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Show - Tooele's New Slag Plant S 'war V " ' ' I The basic purposes of the slag treatment plant is to recover from lead blast furnace slag zinc that is now being wasted on the dump. Its offset commercially will be the recovery of the greater part of the zinc that is now being lost in the smelting of ordinary lead ores, and thus add to current national zinc production of from 1,000,000 to 2,000,000 pounds monthly from Tooele alone. Zinc has always been an element that increases cost in lead blast furnace smelting and will still continue to be; therefore, the value of this operation is entirely en-tirely in the recovery of such zinc and in no way affects the cost of putting it through the blast furnace. fur-nace. By such zinc recovery it is hoped finally, as soon as the economics eco-nomics of the whole operation are worked out, to be able to treat lead ores much higher in zinc than at the present time and hence increase the commercial limit o zincky lead ores, particularly those which, due to more or less oxidation oxida-tion or other causes, are not amenable amen-able to treatment by selective flotation. flota-tion. Incidentally, it will be possible to recover zinc from slag dumps which are sufficiently high in zinc to warrant their re-treatment. Such slag can either be handled by putting put-ting It cold into the slag treatment furnace or by melting first through the lead blast furnace. The choice between the two methods will be dictated by conditions in each case. The metallurgy of this process was worked out at Tooele some 15 years ago under patents granted to U. A. Garred, which were acquired ac-quired by International Smelting & Refining Company and its associated as-sociated companies. A furnace of this tvpe was installed by Hie Anacoiida Copper Mining Company to treat the slag from the American Amer-ican Smelting & Refining Company's Com-pany's East Helena Plant some 12 to 14 years ago. The process consis.s of blowing air and pulverized coal through molten slag in a furnace ot the blast type. The zinc is redural and immediately re-oxidized in the upper part of the furnace, former,' an oxicle fume. Any residu-l'lcrd is also reduced and the lead again re-oxidized in the upper part of the furnace. The gas from the furnace containing the fume is eooled and lead to a bag house where a zinc fume containing some lead is produced. Inasmuch as fume with as little load as possible is preferred by the retort plains for the manufacture of prime western west-ern zinc, the leady zinc fume will be passed through a rotary kiln for the elimination of the lead which will in turn be caught as a lead fume in a separate bag house. The deleaded fume will be shipped to eastern refineries and the lead returned to the lead blast furnace here. |