The relation of expression pressure with equilibrium porosity of bed, sedimentation volume of slurry and angle of repose of slurry have been examined with various electrolyte concentration.
Results and conclusions are as follows……
1. Angle of repose is well related with sedimentation volume.
2. In gneral, expression process could be classified into three porosity region and in the region, ε_II<ε<ε_I, Eq. (3) holds approximately.
3. Effect of electrolyte on expression process is very different than that on angle of repose or on sedimentation volume. potential energy predicted by surface chemical theory does not play any significant role for ε<ε_I.
4. Coefficients “A” in Eq. (3) estimated for samples used are not very different over wide range of electrolyte concentration, on the other hand coefficients “B” suddenly change with electrolyte concentration on some solid-electrolyte system owing to the transformation of network structure in the system at appropriate electrolyte concentration.
Finally, some theoretical considerations are made as to Eq. (3).

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In order to investigate the influence of surface-chemical properties for liquid flow through bed of fine particles, it has been examined on various barium sulfates-electrolyte systems of different mean particle diameters.
All the permeability results are correlated with modified Kozeny-Carman equation, Eq. (5), and indicated that electroviscous effect is appreciable. It is available to classify the electroviscous effect into two cases according to whether the electric double layer being composed of strongly hydrated ions, such as Na ion, or not. On the former case, the double layer is so stiff that effective porosity decrease. The thickness of solidified double layer decrease as electrolyte concentration increase. On the later case, resistance for flow, represented as coefficient “K” in Eq. (5), varies with electrolyte concentration. The maximum resistanc is two times greater than that of the case when ζ potential is zero, in this investigation.
An electrochemical parameter, Nev, is presented to correlate the electroviscous contribution for flow through bed as shown in Fig. 6.

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In this report, the extruding flow characteristics of solid-liquid mixture through perforated nozzle plate were investigated experimentally. Ram type extruders with nozzle plates, of which each has one to five circular holes in symmetrical arrangement, were used as the experimental equipments. The mixture of crushed silicate sand powder and lubricant oil was used as the sample of solid-liquid mixture.
The relation between ram extruding pressure, P, and extruding velocity of the ram, V, are found to be linear with an apparent yield value of extruding pressure, P_ya, as are shown in Figs. 3-6. It is also found that groups of flow lines have each of their virtual source point (P_o, V_o), where all flow curves of a group meet together, as are shown in Figs. 3-6 when the number of hole, n_N, is selected as a parameter. Using the ultimate limited value of extruding pressure, P_o, and the virtual value of ram velocity, V_o, at the source point, we can obtain the expression of eq. 2, (V-V_o)=K(P-P_o) … (2) of which one of the authors has proposed in the preceding report.
The experimental results of P_o and V_o are plotted against liquid content in Figs. 7 and 8, and the values of K are correlated with nozzle factors, total area of holes A and nozzle diameter D_N, and the relation of eq. 9 is obtained, K/A^2/3D_Nⁿ=k₃1/μ_pl … (9) where the values of plastic viscosity μ_pl are measured with the viscometer shown in Fig. 10. In this, the factor of D_Nⁿ shows the effect of nozzle diameter on the flowability of plastic flow by extrusion, and also reveals the fact that when the particle diameter is small enough, this mixture behaves as a fluid, but when it becomes larger, the phenomenon encountered in the discharging process of solid particles through orifice must be considered.
The experimental equation of this extruding flow can be summarized in eq. 10 as follows (V-V_o)=k₃n_N^2/3D_N^4/3+n/μ_pl(P-P_o) … (10)

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In this report are investigated the rheological characteristics of pastes using an extruder and coaxial cylindrical viscometer. Three kinds of the test samples of paste were prepared from titanium dioxide (TiO₂), carbon black and calcium carbonate (CaCO₃) VS. di-octyl-phthalate (DOP).
The transitions from pseudoplastic to Newtonian and finally dilatancy were observed in the flow behaviors, as the mixture ratio of solid and liquid increases. However, the flow of TiO₂-DOP paste changed with the shear rate, and finally became Bingham flow. The viscosity of paste varied in the range of 10³ and 10⁵ poise depending on the measuring method. The both of shear and plug flow were observed in the sxperiments.
These experimental facts suggest the behavior of the solid-liquid mixture can not explained without the flow effects of particulate meterials.

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A crushed hard shale mixed with flocculating or dispersing aqueous solutions and ram-extruded, obeyed the expression P=P_oe^-K(φ-φ_o), where P was the pressure which initiated extrusion, φ was the volume fraction of liquid, and P_o and k were constants. For size fractions having five different particle sizes, plot of logP against φ converged on common points, coordinates logP_o and φ_o, irrespective of the flocculation or dispersion of the system. The slopes -K were less for flocculated than for dispersed particles. At φ=φ_o each particles contact with one another directly and the effect of the liquid at the contact point can be ignored, because φ_o can be considered that the void fraction at most closely packed. Under the above consideration, the interaction force at the contact point of particles f_p can be calculated using the value of P_o. The values of f_p obtained from the P_o agreed with the adhesion force of venous inorganic particles.

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