![]() Fujian Sanming Zheng Yuan Chemical Co., Ltd. ![]() Food processing and pharmaceuticals additive as anti-caking, thickening agent, absorbent to make liquids into powders.Cleaning, thickening and polishing agent in toothpastes for oral health care.Filler, softener and performance improvement in rubber and plastics.Agglomerate size is 1 - 40 µm with average pore size is > 30 nm. Primary structures typically have a diameter of 5 - 100 nm, and specific surface area 5–100 m 2/g. Na 2(SiO 2) 7 + H 2SO 4 + O → 7 SiO 2 + Na 2SO 4 + H 2O Na 2SiO 3 + H 2SO 4 → SiO 2 + Na 2SO 4 + H 2O Properties The resulting white precipitate is filtered, washed and dried in the manufacturing process in order to wash out the produced salts. The formation of a gel stage is avoided by stirring at elevated temperatures. This range offers a wide variety of highly dispersible silicas, including the well-known dust-free Micropearl form. The choice of agitation, duration of precipitation, the addition rate of reactants, their temperature and concentration and pH can vary the properties of the resulting silica. Solvay’s Zeosil Highly Dispersible Silica (HDS) reinforces rubber goods such as tires. Precipitation is carried out under acidic or basic conditions. Sulfuric acid and sodium silicate solutions are added simultaneously with agitation to water. The production of precipitated silica starts with the reaction of a basic silicate solution with a mineral acid. Like pyrogenic silica, precipitated silica is essentially not microporous (unless prepared by the Stöber process). In 1999, more than one million tons were produced, half of it is used in tires and shoe soles. Among them, precipitated silica has the greatest commercial significance. ![]() The three main classes of amorphous silica are pyrogenic silica, precipitated silica and silica gel. Precipitated silica is produced by precipitation from a solution containing silicate salts. Precipitated silica is an amorphous form of silica (silicon dioxide, SiO 2) it is a white, powdery material.
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