating and purifying the platinum group metals comprises, according to one embodiment of the invention, the following steps: A. ADJUSTING THE PH, as necessary, to provide an acidic solution; B. CONTACTING THE ACIDIC SOLUTION WITH A REDUCING AGENT TO EFFECT THE REDUCTION OF IRIDIUM, THAT IS, Ir(IV) to Ir(III); c. contacting the reduced solution with a nitrogen containing or organic compound selected from the group consisting of secondary amines, tertiary amines, and quaternary ammonium compounds; D. REMOVING FROM CONTACT WITH THE SOLUTION AN ORGANIC PHASE CONTAINING SUBSTANTIALLY ALL OF THE PLATINUM PRESENT IN ASSOCIATION WITH THE NITROGEN-CONTAINING ORGANIC COMPOUND USED IN STEP (C); E. RE-OXIDISING IRIDIUM WHICH (WITH RHODIUM) REMAINS IN THE AQUEOUS PHASE FROM Ir(III) to Ir(IV); f. again contacting the oxidised solution with a fresh quantity of a nitrogen-containing organic compound selected from the group consisting of secondary amines, tertiary amines, and quaternary ammonium compounds; and G. REMOVING FROM CONTACT WITH THE RE-OXIDISED SOLUTION THE ORGANIC PHASE CONTAINING SUBSTANTIALLY ALL OF THE IRIDIUM PRESENT IN ASSOCIATION WITH THE NITROGEN-CONTAINING ORGANIC COMPOUND USED IN STEP (F).

대표청구항 ▼

A process for the separation and purification of platinum, rhodium and iridium present as salts dissolved in aqueous solution comprising the steps of: a. contacting the solution at acid pH with a reducing agent to effect the reduction of iridium present as Ir(IV) to Ir(III); b. contacting the reduce

A process for the separation and purification of platinum, rhodium and iridium present as salts dissolved in aqueous solution comprising the steps of: a. contacting the solution at acid pH with a reducing agent to effect the reduction of iridium present as Ir(IV) to Ir(III); b. contacting the reduced solution with a nitrogen containing organic compound selected from the group consisting of secondary amines of the formula R2NH, tertiary amines of the formula R3N and quaternary ammonium compounds of the formula R4NX wherein at least one R is an alkyl group, the remainder being alkyl or aryl, and X is a halide or hydroxide ion; c. removing from contact with the solution an organic phase containing substantially all of the platinum present in association with the nitrogen-containing organic compound used in step (b); d. re-oxidising iridium which with the rhodium remains in the aqueous phase from Ir(III) to Ir(IV); e. again contacting the oxidised solution with a fresh quantity of a nitrogen-containing organic compound selected from the group consisting of secondary amines of the formula R2NH, tertiary amines of the formula R3N and quaternary ammonium compounds of the formula R4NX wherein at least one R is an alkyl group, the remainder being alkyl or aryl, and X is a halide or hydroxide ion; f. removing from contact with the reoxidised solution the organic phase containing substantially all of the iridium present in association with the nitrogen-containing organic compound used in step (e).