Calcium sulfide phosphor

Calcium sulfide occurs in nature as the mineral oldhamite. It has several applications. The luminous calcium sulfide is used in phosphors, luminous paints and varnishes. Calcium sulfide also is used as an additive to lubricants and as a flotation agent in ore extraction. 

Metal sulfates can be cracked to sulfur dioxide. This is the basis of the Muller-Kuhne process, which is operated in several Eastern European countries, the Federal Republic of Germany, Austria and South Africa, but whose importance has strongly diminished of late. In this process calcium sulfate (naturally occurring gypsum or anhydrite or gypsum from the manufacture of phosphoric acid) is reacted with coal in the presence of clay and sand in a rotary tube furnace a temperatures between 700 and 1200°C. Initially calcium sulfide and carbon dioxide are formed, which further react forming calcium oxide and sulfur dioxide ... 

Cadmium iodide Calcium fluoride Calcium molybdate Calcium sulfide Cerium oxide Copper oxide (ic) Germanium cis-Stilbene trans-Stilbene Zinc phosphate phosphors, color TV tubes Yttrium oxide phosphors, lamp... 

A more sensitive phosphor may be obtained by incorporating into the mixture 1 g, of calcium sulfide. 

R-activated CaS. Lehmann (1972) studied calcium sulfide activated by almost all the R elements. His measurements included absorption and emission spectra but not TL. All measurements were made at RT. He found CaS R phosphors to be poorly luminescent, but the addition of co-activators was found to make them well luminescent. The PL of... 

Thin-layer plates were made with silica gel-calcium sulfate and each contained a mixture of zinc silicate and zinc cadmium sulfide as phosphors. Separated components are generally visible under ultraviolet light by fluorescence quenching. This was true, in part, for the pyrethrins, except that some of the separated components possessed a natural fluorescence under the ultraviolet lamps. 

The phosphate manufacturing and phosphate fertilizer industry includes the production of elemental phosphorus, various phosphorus-derived chemicals, phosphate fertilizer chemicals, and other nonfertilizer phosphate chemicals [1-30], Chemicals that are derived from phosphorus include phosphoric acid (dry process), phosphorus pentoxide, phosphorus penta-sulfide, phosphoms trichloride, phosphorus oxychloride, sodium tripolyphosphate, and calcium phosphates [8]. The nonfertilizer phosphate production part of the industry includes defluori-nated phosphate rock, defluorinated phosphoric acid, and sodium phosphate salts. The phosphate fertilizer segment of the industry produces the primary phosphorus nutrient source for the agricultural industry and for other applications of chemical fertilization. Many of these fertilizer products are toxic to aquatic life at certain levels of concentration, and many are also hazardous to human life and health when contact is made in a concentrated form. 

Rotary multitray dryer pulverized coal, pectin, penicillin, zinc sulfide, waste slude, pyrophoric zinc powder, zinc oxide pellets, calcium carbonate, boric acid, fragile cereal products, calcium chloride flakes, caffein, Inorganic fluorides, crystals melting near 100°F, prilled pitch, electronic grade phosphors, and solvent-wet organic solids... 

The coefficients in equations (26) and (27) for the dissociation of a number of acids and the solubility of calcium carbonate are given in Table A6.5 (Millero, 1979, 1995). The results for carbonic and boric acid are taken from the measurements of Culberson and Pytkowicz (1968). The effect of pressure on the solubility of calcite and aragonite has been determined from the measurements of Ingle (1975). The effect of pressure on the dissociation constants of water, hydrogen sulfate, hydrogen sulfide, ammonia, and hydroffuoric and phosphoric acids have been estimated from molal volume and compressibility data. 

WHITE PHOSPHORIC ACID (7664-38-2) A medium-strong acid. Violent reaction with strong bases. Violent reaction if water is added to concentrated acid. To dilute, always add acid to water heat will be generated. Reacts violently with solutions containing ammonia or bleach, azo compounds, epoxides, and other polymerizable compounds. Reacts, possibly violently, with amines, aldehydes, alkanolamines, alcohols, alkylene oxides, amides, ammonia, ammonium hydrox-ide, calcium oxide, cyanides, epichlorohydrin, esters, halogenated organics, isocyanates, ketones, oleum, organic anhydrides, sodium tetrahydroborate, sulfides. 

More than 90 percent of commercial phosphorus production is in the form of calcium salts of phosphoric acid, H3PO4, used as fertilizers. Other significant uses of phosphorus compounds are in the manufacture of matches (phosphorus sulfides), food products and beverages (purified phosphoric acid and its salts), detergents (sodium polyphosphates), plasticizers for polymers (esters of phosphoric acid), and pesticides (derivatives of phosphoric acid). Related to the phosphorus pesticides are nerve gases, poisonons com-potmds that rapidly attack the central nervous system, initially developed during World War II. see also Deoxyribonucleic Acid (DNA) Fertilizer Pesticides. 

Carbon disulfide is obtained industrially from carbon and sulfur and is contaminated by sulfides and other sulfur-containing substances. It can be dried by calcium chloride or phosphoric oxide. Sulfur-containing contaminants can be removed by shaking with mercury and mercury(n) chloride38 or by treatment with concentrated nitric acid38 or potassium permanganate solution.39... 

Mhere materials are labelled with an asterisk, a large number of powders were successfully deposited using the suspension medium described. Mizuguchi et al included alumina barium, strontium and calcium carbonates magnesia, zinc oxide, titanium dioxide, silica, indium oxide, lanthanum boride, tungsten carbide, cadmium sulfide and several metals and phosphors. The list of materials described by Gutierrez et al included several metals carbides of molybdenum, zirconium, tungsten, thorium, uranium, neptunium and plutonium zirconium hydride, tantalum oxide and uranium dioxide. In addition, many metallic and oxide powder suspensions in alcohols, acetone and dinitromethane were studied by Brown and Salt ... 

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