Patent ID: 6554915
Filing Date: 2003-04-29
Classification: C22B,C23C,Y10S

Abstract:
A process for making a final aqueous acidic liquid that contains dissolved nickel cations, said process comprising the following operations:(I) providing a first mass of a solid, predominantly elemental nickel reagent, comprising a non-powdery mass in which each individual piece of said predominantly elemental nickel reagent is longer than about 0.5 mm in at least one linear dimension; (II) providing, separately from said first mass, a second mass of a precursor aqueous acidic liquid reagent that comprises the following components: (A) water; (B) molecules of at least one non-oxidizing acid selected from a group consisting of formic acid, acetic acid, sulfuric acid, hydrochloric acid, hydrobromic acid, hydriodic acid, hydrofluoric acid, and one or more oxyacids of phosphorus selected from orthophosphoric acid, condensed phosphoric acid, phosphorous acid and hypophosphorous acid; (C) from the beginning of the spontaneous chemical reaction described in (III) below, a third mass of oxidizing agent, wherein the oxidizing stoichiometric equivalent as hydrogen peroxide of said third mass has a molar ratio to said non-powdery mass of predominantly elemental nickel reagent that is from about 0.80:1.00 to about 1.6:1.00; and, optionally, (D) dissolved nickel cations, wherein (a) at least 80%, based on weight, of the acid content of said second mass consists of one or more oxyacids of phosphorus, and (b) at the beginning of the spontaneous chemical reaction described in (III) below (1) the concentration of the oxyacid or oxyacids of phosphorus, measured as their stoichiometric equivalent as orthophosphoric acid, is from about 30 to about 55%, based on weight, of said second mass; and (2) the mass of the oxyacid or oxyacids of phosphorus, measured as their stoichiometric equivalent as orthophosphoric acid, in said second mass has a ratio, based on weight, to the mass of nickel in said first mass that is from about 3.0:1.00 to about 7.0:1.00; and (III) effecting contact between said first mass and said second mass under such conditions of temperature and relative motion between said two masses as will result in spontaneous chemical reaction between them, said spontaneous chemical reaction converting at least 80 percent, by weight, of the elemental nickel present in said first mass to dissolved nickel cations in a final aqueous acidic liquid that includes some of the molecules of non-oxidizing acid originally present in said second mass within a time interval, beginning with the first contact between said first and second masses, that is not more than 24 hours.