Minerals importance

Anderson O. L. (1972). Patterns in elastic constants of minerals important to geophysics. In Nature of the Solid Earth, E. C. Robinson, ed. New York McGraw-Hill. 

Anderson, O. L. (1972) Patterns in elastic constants of minerals important in... 

Other clay minerals important in ceramics (and their chemical formulas) are... 

The second example concerns the surface heterogeneity of clay minerals. Important problems, such as limited yield of oil recovery arising during oil exploitation, involve interaction of pore filling fluids with the minerals that form the reservoir walls. The clay minerals, due to their relatively high specific surface area and electrical charge density, are the most active for the retention of oil. Illites and kaolinites are the clay minerals that are most frequently found and their wettability properties are believed to be in relation to the heavy oil ends retention process. 

Table 9-1. Oxide minerals important in soils are listed below, along with their mineral...

The bulk structures of most minerals important to soil chemists are well known from x-ray and neutron diffraction studies. Exceptions to this generality would be the various amorphous oxides and mixed oxide precipitates. Methods pioneered by Catlow s group should find increasing applicability to the structural study of these amorphous soil minerals and mixed phases. Their approach has been to develop ionic-type force fields for performing static energy minimizations of general oxide and halide minerals. Since ionic force fields rei uire far fewer parameters than va-... 

Alkaline earth metals The alkaline earth metals are in group 2. They are also highly reactive. Calcium (Ca) and magnesium (Mg), two minerals important for your health, are examples of alkaline earth metals. Because magnesium is solid and relatively light, it is used in the fabrication of electronic devices, such as the laptop shown in Figure 6.4. 

Olivine. In the olivine group of minerals (important orthorhombic silicates), the energies of the [100], [010], and [001] dislocations are all different. In fact, the energy of the [010] dislocation will be much greater since it has a much larger Burgers vector. 

Clay minerals Associated minerals Import plasticity Do not import plasticity Hardens on drying/firing Kaolinite, montmorillonite, illite, vermiculite, palygorskite etc. Magnetite, hematite, maghemite, goethite, lepidocrocite gibbside, boehmite, diaspore. 

Amphibole A famiiy of minerals whose crystals are formed by long, thin units which have two thin ribbons of double chain siiicate with a brucite ribbon in between. The shape of each unit is simiiar to an I beam . Minerals important in asbestos anaiysis inciude cummingtonite-grun-erite, crocidolite, tremoiite-actinolite and anthophyllite. 

Serpentine A mineral family consisting of minerals with the general composition Mg3(Si205(OH)4 having the magnesium in brucite layer over a silicate layer. Minerals important in asbestos analysis included in this family are chrysotile, lizardite, antigorite. 

Coffinite U(SiO, )j (OH),j is a black mineral, important as a uranium ore. It occurs in sandstone deposits and hydrothermal veins. 

Flotation. Flotation is a gravity separation process which exploits differences in the surface properties of particles. Gas bubbles are generated in a liquid and become attached to solid particles or immiscible liquid droplets, causing the particles or droplets to rise to the surface. This is used to separate mixtures of solid-solid particles and liquid-liquid mixtures of finely divided immiscible droplets. It is an important technique in mineral processing, where it is used to separate different types of ore. 

Polymethacrylates are less soluble than hydrocarbon polymers in mineral oils, they thicken less at low temperatures and are more effective at high temperatures. In this respect, it is important to note that the modification of rheoiogical properties is based on interactions between polymer and oil it will therefore be always dependent of the nature of oil. 

A further important reaction is the replacementot the Ca + ion in calcium carbonate by a magnesium ion. The latter is smaller, hence space or porosity is created in the mineral lattice by the replacement. The resulting mineral is dolomite and the increase in effective porosity can be as high as 13%. The process can be expressed as... 

Table XI-1 (from Ref. 166) lists the potential-determining ion and its concentration giving zero charge on the mineral. There is a large family of minerals for which hydrogen (or hydroxide) ion is potential determining—oxides, silicates, phosphates, carbonates, and so on. For these, adsorption of surfactant ions is highly pH-dependent. An example is shown in Fig. XI-14. This type of behavior has important applications in flotation and is discussed further in Section XIII-4.

A very important but rather complex application of surface chemistry is to the separation of various types of solid particles from each other by what is known as flotation. The general method is of enormous importance to the mining industry it permits large-scale and economic processing of crushed ores whereby the desired mineral is separated from the gangue or non-mineral-containing material. Originally applied only to certain sulfide and oxide ores. 

The importance of the thin film between the mineral particle and the air bubble has been discussed in a review by Pugh and Manev [74]. In this paper, modem studies of thin films via SFA and interferometry are discussed. These film effects come into play in the stability of foams and froths. Johansson and Pugh have studied the stability of a froth with particles. Small (30-/ m), moderately hydrophobic 6c = 65°) quartz particles stabilized a froth, while more hydrophobic particles destabilized it and larger particles had less influence [75]. 

Clearly, it is important that there be a large contact angle at the solid particle-solution-air interface. Some minerals, such as graphite and sulfur, are naturally hydrophobic, but even with these it has been advantageous to add materials to the system that will adsorb to give a hydrophobic film on the solid surface. (Effects can be complicated—sulfur notability oscillates with the number of preadsoibed monolayers of hydrocarbons such as n-heptane [76].) The use of surface modifiers or collectors is, of course, essential in the case of naturally hydrophilic minerals such as silica. 

This interface is critically important in many applications, as well as in biological systems. For example, the movement of pollutants tln-ough the enviromnent involves a series of chemical reactions of aqueous groundwater solutions with mineral surfaces. Although the liquid-solid interface has been studied for many years, it is only recently that the tools have been developed for interrogating this interface at the atomic level. This interface is particularly complex, as the interactions of ions dissolved in solution with a surface are affected not only by the surface structure, but also by the solution chemistry and by the effects of the electrical double layer [31]. It has been found, for example, that some surface reconstructions present in UHV persist under solution, while others do not. 

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