Claims
- 1. A method of preparing vanadium pentoxide comprising the steps of: processing a solution of sodium vanadate at a pH of from 4 to 6 with at least one substance selected from the group consisting of ammonium chloride and ammonium sulphate at a temperature of from 20.degree. to 40.degree. C. to precipitate ammonium-sodium decavanadate, the substance being present in an amount not exceeding 0.84 gram, calculated as NH.sub.4, per gram of vanadium pentoxide in the solution of sodium vanadate; dissolving the ammonium-sodium decavanadate in hot water to prepare a solution of the ammonium-sodium decavanadate with a concentration of from 70 to 100 grams/liter of vanadium pentoxide; processing the obtained solution of ammonium-sodium decavanadate with a mineral acid to precipitate ammonium polyvanadate; and calcining the ammonium polyvanadate to prepare vanadium pentoxide.
- 2. The method as claimed in claim 1, wherein the solution of sodium vanadate is processed with the substance selected from the group consisting of ammonium chloride and ammonium sulphate at a pH of from 4.4 to 4.8.
- 3. The method as claimed in claim 1, wherein the substance selected from the group consisting of ammonium chloride and ammonium sulphate is present in an amount of from 0.5 to 0.6 gram, calculated as NH.sub.4, per gram of vanadium pentoxide in the solution of sodium vanadate.
- 4. The method as claimed in claim 1, further comprising the step of filtering the solution of ammonium-sodium decavanadate prior to processing the solution of ammonium-sodium decavanadate with the mineral acid.
- 5. The method as claimed in claim 1, wherein the solution of ammonium-sodium decavanadate is processed with the mineral acid at a temperature of from 90.degree. to 100.degree. C. and a pH of from 2 to 5.5.
- 6. The method as claimed in claim 5, wherein the solution of ammonium-sodium decavanadate is processed with the mineral acid for a period of from 0.3 to 2 hours.
Parent Case Info
This is a continuation of application Ser. No. 645,099 filed Dec. 29, 1975 which in turn is a Continuation of Ser. No. 424,076 filed Dec. 12, 1973, both of which are now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1,269,639 |
Apr 1972 |
UK |
Continuations (2)
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Number |
Date |
Country |
Parent |
645099 |
Dec 1975 |
|
Parent |
424076 |
Dec 1973 |
|