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This process can be used to grow thick (tens or hundreds of micrometers), largely crystalline, oxide coatings on metals such as aluminium, magnesium [2] and titanium. Because they can present high hardness [ 3 ] and a continuous barrier, these coatings can offer protection against wear , corrosion or heat as well as electrical insulation .
The electrolysis can be done on a molten metal oxide (smelt electrolysis) which is used for example to produce aluminium from aluminium oxide via the Hall-Hérault process. Electrolysis can be used as a final refining stage in pyrometallurgical metal production (electrorefining) and it is also used for reduction of a metal from an aqueous metal ...
Chemical looping combustion (CLC) is a technological process typically employing a dual fluidized bed system. CLC operated with an interconnected moving bed with a fluidized bed system, has also been employed as a technology process. In CLC, a metal oxide is employed as a bed material providing the oxygen for combustion in the fuel reactor.
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite , aluminium 's chief ore, through the Bayer process ) in molten cryolite and electrolyzing the molten salt bath, typically in a purpose-built cell.
DC plasma (violet) enhances the growth of carbon nanotubes in a laboratory-scale PECVD (plasma-enhanced chemical vapor deposition) apparatus. Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high-quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin ...
The most common example of roasting is the oxidation of metal sulfide ores. The metal sulfide is heated in the presence of air to a temperature that allows the oxygen in the air to react with the sulfide to form sulfur dioxide gas and solid metal oxide. The solid product from roasting is often called "calcine".
Mixed metal oxide (MMO) electrodes, also called Dimensionally Stable Anodes (DSA), are devices with high conductivity and corrosion resistance for use as anodes in electrolysis. They are made by coating a substrate, such as pure titanium plate or expanded mesh, with several kinds of metal oxides.
The chemical equation for this process when starting with fluoroapatite, a common phosphate mineral, is: 4 Ca 5 (PO 4) 3 F + 18 SiO 2 + 30 C → 3 P 4 + 30 CO + 18 CaSiO 3 + 2 CaF 2. Of historic interest is the Leblanc process. A key step in this process is the reduction of sodium sulfate with coal: [3] Na 2 SO 4 + 2 C → Na 2 S + 2 CO 2