![]() ![]() Barium sulfate is commonly used as a component of "strobe" pyrotechnic compositions.Īs barium sulfate has a high melting point and is insoluble in water, it is used as a release material in casting of copper anode plates. Palladium on barium sulfate is also used as a catalyst in the Rosenmund reduction.Īs barium compounds emit a characteristic green light when heated at high temperature, barium salts are often used in green pyrotechnic formulas, although nitrate and chlorate salts are more common. With a low surface area, the contact time of the substrate with the catalyst is shorter and thus selectivity is achieved. Catalyst support īarium sulfate is used as a catalyst support when selectively hydrogenating functional groups that are sensitive to overreduction. This together with silica helps the pellet attain a 96.5 shore A hardness. It is also used in brake linings, anacoustic foams, powder coatings, and root canal filling.īarium sulfate is an ingredient in the "rubber" pellets used by Chilean police. In metal casting, the moulds used are often coated with barium sulfate in order to prevent the molten metal from bonding with the mould. In colorimetry, barium sulfate is used as a near-perfect diffuser when measuring light sources. Barium sulfate added to the mixture binds with these particles, making them heavier so they fall to the bottom, leaving a clearer solution. Tests for soil pH and other qualities of soil use colored indicators, and small particles (usually clay) from the soil can cloud the test mixture and make it hard to see the color of the indicator. Niche uses īarium sulfate is used in soil testing. In cases where machinability and weight are a concern, composites with high mass fraction (70–80%) of barium sulfate may be preferred to the more commonly used steel shields. ![]() Such composites are also used as X-ray shielding materials due to their enhanced radio-opacity. It has an effect of increasing acid and alkali resistance and opacity. In polypropylene and polystyrene plastics, it is used as a filler in proportions up to 70%. Plastics filler īarium sulfate is commonly used as a filler for plastics to increase the density of the polymer in vibrational mass damping applications. Baryta has also been used to brighten papers intended for ink-jet printing. Further coatings may then be present for fixing and protection of the image. ![]() The baryta coating limits the penetration of the emulsion into the fibers of the paper and makes the emulsion more even, resulting in more uniform blacks. The light-sensitive silver halide emulsion is then coated over the baryta layer. Paper brightener Ī thin layer of barium sulfate called baryta is first coated on the base surface of most photographic paper to increase the reflectiveness of the image, with the first such paper introduced in 1884 in Germany. By using hexagonal nanoplatelet boron nitride, the thickness of a coating was reduced to 0.15 mm. This contrasts with commercially available white paints which can only reflect 80 - 90% of the sunlight. Researchers used it as an ingredient in paint that reflects 98.1% of all solar radiation, thus cooling surfaces to which it has been applied. It is also used as a coating to diffuse light evenly.īarium sulfate is highly reflective, of both visible and ultraviolet light. In photography it is used as a coating for certain photographic papers. The combination of barium sulfate and zinc sulfide (ZnS) is the inorganic pigment called lithopone. One major manufacturer of artists' oil paint sells "permanent white" that contains a mixture of titanium white pigment ( TiO 2) and barium sulfate. In oil paint, barium sulfate is almost transparent, and is used as a filler or to modify consistency. The majority of synthetic barium sulfate is used as a component of white pigment for paints. Due to the relatively high atomic number ( Z = 56) of barium, its compounds absorb X-rays more strongly than compounds derived from lighter nuclei. Barium sulfate is also readily removed from the body, unlike Thorotrast, which it replaced. Although barium is a heavy metal, and its water-soluble compounds are often highly toxic, the low solubility of barium sulfate protects the patient from absorbing harmful amounts of the metal. It is administered orally, or by enema, as a suspension of fine particles in a thick milk-like solution (often with sweetening and flavoring agents added). It is most often used in imaging of the GI tract during what is colloquially known as a " barium meal". Barium sulfate in suspension is often used medically as a radiocontrast agent for X-ray imaging and other diagnostic procedures. ![]()
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