Silicate matrix, aluminum

Abstract Solidification/stabilization treatment processes immobilize hazardous constituents in the waste by changing these constituents into immobile (insoluble) forms, binding them in an immobile matrix, and/or binding them in a matrix which minimizes the material surface exposed to weathering and leaching. Solidification/stabilization treatment processes can include aluminum silicate and cement-based fixation, pozzolanic-based fixation, or vitrification. 

Composites may be identified and classified many hundreds of ways. There are aggregate-cement matrix (concrete), aluminum film-plastic matrix, asbestos fiber-concrete matrix, carbon-carbon matrix, carbon fiber-carbon matrix, cellulose fiber-lignin/silicic matrix, ceramic fiber-matrix ceramic (CMC), ceramic fiber-metal matrix, ceramic-metal matrix (cermet), concrete-plastic matrix, fibrous-ceramic matrix, fibrous-metal matrix, fibrous-plastic matrix, flexible reinforced plastic, glass ceramic-amorphous glass matrix, laminar-layers of different metals, laminar-layer of glass-plastic (safety glass), laminar-layer of reinforced plastic, laminar-layers of unreinforced plastic. 

Pot life and exotherm Pot life can be increased and exotherm reduced, because fillers reduce the concentration of reactants and function as better heat conductors than the resin matrix. Commonly-used fillers for this are silica, calcium carbonate, alumina, lithium aluminum silicate, and powdered metals. 

Y. Fang, F. Yu, K.W. White, Bimodal Microstructure in silicon Nitride - Barium Aluminum Silicate Ceramic-Matrix Composites by Pressureless Sintering, /. Am. Ceram. Soc., 83 [7] 1828-30(2000)... 

F. Yu, C.R. Ortiz-Longo, K.W. White, D.L. Hunn The Microstructural Characterization of In Situ Grown Si3N4 whisker-Reinforced Barium Aluminum Silicate Ceramic Matrix Composite, J. Mater. Sci, 34 2821-35... 

This problem can be solved by addition of the less-reactive precursor to the solution where the second, more-reactive precursor is partially prehydrolyzed, or equahzation of the reactivity by selection of precursors with different molecular structure, or by using a complexing agent to control the hydrolysis rate. For preparation of aluminum silicates with acidic functionality created by entrapment of tetracoordinated aluminum ions in the silica matrix, the prehydrolysis of the less-reactive silicon alkoxide before addition of aluminum alkoxide suppresses the early formation of Al—OH—A1 bridges and subsequent... 

Chem. uescrip. Vitamin Dj in a Modified food starch matrix of Gelatin and Sucrose, stabilized with BHT and Sodium aluminum silicate as a flow aid CAS 50-14-6 53124-00-8 9000-70-8 57-50-1 128-37-0 1344-00-9 EINECS/ ELINCS 200-014-9 232-554-6 200-334-9 204-8814 215-684-8 Uses Dietary supplement for direct compression of multivitamin-mineral tablets and in hard gelatin capsules... 

Exposure to silicaceous dusts is a major occupational health concern in numerons industries. Much of the silicon in the earth is combined with other elements to form silicates. Various anions and cations are substitnted into the crystalline silica matrix. Minerals such as kaolin, an aluminum silicate, and talc, a magnesium silicate, are silicate minerals that are used in their pnre form. Many minerals of commercial importance are composed of mixtures of silica and silicates, such as feldspar and muscovite, in an infinite range of combinations. The pulmonary disease associated with silica exposure is greatly influenced by the silicate content of the material. It has been estimated that approximately 8.2 million workers in the United States are potentially exposed to crystalline silica dust each year. 

Figure 5.5 Winds in the solar nebula might be one of the possible processes responsible for the mixing of hot and cold components found in both meteorites and comets. Meteorites contain calcium-aluminum-rich inclusions (CAIs, formed at about 2000 K) and chondrules (formed at about 1650K), which may have been created near the proto-Sun and then blown (gray arrows) several astronomical units away, into the region of the asteroids between Mars and Jupiter, where they were embedded in a matrix of temperature-sensitive, carbon-based cold components. The hot component in comets, tiny grains of annealed silicate dust (olivine) is vaporized at about 1600 K, suggesting that it never reached the innermost region of the disk before it was transported (white arrows) out beyond the orbit of Pluto, where it was mixed with ices and some unheated silicate dust ( cold components). Vigorous convection in the accretion disk may have contributed to the transport of many materials and has been dramatically confirmed by the Stardust mission (Nuth 2001).

As much as 15% of CM matrices may be amorphous silicate, which is associated with comparable volumes of very poorly crystalline phyllosilicates (Barber, 1981). In ALH81002, 5 vol.% of the matrix rims are composed of amorphous regions a few micrometers across that are rich in silicon, aluminum, magnesium, iron, and presumably oxygen, and contain 5-40 nm grains of iron-rich olivines and metallic Fe,Ni (Lauretta et al., 2000). Chizmadia and Brearley (2003) found more abundant amorphous material in the CM2 chondrite, Y 791198. (Origins of matrix components are reviewed in Section 5.7.11.)... 

The result of these various processes is that the Earth s cmst, the parent material for soils, is dominated (in mass) by eight elements (oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, and potassium). These elements, with the exception of oxygen, are not the dominant elements of the solar system. Thus, soils on Earth form in a matrix dominated by oxygen and silicon, the elements which form the backbone of the silicate minerals that dominate both the primary and secondary minerals found in soils. 

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