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Utilization of Scrap Preheating and Substitute Slag Conditioners for Electric Arc Furnace Steelmaking.
Elger-GW; Nafziger-RH; Tress-JE; Hartman-AD
MISSING :26 pages
The Bureau of Mines investigated the preheating of continuously fed, fragmented ferrous scrap charges by furnace offgases and the utilization of substitutes for imported fluorspar to condition electric steelmaking slags. Three types of continuous scrap charging procedures were investigated to determine electrical energy consumption in a 1-st (short ton) electric arc furnace. Cold and preheated scrap charges were continuously fed at rates averaging 37.5 and 43.7 Lb/min, respectively. The feed rate varied appreciably from test to test owing to hangup of the scrap in the charge bin. Approximately 7 pct less electrical energy was consumed in melting scrap preheated to 840 deg to 1,110 deg f by furnace offgases than in melting cold scrap. Overall energy consumptions were 888 kw.H/st for cold scrap, 829 kw.H/st for preheated scrap, and 637 kw.H/st for conventional backcharged scrap. Stack gases from scrap preheating averaged 120 deg f and a flow rate of 1,615 standard cubic feet per meter (scfm) compared with 220 deg f and 1,302 scfm for cold-charged scrap. Slag conditioners tested included synthetic fluorspar, boric acid, hydroboracite, used aluminum potlining wastes and aluminum anode tailing wastes, and sorelflux b. The boron-containing conditioners fluidized the slags the best, followed in order by the conditioners containing fluorine and titanium.
IH; Report of Investigations
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division