Betts electrolytic process
Encyclopedia
The Betts electrolytic process is an industrial process for separating lead
and bismuth
. It is named for its inventor Anson Gardner Betts.
for this process is a mixture of lead fluorosilicate (PbSiF6) and hexafluorosilicic acid (H2SiF6) heated to 45°C(113°F). Cathodes are thin sheets of pure lead and anodes are cast from the impure lead to be purified. A potential of 0.5 volts is applied. At the anode, lead goes into solution, as do metal impurities that are less noble than lead. Impurities that are more noble than lead, such as silver, gold, and bismuth, flake from the anode as it dissolves and settle to the bottom of the vessel as "anode mud." Pure metallic lead plates onto the cathode, with the less noble metals remaining in solution. Because of the high cost of electrolysis, this process is used only when very pure lead is needed. Otherwise the Parkes process
followed by the Betterton-Kroll process
are used to purify lead.
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Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
and bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
. It is named for its inventor Anson Gardner Betts.
Process description for lead
The electrolyteElectrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
for this process is a mixture of lead fluorosilicate (PbSiF6) and hexafluorosilicic acid (H2SiF6) heated to 45°C(113°F). Cathodes are thin sheets of pure lead and anodes are cast from the impure lead to be purified. A potential of 0.5 volts is applied. At the anode, lead goes into solution, as do metal impurities that are less noble than lead. Impurities that are more noble than lead, such as silver, gold, and bismuth, flake from the anode as it dissolves and settle to the bottom of the vessel as "anode mud." Pure metallic lead plates onto the cathode, with the less noble metals remaining in solution. Because of the high cost of electrolysis, this process is used only when very pure lead is needed. Otherwise the Parkes process
Parkes process
The Parkes process is a pyrometallurgical industrial process for removing silver from lead, during the production of bullion. It is an example of liquid-liquid extraction....
followed by the Betterton-Kroll process
Betterton-Kroll process
The Betterton-Kroll process is an industrial process for removing bismuth from lead.Calcium and magnesium are added to a molten lead-bismuth bath. The resulting bismuth compounds have higher melting points and lower densities than the lead, and can be removed as dross. The compounds are treated...
are used to purify lead.
External links
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