Reduction furnaces, copper production

Refractories for Electric Reduction Furnaces. Carbon hearth linings are used in submerged-arc, electric-reduction furnaces producing phosphoms, calcium carbide, all grades of ferrosilicon, high carbon ferrochromium, ferrovanadium, and ferromolybdenum. Carbon is also used in the production of beryllium oxide and beryllium copper where temperatures up to 2273 K ate requited. 

Since hydrogen burns cleanly and reacts completely with oxygen to produce water vapor, this makes it more desirable than fossil fuels for essentially all industrial processes. For example, the direct reduction of iron or copper ores could be done with hydrogen rather than smelting by coal or oil in a blast furnace. Hydrogen can be used with conventional vented burners as well as unvented burners. This would allow utilization of almost all of the 30 to 40% of the combustion energy of conventional burners that is lost as vented heat and combustion by-products. 

A large fraction of the iron and steel produced today is recycled scrap. Since scrap does not require reduction, it can be melted down directly in an electric arc furnace, in which the charge is heated through its own electrical resistance to arcs struck from graphite electrodes above it. The main problem with this process is the presence of tramps (i.e., copper from electrical wiring, chromium, nickel, and various other metals) that accompany scrap steel such as crushed automobile bodies and that lead to brittleness in the product. Tin in combination with sulfur is the most troublesome tramp. Only the highest quality recycled steel—specifically, steel with no more than 0.13% tramps—can be used for new automobile bodies, and usually reprocessed scrap has to be mixed with new steel to meet these requirements. 

James and Fisher [1967] reported the use of copper oxychloride (3 CuO.CuCl Hf)) as a coal additive to reduce slagging in pulverised coal boilers. Its use in a UK power station resulted in a dramatic reduction in slagging by the production of a soft friable deposit which was easily removed fi-om the furnace walls. 

Because of a strong reduction atmosphere in the furnace, some lead metal forms a layer in the bottom of the furnace. The metal is tapped every two or three days through a hole surrounded by a copper block. Molten metal is tapped into kettles through a castable-lined launder. The production rate is 10 -12 tons per each tapping. It is sent to the present anode casting plant to be used as an antimony additive. Typical analysis of the metal is shown in Table III and the minor elements in the metal are ... 

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