Abstract The present invention relates to a process for the recovery of a thiotungstate from an organic composition. More particularly, the present invention relates to an improvement in a solvent extraction process wherein tungsten in an alkaline solution is sulfidized to convert it to a thiotungstate species, contacted with an organic phase comprising an extractant in an organic diluent whereby the thiotungstate is extracted into the organic phase and subsequently recovered. The improvement comprises contacting the thiotungstate containing organic phase with sulfur dioxide whereby at least a portion of the thiotungstate is converted to a tungstate species, stripping the tungstate species from the organic phase with an aqueous salt solution and recovering the tungstate.
Inventors
👤 J Bradford
👤 M Woyski
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-01 12:13
CPC Classifications
C; C01; C01G; C01G41/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
21 words
The process of claim 1 wherein said sulfur dioxide is in an aqueous solution having a pH of less than 7.
Claim 2
Dependent Claim
27 words
The process of claim 2 wherein the sulfur dioxide is in the form of an ion selected from the group consisting of sulfite ions and bisulfite ions.
Claim 3
Dependent Claim
28 words
The process of claim 1 wherein said thiotungstate containing organic phase is contacted with gaseous sulfur dioxide and said aqueous salt solution has a pH greater than 9.
Claim 4
Dependent Claim
43 words
The process of claim 1 wherein the sulfur dioxide is in an aqueous solution having a pH within the range from about 4.5 to 6.5 and the organic phase subsequently is contacted with an aqueous salt solution having a pH greater than 9.
Claim 5
Dependent Claim
17 words
The process of claim 5 wherein the aqueous salt solution comprise a solution of NH4Cl and NH4OH.
Claim 6
Dependent Claim
13 words
The process of claim 6 wherein the brine is a Searles Lake brine.
Claim 7
Dependent Claim
17 words
The process of claim 1 wherein the aqueous salt solution comprises a solution of NH4Cl and NH4OH.