Recovery of clean coal from blast furnace dusts by flotation column

The paper presents the results of the study on recovery of clean coals from blast furnace dusts of the Cao Bang Iron Steel plant. The study has explored the effects of the most important operating parameters on the coal flotation performance including flotation reagent dosage, solid concentration, froth wash-water rate, flotation time and the froth thickness. The results of the study showed that using a combination of a rougher and a cleaning flotation operations at respectively collector dosage, solid concentration, flotation time, froth wash-water rate and froth thickness of 1000 g/t, 100 g/l, 10 minutes and 1.5 l/minute and 450 mm, has obtained a clean coal product with the yield, ash content and combustible matter recovery respectively of 44.90%, 19.15% and 77.63%. The clean coal has met the quality strandards requirements of the fuel for sintering.

Electromagnetic De-Shaling of Coal

The efficiency with which an electromagnetic sensor array is able to distinguish density and ash content of coal and shale mixtures was determined experimentally. The investigated sensor was originally designed for automatic metal detection and sorting in industrial glass recycle processing, where it is widely applied. In coal preparation, the results indicate good possibilities to remove automatically the remaining shale from the coal product, or to recover the remaining coal from the waste rock. Compared to alternative methods, the system has advantages of simple construction, insensitivity to fluctuating dust or moisture levels and a proven industrial reference. Applications can be either sorting of lump-sized coal or coal separation in the 10–50mm size range in a dry preparation process.