Masters Theses

Abstract

"The constitution of the matte and bullion obtained by the smelting of lead drosses coming from the cooling of lead blast furnace bullion was investigated by metallographic, chemical, electron-microprobe, and X-ray means. At smelting temperatures (1200°C to 1300°C) two liquid phases are in equilibrium. A liquid lead phase with low concentrations of copper and sulfur, and a lighter liquid matte phase containing a high concentration of copper and sulfur with some dissolved lead. On cooling to room temperature the matte precipitates cuprous sulfide, a eutectic mixture of cuprous sulfide and lead sulfide with a deficiency of sulfur, and metallic lead rich in copper and sulfur. Simultaneously the lead bullion precipitates some metallic copper which reacts with the sulfur going out of solution to form particles of copper surrounded by Cu2+xS which remain entrapped in the metallic lead. The lead showed small amounts of copper in solution. Samples of dross and matte from industrial practice were also studied by metallographic and X-ray diffraction methods. The influences of time and temperature of smelting upon matte formation were studied. A holding time of two hours at 1200°C - 1250°C was found to give the most fluid matte formation with a minimum of losses due to volatilization. Silica sand was found to increase the fluidity of dross fusions when used up to 2% by weight of the total dross fused. Additions of soda ash above 2% by weight did not show any improvement in the matte or bullion formed. Increased amounts of soda additions resulted in a decrease of the lead content of the slags. A slight decrease of copper in the bullion was also noted. Sulfur additions to dross fusions were investigated. The copper content of the bullion formed by dross smelting can be lowered from 13% Cu to about 4% Cu by the use of 2 to 3% by weight sulfur. Additions of sulfur over 3% were detrimental, because the matte formed contained a considerable amount of lead as lead sulfide (31% Pb). The effects of PbO and FeS₂ additions were also investigated. Although it was not possible to measure the efficiency of sulfur additions, it is believed that a considerable amount of sulfur was volatilized before having time to react"--Abstract, pages ii-iii.

Advisor(s)

O'Keefe, T. J. (Thomas J.)

Committee Member(s)

Mayhan, Kenneth G.
Wolf, Robert V., 1929-1999

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering

Sponsor(s)

St. Joseph Lead Company

Publisher

University of Missouri--Rolla

Publication Date

1970

Pagination

x, 80 pages

Note about bibliography

Includes bibliographical references (pages 61-62).

Rights

© 1970 Humberto Adoflo Arzabe, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Lead -- MetallurgySmelting

Thesis Number

T 2348

Print OCLC #

6018996

Electronic OCLC #

853508428

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