US4256485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enzyme oxidation of sulfides in minerals
Assignee: Northwest Ecological Research and Development Inc
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Filing: 1979-10-11
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Granted: 1981-03-17
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Expires: 1999-10-11
Abstract
Abstract A process for treating sulfide ores to reduce the sulfur content or recover the metal content therefrom comprises the use of enzymatic action to solubilize the sulfur and metal content. A nutrient, such as a saccharide, is used along with yeast spores which feed on the sugar and produce enzymes which act on sulfur in the sulfide ore to cause the sulfur to go into solution and to dissolve those metals which are soluble in strongly acidic solution. Sulfuric acid can be formed from the sulfide ores or from free sulfur by reaction with water, with evolution of hydrogen sulfide gas. Oxidation of at least a portion of the hydrogen sulfide can be achieved to regenerate sulfuric acid.
Inventors
- 👤 Frederick J. Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:27
CPC Classifications
C; C22; C22B; C22B3/00; C22B3/18; C22B1/00; C22B1/11; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y10; Y10S; Y10S423/00; Y10S423/09; Y10S423/17; Y10S435/00; Y10S435/8215; Y10S435/911; Y10S435/94; Y10S435/942
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
128 words
A process for treating a solid mineral ore containing one or more contaminants in the form of free or combined sulfur as metal sulfides, comprising the following steps: (a) reducing or pulverizing the mineral ore to granular or smaller particle size; (b) forming a mixture of pulverized ore and water at room temperature; (c) adding microorganisms in the form of baker's yeast or malt and a saccharide to the mixture of ore and water; (d) allowing the mixture of step (c) to stand for a period sufficient for enzymatic action to carry a significant amount of free or combined sulfur into aqueous solution as sulfuric acid or a metal sulfate; and (e) removing at least a portion of said sulphuric acid or metal sulphate from said aqueous solution.
Claim 2
Dependent Claim
128 words
A process for treating a solid mineral ore containing one or more contaminants in the form of free or combined sulfur as metal sulfides, comprising the following steps: (a) reducing or pulverizing the mineral ore to granular or smaller particle size; (b) forming a mixture of pulverized ore and water at room temperature; (c) adding microorganisms in the form of baker's yeast or malt and a saccharide to the mixture of ore and water; (d) allowing the mixture of step (c) to stand for a period sufficient for enzymatic action to carry a significant amount of free or combined sulfur into aqueous solution as sulfuric acid or a metal sulfate; and (e) removing at least a portion of said sulphuric acid or metal sulphate from said aqueous solution.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein the contaminant is selected from the group consisting of a metal sulfide of iron, copper, arsenic, antimony, zinc and mixtures thereof.
Claim 4
Dependent Claim
15 words
The process of claim 2 wherein the mineral ore is a silver mineral ore concentrate.
Claim 5
Dependent Claim
27 words
The process of claim 1 wherein the mineral ore is a mineral containing primarily coal, and the contaminant is in the form of free or combined sulfur.
Claim 6
Dependent Claim
36 words
The process of claim 1, together with the following additional step: (f) adding to the liquid phase solution of step (d) a water soluble strong oxidizing agent to form a liquid phase product containing sulfuric acid.
Claim 7
Dependent Claim
17 words
The process of claim 5 wherein said oxidizing agent is a solution of hydrogen peroxide in water.
Claim 8
Dependent Claim
12 words
The process of claim 5 wherein said oxidizing agent is potassium peroxymonosulfate.
Claim 9
Dependent Claim
43 words
The process of claim 1 wherein the microorganism is baker's yeast present in a proportion of at least 4.5 lb. per ton of ore and the saccharide is sucrose present in a proportion of at least about 13.4 lb. per ton of ore.
Claim 10
Dependent Claim
35 words
The process of claim 1 wherein the ore contains in addition further contaminants in the form of oxides and chlorides of contaminant metals, said oxide and chloride contaminants being taken into solution during step (d).
Claim 11
Dependent Claim
22 words
The process of claim 2 wherein the sulfuric acid in liquid phase product is concentrated by removing water and metal sulfates therefrom.
Claim 12
Dependent Claim
27 words
The process of claim 4 wherein said free or combined sulfur contaminant is reduced at least about 40.4 lb. per ton of mineral ore, measured as sulfur.
Claim 13
Dependent Claim
42 words
The process of claim 2 wherein said mineral ore contains a copper sulfide contaminant comprising 26% copper and said period is 24 hours and wherein said contaminant is reduced from 26% copper to 22% copper with a substantial lowering of sulfur content.
Claim 14
Dependent Claim
37 words
The process of claim 12 wherein said contaminant contains 3% zinc in addition, and said aqueous solution formed in step (d) contains about 9.5 grams per liter of copper and about 7 grams per liter of zinc.
Claim 15
Dependent Claim
19 words
The process of claim 1 wherein step (b) is performed in an acid resistant leaching tank at room temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |