Clay, commercial

Refractory fireclays embrace all types of clays commercially available. Because of the abundant supply of fireclay and its comparative cheapness, refractory bricks made out of it are the most common and extensively used in all places of heat generation. In fact, several technical designations are used in the ceramic industry for classifying refractory clays these are fire clay, China clay, ball clay, flint clay, and chamotte. 

Others would include the addition of materials aimed at increa sing the bioavailabiUty of the contaminant to the degrading organisms. The most studied compounds are surfactants, but cations have been reported to increase the bioavailabiUty of some organic compounds, and sorbents and clays are also considered. The dispersion of spilled oil on water by the appHcation of dispersants is perhaps the major commercial use of this idea. 

New Adsorbent Materials. SihcaUte and other hydrophobic molecular sieves, the new family of AlPO molecular sieves, and steadily increasing families of other new molecular sieves (including stmctures with much larger pores than those now commercially available), as well as new carbon molecular sieves and pillared interlayer clays (PILCS), will become more available for commercial appHcations, including adsorption. Adsorbents with enhanced performance, both highly selective physical adsorbents and easily regenerated, weak chemisorbents will be developed, as will new rate-selective adsorbents. 

All lnaphthalenesulfonic Acids. The aLkyLnaphthalenesulfonic acids can be made by sulfonation of aLkyLnaphthalenes, eg, with sulfuric acid at 160°C, or by alkylation of naphthalenesulfonic acids with alcohols or olefins. These products, as the acids or their sodium salts, are commercially important as textile auxiUaries, surfactants (qv), wetting agents, dispersants (qv), and emulsifying aids, eg, for dyes (qv), wettable powder pesticides, tars, clays (qv), and hydrotropes. 

The paster is a nonheated operation. The most common paster adhesive formulation consists of poly(vinyl alcohol)—clay—starch blends (10). A 100% area adhesive coverage is used. The rate of bond strength development of the adhesive is an important commercial concern and rapid bond formation rates are desirable. 

Although numerous mud additives aid in obtaining the desired drilling fluid properties, water-based muds have three basic components water, reactive soHds, and inert soHds. The water forming the continuous phase may be fresh water, seawater, or salt water. The reactive soHds are composed of commercial clays, incorporated hydratable clays and shales from drilled formations, and polymeric materials, which may be suspended or dissolved in the water phase. SoHds, such as barite and hematite, are chemically inactive in most mud systems. Oil and synthetic muds contain, in addition, an organic Hquid as the continuous phase plus water as the discontinuous phase. 

Other THF polymerization processes that have been disclosed in papers and patents, but which do not appear to be in commercial use in the 1990s, include catalysis by boron trifluoride complexes in combination with other cocatalysts (241—245), modified montmorrillonite clay (246—248) or modified metal oxide composites (249), rare-earth catalysts (250), triflate salts (164), and sulfuric acid or Aiming sulfuric acid with cocatalysts (237,251—255). 

Four minerals are the principal commercial sources of potash (Table 2). In all ores, sodium chloride is the principal soluble contaminant. Extraneous water-iasoluble material, eg, clay and siUca, is a significant contaminant ia some of the evaporates being mined from underground deposits. Some European potassium ores contain relatively large amounts of the mineral kieserite, MgS04-H2 0. It is recovered for captive use to produce potassium sulfate compounds or is marketed ia relatively pure form as a water-soluble magnesium fertilizer. 

The value of langbeinite as a fertilizer is enhanced because, in pure form, it contains 18.8 wt % potassium, 11.7 wt % magnesium, and 23.0 wt % sulfur. AH three elements are essential nutrients for plant growth. Commercial grades contain ca 97 wt % mineral the remaining 3 wt % consists of water-insoluble clays and residual sodium chloride. 

Aluminum sulfate is a starting material in the manufacture of many other aluminum compounds. Aluminum sulfate from clay could potentially provide local sourcing of raw materials for aluminum production. Processes have been studied (24) and the relative economics of using clay versus bauxite have been reviewed (25). It is, however, difficult to remove impurities economically by precipitation, and purification of aluminum sulfate by crystallization is not practiced commercially because the resulting crystals are soft, microscopic, and difficult to wash effectively on a production scale (26—28). 

The main use of these clays is to control, or adjust, viscosity in nonaqueous systems. Organoclays can be dispersed in nonaqueous fluids to modify the viscosity of the fluid so that the fluid exhibits non-Newtonian thixotropic behavior. Important segments of this area are drilling fluids, greases (79,80), lubricants, and oil-based paints. The most used commercial products in this area are dimethyl di (hydrogen a ted tallow) alkylammonium chloride [61789-80-8] dimethyl (hydrogen a ted tallow)aLkylbenzylammonium chloride [61789-72-8] and methyldi(hydrogenated tallow)aLkylbenzylammonium chloride [68391-01-5]. 

The nitrate deposits are made up of several layers (Fig. 1). The ore bodies are very heterogeneous and variable in size, thickness, composition, and hardness. The overburden may include chuca a layer of unconsoHdated sand, silt, and clay, andpanqueque a layer of semiconsoHdated and porous material poody cemented by salts over poody cemented gravel. The ore composition has degraded considerably since the eady days of the industry, when it was reported that ores of up to 50% sodium nitrate were mined. There are stiU reserves that can be commercially mined well into the twenty-first century (1). 

Barite [13462-86-7], natural barium sulfate, BaSO, commonly known as barytes, and sometimes as heavy spar, tiU, or cawk, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. Commercial deposits are of three types vein and cavity filling deposits residual deposits and bedded deposits. Most commercial sources are replacement deposits in limestone, dolomitic sandstone, and shales, or residual deposits caused by differential weathering that result in lumps of barite enclosed in clay. Barite is widely distributed and has minable deposits in many countries. 

Sodium Tetrahydroborate, Na[BH ]. This air-stable white powder, commonly referred to as sodium borohydride, is the most widely commercialized boron hydride material. It is used in a variety of industrial processes including bleaching of paper pulp and clays, preparation and purification of organic chemicals and pharmaceuticals, textile dye reduction, recovery of valuable metals, wastewater treatment, and production of dithionite compounds. Sodium borohydride is produced in the United States by Morton International, Inc., the Alfa Division of Johnson Matthey, Inc., and Covan Limited, with Morton International supplying about 75% of market. More than six million pounds of this material suppHed as powder, pellets, and aqueous solution, were produced in 1990. 

The commercial value of a clay deposit depends on market trends, competitive materials, transportation faciflties, new machinery and processes, and labor and fuel costs. Naturally exposed outcrops, geological area and stmcture maps, aerial photographs, hand and power auger drills, core drills, earth resistivity, and shallow seismic methods are used ia exploration for clays (32). Clays are mined primarily by open-pit operation, including hydraulic extraction however, underground mining is also practiced. 

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