Consumable electrodes

Arc melting also can be used to consoHdate bars of metal that are pressed from powder or sponge and used as consumable electrodes in a low voltage, high current arc. The bar is suspended vertically and the molten metal falls from the bottom of the bar onto a water-cooled copper cmcible, from which it is removed as an ingot. 

If the cations in solution are condensable as a soHd, such as copper, they can plate out on the cathode of the cell. As the same time, perhaps some hydrogen is also produced at the cathode. The SO can react with a copper anode material by taking it into solution to replace the lost copper ions. Thus the anode is a consumable electrode in the process. 

Consolidation. ConsoHdation by the consumable-electrode electric-arc melting technique is ideally suited for vanadium and is used extensively... 

Metal-arc Welding arc welding using a consumable electrode. 

TIG-welding tungsten inert-gas arc welding using a non-consumable electrode of pure or activated tungsten. 

It will be seen that the impressed current electrode discharges positive current, i.e. it acts as an anode in the cell. There are three generic types of anode used in cathodic protection, viz, consumable, non-consumable and semi-consumable. The consumable electrodes undergo an anodic reaction that involves their consumption. Thus an anode made of scrap iron produces positive current by the reaction ... 

The semi-consumable electrodes, as the name implies, suffer rather less dissolution than Faraday s law would predict and substantially more than the non-consumable electrodes. This is because the anodic reaction is shared between oxidising the anode material (causing consumption) and oxidising the environment (with no concomitant loss of metal). Electrodes made from silicon-iron, chromium-silicon-iron and graphite fall into this category. 

Carbon is a relatively inert element chemically and is used in its graphitic and pre-graphitic forms as a construction material under a variety of corrosive conditions. Modern uses include heat exchangers in chemical plants, consumable electrodes in a variety of metallurgical processes and the components of rocket motors and the moderators of gas- and litiuid-cooled nuclear reactors. The demand for carbon products at the present time is I0 t/year. 

High-frequency plasma source having no consumable electrodes ... 

In the first of the four examples, the electrode material (metallic silver) is chemically involved in the electrode reaction hence it becomes more [less] as a function of time. Such electrodes are called reacting [or consumable] electrodes. 

Specific types of consumable electrode are designated in terms of the constituent material (e.g., as a silver electrode ). Nonconsumable electrodes are designated either in terms of the electrode material or in terms of the chief component in the electrode reaction for instance, the terms platinum electrode and hydrogen electrode are used for electrode (1.27). Neither of these names completely describes the special features of this electrode. 

Table 9b. Products manufactured by indirect electrochemical technologies using consumable electrodes [115]...

SNPE in France has developed a new technology specially adapted to electrolysis with consumable electrodes. SNPE has been operating for a few years a multi-purpose lOt/year pilot unit located in ISOCHEM s plant in Pithiviers (France), Fig. 14. 

Mg is used as the consumable electrode. Industrial grade magnesium is of sufficient purity for these reactions (Pechiney manufactures 99.7% Mg costing about 4 dollars per kg). For most syntheses only about 0.2 kg of magnesium are consumed per kg of product which means about 0.8 dollars per kg. Magnesium salts are disposed of by standard procedure or can be transformed into valuable magnesium stearate [149]. 

Consumable-electrode melting, 12 302 Consumable-electrode electric-arc melting technique, 25 522... 

Consumable-electrode melting, 23 254 Consumer applications, for polyamide plastics, 19 795... 

REP, a rod of metal or alloy, referred to as a consumable electrode, is rotated at high speed about its longitudinal axis. Simultaneously, it is melted gradually at one of its ends by a heat source, such as an arc, a plasma, or an electron beam, etc. A thin film of the molten metal is detached from the rod end and ejected from the periphery of the rod by centrifugal force, forming spherical droplets. The atomization is conducted in an inert atmosphere, usually argon. Helium may be used to increase arc stability and convective cooling efficiency of droplets. 

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