Showing papers in "Advanced Powder Technology in 1992"

TL;DR: In this article, the conformation characteristics of polyacrylic acid (PAA) adsorbed on alumina were studied along with stability of its suspension in order to delineate the mechanism by which polymer conformation affects the stability of fines.

TL;DR: In this paper, three types of calcite particles, i.e. rhombohedral, rounded and slender particles, were finally obtained by changing the operating conditions, though in the early stage of the reaction amorphous calcium carbonate is always formed.

TL;DR: In this article, the experimental and theoretical investigations on the variation of fluidized bed expansion with gas flow rate, particle size, temperature and the presence of immersed surfaces are described and analyzed.

TL;DR: In this paper, the reaction of an MgO-H3BO3-KCl mixture was driven at 850°C to obtain acicular Mg2B2O5 without agglomerate, but the crystal length did not exceed 10μm.

TL;DR: In this paper, the stability of fine particle suspensions of single and bimineral mixtures has been studied and the common rules of heterocoagulation are summarized, and the chemical and physical dispersion methods have also been studied.

TL;DR: In this article, a self-control method for the fluidized bed granulation process is described, which consists of moisture feedback control and program control of each operation (i.e. mixing, granulation and drying).

TL;DR: In this article, a Fraunhofer diffraction and Mie scattering (FAM) laser particle sizer has been constructed based on this idea, and experiments made with a Photomask calibration reticle and latex spheres show that FAM gives very good measurement in both large and small size ranges.

TL;DR: In this article, the effect of grinding aids on the grinding of ultrafine particles was demonstrated by comparing particles such as Portland cement clinker, alumina, zircon and quartz produced by a vibration mill and a planet-vibration mill, respectively.

TL;DR: In this paper, a method for scale-up and prediction of power consumption of agitated ball mill is described, and a mathematical and experimental investigation of the transport behaviour in the mill also allows the prediction of comminution results during continuous operation as a function of operational parameters.

TL;DR: In this article, an improved light extinction method with which particle size distribution can be measured was presented, and numerical simulations and experiments were carried out with this method, but some technical problems which limit the application of the method remain unsolved.

TL;DR: In this article, the amount of fines (below 250 μm in diameter) generated during transport and fluidization were measured and modes of attrition were determined using scanning electron microscopy, which was correlated to attrition measurements performed in both a 5.08 cm diameter dense-phase and a 2.54 cm diameter dilute-phase pneumatic conveyer.

TL;DR: In this paper, the effects of solid and liquid additive on a dry grinding process were studied at four additive concentrations and two grinding times, using a laboratory vibration ball mill with calcite as the feed material, under selected milling conditions.

TL;DR: In this paper, experimental optimization studies were carried out with the design and operating variables of an elliptical fluid energy mill in order to explore the possibilities of improving its grinding efficiency, and it was noticed that the performance of the mill varied with the locations of the nozzles around the outer periphery of the grinding chamber.

TL;DR: In this paper, an operational matrix was established with its elements representing the particular angle between the nozzles giving maximum performance for a given nozzle size and grinding pressure, and the results and observations were used of to develop a circular fluid energy mill, which can be an efficient alternative to the existing mills.

TL;DR: In this article, a more complex and random model is developed to build random rectangular block heaps and analyse the force distributions at the base of the heaps, in which every block is put randomly, but with the limitation of stability.

TL;DR: In this article, it has been proved that the correct expression for Qi should be [r¯i/(r¯ik+12Δti)]2 for cylindrical pores and r¯i/Δt for slit-shaped pores.

TL;DR: Based on the nth order grinding kinetic equation and the theory of linear additivity in the grinding process, the grinding kinetic characteristics of the feed and the circulating load in standard Bond rod-mill grindability tests are studied in this paper.

TL;DR: In this article, it was shown that the critical isotherms of the Redlich-Kwong and Virial models are given by the following equations: ==================Pr=Ω3θr1-Ω1 θr(Ω41+Ω 1 θ r)Ω2exp[11-Φ1θ r+Φ21 +Φ 1 Φ rk-1]-exp[(-1)kCn+1kk(Φ k-1)]}(viral)

TL;DR: In this article, a planetary vibration mill (PVM) was used for fine-grinding a number of materials, and its working principle, the influence of technical parameters on grinding and the motion of the grinding media within the mill were discussed.

TL;DR: In this paper, the authors measured the electric charge on fly ash particles at three Australian power stations, Eraring, Tallawarra and Bayswater, and found that the inherent charge on the fly ash remains indefinitely (−0.018 μC/g for the Eraring ash and −0.25 μC /g for Tallawarras ash).

TL;DR: In this paper, the mixing and segregation of an iron-sand mixture was investigated in a 38 mm diameter moving fluidized bed, where the mixture is fed into the middle of the bed and discharged from both the top and bottom ends.

TL;DR: In this article, the effect of feed size, additive concentration, weight ratio of the feed to grinding media and ball filling on the grinding characteristics was studied. But the results were limited to the case where the feed size was an insignificant variable in the range studied.

TL;DR: Shinohara et al. as mentioned in this paper considered a simplified block-flow model and derived an equation of motion of the block during discharge for the case of powders with comparatively small values of internal friction coefficient and cohesive shear and tensile strengths.

TL;DR: In this article, fine silicon particles were produced by a continuous wave CO2 laser driven reaction of SiH4 and the size distributions obeyed a log-normal relation and the geometric standard deviation was 1.7-1.9.

TL;DR: In this article, a mathematical model has been developed which predicts that natural and synthetic fibers may be preferentially deposited at lung airway bifurcations, and a mathematical description of centrifuge operation is refined to permit the characterization of irregularly shaped particles, with specific application to fibers.

TL;DR: In this article, a study was made to correlate the maximum hold-up and mean residence time of hammer mills to the properties of raw materials, and an empirical equation to estimate the maximum crushing capacity of hammer mill was obtained.

TL;DR: In this article, an attempt was made to obtain the characteristics of choking velocity in vertical air-solid two-phase flow by using experimental results which cover a wide range of particle characteristics and pipe inner diameters.

TL;DR: In this article, gas and liquid velocities for particle suspension in a countercurrent flow bed, or counter-current three-phase fluidized bed, were studied, where solid particles are suspended in a continuous liquid phase by gas sparging, while the liquid is fed from the top countercurrent to the gas flow.

TL;DR: In this article, the viability of uniaxial compression of cylindrical specimens for obtaining the governing equations associated with the bulk and wall behaviour is investigated, and the results show that the feasibility of this approach is not limited to the case of a single cylinder.

TL;DR: The authors used a high-precision classifier and two flow meters to succeed in developing an on-line particle size measuring instrument for use in finished cement mill processes.