Amax Incorporated

Eddie C Chou

Paul B Queneau

Leo W Beckstead

Dale K Huggins

Raymond D Symens

Ben W Wiegers

Ranko P Crnojevich

Edward I Wiewiorowski

Guy W Lussiez

John M Laferty

Helen S Leaver

Luther R Tinnin

Mark W Cooperrider

John R Carlberg

John D Bruno

Franklin F Clark

Charles J Kucera, Jr

Pandelis Papafingos

Tom C Kearns

Harold Koehler

Craig B Barlow

Directed to a process for producing a tungsten product of enhanced purity from ammonium paratungstate (APT) with a minimum number of processing steps which comprises mixing the APT with an ammonium solution, autoclaving the mixture at a temperature above the boiling point thereof to dissolve the APT and recrystallizing APT from the solution to yield an APT product of enhanced marketability.

Purification of APT

Waste materials containing chromium, such as the sludge resulting from neutralization of chromic acid bleed streams from metal cleaning and plating operations, are (1) rendered innocuous for land fill purposes by heating to temperatures of at least about 700.degree. C. to stabilize the materials for safe disposal and (2) activated by heating to temperatures of about 400.degree. to 500.degree. and the chromium content in the resulting calcine can be recovered by thermite reduction.

Chromium recovery process

Sulfate solutions containing nickel and cobalt ions are treated by solvent extraction to provide a nickel raffinate with a high Ni:Co ratio and a cobalt raffinate with a high Co:Ni ratio and with low recycle of cobalt by treating the solution with a cobalt extractant to provide a nickel raffinate of high Ni:Co ratio and a loaded extractant, acid stripping the loaded extractant to provide a cobalt sulfate solution containing some nickel and a regenerated cobalt extractant, treating the cobalt sulfate solution with a nickel extractant to provide a cobalt raffinate with a high Co:Ni ratio and acid stripping the loaded nickel extractant to regenerate the extractant and to provide a recyclable sulfate solution containing only a small proportion of the original cobalt.

Separation of nickel and cobalt from sulfate solutions by solvent

Hexagonal cadmium sulfide, a bright yellow pigment useful in high temperature processing, is produced by reacting cadmium sulfate solution with a solution of a soluble sulfide under pressure and at a temperature of about 250.degree. C.

Production of hexagonal cadmium sulfide pigment

Fine cobalt or nickel powder is produced by hydrogen reduction of a sulfate solution in the presence of a base and a strong reductant such as a metal borohydride wherein the base is added stagewise to the solution with the initial addition of base being sufficient to insure an essentially neutral pH at the time of reductant addition.

Production of cobalt and nickel powder

Nickel powder of high surface area is produced by pressurized hydrogen reduction of an ammoniacal aqueous nickel sulfate solution using a small amount of a catalytic reductant compound exemplified by formaldehyde sulfoxalate (rongalite).

Production of high surface area nickel powder

Nickel and cobalt contained in aqueous sulfate solution are separately recovered by counter-current solvent extraction using a cobalt-selective organic extractant while scaling of equipment and cobalt recycle are minimized by controlling aqueous pH at the extraction, scrubbing and stripping stages to maximize cobalt loading and selectivity of the extractant while loading scale-causing ions such as calcium and magnesium in the extractant and removing them from the circuit with the aqueous cobalt strip solution.

Solvent extraction of cobalt (II) from sulfate solutions with cobalt

Ultrafine cobalt and nickel powders are produced from sulfate solutions containing ammonia under hydrogen pressure in the presence of a small amount of a reductant from the group consisting of metal hydrides, metal borohydrides and metal borides. Cobalt powders having a particle size of about 2 micrometers produced in accordance with the invention have been used successfully in the production of cobalt-cemented tungsten carbide.

A process is provided for removing hexavalent selenium from an acidic sulfate solution containing at least one metal ion from the group consisting of nickel, cobalt and copper at ambient pressure and at a temperature not exceeding the boiling point of the solution. The solution is treated with an agent from the group consisting of a compound which will produce nascent hydrogen in the solution and finely divided metal from the group consisting of nickel, cobalt and copper resulting from in situ precipitation of the metal in the acid sulfate solution. Thus, following treatment with the compound, the hexavalent selenium is reduced to a form separable from the solution by solid-liquid separation.

Removal of hexavalent selenium from nickel, cobalt or copper sulfate

A method is provided for leaching comminuted nickeliferous sulfide matte containing by weight about 20 to 75% nickel, about 5 to 50% copper, non-stoichiometric sulfur in the range of over 4 to about 24%, over 0.5 to about 20% iron, the sum of the nickel, copper and sulfur contents being at least about 80% of the matte composition, with the balance gangue or slag and incidental impurities. Nickel is selectively leached from the comminuted matte using sulfuric acid or spent copper electrolyte solution at substantially atmospheric pressure while vigorously aerating the solution, wherein the pH is raised sufficiently to produce a nickel solution with an iron content of less than about 10 ppm and a copper content of over 5 ppm, the copper being thereafter selectively removed from the nickel solution by passing the solution through an ion-exchange resin selective to the absorption of copper.

Atmospheric leach ion-exchange process for treating iron-containing

A method is provided for enhancing the neutralization capability of high-magnesium serpentine silicate ore in the neutralization of nickel-containing pregnant leach solution, said solution having a pH of less than about 1 which comprises, providing said high magnesium serpentine ore in particulate form containing by weight over about 5% magnesium, roasting said ore under oxidizing conditions at a temperature below that temperature at which forsterite in said ore recrystallizes, and then adding an amount of said serpentine roasted ore to said pregnant liquor sufficient to raise the pH of the leach solution to a level above 2.

Roast-neutralization-leach technique for the treatment of laterite ore

Nickel is selectively leached efficiently and rapidly from Ni-Cu-Fe-S matte under oxidizing conditions at ordinary pressure by controlling in combination the following variables: (1) the acid-to-copper mole ratio in the leaching solution, (2) the temperature, and (3) the sulfur content of the matte, whereby an enriched nickel solution is obtained low in copper and iron.

Leaching of Ni-Cu-Fe-S matte

The leaching efficiency of nickeliferous lateritic ore is optimized by scalping the ore to remove a coarse low-nickel fraction and provide a fine nickel-rich fraction which is then high pressure leached in a sulfuric acid solution by controlling the parameters temperature, pulp density, the rate of acid addition, leaching time, agitation rate, etc., whereby a pregnant solution is obtained with the nickel to (Fe+Al+Cr) ratio exceeding about 2.

Sulfuric acid leaching of nickeliferous laterite

The pregnant solution obtained from high pressure and high temperature leaching of nickel-cobalt bearing low magnesium oxidic ores is neutralized at high temperature and pressure by coordinating the leaching of the low magnesium ores with the leaching of nickel-cobalt bearing high magnesium ores, the leach slurry from said low magnesium ore being neutralized by mixing it with said high magnesium ore which is simultaneously leached with said solution to produce a final pregnant solution from which metal values are subsequently recovered.

High temperature neutralization of laterite leach slurry

An improved method is provided for efficiently precipitating metal powder selected from the group consisting of nickel, cobalt and copper from aqueous solutions using sulfur-free hydrogen at elevated pressure and temperature, the improvement residing in adding to the solution a small but effective amount of a catalyst as an anti-plating agent, said catalyst comprising an alkali metal or ammonium salt of a copolymer of maleic acid anhydride and an unsaturated branched chain aliphatic olefinic hydrocarbon containing 4 to 10 carbon atoms.

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Arvada, CO, United States of America

Eddie C Chou