The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 31, 1992
Filed:
May. 02, 1991
Michael H Blenk, Youngstown, NY (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A method for processing crude lead bullion using a reactive metal mixture intermediate by-product having sodium and calcium includes the steps of pouring molten crude lead bullion from a blast furnace into a casting vessel, cooling the crude lead bullion so that a crust forms on top thereof, punching a hole in the crust, injecting a reactive metal mixture intermediate by-product comprising sodium and calcium below the crust and into the crude lead bullion, and allowing the contents of the casting vessel to cool to form three equilibrium phases, including a bottom phase of refined lead bulletin, a speiss phase formed on top of the lead bullion phase and including Cu.sub.3 As and Fe.sub.2 As, and a matte phase formed on top of the speiss phase and including copper, sodium, calcium and sulfur. A method for processing a previously-produced lead dross containing entrained lead using a reactive metal mixture intermediate by-product includes adding molten lead to a kettle, agitating the lead, adding a reactive metal mixture intermediate by-product comprising sodium and calcium to the lead to form an alloy of lead, sodium and calcium, adding a lead dross comprisingy Cu.sub.2 S, PbS and entrained lead to the alloy, discontinuing the agitation, and allowing the alloy to equilibrate to form a matte phase including Cu.sub.2 S, Na.sub.2 S, CaS and CaO and a lead phase that included a portion of the lead that was formerly entrained and/or chemically bound in the dross.