Two stage sulfuric acid leaching of sea nodules
AssigneeThe International Nickel Company, Inc.
InventorsKohur Nagaraja Subramanian, Gerald Vernon Glaum
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Abstract
A process for extracting metal values from manganiferous sea nodules is provided in which nickel, copper, and cobalt values are selectively leached in a sulfuric acid medium in two stages, the first stage being effected at a temperature up to about 100.degree. C and to a final pH of not less than about 1.5 and the second stage being effected at a temperature of about 160.degree. C to about 260.degree. C and at an initial pH of not less than about 1.5.
Claims11
A two-stage process for treating manganiferous sea nodules containing acid soluble gangue minerals, a major amount of manganese and iron, and a minor amount of at least one of the nonferrous metals nickel, cobalt, and copper, for the selective extraction of said nonferrous metal values comprising:
- a. effecting a first stage leach of raw sea nodules slurried in a sulfuric acid medium at an elevated temperature up to about 100.degree. C., said slurry having a pulp density of about 10% to 40% solids and having a sulfuric acid content of about 20% to 50% based on the weight of the nodules, the acid being present in sufficient amount to dissolve a preponderant part of the acid soluble gangue minerals and to obtain a resultant slurry having a final pH of no less than about 1.5, and
- b. effecting a second stage leach of the resultant nodules of the first stage leach in the resultant leach solution of the first stage leach at a temperature in the range of above about 100.degree. C. up to about 260.degree. C. at an initial pH no lower than about 1.5 to extract nickel, cobalt and copper from said nodules;
- whereby said nickel, cobalt and copper values are extracted from said nodules with reduced tendency for scale formation.
A two-stage process for treating manganiferous sea nodules containing acid soluble gangue minerals, a major amount of manganese and iron, and a minor amount of at least one of the nonferrous metal values nickel, cobalt and copper for the selective extraction of nonferrous metal values, comprising:
- (a) effecting a first stage leach of raw sea nodules in a sulfuric acid medium at an elevated temperature up to about 100.degree. C., said slurry having a pulp density of about 10% to 40% solids and having a sulfuric acid content of about 20% to 50% based on the weight of the nodules, the acid being present in sufficient amount to dissolve substantially all of the acid soluble gangue minerals and to obtain a slurry having a final pH of no less than about 1.5, a portion of the nickel, cobalt and copper values being extracted into said first stage leach solution, and
- (b) effecting a second stage leach of the resultant nodules directly in the product of the first stage leach at a temperature in the range of about 160.degree. C. to about 260.degree. C. and at an initial pH of no less than about 1.5 for a period of time sufficient to maximize extraction of the nickel, cobalt and copper in the second leach solution;
- whereby said nickel, cobalt and copper values are extracted from said nodules with reduced tendency for scale formation.
Dependencies are inferred from the claim text.