METHOD FOR DRYING FINELY DIVIDED CONCENTRATE IN ROTATING DRUMS Russian patent published in 1995 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: method for drying finely divided concentrate in rotating drums includes feed of main bulk of concentrate into two-layer flow of hot gases. Two-layer flow is formed of central high-temperature flow of combustion products and encircling flow of diluting air; and stabilization of temperature potential along the drum length by regulated mixing of combustion products with separately supply of diluting air. When concentrate contain 40-50% of fine particles sizing 0.01-0.10 mm during the first time period equalling 0.03-0.08 of the total time of concentrate treatment in drum, the temperature of the central part of the two-layer flow is maintained constant and equal to the temperature of combustion products at drum inlet by supplying to it the diluting air at rate equalling 1.4-1.5 rate of supply of combustion products. When the content of fine particles in concentrate reduces from 40% by every 10%, rate of supply of diluting air is reduced from 1.4 by 0.08-.10 of rate of supply of combustion products into drum. EFFECT: improved quality of product and intensified process.