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.

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To investigate the influence of operational condition affecting the mixing performance in a continuous mixer, we have made some experiments using a simple mixer with multiple blades.
In this study, the experiments were carried out by sampling and inpulse response method using Toyoura Standard Sand, with coloured sand and salts as tracer, and we investigated chiefly the mixing state of particles in the vessel when the depth of the particle layer was many times larger than the diameter. The results obtained are as follows:
1) The mass of particles fed from the upper part of the agitator, is pushed out toward the wall side of the vessel as the blade moves, and then it flows down to the bottom with spiral rotation. Near the axis of the agitator, the separate zone is formed, in which particles moves slowly than other.
2) It may be applied “The Distributed Side Capasity Model” to the experimental response curves.
3) In order to find better mixing state, the flow pattern in the vessel and the relation between the parameters of the model and the experimental conditions have been observed. We have obtained the fllowing results:
3-1) There was no influence of depth of the particles layer on the mixing rate per unit height of vessel.
3-2) Better mixing state could be expected, with increase of rate of agitation and with decrease of the feed of particls.

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An experiment on the behavior of a wet particle on a rotating disk was carried out with two kinds of spherical and non-spherical particles. The average diameter of them ranged from 0.261 to 0.620cm and the running speed of the a disk ranged from 92 to 880rpm.
As the result, it was found that motion locus of a wet particle on the rotating disk followed to Archimedes' spiral irrespective of the particle shape.

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In sedimentation balance method which is one of particle-size measurement methods, the weight on weighing tray is detected by using strain gages. By this method the following merits are obtained;
(1) Electric auto-recording is possible.
(2) It is possible to measure with small amount of sample.
The sedimentation tests for calcium carbonate and white alundum were carried out in both our apparatus and Sedimentograph SA-2, produced by Shimadzu Seisakusho Ltd. The results of both sedimentation balances agreed well.

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