Grain-size separation

Silicon carbide. Analyses of grain size separates of SiC have shown that the sensitive Kr isotopic ratios vary as a function of size of the SiC grains (Lewis et al. 

Caffee MW, Hohenberg CM, Horz F, Hudson B, Kennedy BM, Podosek FA, Swindle TD (1982) Shock disturbance of the I-Xe system. J Geophys Res 87 A318-A330 Cameron AGW (1993) Nucleosynthesis and star formation. In Protostars and Planets III. Levy EH, Lunine JI (eds) University of Arizona, Tucson, p 47-73 Clayton DD (1977) Interstellar potassium and argon. Earth Planet Sci Lett 36 381-390 Clayton DD (1980) Chemical and isotopic fractionation by grain-size separates. Earth Planet Sci Lett 47 199-210... 

Vogel, N. and Reime, P.R. (2008) Ar- Ar dating of plagiodase grain size separates from silicate indusions in lAB iron meteorites and implications for the thermochronological evolution of the lAB parent body. Ceochim. Cosmochim. Acta, 72, 1231-1255. 

Haidness decreases with increasing porosity and increased grain size. SoHd solution impurities influence hardness, but it is often hard to separate the effect of the impurity on the hardness, from the effect of the impurity on other microstmctural effects that influence hardness such as grain size. Further information on hardness of ceramics is available (45). 

Adsorption for gas purification comes under the category of dynamic adsorption. Where a high separation efficiency is required, the adsorption would be stopped when the breakthrough point is reached. The relationship between adsorbate concentration in the gas stream and the solid may be determined experimentally and plotted in the form of isotherms. These are usually determined under static equilibrium conditions but dynamic adsorption conditions operating in gas purification bear little relationship to these results. Isotherms indicate the affinity of the adsorbent for the adsorbate but do not relate the contact time or the amount of adsorbent required to reduce the adsorbate from one concentration to another. Factors which influence the service time of an adsorbent bed include the grain size of the adsorbent depth of adsorbent bed gas velocity temperature of gas and adsorbent pressure of the gas stream concentration of the adsorbates concentration of other gas constituents which may be adsorbed at the same time moisture content of the gas and adsorbent concentration of substances which may polymerize or react with the adsorbent adsorptive capacity of the adsorbent for the adsorbate over the concentration range applicable over the filter or carbon bed efficiency of adsorbate removal required. 

Mechanical attrition is used to remove most of the spent binder. First, dry attrition or abrasion processes crush lumps to grain size. Mechanical abrasion is then used to separate the binder from the sand grains. Sometimes, sand is pneumatically propelled against a metal target plate. The impact of the sand on the plate scrubs off the clay and resin coating from the sand grains. Fines are separated and removed by dry classification. 

Flotation. In many cases, contaminants adsorbed on the surface of clay particles, or contaminants occurring in soil as discriminate particles, have different surface properties to clean soil particles. By adding special chemical substances, the formation of a hydrophobic surface on the contaminated particles is possible. Pulp aeration results in the attachment of hydrophobic contaminated particles to the surface of the small bubbles that are formed. In this way, selective flotation of these particles is achieved. Contrary to the gravimetric separation methods, flotation offers the possibility to separate contaminated and noncontaminated particles of the same grain size and density but with different surface properties. 

In order to prepare standard mineral mixtures, pyrite (Py), pyrrhotite (Po), chalcopyrite (Cp), sphalerite (Sp), siderite (Sid), dolomite (Dol), calcite (Cal) and quartz (Qz) were acquired as pure mineral samples through a specialized distributor (Minerobec, Canada). These 8 pure minerals were further cleaned under a binocular microscope and separately crushed to reach 95% under 150pm (typical tailings grain size distribution e.g. Aubertin et al. 2002). Each pure mineral powder was characterized thereafter with a series of chemical and mineralogical techniques. More details can be found in Bouzahzah et al. (2008). The relative density of each mineral specimen were measured with an He pycnometer and are... 

The viscosity of separate LNAPL products varies significantly, ranging from far less to many times that of water. Flow of LNAPL in the unsaturated zone is largely dependent upon viscosity and soil grain size. Finer-grained materials have a higher residual saturation of water, which restricts the number of pores available for LNAPL entry in this region. 

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