Dust properties, determined in part by char recovery, are major factors in pressure loss of ceramic candle filters applied to hot coal gas cleaning. A cyclone was applied to char recovery to investigate the effects on dust properties at 1.67-1.87 MPa and 573-723 K. After the cyclone, dust concentration was monitored continuously. Dust concentration entering filters increased intermittently because of re-entrainment of collected particles from the cyclone. The particles were blown up during char discharging from the cyclone hopper and affected measurement of the dust concentration. The cyclone decreased the dust concentration entering the filter from 60 to 3 g/m(N)(3) but did not lower the filter pressure loss. The cyclone collected larger particles and increased their specific surface area with consequent ineffectiveness in pressure loss reduction in the dust cake.