There is only one keyword in selecting kaolin: stickiness. It comes from the extremely fine particle size, and it shows up in two states. Wet, the material balls up and the feed bridges, so it cannot get in. Dry, it builds a hard crust on the drum wall, and the thicker the crust grows the less material the flights can lift, so throughput drifts down steadily and it is not easy to notice. Three questions therefore decide a kaolin machine: the flight pattern, the available speed range, and whether there is pre-treatment to break up the lumps. Our standard configuration is the rotary drum.
There is only one keyword in selecting kaolin: stickiness. It comes from the extremely fine particle size, and it shows up in two states. Wet, the material balls up and the feed bridges, so it cannot get in. Dry, it builds a hard crust on the drum wall, and the thicker the crust grows the less material the flights can lift, so throughput drifts down steadily and it is not easy to notice. Three questions therefore decide a kaolin machine: the flight pattern, the available speed range, and whether there is pre-treatment to break up the lumps. Our standard configuration is the rotary drum, because the working volume is large enough to spread sticky material out at a reasonable fill ratio, and because the continuous lifting and dropping of the flights keeps the bed from sitting against the wall long enough to crust over. The flash dryer is the alternative for the second half of the process, once the moisture has come down far enough and the stickiness has been released. White clay and red clay, being kaolin derivatives, are stickier than pure kaolin, so the flights have to be specified on the more conservative side.