Smelting reduction economics

Ferromanganese is produced iu blast fiimaces and electric smelting fiimaces. Economics usually determine which smelting process is chosen for ferromanganese. Both methods require about the same amount of coke for reduction to metal, but iu the case of the blast fiimace, the thermal energy required for the smelting process is suppHed by the combustion of additional coke, which iu most countries is a more expensive form of energy than electricity. 

Primary smelting can be carried out in a reverberatory, rotary, or electric furnace. The choice depends more on economic circumstances than on technical considerations (3). Thus, in the Far East, reverberatory furnaces fired with anthracite coal as the reductant were and still are widely used. 

The burning of the ligneous portion of the blackliquor produces sufficient heat in the furnace to sustain flash drying of residual moisture, salt-cake reduction, and chemical smelting. The heat in the gas passing through the furnace, boiler, and economizer produces steam for power and process. 

For economic reasons, industrial catalysts consist of smelted iron oxides (60-70 % Fe) mixed with oxides of Al, Ca, Mg, and L, ground to 6-20 mm. During the activation of the catalyst by reduction, iron crystallites are formed with an interconnected pore system and an inner surface area of 10-20 m /g. The surface is partially covered by promoter oxides. 

Slag reduction is a less economic exercise than smelting of high-lead content material directly to bullion, particularly with solid slag processed on a campaign basis. This step will, however, usually need to be carried out to meet TCLP requirements for long term storage of the... 

Hydrometallurgical processes may be used when the metal ion is readily reduced to the parent metal and hence the electrolytic reduction may be carried out in aqueous solution. Such chemistry, however, implies that other routes from the ore to the metal must be possible and, indeed, smelting techniques are always applicable. Hence the choice between smelting and electrolysis will depend on the quality and type of ore available and local economic factors, particularly the cost of various forms of energy. 

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