Metal winning

Beryllium. Beryllium [7440-41-7], Be, metal is produced by electrolysis of KCl—NaCl—BeCl2 melts. Temperatures up to 900°C are required. CeU voltages are 6 to 9 V (115). Electrolysis of mixtures of beryUium oxide [1304-56-9], BeO, ia lithium fluoride [7789-24-4], LiF, and beryUium fluoride [7787-49-7], BeF2, has produced beryUium metal at about 700°C and 2.6 V (116). DetaUs of fused salt metal winning processes are given ia Table 7. 

A Survey ofi Electrochemical Metal Winning Processes, ANL/OEPM-79-3, BatteUe Columbus Laboratory, Argoime, lU., Mar. 1979. 

Consequently, working temperatures of metal-winning and metal-plating electrolyses with anodic 02 evolution must be operated below 40°C if titanium anodes are intended to be used. Fortunately usually these types of electrolyses are operated at relatively low current densities allowing for relatively low process temperatures. 

The preceding chapters have shown that the majority of metals can now be electrodeposited from ambient-temperature ionic liquids. However, this does not necessarily mean that the liquid with the widest potential window will negate the use of all other ionic liquids. Rather, it is most likely that ionic liquids will be task-specific with discrete anions being used for metals that cannot be electrodeposited from aqueous solutions such as Al, Li, Ti, V and W. Type I eutectics will probably be the most suitable for Al, Ga and Ge. Type II eutectics are most suitable for Cr and Type III are most suited to Zn, Cu, Ag and associated alloys. Type III will also find application in metal winning, oxide recycling and electropolishing. To date most practically important metals have been electrodeposited from ionic liquids and a comprehensive review is given in articles by Abbott [99] and Endres [100-102],... 

Electrometallurgy — Metal winning and refining processes based on electrochemical reactions (processes where a flow of electric current provides only heat but no electrochemical reaction are electrothermal ones). Ref. [i] Popov K, Djokic S, Grgur B (2002) Fundamental aspects of electrometallurgy. Kluwer Plenum, Boston... 

Fray-Farthing-Chen Process — Metal winning by - electrolysis of solid metal oxides, e.g., TiC>2 and Tb4C>7, dispersed in molten salts, e.g., CaCh [i,ii]. The technology is still under development. 

The most obvious way to proceed would seem to be with the use of an appropriate molten salt. Magnesium can be deposited from anhydrous molten MgCl, and aluminum can be deposited from a cryolite bath, since in these baths metal deposition is the only cathodic reaction that can take place. The quality of the deposits in these baths is usually poor, however, and they are used for metal winning rather than electroplating. 

L. E. Vaaler and co-workers, Battelle Columbus Laboratories, Final Report on a Survey of Electrochemical Metal Winning Processes, ANL/OEPM-79-3, Argonne National Laboratory, Mar. 1979. Available from National Technical Information Service, Washington, D.C. 

Roberts GM. "The Role of Electrolytic Processes for Metal Winning from Dilute Solutions", Conference at the University of Newcastle-Upon-Tyne, UK, July 1980. 

Very often applications with reactive extraction (e.g., metal winning from brines and effluents) are with diluted feed solutions, where ideality can be assumed. There are two attempts to tackle nonidentities, which is to introduce activity coefficients or a more complex chemistry. An extended... 

It is therefore proposed that the waste hydrogen from say, the chlor-alkali electrolysis process might be used (in tandem) to depolarize ready metal winning cells. The resulted overall reduction of overvoltage energy ions could be as much as 0.8 V. 

High temperature electrolysis in molten salts is confined primarily to electronegative high reactive and refractory metal winning. The most important process is evidently the high energy consuming aluminium elec-... 

We mentioned in Section 1.3 some important industrial applications of electrolysis—in the chloralkali industry, metal winning and refining, and organic electrosynthesis. As indicated in Section 1.2, we do not intend to describe electrochemical processes in detail, since there are many books on electrochemical technology. We will discuss the design of individual reactors, with emphasis on modularized, general purpose flow electrolyzers. We will classify reactors by their mode of operation. 

In (2), again, trace amounts of additives seem to provide a solution. The commonest use of additives is in the metal-winning and finishing industries. 

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