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US 5,183,497 AGranted
Iron and a copper speiss as co-additives in refining crude lead bullion
AssigneeE. I. Du Pont de Nemours and Company
InventorsMichael H. Blenk, Russell B. Diemer, Jr., John P. Hager
Life of this patent
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Abstract
A process for using an iron-containing sulfide reagent and a previously formed copper speiss as joint co-additives to extend the usefulness of the sodium in refining crude bullion which has less than about 1.3 wt. % sulfur.
Claims6
A process for concentrating elemental lead in molten crude lead bullion, in which the crude lead bullion contains less than about 1.3% by weight sulfur, which comprises:
- (a) casting the molten bullion at a temperature in the range of from about 1100.degree. C. to about 1200.degree. C.;
- (b) cooling the cast bullion to a temperature in the range of from about 750.degree. C. up to a value which is less than the boiling point of sodium whereby to form a partial matte crust over the surface thereof;
- (c) introducing sodium or a sodium-containing reagent into the bullion;
- (d) prior to or substantially simultaneously with the sodium, introducing an amount of iron metal or an iron-containing sulfide reagent into the crude lead bullion which is in the range of from about 50% up to about 100% of the stoichiometric iron requirement based on the concentration of arsenic in the bullion;
- (e) prior to or substantially simultaneously with the sodium, introducing an amount of previously isolated copper speiss into the crude lead bullion which is at least about 5% by weight of the bullion;
- and
- (f) cooling the cast bullion to separate a matte phase and a speiss phase from the lead bullion phase.
4 more elements
Dependencies are inferred from the claim text.