Mass mineral particles

The abyssal clays are composed primarily of clay-sized clay minerals, quartz, and feldspar transported to the siuface ocean by aeolian transport. Since the winds that pick up these terrigenous particles travel in latitudinal bands (i.e., the Trades, Westerlies, and Polar Easterlies), the clays can be transported out over the ocean. When the winds weaken, the particles fell to the sea siufece and eventually settle to the seafloor. Since the particles are small, they can take thousands of years to reach the seafloor. A minor fraction of the abyssal clays are of riverine origin, carried seaward by geostrophic currents. Despite slow sedimentation rates (millimeters per thousand years), clay minerals, feldspar, and quartz are the dominant particles composing the surface sediments of the abyssal plains that lie below the CCD. Since a sediment must contain at least 70% by mass lithogenous particles to be classified as an abyssal clay, lithogenous particles can still be the major particle type in a biogenous ooze. 

Bubbles of air or of water vapor present in a system of water, mineral matter and small masses of oil, will become attached to the oil masses and will float them to the surface. However, only small bubbles a few millimeters and less in diameter are effective in floating the oil. Air and water vapor bubbles also become attached to and float mineral particles. Particles of minerals other than quartz are floated more readily than quartz. 

In applying the model, some mineral parameters, such as numbers, n, and mean radii, Rq of various mineral particles may be estimated by mineralogical techniques. For physical properties such as phase equilibrium constants, K, published ternary and binary data may be used on an approximate basis. Kinetic parameters such as reaction rate constants, k, or mass transfer coefficients can be very roughly estimated based on laboratory experiments. Their values may then be varied in a series of computer runs until the results match pilot plant data. A reasonably good match will, at the same time, confirm the remaining variables, rate equations and other assumptions. 

The accumulation of bacterial mass is accompanied by weakening of interaction between mineral particles, thus, promoting decrease of their shear strength and deformation capacity. It should be pointed out, that anaerobic medium defines processes of iron reduction, which results in degradation of cementing bonds. 

The hot water flotation process for oil sands is a separation process in which the objective is to separate bitumen from mineral particles by exploiting the differences in their surface properties. The slurry conditioning process involves many process elements as illustrated in Figure 3. Given that ablation and mixing, mass and heat transfer, and chemical reactions are accommodated, the conditioning step involves separating bitumen from the sand and mineral particles. 

Physical properties SOM significantly contributes to the stabilization of soil structure, because it binds to soil mineral particles thus, it is capable of binding these particles together into water-resistant aggregates. It has an important contribution to soil water retention because of its ability to absorb up to 20 times its mass in water the low solubility of SOM adds to its stability in upper horizons, without leaching, and the dark color of SOM contributes to soil thermal properties. 

These are composed of fine mineral particles (bentonites, ground limestone, ground dolomite or lime, rock dust) and chemical compounds (e.g. sulpho-nates) in order to limit water migration when added as 1-2% of mass of Portland cement. Other effects are the workability improvement and decrease of mixing water by 5-10%. 

Continental soil dust is usually contained in the size fraction between 1 and 20 pm in diameter, with the mass median diameter about 2-4 pm. Larger particles fall out quickly because of their large sedimentation velocities, although individual dust particles of several 100 pm have been collected in South America that have been transported from the Sahara (46). The reported size spectra of mineral particles (41,47) indicate that the mass of fine clay particles is one to two orders of magnitude smaller than that of coarse silt particles (1-10 pm). Noll et al. (48) compared the composition of coarse atmospheric particles at a urban and rural site. At the rural site, the coarse particles contained predominantly cmstal material (limestone 89% and silicates 6%) and biogenic material. Limestone had a mean mass diameter of about 20 pm, and silicates 12 pm. In urban samples, a significant fraction (25%) of rubber tire was found with a mean mass diameter of 25 pm. 

Size reduction (qv) or comminution is the first and very important step in the processing of most minerals (2,6,10,20—24). It also involves large expenditures for heavy equipment, energy, operation, and maintenance. Size reduction is necessary because the value minerals are intimately associated with gangue and need to be Hberated, and/or because most minerals processing/separation methods require the ore mass to be of certain size and/or shape. Size reduction is also required in the case of quarry products to produce material of controlled particle size (see Size measurement of particles). In some instances, hberation of valuables or impurities from the ore matrix is achieved without any apparent size reduction. Scmbbers and attritors used in the industrial minerals plants, eg, phosphate, mtile, glass sands, or clay, ate examples. 

Although the size separation/classification methods are adequate in some cases to produce a final saleable mineral product, in a vast majority of cases these produce Httle separation of valuable minerals from gangue. Minerals can be separated from one another based on both physical and chemical properties (Fig. 8). Physical properties utilized in concentration include specific gravity, magnetic susceptibility, electrical conductivity, color, surface reflectance, and radioactivity level. Among the chemical properties, those of particle surfaces have been exploited in physico-chemical concentration methods such as flotation and flocculation. The main objective of concentration is to separate the valuable minerals into a small, concentrated mass which can be treated further to produce final mineral products. In some cases, these methods also produce a saleable product, especially in the case of industrial minerals. 

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