Reducing agents in metallurgy

One of the most common chemical reducing agents for metallurgy is coke, a form of carbon made by heating coal at high temperature until all of the volatile impurities have been removed. Metals whose cations have moderately negative reduction potentials—Co, Ni, Fe, and Zn—are reduced by coke. For example, direct reaction with coke in a furnace frees nickel from its oxide NiO(.j) + C( ) Ni(/) -F CO(g)... 

Roasting furnaces are used to react sulfides to produce metal oxides, which can be converted to metals in the next process step. The sulfides are used as a reducing agent in nonferrous metallurgy for the recovery of metals. The process has been used for metals such as copper, lead, zinc, nickel, magnesium, tin, antimony, and titanium. 

Carbon being cheap is the most commonly used reducing agent in extractive metallurgy. 

Only about one-fourth of the elements occur naturally in the free state. Most are found in a combined state. The process of obtaining a metal from its ore is called metallurgy. Since the metals in ores are found in the form of cations, the chemistry of metallurgy always involves reduction of the ions to the elemental metal (with an oxidation state of zero). A variety of reducing agents can be used, but carbon is the usual choice because of its wide availability and relatively low cost. For example, carbon is the primary reducing agent in the production of steel. Carbon can also be used to produce tin and lead from their oxides ... 

Sodium is by far the most widely used alkali metal because it is so abundant. Its salts are essential for life. The metal itself is used as a reducing agent in the manufacture of drugs and dyes and in the metallurgy of such metals as titanium and zirconium. 

Calcium and its compounds are widely used commercially. The element is used as a reducing agent in the metallurgy of uranium, thorium, and other metals. It is also used as a scavenger to remove dissolved impurities such as oxygen, sulfur, and carbon in molten metals and to remove residual gases in vacuum tubes. It is a component of many alloys. 

USE In metallurgy as reducing agent in pharmaceutical prepns as mordant in dyeing. Caution Mild irritant. 

USE Powerful reducing agent in acid solution or at high temps hydrogenation catalyst in the vacuum tube industry and powder metallurgy. 

Process Chemistry. Manganese is combined with oxygen in its ores (see Table 3) and carbon is the most economical reducing agent for oxides. Therefore, the essential characteristics of manganese metallurgy is evident from examination of the interactions between manganese oxides and... 

Silicon s atomic structure makes it an extremely important semiconductor. Highly purified silicon, doped with such elements as boron, phosphorus, and arsenic, is the basic material used in computer chips, transistors, sUicon diodes, and various other electronic circuits and electrical-current switching devices. Silicon of lesser purity is used in metallurgy as a reducing agent and as an alloying element in steel, brass, and bronze. 

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