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Showing papers in "Powder Technology in 1997"


Journal ArticleDOI
TL;DR: In this paper, the authors present a general theoretical and practical framework of binder granulation that takes an agglomeration process from binder selection and testing to granule formation, growth and consolidation.

320 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of absolute particle size on particle packing is modelled by use of an initial porosity to take into account the packing of mono-sized particles and the concept of packing size ratio as a measure of the particle-particle interaction in forming a packing of mixed powders.

225 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the settling of loosely packed, cohesionless granular material under mechanical vibrations and showed how the occupied volume fraction can be optimized by slowly reducing the vibration intensity along the reversible branch.

183 citations


Journal ArticleDOI
TL;DR: The dimensionless tensile strength σd/α of wet granular materials with saturation levels in the plateau region of the pendular state was correlated with the void fraction of the agglomerate as mentioned in this paper.

146 citations


Journal ArticleDOI
TL;DR: In this paper, the thermal conductivity and mechanical properties of composites formed by copper powder filler embedded in a high density poly(ethylene) matrix are investigated experimentally and the results compared with existing theories.

136 citations


Journal ArticleDOI
TL;DR: In this paper, a new fluidization regime is identified for the upwards liquid-solid fluidization operation, which is characterized by non-uniform radial distribution of liquid velocity, particle velocity, and particle hold-up in the bed.

132 citations


Journal ArticleDOI
TL;DR: In this paper, the Navier-Stokes equations are combined with a set of differential equations which take the place of these equations; however, only very few solutions of this set of equations exist.

124 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of gas adsorption on van der Waals forces has been studied theoretically using the Hamaker theory and the calculated results show that the adsorment of CO 2 on FCC particles increases the van derWaals forces by 1 to 2 orders of magnitude, corresponding to pressure from 1 to 15 bar at room temperature.

108 citations


Journal ArticleDOI
TL;DR: In this article, a shape factor for particles is proposed based on the deviations of the two-dimensional particle outline from standard images of a circle, triangle and square, and considers the particle elongation and the number of characteristic corners of the apparent shape.

108 citations


Journal ArticleDOI
TL;DR: In this article, the effects of binder viscosity and size of the constituent particles on agglomeration behavior using a high shear mixer were investigated using Silicone fluids having viscosities in the range 0.001-56 Pa s were used as the binder liquid and non-porous calcium carbonates having mean particle sizes of 8-230 μm.

105 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the properties, settling behavior and the rheology of fine particulate slurries and found that the three-parameter Sisko model, which combines low and intermediate shear power-law with high-shear Newtonian limiting behavior, provides the best overall description of the flow curves for all slurries, at all solids loadings, over the entire measured range of shear rates.

Journal ArticleDOI
TL;DR: In this article, a sound, mathematically rigorous, yet simplified and practical approach has been formulated that aims to address the needs of both powder manufacturers and scientists, which can be adapted to any mathematical expression that closely describes the particle size distribution, in particular the influence of coarse and fine particles on the Rosin-Rammler mean size and n-value.

Journal ArticleDOI
TL;DR: In this paper, a new test-design procedure is presented for low-velocity slug flow pneumatic conveying, based on particle properties and data from a simple vertical test chamber, which can be applied to bulk solid materials with regular, irregular and/or unusual physical properties.

Journal ArticleDOI
TL;DR: In this article, the potential and limits of turbidimetry as a particle sizing method are discussed with respect to several aspects, theoretical and experimental, and a complete experimental set-up consisting of a spectrophotometer and different types of in situ sensors, a data acquisition system and a calculation program are described.

Journal ArticleDOI
TL;DR: In this article, the influence of particle shape on internal friction was investigated using fractal measurements of particle shapes and the Hausner ratio, flow time and coefficient of internal friction.

Journal ArticleDOI
TL;DR: In this paper, an experimental investigation was performed in a two-dimensional gas-solid fluidized bed with a vertical jet in the center and an inclined jet at the side of the bed, Miller or two kinds of silica sand were used as bed materials in the experiment.

Journal ArticleDOI
TL;DR: In this article, the segregation coefficient was measured and found to increase with vibrational acceleration until reaching a maximum and then to decrease with acceleration, and the greatest segregation effect occurred when the bed transformed from a dense state to a loose state.

Journal ArticleDOI
J. Fernández1, J. Renedo1, Aurora Garea1, J.R. Viguri1, J.A. Irabien1 
TL;DR: In this article, coal fly ash has been slurried with hydrated lime in a Parr pressure reactor, and the influence of the operation variables (temperature, time, fly ash/Ca(OH) 2 ratio, pressure and water/solids ratio) on the structural properties of the final sorbent, the BET-nitrogen specific surface area and the pore volume distribution are studied using a factorial design for the experiments.

Journal ArticleDOI
TL;DR: In this paper, X-ray powder diffractometry showed the resulting TiO2 powders to consist of anatase crystallites, irrespective of the base hydrolysis conditions applied.

Journal ArticleDOI
TL;DR: In this article, the entrainment rate at low air velocities is strongly reduced by interparticle adhesion forces, while at higher air velocity the hydrodynamic forces overrule adhesion effects.

Journal ArticleDOI
TL;DR: In this paper, the effects of additives (sodium hydroxide, sodium carbonate, sodium oleate, oleic acid and poly(acrylic) acid) on stirred media milling of limestone have been investigated.

Journal ArticleDOI
TL;DR: In this article, the load which is imposed on a screw feeder by the bulk solid in the hopper is assumed to be the flow load determined on the basis of the major consolidation stress.

Journal ArticleDOI
TL;DR: In this article, experimental measurements of solids mass flux profiles in a circulating fluidized bed riser over a wide range of operating conditions are described, and three types of radial solids flux profiles are found to exist: parabolic/core-annular, radially uniform, and U-shaped.

Journal ArticleDOI
TL;DR: In this paper, a composite ceramic membrane filter for hot gas cleaning operations from fly ash and titania particles on stainless steel woven mesh substrates has been presented, with a structure like a solid packed bed with a thickness less than 100 μm.

Journal ArticleDOI
TL;DR: The technique of measuring the aerated and tapped bulk density of powders has been refined and use made of the rate of densification between the aerosolized and tapped states to provide an additional descriptor of the bulk structure and the microstructure of the powder as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, a measurement technique which relies on the measurement of the local dielectricity is described, through the application of a guard circuit and specially designed probes, an extremely high resolution and stability has been achieved.

Journal ArticleDOI
TL;DR: In this paper, it is shown that the mastering of these two processes enables the production of ceramics possessing good magnetic characteristics for microwave applications, which is a well understood and controlled industrial process.

Journal ArticleDOI
TL;DR: In this paper, a steady-state dispersion model was used to determine the radial gas mixing coefficients in the dilute region of a cold fast fluidized bed, 0.1 m i.d. and 4 m high.

Journal ArticleDOI
TL;DR: In this paper, the fluidization characteristics of a bed consisting of an admixture of iron and copper shot stabilized by an external uniform magnetic field collinear with the gas velocity vector are investigated over an extended range of magnetic field intensity (up to 17 430 A/m) and air velocity ( up to a maximum of 8.3 m/s) at ambient conditions of temperature and pressure.

Journal ArticleDOI
TL;DR: In this paper, the authors describe a computer simulation study of brittle particle attrition in a shear cell in two dimensions and show that the rate of attrition is directly related to the total amount of work performed on the system, including the initial work required to accelerate and expand the bed.