Amax Incorporated

Antonio E Blandon

Paul B Queneau

Mahesh C Jha

Malcolm T Hepworth

Raymond D Symens

Durable, porous sulfur sorbents useful in removing hydrogen sulfide from hot coal gas are prepared by water pelletizing a mixture of fine zinc oxide and fine iron oxide with inorganic and organic binders and small amounts of activators such as sodium carbonate and molybdenite; the pellets are dried and then indurated at a high temperature, e.g., 1800.degree. C., for a time sufficient to produce crush-resistant pellets.

Durable zinc ferrite sorbent pellets for hot coal gas desulfurization

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 20%, over 0.5% to about 15 or 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. The matte, because of the iron content, is first granulated by quenching molten matte from a temperature at least about 10.degree.C above its solidus-liquidus temperature but below its boiling point, following which the matte is comminuted and subjected to atmospheric leaching to dissolve nickel selectively therefrom using a spent copper electrolyte solution containing sulfuric acid having a pH ranging up to about 2 while aerating said solution to cause the pH to rise to above 5 and effect substantial precipitation of copper and iron. Preferably, a two-stage atmospheric leaching is employed, the first stage in which the solution is aerated until the solution reaches a pH level of about 3.5 to 4.5 and a second stage atmospheric leaching step in which the aeration is replaced with a stronger oxidant, such as oxygen, in order to speed up the atmospheric leaching of the matte and to complete further said atmospheric leaching until the aqueous copper and iron are each reduced to less than 20 ppm as evidenced by a rise in pH to over about 5.

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Arvada, CO, United States of America

Antonio E Blandon