A Qualitative Evaluation of Several Electrolytes for Electrorefining Bismuth

Technical Report · Sun Jan 01 04:00:00 EST 1956

DOI:https://doi.org/10.2172/4359041· OSTI ID:4359041

Gruzensky, P. M. ^[1]; Crawford, W. J. ^[1]

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1. Bureau of Mines, Albany, OR (United States)

Several experiments have been carried out in efforts to evaluate qualitatively a variety of electrolytes for refining bismuth. Most extensive work was done with the basic tartrate, hydrochloric acid, and hydrofluosilicic acid electrolytes. Deposits that are smooth and adherent can be obtained from these three electrolytes if low cathode current densities are employed. All three electrolytes were effective in purifying crude bismuth considerably, with additional purification indicated in each instance by a reelectrolysis step. With the basic tartrate electrolyte best results were obtained when the electrolyte was at 40° C. and contained at least 100 grams of bismuth per liter. An apparent disadvantage was depletion of bismuth from this electrolyte, causing the deposits to become spongy and nonadherent. The hydrochloric acid electrolyte had the greatest tendency to yield rough, dendritic deposits. Best deposits were obtained at cathode-current densities below 2 amperes per square decimeter. A small amount of glycerin helped to produce a smoother deposit, and adding sulfuric acid or methyl sulfuric acid retarded the deposition of impurities. Very good results were obtained in electrowinning bismuth from a bismuth trichloride-hydrochloric acid electrolyte. Smooth and adherent deposits were obtained from a hydrofluosilicic acid electrolyte, with very good refining as regards lead and silver impurities; however, higher reagent costs and slow decomposition of the electrolyte have discouraged its use.

• Research Organization: Bureau of Mines, Albany, OR (United States)
• Sponsoring Organization: US Department of the Interior
• NSA Number: NSA-10-005737
• OSTI ID: 4359041
• Report Number(s): BM-RI--5182
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALCOHOLS
BISMUTH
BISMUTH CHLORIDES
CATHODES
CLEANING
CONFIGURATION
CRYSTALLIZATION
CURRENTS
DENDRITES
ELECTROLYSIS
ELECTROLYTES
GLYCERIN
GRAIN SIZE
HYDROCHLORIC ACID
HYDROFLUORIC ACID
IMPURITIES
LEAD
MEASURED VALUES
METHYL RADICALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
REFINING
SILICON FLUORIDES
SILVER
SOLUTIONS
SULFURIC ACID
TARTARIC ACID