佐賀関製錬所における買鉱製錬所としての総合的効率の向上

抄録

Since 1980, improvements in the entire process of copper smelting and refining at Saganoseki Smelter and Refinery have been effected to reinforce its competitiveness as a custom smelter.
I. About 10 percent reduction in the total operation cost has been achieved due mainly to lowered energy consumption:
(1) Energy cost was considerably reduced by completely switching fuel for flash furnace from C heavy oil to powdered coke and by constructing low electricity consuming type of converter for acid plant.
(2) In order to improve smelting capacity of flash furnaces and converters without adding extra facilities, matte grade was raised from previous 60% to 62% by means of higher concentration of oxygen in the blast only with a construction of an additional oxygen plant (3, 700 Nm3/H). Thus, an increase in the concentrate treatment capacity and higher matte grade were made possible, thereby increasing copper.smelting capacity by 25% to 300, 000 tonnes in copper content per annum.
(3) A new efficient tank house equipped with a special double-hook loading system was built, replacing both No.1 tank house at Saganoseki and No.1 tank house at Hitachi.
(4) A set of belt conveyors covered by large steel pipes was extended to link the conveyor network right from the wharf to storage facilities, etc. to rationalize the transportation system for receiving concentrates and nickel ores. It also serves for shipment of slag. This sytem not only entirely replaced truck haulage but also effectively eliminated handling loss and environmental pollution.
II. Complexed copper concentrates treating capability has been increased:
(1) To separate and recover such impurity elements as Pb, Zn, As, Bi, etc., a new plant for processing Hot Cottrell converter dust was constructed.
(2) Both electrolyte purification capacity of the tank house and arsenic separation and recovery capacity of the acid plant were increased.