Abstract
Wet particulate material is a difficult to screen, because the particles are adhered to the screen wires, causing rapid blinding of the apertures in the screening surface.
The object of the research described in this report is to evaluate the influence of the addition of dry fine powder to the wet particulate material to be screened. Materials tested are three kinds of crushed coals from different sources containing about 10% moisture. Particle size distributions of coals are shown in Fig. 3. Dry fine powders, whose particle size distributions are shown in Fig. 8, were produced by grinding coal itself with various mills. Fig. 4 illustrate the experimental apparatus, holding 3360 and 2830μ sieves, whose vibrating speed is 610rpm and stroke is 7.5mm.
The main results are as follows:
1) Size frequency distributions of particles adhered to the screen wire had bimodal character.
2) Addition of dry fine powder had remarkable effect upon the blinding elimination of apertures. For the evaluation of adhesiveness, degree of saturation by adhered particles was defined in Fig. 7.
3) The effect of the particle size of added fine particles upon the blinding elimnation has been tested in Fig. 9, 10, 11, 12, and it appear that % occupied area by added fine particles on the surface of feed particles were the most important factor.
