E.i. Dupont De Nemours and Company

Michael H Blenk

John P Hager

Russell Bertrum Diemer, Jr

A process for using iron metal or an iron-containing sulfide reagent as a co-additive to extend the usefulness of sodium in refining crude lead bullion.

Iron as a co-additive in refining crude lead bullion

Previously formed copper speiss in an amount of about 6.5% by weight is a co-additive which extends the usefulness of sodium in refining crude lead bullion, which has a sulfur content generally less than about 1.3% by weight.

Copper speiss as a co-additive in refining crude lead bullion

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.

Iron and a copper speiss as co-additives in refining crude lead bullion

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.

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Youngstown, NY, United States of America

Michael H Blenk