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Removing Bismuth from Lead With a Submersible Centrifuge.

Authors
Montagna-D; Ruppert-JA
Source
NTIS: PB 208 005 :10 pages
Link
NIOSHTIC No.
10008836
Abstract
The kroll-betterton process for debismuthizing lead is based on adding calcium and magnesium to impure molten bullion to form solid ca-mg-bi intermetallic compounds that float on the surface as drosses. Present practice in industry is to hand-skim off these drosses, often followed by hydraulic pressing to squeeze out some of the entrapped liquid lead. In an effort to develop an improved technique, the use of an argon-shrouded dipping centrifuge to perform the required phase separation was investigated. Centrifugation experiments demonstrated that the bismuth content of an impure bullion could be lowered from an initial 0.5 percent down to 0.03 percent with a lead recovery of 90 percent, which is comparable to lead recovery after hand skimming of drosses in commercial lead-debismuthizing operations. Centrifugation provides better control in removing drosses, faster operation with less oxidation and relatively little fuming, and recovery of a lead bullion that approaches commercial specifications.
Publication Date
19720101
Document Type
IH; Report of Investigation;
Fiscal Year
1972
NTIS Accession No.
PB-208005
NTIS Price
A02
Identifying No.
RI 7602
NIOSH Division
CPRC;
Source Name
NTIS: PB 208 005
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