Specialized metallurgical processes – compositions for use therei – Processes – Free metal or alloy reductant contains magnesium
Patent
1991-05-02
1992-03-31
Andrews, Melvyn J.
Specialized metallurgical processes, compositions for use therei
Processes
Free metal or alloy reductant contains magnesium
C22B 1306
Patent
active
051004666
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.
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"Sodium Treatment of Copper Dross", C. Bates and C. Di Martini, Journal of Metals, Aug. 1986, pp.43-45.
"Process for Separating Impurities from Crude Lead Bullion Via Sodium Metal Injection", M. B. Blenk, R. B. Diemer and J. P. Hager, International Symposium on Injection in Process Metallurgy, 2-21-91.
Andrews Melvyn J.
E. I. Du Pont de Nemours and Company
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