US3860419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the recovery of molybdenum from roasted molybdenum concentrates
Assignee: H.C. Starck GmbH
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Filing: 1972-12-12
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Granted: 1975-01-14
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Expires: 1992-12-12
Abstract
Abstract A process for recovering molybdenum, either as a compound or as the elemental metal, from roasted molybdenum concentrates, e.g. resulting from the roasting of molybdenum sulfide compositions, comprises digesting the concentrate in aqueous nitric acid containing ammonium nitrate, separating the solid phase from the liquid phase, and treating the solid phase with alkali, preferably ammonium hydroxide, to produce ammonium molybdate. The latter may be converted into metallic molybdenum.
Inventors
- 👤 Theodor Alexander Weber
- 👤 Ralf Fritz Borrmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:19
CPC Classifications
C; C22; C22B; C22B34/00; C22B34/30; C22B34/34; C01; C01G; C01G39/00; C01G39/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
99 words
A METHOD OF RECOVERING ROASTED MOLYBDENUM CONCENTRATE CONTAINING MOLYBDENUM IN THE PRESENCE OF IMPURITIES OF THE GROUP WHICH CONSISTS OF COPPER, LEAD, ZINC, BISMUTH, ALKALI METALS AND ALKALNE-EARTH METALS; SAID METHOD COMPRISING THE STEPS OF: A. DIGESTING THE ROASTED CONCENTRATE IN AN AQUEOUS NITIC ACID SOLUTION CONTAINING AMMONIUM NITRATE AT A TEMPERATURE OF 50*C TO 100*C, SAID SOLUTION CONTAINING SUBSTANTIALLY 1.0 TO 4.0 MOLES/LITER OF FREE NITRIC ACID AND 0.5 TO 2.0 MOLES/LITER OF AMMONIUM NITRATE; B. SEPARATING THE DIGESTED CONCENTRATE FROM THE NITRIC ACID SOLUTION TO YIELD A SOLID PRODUCT; AND WASHING SAID SOLID PRODUCT WITH HOT WATER.
Claim 2
Independent Claim
99 words
A METHOD OF RECOVERING ROASTED MOLYBDENUM CONCENTRATE CONTAINING MOLYBDENUM IN THE PRESENCE OF IMPURITIES OF THE GROUP WHICH CONSISTS OF COPPER, LEAD, ZINC, BISMUTH, ALKALI METALS AND ALKALNE-EARTH METALS; SAID METHOD COMPRISING THE STEPS OF: A. DIGESTING THE ROASTED CONCENTRATE IN AN AQUEOUS NITIC ACID SOLUTION CONTAINING AMMONIUM NITRATE AT A TEMPERATURE OF 50*C TO 100*C, SAID SOLUTION CONTAINING SUBSTANTIALLY 1.0 TO 4.0 MOLES/LITER OF FREE NITRIC ACID AND 0.5 TO 2.0 MOLES/LITER OF AMMONIUM NITRATE; B. SEPARATING THE DIGESTED CONCENTRATE FROM THE NITRIC ACID SOLUTION TO YIELD A SOLID PRODUCT; AND WASHING SAID SOLID PRODUCT WITH HOT WATER.
Claim 3
Dependent Claim
42 words
The method defined in claim 1 wherein said concentrate is digested in step (a) for a period of up to about eight hours, said solution being present in step (a) in a weight ratio to said concentrate of substantially 1:1 to 3:1.
Claim 4
Dependent Claim
50 words
The method defined in claim 2 wherein said concentrate is digested in step (a) for a period of about two hours, said solution contains about 2.0 to 2.3 moles/liter of free nitric acid and about 1.5 to 2.0 moles/liter of ammonium nitrate, and said temperature is substantially 75*C to 80*C.
Claim 5
Independent Claim
129 words
A method of recovering roasted molybdenum concentrate containing molybdenum in the presence of impurities, said method comprising the steps of: a. digesting the roasted concentrate in an aqueous nitric acid solution containing ammonium nitrate at an elevated temperature; b. separating the digested concentrate from the nitric acid solution to yield a solid product; and c. washing said solid product with hot water, said concentrate being digested in step (a) for a period of about two hours, said solution contains about 2.0 to 2.3 moles/liter of free nitric acid and about 1.5 to 2.0 moles/liter of ammonium nitrate, and said temperature is substantially 75*C to 80*C, said concentrate is a roasted molybdenum sulfide ore containing impurities selected from the group which consists of copper, lead, zinc, bismuth and alkali metals.
Claim 6
Independent Claim
129 words
A method of recovering roasted molybdenum concentrate containing molybdenum in the presence of impurities, said method comprising the steps of: a. digesting the roasted concentrate in an aqueous nitric acid solution containing ammonium nitrate at an elevated temperature; b. separating the digested concentrate from the nitric acid solution to yield a solid product; and c. washing said solid product with hot water, said concentrate being digested in step (a) for a period of about two hours, said solution contains about 2.0 to 2.3 moles/liter of free nitric acid and about 1.5 to 2.0 moles/liter of ammonium nitrate, and said temperature is substantially 75*C to 80*C, said concentrate is a roasted molybdenum sulfide ore containing impurities selected from the group which consists of copper, lead, zinc, bismuth and alkali metals.
Claim 7
Dependent Claim
40 words
The method defined in claim 4, further comprising the step of treating said solid product after step (c) with an alkali selected from the group which consists of ammonium hydroxide and sodium hydroxide to solubilize molybdenum from said solid product.
Claim 8
Dependent Claim
39 words
The method defined in claim 5 wherein said solid product is treated subsequent to step (c) with ammonium hydroxide to solubilize molybdenum as ammonium molybdate, further comprising the step of concentrating said alkali by evaporation to precipitate ammonium molybdate.
Claim 9
Dependent Claim
18 words
The method defined in claim 6, further comprising the step of converting said ammonium molybdate to metallic molybdenum.
References Cited (Backward Citations)
US3739057A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |