摘要:
Es wird ein Verfahren zur Herstellung von Ammoniak beschrieben. Aus SiO 2 und/oder Al 2 O 3 oder SiO 2 - und/oder AI 2 O 3 - haltigem Material wird Siliciumnitrid und/oder Aluminiumnitrid gewonnen, das in Gegenwart einer basischen Alkali- und/oder Erdalkalimetallverbindung mit Wasser bei erhöhter Temperatur zu Ammoniak und Alkali- und/oder Erdalkalimetallsilikaten umgesetzt wird. Das Verfahren ermöglicht eine besonders effektive Ausnutzung von natürlichen Ressourcen.
摘要:
A method for producing carbon-silica products from silica-containing plant matter such as rice hulls or straw by leaching with sulfuric acid to remove non-silica minerals and metal while adjusting the mole ratio of fixed carbon to silica in the resultant product. The carbon and silica are intimately mixed on a micron or submicron scale and are characterized by high purity and reactivity, small particle size, high porosity, and contain volatile carbon that can be used as a source of energy for the production of silicon-containing products from the carbon-silica products. High purity silicon-containing products made from the carbon-silica products of the invention are also disclosed.
摘要:
A fluidized bed reaction pipe (1) made of sintered silicium carbide has a fritted plate (2) made of silicium nitride or carbide. The fritted plate is preferably sintered together from individual, preferably spheric, sintered silicium nitride bodies. The reaction pipe is characterized by good thermal and thermal change resistances and is suitable for carrying out reactions at up to 1650 DEG C. Also disclosed is a process for high temperature treatment of corundum micro-grains in the fluidized bed which can be carried out without the admixture of coarse grains and which supplies an agglomerate-free product.
摘要:
Es geht um Verfahren und Vorrichtungen zum Bereitstellen von Energie mit den folgenden Schritten : - Bereitstellen von siliziumhaltigem Ausgangsmaterial, - Bereitstellen von stickstoffhaltigem Ausgangsmaterial, - Zusammenbringen des siliziumhaltigen Ausgangsmaterials und des stickstoffhaltiges Ausgangsmaterials, - externes Anregen des stickstoffhaltigen Ausgangsmaterials, um eine exotherme Reaktion der beiden Ausgangsmaterialien auszulösen.
摘要:
The invention relates to a method for producing ammonia. Using SiO2 and/or Al2O3 or SiO2- and/or AI2O3-containing material, silicon nitride and/or aluminum nitride is obtained, which is reacted with water in the presence of a basic alkali and/or earth alkali metal compound at an elevated temperature to form ammonia and alkali and/or earth alkali metal silicates. The method enables particularly effective utilization of natural resources.
摘要:
Silicon-containing products, such as silicon, silicon carbide and silicon nitride, containing less than 0.01 weight percent total mineral impurities and selectively determined carbon-to-silicon ratios. The products are derived from plant matter, such as rice hulls and rice straw, containing at least three weight percent silica. Methods are provided for making such high purity silicon-containing products by leaching silica- containing plant matter with aqueous sulfuric acid under controlled temperatures, pressures and reaction times to remove minerals and metals while adjusting the mole ratio of fixed carbon to silica, and then thermally treating under controlled conditions to produce the desired product.
摘要:
Systems, methods and compositions for the production of silicon nitride nanostructures are herein disclosed. In at least one embodiment, a carbon feedstock is preprocessed, combined with a silicon feedstock and annealed in the presence of a nitrogen containing compound to produce a silicon nitride nanostructure.
摘要:
A process for producing a silicon nitride compound is presented. A starting solution comprising fluorosilicic acid is provided. The starting solution is derived from a silicon etching process wherein silicon is etched with a solution comprising hydrofluoric acid and where silicon powder has been removed. The starting solution is heated to yield a vapor solution comprising silicon tetrafluoride, hydrogen fluoride, and water. The hydrogen fluoride is separated from the vapor solution wherein a pure stream of silicon tetrafluoride and water vapor remain. The silicon tetrafluoride and water vapor are hydrolyzed to yield a concentrated flluorosilicic acid solution. The fluorosilicic acid is reacted with a base to yield a fluorosilicic salt. The fluorosilicic salt is heated to yield anhydrous silicon tetrafluoride. The anhydrous silicon tetrafluoride is reacted with a metal hydride to yield a monsilane. The monosilane is reacted to form a silicon compound and a silicon nitride compound. The silicon and the silicon nitride compounds are recovered. In an alternate embodiment, the hydrogen fluoride is recovered from the reaction process and reintroduced into the porous silicon etching process.
摘要:
Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.