Papers by Keyword: Mean Particle Size

Abstract: To save land resources by the use of low-grade natural resources to realize a high cost performance product, the technology of prepared superfine quartz sand powder via the ball milling methods were investigated. The results are shown the mean particle size of quartz sand powder is gradually become small varied with prolonging the ball milling time. Before 60 minutes, the mean particle size is slashed, however, the range of varying mean particle size is less after 60 minutes under the ball milling rotate speed for 200r/min and the charge amount for 200g/L, so the ball milling time for 60 minutes is decided.The mean grain size of quartz powders are decreased vary with an increasing the ball milling rotate speed, and the rotate speed is lower, the distribution is wider, however, the rotate speed is higher, the distribution is narrower.The mean grain size of quartz powders are 11.25μm via a roller ball milling, the mean grain size of quartz powders are 7.37μm via a planetary ball milling, and the particle size distribution of quartz powders milled via a roller ball milling is wider than that of quartz powders milled via a planetary ball milling, which shows the of quartz powders milled via a roller ball milling is not more uniform than that of quartz powders milled via a planetary ball milling, the asymmetry powder is advantage for forming the high performance building materials body.

Abstract: Mesophase pitch and natural graphite flake were applied as raw materials to prepare the graphite materials by a hot-pressing technique at a relatively low temperature. In this work, the effect of mean size of natural graphite flake on physical properties and microstructure of the graphite materials were investigated. X-ray analyses, field emission scanning electron microscopy and polarized light microscopy observations indicate that the graphite blocks have highly preferred structural orientation perpendicular to the hot-pressing direction. Results shows that the graphite materials have a low electrical resistivity of 2.45μΩ·m and a high thermal conductivity of 498 W/m·K ,as well as a high bending strength of 26.71 MPa when the mean size of graphite flake in raw materials was 425μm.

Abstract: In conventional studies, different empirical atomization equations are correlated for different kinds of atomization methods or even in the same method. In the present study, it was found that the basic law of melt breakup from bulky liquid into droplets can be universally applied to all atomization methods. Based on theoretical analysis, a new general equation of mean particle size applicable to both conventional atomization methods and new atomization processes is presented. The mean particle size in melt atomization is mainly controlled and decided by two key dimensionless parameter groups representing the liquid stability of melts and the breakup ability of atomizer respectively. Different specific atomization mechanisms result in different formulae in conventional atomization methods. In case of gas atomization, it is equivalent with and can be changed into Lubanska Equation. In case of centrifugal atomization, it can be changed into the equations that are currently the most widely used. In case of water atomization, it is similar to the equation proposed by Grandzol and Tallmadge. According to the universal equation, new correlations for mean particle size in novel atomization processes such as Hybrid Atomization and Multistage Atomization were proposed and agreed with our experimental data well.