Electrolytic salt bath

Kolene Process. Trade-name an electrolytic salt-bath treatment of sheet-steel before it is enamelled (Kolene Corp., Detroit, USA). 

The principal use of AIF. is as a makeup ingredient in the molten cryoflte, Na.. AIF AI2O2, bath used in aluminum reduction cells in the HaH-Haroult process and in the electrolytic process for refining of aluminum metal in the Hoopes cell. A typical composition of the molten salt bath is 80—85%... 

Metalliding. MetaUiding, a General Electric Company process (9), is a high temperature electrolytic technique in which an anode and a cathode are suspended in a molten fluoride salt bath. As a direct current is passed from the anode to the cathode, the anode material diffuses into the surface of the cathode, which produces a uniform, pore-free alloy rather than the typical plate usually associated with electrolytic processes. The process is called metalliding because it encompasses the interaction, mostly in the soHd state, of many metals and metalloids ranging from beryUium to uranium. It is operated at 500—1200°C in an inert atmosphere and a metal vessel the coulombic yields are usually quantitative, and processing times are short controUed... 

Electrolytic Processes. The electrolytic procedures for both electrowinning and electrorefining beryUium have primarily involved electrolysis of the beryUium chloride [7787-47-5], BeCl2, in a variety of fused-salt baths. The chloride readUy hydrolyzes making the use of dry methods mandatory for its preparation (see Beryllium compounds). For both ecological and economic reasons there is no electrolyticaUy derived beryUium avaUable in the market-place. 

Bad-kasten, m. (electrolytic) cell, -nitrieren, n. Metal.) fused-salt nitriding, -patentieren, n. Wire) patenting with cooling in a lead or salt bath, -spannung, /. bath tension, cell voltage, -Spiegel, m, bath level, bath surface, -zementieren, n. Metal.) bath cementation, liquid carburizing,... 

The electrolyte is made by in situ chlorination of vanadium to vanadium dichloride in a molten salt bath. Higher valent chlorides are difficult to retain in the bath and thus are not preferred. The molten bath, which is formed by sodium chloride or an equimolar mixture of potassium chloride-sodium chloride or of potassium chloride-lithium chloride or of sodium chloride-calcium chloride, is contained in a graphite crucible. The crucible also serves as an anode. Electrolysis is conducted at a temperature about 50 °C above the melting point of the salt bath, using an iron or a molybdenum cathode and a cathode current density of 25 to 75 A dnT2. The overall electrochemical deposition reaction involves the formation and the discharge of the divalent ionic species, V2+ ... 

Salt bath descaling is the process of removing surface oxides or scale from a workpiece by immersion of the workpiece in a molten salt bath or a hot salt solution. The workpiece is immersed in the molten salt [temperatures range from 400°C to 540°C (750-1000°F)], quenched with water, and then dipped in acid. Oxidizing, reducing, and electrolytic baths are available, and the particular type needed depends on the oxide to be removed. 

The aluminum industry consumes much more carbon, as baked anode composites, than the total of all other industrial uses for baked and graphitized carbon products. The free world s total annual aluminum production capacity is approximately 16 million short tons, about one-third being produced in the United States. World aluminum production involves the consumption (oxidation) of about eight million tons of anode carbon. Production occurs by electrolytic deposition from cryolite-alumina melts using a process patented simultaneously, but independently, in 1886 by Hall in America and Heroult in France. While minor process modifications have been made in the intervening years, and productivity greatly increased, substantially the same process is still used. The industrial electrolytic cell consists of a shallow carbon vessel about 10 ft. wide by 30 ft. long, and 1-2 ft. deep, which acts as the cathode and contains the fused salt bath and molten aluminum product. The carbon anodes are supported above the cathode and lowered into the cell at the rate of... 

Use Production of fluoborates, electrolytic brightening of aluminum, throwing power aid in electrolytic plating baths, esterification catalyst, metal cleaning, making stabilized diazo salt. 

Electrodeposition of aluminum is severely limited by the necessity of using molten salt baths or anhydrous organic electrolytes. 

Thin walled pieces are only pickled in an electrolytic or salt bath. It is important that not only the surface layer of oxide, but also the underlying oxygen enriched diffusion zone is removed. Otherwise, the machinability and the service life of turning and milling tools would be negatively affected. 

Although Mo is generally the container for the molten fused salt bath and Ce in the electrolytic method and Ta in the Ca reduction method, there is no reason why these two metals could not be substituted for one another as long as the level of the Mo or Ta impurity can be tolerated. Of the refractory metals, W is the least reactive with Ce, Ta is next and Mo is the most reactive. The choice of the refractory metal is not dictated by the method, but by costs and purity levels in the final product. 

The only electrolytic processes of any commercial importance for rare metal extraction are based upon the use of molten salt baths. Chlorides or fluorides of the rare metal are invariably electrolysed from solutions in similar but inert salts, usually of the alkali or alkaline earth metals. 

In order to keep the maintenance cost of the electrolytic equipment low, an inert salt mixture which has a low melting-point is often selected. Since the melting-point is then below that of the rare metal product, the latter is produced in solid form, usually as a powder or a collection of adhering crystals with a dendritic appearance. If a molten metal product is required, it is necessary to use a salt bath with a higher temperature, but this is rarely practicable. Table 8 gives the melting-points of a number of rare metal... 

This is known to be affected by the nature of the electrolyte salt in the silent system, and we repeated this reaction with insonation from either a 38-kHz or an 800-kHz bath, using a platinum anode in MeCN/CH2Cl2 containing either tetrabutyhammonium tetrafluoroborate (TEAT) or perchlorate (TBAP). We noticed some small effect of electrolyte salt as previously reported, but little effect... 

During startup and the early operation period, the planned losses of cryolite (and aluminium fluoride) are up to 12-18 t/cell. This amount of the bath (electrolyte) should be refilled at the start-up period and it is plaimed at the smelter. Aluminium and these fluorine salts (bath) appear at first in the cathode block and then reach the refractory barrier layer. In a pessimistic scenario, the molten fluorine salts reach the heat insulation layer. 

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