Study of the potentials for rewashing the middling product produced through primary scarce coking coal washing process

In order to explore the possibility of making rewashing of the middling product of the scarce coking coal primary washing process at Qianjiaying Coal Preparation Plant, flotation test is conducted on 3 kinds of crushed and ground middling products for determining their respective rewashing potentials. According to the test result and techno-economical analysis, it is found that: the coarse middling product which accounts for 6.97% of the total is highly adaptable to rewashing in quality, yet the process is difficult and high in cost. So the possibility of making rewashing of the middling product on an industrial basis needs to be further investigated; for the small-size middling which makes up 60.47% of the total, its rewashing process is extremely difficult because only through ordinary liberation process, the ash of rewashed clean coal can hardly meet the required standard; rewashing of the liberated flotation middling product, which shares 32.56% of the total, can have a high yield of up-to-standard product, indicating that the middling has a high rewashing potential.