A new preparation scheme for a difficult-tofloat coking coal by column flotation following grinding
Y Liaoa, Y Caoa, Z Hub, X Taoc
A new preparation scheme for a difficult-to-float coking coal from the
Kailuan Mine, Tangshan, China was investigated. The results showed that
grinding followed by column flotation was beneficial for obtaining products
with low ash content. The positive effect of grinding on the coal floatability
is attributed to the liberation of intergrowths and coal surface
improvement. Tests indicated that 10 minutes was the optimum grinding
time, and overgrinding resulted in a deterioration in flotation performance.
With a grinding time of 10 minutes, conventional flotation had potential to
yield a product with around 12.42% ash content and 69.15% combustible
recovery. Column flotation can reduce the product ash content to 11.15%
and increase combustible recovery to 74.47%. Consistently better flotation
results reveal that column flotation is more efficient than conventional
flotation for such fines.
Keywords: coal flotation, column flotation, grinding, difficult-to-float, liberation.