Showing papers in "Powder Technology in 1984"

TL;DR: In this article, the influence of particle size and other parameters on the fluidization behavior of fine powders has been investigated and can be readily assessed by measuring the ratio of tap to aerated bulk density.

TL;DR: In this paper, it was shown that addition of small quantities of a non-volatile liquid to a material in Geldart's Group B causes its fluidisation behavior to move through Group A to Group C. The results lead to a numerical adjustment of Molerus' criterion for the B/A transition, and give some insight into the physical mechanisms causing the difference in behaviour between these two groups.

TL;DR: In this paper, the authors used three dimensionless parameters, indices, that characterize the relative tableting performance of individual components and mixtures, i.e., strain index P/E′ is derived from the dynamic indentation hardness experiment, E′ is the reduced Young's Modulus.

TL;DR: The concept of work function may be applied to some insulator materials, especially those that charge negatively as many polymeric materials do as mentioned in this paper, and is often more appropriate to describe such a contact electrification process as triboelectrification as sliding/frictional contact is invariably involved.

TL;DR: In this paper, the capillary binding forces in dependence on the essential variables are briefly discussed, after which the liquid retention in bulk materials and strength models for moist particulate systems are dealt with.

TL;DR: In this paper, the initial sintering temperature (IST) is estimated using a dilatometer to measure thermal expansion and contraction of a loosly packed sample of the bed particles.

TL;DR: In this article, the efficiency of energy utilization in tumbling mills is discussed in terms of component processes taking place inside the mill and the past reports on the effect of physicochemical parameters of the environment on mechanical properties and grindability of materials are reviewed.

TL;DR: In this article, the essential features of this fine coal preparation technique, including a classification and review of the extensive literature from the past decade on the subject, are reviewed and compared.

TL;DR: In this article, an approach based upon the plane plastic flow theory of incompressible Coulomb material is applied to analyze flow patterns of sand in a plane, wedge-shaped hopper model and also an approach to a theoretical description of the discharge process.

TL;DR: In this article, a review and critical assessment of topics relevant to dry processing of coal, comprising comminution, size classification, characterisation and analysis, sorting at coarse sizes, mechanical beneficiation according to density at medium sizes, and electrical and magnetic beneficiation at fine particle sizes.

TL;DR: In this paper, the fluidization behavior of cracking catalyst has been studied up to pressures of 15 bar with different fluidization gases (Ar, N 2, H 2 ), and the experimental results reveal that the minimum fluidization velocity (U mf ) is independent of the pressure.

TL;DR: In this article, the elutriation characteristics of widely different solids (density from 920 to 5900 kg/m 3 ) were measured in fluidized beds (up to 0.9 m in size) having high freeboard (7.5 m), using gas velocities up to 4 m/s.

TL;DR: In this paper, the authors present correlations andablies a partir de mesures du taux d'expansion and des vitesses minimales de fluidisation for divers materiaux de forme spherique dans des colonnes de diametres compris entre 50 and 434 mm.

TL;DR: In this article, the efficiency of separation for fine coal in a 150 mm dia. dense-medium hydrocyclone has been determined, and the results lead to an accurate predictive model for the calculation of the partition curve as a function of coal particle size and medium specific gravity.

TL;DR: In this article, the steady shear properties of a dense suspension are characterized by a wide viscosity distribution or a shear stress -shear rate flow band whose mean and standard deviation are functions of solids concentration, particle size distribution and viscometric geometry and dimensions.

TL;DR: In this paper, a series of statistical tests to determine the statistically acceptable ranges of values are presented, and the most reliable test uses independent estimates of error variance calculated from replicated data.

TL;DR: The effects of temperature on the spherical crystallization of salicyclic acid were investigated in this paper, where an ethanolic solution held at 40 °C was introduced into a well-dispersed mixture of chloroform and water at 5 to 30 °C.

TL;DR: In this article, the authors present correlations established by measuring the rate of expansion and the minimum speeds of fluidization for binary solids mixtures for a single-dimensional particle suspension.

TL;DR: In this article, the authors determine whether cold scaled models with scaled particles give the correct hydrodynamic predictions for the gas and solids in an actual hot atmospheric pressure fluidized-bed combustor.

TL;DR: In this article, the deformation hardness of a powder is analyzed as a function of the applied pressure σc and the relative density of the powder, and it is shown that as a first approximation the following equations are applicable if Pmax and γ behave additively.

TL;DR: In coal, coal is a complex heterogeneous material composed of microcrystalline and amorphous materials and exists as small condensed aromatic layers as discussed by the authors, and the packing of coal layers improves with rank.

TL;DR: In this article, an experimental study of solids mixing in a freely bubbling two-dimensional bed of 600 to 850 μm glass particles was performed, where the steady state temperature patterns around a heated wire and the transient response to an injected pulse of heated particles were measured.

TL;DR: In this paper, a modified form of the Charles energy-size reduction equation was used to resolve the net energy expended by the mill into that consumed by each of the components of the mixture.

TL;DR: In this article, the authors measured heat transfer coefficients between gas-fluidized beds and spherical calorimetric probes of different sizes and to a water-cooled horizontal tube.

TL;DR: In this paper, the relationship between porosity and the pre-compressive stress and tensile strength of a powder bed measured by split cell methods has been discussed, and the physical base of the proposed experimental equation is proved theoretically.

TL;DR: In this paper, two field trials of electroosmotic dewatering were carried out in tailings ponds at a coal washery, using three horizontal electrodes and two vertical electrodes.

TL;DR: In this article, a two-phase flow analysis for coal slurry pipelines is presented, which gives numerical solutions for the concentration, velocity and particle size distributions in the pipeline cross-section, which can be integrated to provide mean velocities and flowrates.

TL;DR: In this paper, the authors dealt with Van der Waals forces, electric double layer forces, and steric forces connected with the presence of layers of large molecules on the particles, and a few words are said about magnetic and structural forces (due to modifications of the solvent structure near interfaces).

TL;DR: In this paper, magnetically stabilized fluidized beds with continuous solids throughput have been studied to determine their operating characteristics and properties, and they were operated in both counter-current and cross-flow configurations.