Strontium, powder

Small metal particles are produced by mechanical comminution, chemical reaction, electrolytic deposition, and liquid-metal atomization  

Alkali metals and alkaline earth metals are often prepared in commerce as dispersions in which the metal is suspended in some liquid, often flammable. 

Powder metallurgy and other types of process metallurgy (i.e., casting, working, machining, and electroforming) result in a vast number of finished or intermediate products  

Titanium is produced commercially by converting titanium oxide ore to titanium tetrachloride, then reducing it to produce a crude titanium product, //-tanium sponge. Titanium sponge can react with carbon dioxide to generate oxygen. 

Many metals oxidize in contact with the air or moisture. For reactive metals, this reaction may be particularly violent and evolve high heat. When in contact with water, hydrogen gas is liberated which will ignite if temperatures are sufficiently high. Alternatively other combustibles may be similarly ig- 

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Strontium Hexaferrite. Strontium hexaferrite [12023-91 -5] SrO-6 Fe2 03, is made by combining powdered ferric oxide, Fe203, and strontium carbonate, SrCO, and calcining the mixture at ca 1000°C in a rotary kiln (9). The material is cmshed, mixed with a binder, and pressed or extmded into... 

Strontium fluoride [7783-48-4] SrF2, forms colorless cubic crystals or a white powder with a specific gravity of 4.24 and a melting point of 1190°C. 

Strontium Nitrate. Strontium nitrate, Sr(N02)2, in the anhydrous form is a colorless crystalline powder with a melting point of 570—645°C... 

Strontium Oxide, Hydroxide, and Peroxide. Strontium oxide, SrO, is a white powder that has a specific gravity of 4.7 and a melting point of 2430°C. It is made by heating strontium carbonate with carbon in an electric furnace, or by heating celestite with carbon and treating the sulfide formed with caustic soda and then calcining the product (10). It reacts with water to form strontium hydroxide [18480-07-4] and is used as the source of strontium peroxide [1314-18-7],... 

Barium titanate thin films can be deposited on various substances by treating with an aqueous solution containing barium salts and an alkanolamine-modifted titanate such as TYZOR TE (151). In a similar fashion, reaction of a tetraalkyl titanate with an alkah metal hydroxide, such as potassium hydroxide, gives oxyalkoxide derivatives (KTi O(OR) ), which can be further processed to give alkali metal titanate powders, films, and fibers (152—155). The fibers can be used as adsorbents for radioactive metals such as cesium, strontium, and uranium (156). 

The alkaline earth metals can be detected in burning compounds by the colors that they give to flames. Calcium burns orange-red, strontium crimson, and barium yellow-green. Fireworks are often made from their salts (typically nitrates and chlorates, because the anions then provide an additional supply of oxygen) together with magnesium powder. 

Nineteen bone samples were prepared for analysis of the trace elements strontium (Sr), rubidium (Rb), and zinc (Zn). The outer surface of each bone was removed with an aluminum oxide sanding wheel attached to a Dremel tool and the bone was soaked overnight in a weak acetic acid solution (Krueger and Sullivan 1984, Price et al. 1992). After rinsing to neutrality, the bone was dried then crushed in a mill. Bone powder was dry ashed in a muffle furnace at 700°C for 18 hours. Bone ash was pressed into pellets for analysis by x-ray fluorescence spectrometry. Analyses were carried out in the Department of Geology, University of Calgary. 

Fine powdered strontium combusts spontaneously in air. It reacts more violently with water than calcium and produces hydrogen and strontium hydroxide. 

Mixtures with calcium hydride or strontium hydride may explode readily, and interaction of the molten chlorate is, of course, violent. A mixture of syrupy sodium phosphinate ( hypophosphite ) and the powdered chlorate on heating eventually explodes as powerfully as glyceryl nitrate. Calcium phosphinate mixed with the chlorate and quartz detonates (the latter producing friction to initiate the mixture). Dried mixtures of barium phosphinate and the chlorate are very sensitive and highly explosive under the lightest confinement (screwed up in paper). 

Domen, K., Kudo, A., Onishi, T., Kosugi, N., and Kuroda, H., Photocatalytic decomposition of water into hydrogen and oxygen over nickel (II) oxide-strontium titanate (SrTiOj) powder. 1. Structure of the catalysts, ]. Phys. Chem., 90, 292,1986. 

In the past, dissociation of the nucleoprotein complex has been brought about by salt solutions or by heat denaturation,129 but, more recently, decomposition has been effected by hydrolysis with trypsin,126 or by the use of dodecyl sodium sulfate130 or strontium nitrate.131 Some virus nucleoproteins are decomposed by ethyl alcohol.132 This effect may be similar to that of alcohol on the ribonucleoproteins of mammalian tissues. If minced liver is denatured with alcohol, and the dried tissue powder is extracted with 10% sodium chloride, the ribonucleoproteins are decomposed to give a soluble sodium ribonucleate while the deoxyribonucleoproteins are unaffected.133 On the other hand, extraction with 10 % sodium chloride is not satisfactory unless the proteins have first been denatured with alcohol. Denaturation also serves to inactivate enzymes of the tissues which might otherwise bring about degradation of the nucleic acid during extraction. 

Baythoun, M. S. G Sale, F. R. 1982. Production of strontium-substituted lanthanum manganite perovskite powder by the amorphous citrate process. /. Mat. Sci. 17 2757-2769. 

Tai TW and Lessing PA. Modified resin-intermediate of perovskite powders. Part II. Processing for fine, nonagglomerated strontium-doped lanthanum chromite powders. J. Mater. Res. 1992 7 511-519. 

When strontium metal is exposed to water, it releases hydrogen, as do the other earth metals (Sr + 2HjO —> Sr(OH)2 + H T). Strontium can ignite when heated above its melting point. When in a fine powder form, it will burn spontaneously in air. It must be stored in an inert atmosphere or in naphtha. Several of its salts burn with a bright red flame, making it useful in signal flares and fireworks. 

As a powder, strontium metal may spontaneously burst into flames. Both its metal and some of its compounds will explode when heated. Some of the compounds will explode if struck with a hammer. 

Strontium carbonate may be included to enrich the colour, but this substance is not an oxidiser and the balance must be redressed by adding a further oxidiser such as potassium perchlorate together with a balance of fuels such as aluminium powder and organic binders. 

Glass-ionomers have been used in various areas of restorative dentistry since the mid 1970s. They were invented and originally described by Wilson and Kent [208], and consist of a basic glass powder and a water-soluble acidic polymer. The most widely used polymer is poly(acrylic acid), but acrylic/maleic acid copolymer is also widely used [209]. The glass powder is a complex calcium (or strontium) aluminofluorosilicate [210] that is typically at least partially phase separated. 

Same Specs as listed under Method No 219 gives its composition as Strontium Nitrate (anhydrous) 56.0t2.0, Magnesium - Aluminum Alloy (powdered) 37.0t2.0 Polyvinyl Chloride 7.011.0%... 

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