Low ash coal with an ash content lower than 2% can be separated from some suitable coal with its purification ability and by a high efficient cyclonic microfoam columned pneumatic floatation machine.

• 对于一些适宜的煤种，利用净化能力强、分选效率高的旋流微泡浮选柱可以分选出灰分小于2%25的低灰煤。