The method of obtaining individual and complex metal oxides
(57) Abstract:Usage: upon receipt of pigments, catalysts, semiconductor materials. The inventive nitrates of the metals are heated in an atmosphere of water vapor fed to the reactor in an amount of 1.2 times theoretically required for hydrolysis, and gaseous reaction products remove and cool before the formation of nitric acid. The invention simplifies the technology of metal oxide, improves working conditions, ensures the safety of the environment. table 2. The invention relates to inorganic chemistry, and in particular to methods for producing metal oxide, and can be used to obtain pigments, catalysts, semiconductor materials.Known methods for producing individual metal oxides (MP, Zn, Ce and others) from their nitrate neutralization with an alkaline agent, followed by separation of the precipitate (e.g., in the form of a gel) and its decomposition to obtain the target product (for example, when heated or in the presence of an oxidant) (1).The disadvantage of this method is the presence of liquid wastes in the form of solutions of nitrates of alkali and alkaline-earth metals.Known from the second mixture is added water-soluble thickener, the mixture is then dried, the dry residue is subjected to thermal decomposition.The disadvantage of this method is the presence of waste gases containing oxides of nitrogen.Closest to the claimed is a method of thermal decomposition of metal nitrates (3). The way envisaged that involves the following stages: introduction into the reactor for the decomposition of solid particles of a metal oxide coated with liquid metal nitrate: temperature rise to a level above the decomposition temperature of nitrates; maintenance of coated particles in the atmosphere, resulting allocation of water vapor in the process of decomposition of crystalline, in a period of time sufficient to decompose the nitrate; metal oxide, which is a product of decomposition, is formed on the surface of particles and tightly grips the surface; removing the metal oxide in the gas mixture containing nitrogen dioxide.The disadvantage of this method is the presence of the gaseous waste containing nitrogen dioxide.The objective of the invention is the elimination of liquid and gaseous wastes reactions due to the complete regeneration of nitric acid and its reuse.This object is achieved in that the sphere of water vapor, with the formation of gaseous reaction products containing nitrogen oxides, water vapor serves in the amount of at least 1.2 times theoretically necessary, and gaseous reaction products remove and cool before the formation of nitric acid. Getting individual and complex oxides occurs by thermal hydrolysis of metal nitrates. The feed to the reactor of excess water vapor in a quantity which is at least 1.2 times higher than theoretically required for hydrolysis, provides complete separation resulting from the reaction of metal oxides and gaseous reaction products consisting of a mixture of oxides of nitrogen (II, III, IV), nitric and nitrous acids, oxygen (air) and water vapor. Cooling the gaseous products of the reaction prior to the formation of nitric acid provides a complete regeneration of nitric acid and re-use that eliminates liquid and gaseous wastes reactions.The claimed method was carried out obtaining the individual oxides of Mg, AI, Cr, Mn, Fe, Ni, Cu, Cd and complex oxides of the systems Zn-Mn-Fe, Ni-Fe.Chemically pure nitrates of the metals of mass 3 kg (calculated on the anhydrous salt) were loaded into cylindrical screw PE is Alceste, exceeding 1.2 times theoretically required for hydrolysis and steam in an amount to provide the formation of nitric acid with a concentration of 20% of
Gaseous reaction products were cooled in stainless steel heat exchanger with volume annulus 0.01 m3. After completion of the reactions was carried out weighting of target products, the determination of their density and purity, as well as the concentration of the regenerated nitric acid on the basis of standard techniques.The process parameters for obtaining individual oxides, the weight and characteristics of the target products, the concentration of the regenerated nitric acid are given in table.1, for complex oxides in the table.2.As seen from the above examples, the inventive method allows to obtain individual and complex chemically pure metal oxides. When this charge by complete regeneration of nitric acid, the resulting reaction and its reuse, eliminating liquid and gaseous wastes reactions.The use of the invention simplifies the technology of production of metal oxides by reducing the number of operations, improve working conditions, provide sahrani by thermal decomposition in an atmosphere of water vapor with the formation of gaseous reaction products, containing nitrogen oxides, characterized in that the water vapor serves in the amount of at least 1.2 times theoretically necessary, and gaseous reaction products remove and cool before the formation of nitric acid.
FIELD: production of powder from finely-dispersed and ultra finely-dispersed particles.
SUBSTANCE: flame synthesis of powder particles includes mixing of chelate of at least one hydride of non-metal and organic solvent and ignition of mixed solution with forming the self-sustaining flame. For forming the smoothly distributed coat from said powder on surface of item, non-vacuum physical spraying is performed. This process is characterized as burning or passing of powder particles through self-sustaining flame on surface of item.
EFFECT: enhanced efficiency.
10 cl, 2 dwg
FIELD: production of film catalysts, magnetoresistors, fuel cells, magnetic information recording and storage head materials and sensors showing content of different gases.
SUBSTANCE: proposed method consists in production of water soluble salt or mixture of water soluble salts of volatile acid or volatile acids of respective metals, for example manganese chloride or mixture of yttrium, barium, iron and cobalt oxides. Mixture thus obtained is applied onto substrate and is dried at temperature of 100C. Then, substrate is heated to melting point of the most high-melting salt and is cooled to temperature below 500C, after which heat treatment is performed at this temperature in flow of mixture of air and steam and rate of delivery of 0.1-100 ml/min and partial pressure of steam not below 0.1 atm.
EFFECT: facilitated procedure; enhanced ecological safety; improved quality of films.
4 dwg, 4 ex
FIELD: chemical industry; other industries; methods of production of the metal oxides powders.
SUBSTANCE: the invention is pertaining to production of the metal oxides powders and may be used in the chemical industry at production of the powders of the metals oxides. The method of production of the finely dispersed powders of the metals oxides includes preparation of the mixture containing the water solution, the melt or the water suspension of the salt of at least one metal, demonstrating the oxidative properties, and organic reducing agent. The obtained mixture is homogenized and heated up at its continuous feeding on the hot surface of the rotating heater. Then the evaporation and inflammation of the mixture is exercised. The released gaseous substances and the formed solid final product are continuously removed from the surface of the heater. The invention allows to receive the finely dispersed powders of the metals oxides in the continuous mode with the high specific productivity and to exclude the pulsing release of the gases.
EFFECT: the invention ensures production of the finely dispersed powders of the metals oxides in the continuous mode with the high specific productivity at exclusion of the pulsing release of the gases.
4 cl, 8 ex, 4 tbl
SUBSTANCE: invention relates to chemical industry, specifically to production of magnetrostrictive materials based on composite metal oxides, particularly ferrites. The method of producing the iron-based metal oxide involves thermal processing of inorganic hydrated salts of corresponding metals in a water vapour atmosphere. The inorganic hydrated salts used are powdered halides of corresponding metals, and thermal processing is carried out in a current of air and water vapour, while feeding the mixture at a rate of V=0.1 volume of reaction space/min. The obtained complex metal oxide is among a group comprising oxides of cobalt, nickel and copper.
EFFECT: method is simple and reliable, and also ensures high purity of the end product.
1 dwg, 3 ex
FIELD: process engineering.
SUBSTANCE: invention relates to hydrometallurgy of metals and may be used for production of metal oxides. Proposed method comprises heating of hydroxides at the temperature of their decomposition. Note here that hydroxide heating is carried out in autoclave without evaporation of water bulk provided that pressure of hydroxide dissociation exceeds that of saturated water vapors at said temperature.
EFFECT: lower costs of dehydration.
4 dwg, 1 ex
SUBSTANCE: method of producing perovskites involves mechanical mixture of initial precursor salts in stoichiometric ratio, microwave treatment of the mixture of initial salts in a microwave oven, followed by thermal treatment at temperature 500-900°C for 1-5 hours. The initial salts used for synthesis are crystalline hydrates of nitrates of rare-earth, alkali-earth and transition metals, as well as unhydrated nitrates or carbonates of the same precursors. Microwave radiation is used at operating frequency of 2.45 GHz and power of 600-1000 W for 3-10 minutes.
EFFECT: method is fast, low-waste, energy- and labour-saving and enables to obtain pure single-phase perovskites with the required characteristics, for example with a developed specific surface area or are well crystallised or thermally stable for specific regions of use.
5 cl, 4 ex, 6 tbl, 6 dwg