Cathodes production process

FIGURE 24.5 Estimated investments for the continuous cathode production process [1 ]. (For color version of this figure, the reader is referred to the oniine version of this book.) (Source Roland Berger, The LIB Value Chain (2012).)... 

Scanning electron beam systems are available commercially, and are commonly used for mask generation. Electron projection systems are also used to obtain resolution over a large field. Current cathode sources have a short lifetime, limiting use in production processes. 

Buried steel pipelines for the transport of gases (at pressures >4 bars) and of crude oil, brine and chemical products must be cathodically protected against corrosion according to technical regulations [1-4], The cathodic protection process is also used to improve the operational safety and economics of gas distribution networks and in long-distance steel pipelines for water and heat distribution. Special measures are necessary in the region of insulated connections in pipelines that transport electrolytically conducting media. 

The cast grids are made into battery anode and cathode plates by the application of a lead oxide paste of 70 percent lead oxide (PbO) and 30 percent metallic lead. Lead ingots are tumbled in a ball mill with airproducing lead oxide and fine lead dust (referred to as leady oxide ). Leady oxide particulates are entrained in the mill exhaust air, which is treated sequentially by a cyclone separator and fabric filter. The used fabric filter bags are shipped to a RCRA-permitled commercially operated ha2ardous waste landfill located in Colorado. The leady oxide production process does not produce wastewater. 

Fuel cells are electrochemical devices transforming the heat of combustion of a fuel (hydrogen, natural gas, methanol, ethanol, hydrocarbons, etc.) directly into electricity. The fuel is electrochemically oxidized at the anode, whereas the oxidant (oxygen from the air) is reduced at the cathode. This process does not follow Carnot s theorem, so that higher energy efficiencies are expected up to 40-50% in electrical energy and 80-85% in total energy (heat production in addition to electricity). 

Figure 5.8 Outokumpu process for nickel cathode production.

The cathodes removed from the electrolytic cell are the primary product of the copper producer and contain >99.99% copper. These may be sold to wire-rod mills as cathodes or processed further to a product called rod. In manufacturing rod, cathodes are melted in a shaft furnace and the molten copper is poured onto a casting wheel to form a bar suitable for rolling into a 3/8-in.-diameter continuous rod. This rod product is shipped to wire mills, where it is extruded into various sizes of copper wire. 

Note Most process operations are accomplished without the use of process water No wastewater characterization data available Anode production (zinc, mercury, TSS, oil, and grease) Cathode production (copper, chromium, zinc, lead, silver, nickel, mercury, and TSS)... 

A process for the direct reduction of nitrobenzene to -p-ammophenol, an important intermediate for the production of dyes, depends on the above interesting transformation. Nitrobenzene in alcoholic solution is mixed with concentrated sulphuric acid and electrolysed with a lead cathode. This process proves that phenylhydroxylamine is also an intermediate in the reduction of nitrobenzene in acid solution, as was mentioned above. Here, as a result of the rapidity of the rearrangement which takes place, it is not converted into aniline. 

Identifying the electro-oxidation product At higher concentration [1] > 1 mM [I-] < 5 luM (Fig. 27.1), there are two anodic and corresponding two cathodic peaks. Processes may be, suggested to be... 

In dilute supporting electrolyte, the maximum on the polarographic waves was observed, which is connected with accumulation of insoluble reduction product on the electrode surface. The apparent rate constant for cathodic reduction process of ammonia complexes of Zn(II) was obtained. 

Xanthine and xanthosine were investigated on HMDE, applying out-of-phase ac and dc voltammetries [74]. It has been shown that both compounds are strongly adsorbed and interact chemically. In the cathodic stripping process, one could determine both compounds at trace level. Naidu et al. [146] have performed polaro-graphic studies to show that the product of anodic reaction (prewave) of potassium isobutyl xanthate is strongly adsorbed at the mercury electrode. 

The electrolysis Of fused alkali salts.—Many attempts have been made to prepare sodium directly by the electrolysis of the fused chloride, since that salt is by far the most abundant and the cheapest source of the metal. The high fusion temp. the strongly corrosive action of the molten chloride and the difficulty of separating the anodic and cathodic products, are the main difficulties which have been encountered in the production of sodium by the electrolysis of fused sodium chloride. Attention has been previously directed to C. E. Acker s process for the preparation of sodium, or rather a sodium-lead alloy, by the electrolysis of fused sodium chloride whereby sodium is produced at one electrode, and chlorine at the other but the process does not appear to have been commercially successful. In E. A. Ashcroft s abandoned process the fused chloride is electrolyzed in a double cell with a carbon anode, and a molten lead cathode. The molten lead-sodium alloy was transported to a second chamber, where it was made the anode in a bath of molten sodium hydroxide whereby sodium was deposited at the cathode. A. Matthiessen 12 electrolyzed a mixture of sodium chloride with half its weight of calcium chloride the addition of the chloride of the alkaline earth, said L. Grabau, hinders the formation of a subchloride. J. Stoerck recommended the addition of... 

According to the last mechanism an electrochemical active particle is carbon dioxide. Therefore direct electroreduction of carbon dioxide, dissolved in the salt melts must also give a carbon as a cathode product. It was confirmed in the [6, 7], but there were no any data about morphology and structure of obtained carbon powders. The electrodeposition of carbon from carbon dioxide was taken as the base process for high-temperature electrochemical synthesis (HTES) of refractory carbides [8, 9]. 

A great volume of work has been carried out on the important reaction of electrochemical reduction of O2, especially in the areas of fuel-cell development and air-cathode production for gas batteries. This field has been pioneered by Yeager (evolution reaction, it will not be treated here except... 

The undivided cell is used in cases where the electrode processes don t adversely affect one another negatively. The most common case is the anodic oxidation of an organic substrate combined with the cathodic production of hydrogen. If the evolution of oxygen as the anodic by-product can be excluded, this alternative is most convenient and—usually—the least costly. A typical thin-film cell is the trickle tower cell (Fig. 5b) [52]. The trickle tower cell has been applied to the production of propylene [53]. 

In 2003, the world zinc production was 9 880000 tons [55]. The most important zinc production process is the electrolytic or roast-leach-electrowinning (RLE) process. This was first used in 1916 by Anaconda and Cominco. The industrial processes of zinc production use zinc oxides as raw materials. The most important natural raw material is zinc sulfide, and, therefore, it needs to be roasted and converted to oxide. The main problem in leaching and liquor purification is separation of zinc and iron. As dissolution of iron cannot be avoided, it must be precipitated from the zinc sulfate solution. Impurities still present after the iron precipitation stage can lead to lower current efficiency and impurities in the zinc cathode. Therefore, the solution is further purified by cementation with zinc powder. 

Electron Production Processes. The important electron production processes occur in the gas phase and, in the case of discharges with electrodes, at electrode surfaces. The major surface processes are (a) secondary electron emission on ion impact at the cathode, (b) field emission at sharp points on electrodes, and (c) thermionic emission in the case of arc-type discharges where electrodes become strongly heated. These are the sources of the primary electrons in d.c. and low frequency discharges. 

In recent years, a number of electrolytic processes have utilized membranes in producing both anodic and cathodic products. By far, however, the most important application of this technology has been in the chlor-alkali industry. Intense commercial and academic interest has been focused into this field during the past decade so that ion exchange theory as applied to membranes is in a more advanced state than any of the other ion exchange systems. The primary examples of industrial chlor-alkali electrochemistry are found in the production of chlorine, caustic soda and potash, hydrogen and hypochlorite (1) (4). 

Interaction of anode and cathode products, Since the products of the reactions at the anode of any electrolytic cell have been reduced and those at the cathode have been oxidized, it is evident that mixing of the electrode products may result in chemical reactions which will be in the direction of lowering the efficiency of both electrode processes, and the observed amounts of the products of the electrode reactions will consequently be less than the computed values. For instance, in the electrolysis of water containing a salt the reaction at the anode is usually,... 

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