Ores, hydrogen reduction

Fluoridation of UO2 peUets Catalyst regeneration Hydrogen reduction of ores Titanium dioxide... 

Sherritt-Cominco A process for extracting copper from chalcopyrite, CuFeS2. The ore is reduced with hydrogen, the iron leached out with sulfuric acid, the residual Cu5FeS4 dissolved in concentrated sulfuric acid, and the copper isolated by electrowinning or hydrogen reduction. Pilot testing was complete in 1976. 

About a third of the hydrogen manufactured is used in mining for the hydrometallurgical extraction of copper and other metals, the extraction of the metals from their ores by reduction in aqueous solution ... 

The authors are now studying the simultaneous recovery of metal and sulfur by a combination of the hydrogen reduction of sulfide ore and the decomposition of H2S to H2 and S as follows. 

Available forms (2) Powdered iron. Derived (a) by treatment of ore or scrap with hydrochloric acid to give ferrous chloride solution, which is then purified by filtration, vacuum crystallized, and dehydrated to ferrous chloride dehydrate powder this is reduced at 800C to metallic iron (briquettes or powder) of 99.5% purity (b) by thermal decomposition of iron carbonyl [Fe(C05)] at 250C (99.6-99.9% pure) (c) by hydrogen reduction of high-purity ferric oxide or... 

The Swedish chemist Scheele (1778) produced the oxide of a new element from (black) M0S2, thereby distinguishing the element from graphite with which it had been confused. The metal was isolated by Hjelm in Sweden three to four years later by heating the oxide with charcoal. In the procedure now used to isolate the metal, the M0S2 component in ores is concentrated by flotation methods. The concentrate is then converted by roasting into MoOs, which, after purification, is reduced with hydrogen. Reduction with carbon is avoided since carbides rather than the metal are obtained. 

Other uses of hydrogen include the hydrogenation of oils, methanol production, rocket fuel, welding, the production of hydrochloric acid, and the reduction of metallic ores. Hydrogen is also important in cryogenics techniques and in superconductivity experiments since its melting point is only just above absolute zero. 

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