Refractory pyrometallurgy

CVD developed slowly in the next fifty years and was limited mostly to extraction and pyrometallurgy for the production of high-purity refractory metals such as tantalum, titanium, and zirconium. Several classical CVD reactionswere developedatthattimeincludingthecarbonyl cycle (the Mond process), the iodide decomposition (the de Boer-Van Arkelprocess)andthemagnesium-reduction reaction (the Kroll process). 

Metals are important resources and have a wide range of applications. Metals are often extracted from ores. Once the ore is mined, the metals must be extracted, usually by chemical or electrolytic reduction. Pyrometallurgy uses high temperatures to convert ore into raw metals, while hydrometalluigy employs aqueous chemistry for the same purpose. The methods used depend on the metal and their contaminants. Most metals are obtained by hydrometallurgical processes such as aqueous acids or alkalis are predominantly used to dissolve the metal oxides, sulfides, or silicates. Electrowinning and solvent extraction are frequently used to recover and concentrate the metals. A limited number of high-temperature molten salts have also been used for the recovery of refractory metals, such as titanium and aluminum, from their ores... 

The pyrometallurgy process for refractory gold ores mainly refers to oxidative roasting. Since As and S are volatilized in the form of AS2O3 and SO2 during the roasting, not only a porous roasted... 

Today, it is not rare to come across products containing more than a dozen constituents at the time of production. This shows the exterrt of improvement in the know-how and techrrical skill of manufacturers, in order to better satisfy the specific needs of the users and to increase the service life and the safety of the irrstallatiorrs. Examples of types of refractory materials used in different industrial sectors like cement works, electrometallurgy, pyrometallurgy, steel industry, chemical industry will be given later. 

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