Method for producing elemental rhodium

Patent metadata

Field	Value
Publication number	US-2018051358-A1
Application number	US-201615555238-A
Country	US
Kind code	A1
Filing date	Feb 1, 2016
Priority date	Mar 5, 2015
Publication date	Feb 22, 2018
Grant date	—

Abstract

Method for producing elemental rhodium, comprising the steps of:
(1) providing an aqueous suspension of diethylene triammonium hexahalogenorhodate adjusted with hydrohalic acid to a pH value of −1 to +2; (2) adding a sufficient quantity of reducing agent for complete conversion of the diethylene triammonium hexahalogenorhodate to the suspension provided in step (1) and allowing the reaction to proceed until the formation of elemental rhodium is completed; and (3) separating the elemental rhodium formed in step (2) from the hydrohalic aqueous composition formed in step (2);

whereby halogen is bromine and/or chlorine.

First claim

1 . Method for producing elemental rhodium, comprising the steps of:
(1) providing an aqueous suspension of diethylene triammonium hexahalogenorhodate adjusted with hydrohalic acid to a pH value of −1 to +2; (2) adding a sufficient quantity of reducing agent for complete conversion of the diethylene triammonium hexahalogenorhodate to the suspension provided in step (1) and allowing the reaction to proceed until the formation of elemental rhodium is completed; and (3) separating the elemental rhodium formed in step (2) from the hydrohalic aqueous composition formed in step (2); whereby halogen is bromine and/or chlorine.

2 . Method according to claim 1 ,
whereby the pH value of the aqueous suspension provided in step (1) is in the range of −0.5 to +0.5.

3 . Method according to claim 1 ,
whereby the diethylene triammonium hexahalogenorhodate originates from the rhodium separation step of precious metals refining.

4 . Method according to claim 1 ,
whereby the diethylene triammonium hexahalogenorhodate is suspended in water and hydrohalic acid is added until the pH value of the aqueous suspension is adjusted to within the range of −1 to +2 or the diethylene triammonium hexahalogenorhodate is added to and suspended in a hydrohalic acid having a pH in the range of −1 to +2.

5 . Method according to claim 1 ,
whereby the fraction of the diethylene triammonium hexahalogenorhodate in the aqueous suspension provided in step (1) is in the range of 5 to 40% by weight.

6 . Method according to claim 1 ,
whereby the aqueous suspension is being agitated during step (2).

7 . Method according to claim 1 ,
whereby one reducing agent or a combination of reducing agents is used and the reducing agents, in the case of a combination of reducing agents, are one after the other, at the same time or overlapping in time.

8 . Method according to claim 1 ,
Whereby the reducing agent(s) is/are selected from the group consisting of hydrazine, hydrazine hydrate, Sn(II) compounds, zinc, iron, aluminium, and tin.

9 . Method according to claim 1 ,
whereby iron powder is used as reducing agent.

10 . Method according to claim 1 ,
whereby the pH value is maintained in the range of −1 to +2 during step (2), possibly by adding hydrohalic acid.

11 . Method according to claim 1 ,
whereby the temperature of the reaction material is maintained in the range of 20 to 70° C. during step (2).

12 . Method according to claim 1 ,
whereby the hydrohalic filtrate obtained during the separation of the elemental rhodium is used in a step (4) of precious metals refining to precipitate Rh 3+ as diethylene triammonium hexahalogenorhodate.

13 . Method according to claim 12 ,
any reducing agent or oxidation products of the reducing agent(s) is/are removed from the hydrohalic filtrate before using it in step (4).

14 . Method according to claim 1 ,
whereby the diethylene triammonium hexahalogenorhodate is diethylene triammonium hexachlororhodate.

Assignees

• Heraeus Deutschland Gmbh & Co Kg

Inventors

• Stettner Martin
• Thiel Vasco
• Alameda Stefanie F
• Voss Steffen

Classifications

• C22B11/06 Primary

  Chloridising · CPC title

• C22B11/04 Primary

  by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C22B5/00

  General methods of reducing to metals · CPC title

• C22B11/00 Primary

  Obtaining noble metals · CPC title

• C22B3/44

  by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42) · CPC title