US3880981A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cyclic acid leaching of nickel bearing oxide and silicate ores with subsequent iron removal from leach liquor
Assignee: Individual
•
Filing: 1972-10-10
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Granted: 1975-04-29
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Expires: 1992-10-10
Abstract
Abstract A hot solution of sulfuric acid and ammonium bisulfate is used to leach nickel and cobalt from finely ground, low grade nickel ores such as garnierite. Substantial quantities of iron and magnesium impurities pass into the leach liquor. The leach liquor is cyclically filtered, adjusted to its original acid content, and reused with a fresh batch of ore until the magnesium content is about 40-60 grams per liter. The resulting leach liquor is then slurried with an excess of oxidized ore to use up free acid and thereby precipitate a substantial proportion of the iron. Hydrogen sulfide is then added to the filtrate to separate out chromium, aluminum and copper. The resulting filtrate is treated with ammonium hydroxide to precipitate out the hydroxides of metal impurities including the residual iron. Nickel and cobalt salts are then precipitated with hydrogen sulfide and filtered out. Magnesium can be recovered as magnesium carbonate by treating the resulting filtrate with carbon dioxide. The final filtrate, containing essentially ammonium sulfate, is evaporated to dryness and heated to about 330*C. to form ammonia and ammonium bilsulfate. The ammonia is recycled to the nickel complexing step and the ammonium bilsulfate is recycled to the leaching liquor, together with sulfuric acid made from sulfur dioxide derived from the conversion of the nickel sulfide to nickel oxide.
Inventors
- 👤 Renato M Garingarao
- 👤 Michaelangelo A Palad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:39
CPC Classifications
C; C22; C22B; C22B23/00; C22B23/04; C22B23/0407; B; B01; B01D; B01D11/00; B01D11/02; B01D11/0288; C22B3/00; C22B3/04; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
182 words
In a method wherein particles of a nickeliferrous oxide and silicate type of ore containing nickel, cobalt, iron, magnesium and other metal values are leached with an aqueous solution of an acid leaching agent selected from the group consisting of sulfuric acid, ammonium bisulfate and mixtures thereof at an elevated temperature, and wherein iron is separated from the leach liquor, the improvement which comprises: a. carrying out said leaching at ambient pressure and at a temperature below about 100*C; b. periodically separating the leached ore from the leach liquor and using said separated leach liquor to leach additional batches of said ore prior to the separation of iron therefrom; c. periodically adding make-up acid to said leach liquor to replace the acid used up in said leaching; d. contacting the final hot leach liquor with an excess of said ore to effect an increase in pH and to effect the precipitation of an insoluble iron compound therefrom; e. then separating the resulting insoluble iron compound and insoluble ore from said leach liquor; and f. then recovering metal values from the resulting liquor.
Claim 2
Dependent Claim
182 words
In a method wherein particles of a nickeliferrous oxide and silicate type of ore containing nickel, cobalt, iron, magnesium and other metal values are leached with an aqueous solution of an acid leaching agent selected from the group consisting of sulfuric acid, ammonium bisulfate and mixtures thereof at an elevated temperature, and wherein iron is separated from the leach liquor, the improvement which comprises: a. carrying out said leaching at ambient pressure and at a temperature below about 100*C; b. periodically separating the leached ore from the leach liquor and using said separated leach liquor to leach additional batches of said ore prior to the separation of iron therefrom; c. periodically adding make-up acid to said leach liquor to replace the acid used up in said leaching; d. contacting the final hot leach liquor with an excess of said ore to effect an increase in pH and to effect the precipitation of an insoluble iron compound therefrom; e. then separating the resulting insoluble iron compound and insoluble ore from said leach liquor; and f. then recovering metal values from the resulting liquor.
Claim 3
Dependent Claim
40 words
The method of claim 1 wherein said leaching of successive batches of ore is discontinued when the percentage of nickel extracted from a batch of said ore decreases to less than 50 percent of the nickel content of said ore.
Claim 4
Dependent Claim
37 words
The method of claim 1 wherein said leaching is discontinued when the concentration of magnesium reaches about 60 grams per liter in a liquor where the concentration of iron is less than about 5 grams per liter.
Claim 5
Dependent Claim
37 words
The method of claim 1 wherein said leaching is discontinued when the concentration of magnesium reaches about 40 grams per liter in a liquor wherein the concentration of iron is at least about 10 grams per liter.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said acid comprises an aqueous solution of ammonium bisulfate and sulfuric acid.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein said temperature is the boiling temperature of the leach liquor and wherein said heating is carried out with reflux.
Claim 8
Dependent Claim
30 words
THE METHOD OF CLAIM 1 WHEREIN SAID PARTICLES ARE SLURRIED TO A PULP DENSITY OF ABOUT 5-10 PERCENT BY WEIGHT IN LEACH LIQOUR HAVING AN ACID STRENGTH OF ABOUT 1-1.7N.
Claim 9
Dependent Claim
50 words
the method of claim 1 wherein said mixture of excess ore and liquor has a pulp density of about 15-30 percent by weight and said contacting step is carried out at about the boiling temperature of the liquor at ambient pressure for a period of about 1/2 - 1 hour.
Claim 10
Dependent Claim
156 words
The method of claim 1 wherein: a. the filtrate resulting from said iron separation is treated with hydrogen sulfide and insoluble solids are separated therefrom; b. then adding ammonium hydroxide to the resulting filtrate to effect the precipitation of substantially all the iron therein as a hydroxide and separating said hydroxide from said filtrate; c. then passing hydrogen sulfide through the resulting fltrate to effect the precipitation of nickel from said filtrate as nickel sulphide and separating said nickel sulfide from said filtrate; d. then adding carbon dioxide to said filtrate to effect the precipitation of magnesium as magnesium carbonate and separating the latter from said filtrate; e. then drying said filtrate and thermally decomposing the resulting solids to effect the recovery of ammonium bisulfate and ammonia from said filtrate; f. effecting the recovery of carbon dioxide by the thermal decomposition of said separated magnesium carbonate; and g. recycling said ammonium bisulfate, ammonia, and carbon dioxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |