Use of sludges from waste water treatment plants - replace part of fuel in ore smelting furnaces and reduce fuel cost

摘要

Sludges are burnt in shaft furnaces using for the smelting of ores, and esp. in blast furnaces used for smelting iron ore. The sludge may be dried and blown into the furnace in a powder form, of or may be powdered and sprayed into the furnace in a liq. form. In either case, the sludge is introduced into the furnace via nozzles in the furnace tubere or air inlet pipe. USE/ADVANTAGE - Sludges from water treatment operations have customarily been used as soil additives and fertilizeers, but the metallic element content of the sludges now makes this method of disposal less attractive because of the increasingly strict environmental constraints which apply to the disposal of these elements. Similar constraints apply to the disposal of the sludges as land-fill, since the harmful elements can find their way from the land-fill site into ground water etc. The method provides a means of disposing of the sludges completely and without threat of damages to the environment. Up to 30% of the fuel required in the furnace can be replaced by the sludge, and a considerable economy in fuel consumption is thus achieved.