66results about How to "Large crystals" patented technology

The invention provides a powder metallurgic process, which comprises the following steps of: pressing, sintering, soaking in oil, finishing and treating with steaming. In the process steps, iron-based powders are uniformly mixed according to a ratio and are transmitted to a presser; the presser transmits the iron-based powders into a preset product mold and presses to obtain a rough product; the rough product is arranged in a conveying mesh belt, which conveys the rough product to a sintering furnace according to a set speed; air is used for repeated extraction and pressurization in the sintering process, and the temperature of the sintering furnace is adjusted to sinter the rough product to a semi-product; the semi-product is cooled and soaked in engine oil and is subjected to fine correction in a sizing die; the corrected semi-product is subjected to steam treatment to form a rustproof layer and to deburring treatment by shot blasting, vibration and manual deburring. The product has high performance-price ratio, and a dense protection film is formed on the product surface to improve the rustproof performance.

The invention discloses a method for directly producing environment-friendly lithium hydroxide monohydrate from spodumene. The method includes (1) calcining: calcining 80-200 mesh spodumene powder under high temperature; (2) ball-milling: ball-milling the calcined spodumene to 200 mesh; (3) acidifying: mixing the milled spodumene with concentrated sulfuric acid, introducing into an acidification kiln, and acidifying at 200-300 DEG C; (4) leaching: mixing the acidified mineral powder with washing water in subsequent step to prepare pulp, and regulating pH value with calcium carbonate heavy. The environment-friendly lithium hydroxide has no air pollution, and no influence on application quality. Fine dust of the environment-friendly lithium hydroxide is adsorbed through a novel activator (alkane or cycloalkane), to agglomerate dust, cut off dust source, remove irritant odor of original product, and solve human body damage problem caused by original product.

The invention relates to a preparation method for a gold plating on the surface of a silicon carbide particle reinforced aluminum-based composite material, and belongs to the technical field of surface engineering. The preparation method comprises the following steps that pretreatment is performed on the silicon carbide particle reinforced aluminum-based composite material; micro-arc oxidation isperformed on the pretreated silicon carbide particle reinforced aluminum-based composite material; surface sensitization, activation and reduction treatment is performed on the material subjected to the micro-arc oxidation; chemical nickel plating is performed on the surface of the material to obtain the material with a nickel layer; and gold plating is performed on the surface of the nickel layerto obtain the gold plating located on the surface of the silicon carbide particle reinforced aluminum-based composite material. According to the preparation method, a ceramic membrane layer is formed, so that the homogenization of chemical properties of an interface of the high-volume-fraction SiCp/Al composite material is realized, it is guaranteed that the subsequent plating is uniform in crystallization, then the porosity of the subsequent plating is reduced, and the compactness of the plating is improved.

The present invention provides a preparation method of magnesium oxide by using bittern and carbonate, comprising the following steps: a. evaporating the bittern for crystallization to remove the sodium salt and sylvine; b. adding a precipitant into the processed bittern at the temperature of 10 to 50 DEG C, reacting at the temperature to obtain the bittern containing the sediment of trihydrate magnesium carbonate, keeping the pH value of 7.0 to 10.0 during the addition of the precipitant, the molar ratio of the precipitant and the magnesium ions is between 1:1.1 to 1:1.2, and the precipitant is carbonate solution or carbonate solid; c. filtering the obtained bittern containing the sediment of trihydrate magnesium carbonate; d. calcining the solid sediment of step c to obtain the magnesium oxide. By the process of the invention, the solid sediment of trihydrate magnesium carbonate obtained in step c has the purity of 99.0%, and the magnesium oxide obtained in step d has the purity of 99.4%.

The invention relates to a freeze-dried preparation moisture control method and application thereof, and belongs to the technical field of preparation of freeze-dried preparations. The freeze-dried preparation with low impurity content and low moisture content is obtained by controlling various operation parameters of the cooling speed, the annealing temperature, the annealing frequency, the sublimation drying temperature and the sublimation drying vacuum degree in the pre-freezing process of the preparation, and the method solves the problems of high moisture content, poor stability in the storage period, short expiration date and the like of the final product of the freeze-dried preparation.

The invention is related to an ultrafast freezing equipment for food contained in a packing with multiple cavities, for public sale, by applying a liquid nitrogen trickle, in an amount enough to produce an ultrafast freezing of food. Liquid nitrogen is dispensed from a container at atmospheric pressure, vacuum isolated, through a plurality of nozzles, by gravity, into the center of the upper surface for each cavity, producing short-time immersion in the individual cavity. Nitrogen gas produced is used to make a practically oxygen-free atmosphere, cold enough to maintain the freezing process after dispensing. The process diminish the amount of liquid nitrogen required as compared to other freezing processes, as well as personnel, facilities and physical space needed for install and operate it, reducing the associated costs.

The invention relates to a method for producing large-grained nitrofurantoin crystals, and belongs to the field of chemical synthesis. The invention adopts a technical proposal which comprises: placing a crude product of nitrofurantoin formed by the condensation of raw materials of 5-nitrofurfural diacetate and 1-aminohydantoin, and DMF of which the weight is two times of that of the crude product of the nitrofurantion in a retort, heating the mixture to between 85 and 90 DEG C, stirring the mixture, maintaining the temperature for 10 minutes, stirring the mixture, opening a clamping sleeve, cooling the retort by cooling water for 80 to 90 minutes to between 30 and 35 DEG C, stopping stirring, standing the retort for 2.5 to 3 hours to less than 2 DEG C below zero, casting material, and washing the material with 95 percent ethanol to obtain odorless DMF. Nitrofurantoin crystals prepared by the process are larger and the granularity of 95 percent of the products is more than 80 meshes, so the process facilitates filtration and separation and contributes to the reduction of production cost.

A preparation method of a ceramic membrane support is disclosed. Take aluminium hydroxide, produced through a carbon decomposing process by a sintering method, as a raw material, pre-sinter the aluminium hydroxide, and obtain a low-temperature alumina product A; add a first amount of mineralizer into the product A, grind after calcining the added product A, and obtain a α-alumina product B; mix the product B with Al₂O₃.nH₂O, calcine after adding a second amount of mineralizer into the mixed product B, and obtain a α-alumina product C; grind, scatter and grade the calcined and heat-preserved α-alumina product C, and obtain polyhedral alumina powders; mix the polyhedral alumina powders, water, humectant and dispersant and then sinter, and finally obtain the porous alumina support. The prepared support is easy to be sintered, is high in alumina purity, is good in corrosion resistance, and is improved in porosity and flux.

The invention discloses a novel lead-acid storage battery negative electrode lead paste and a preparation method thereof. The lead paste is prepared from 84-86% of lead powder, 6-8% of sulfuric acid,0.05-0.15% of conductive fiber, 0.1-1.0% of induline base N, 0.05-0.10% of graphite, 0.3-0.5% of humic acid, 0.5-3% of barium stearate and the balance of deionized water. The negative electrode lead paste prepared by the preparation method provided by the invention significantly reduces phenomena of the difficulty in passivation of a negative electrode, falling, softening, and shedding too early,and also significantly reduces a phenomenon of non-uniform distribution of active material particles on a negative electrode plate; the initial capacity and the battery capacity of a battery preparedfrom the negative electrode lead paste are improved to a certain extent, so that the cycle life of the battery is prolonged.

A device and method for purifying sodium thiosulfate by using coking desulfurization waste liquid salt extraction and filter residue as raw material, the device includes a dissolution kettle, a plate and frame filter, a precision filter, an evaporation crystallizer and a centrifugal machine. The present invention uses coking desulfurization waste liquid salt extraction filter residue as raw material, dissolves, plate and frame filter, precision filter, crystallizes in Oslo cooling crystallizer, and centrifugally separates the product sodium thiosulfate. Compared with other methods for preparing sodium thiosulfate, the present invention not only has easy-to-obtain raw materials, simple process, energy-saving, larger crystal particles of the product sodium thiosulfate, but also realizes resource utilization of extraction filter residue, low cost and environmental protection.

The invention belongs to the technical field of storage of sugars and particularly relates to a method for delaying crystallization of high fructose syrup. The method for delaying crystallization of the high fructose syrup is characterized in that finished product high fructose syrup is heated and then cooled. The method has the benefits as follows: with the adoption of the method, the finished product high fructose syrup is firstly heated to a certain temperature and then cooled to a specific temperature, the method adopts a process designed according to the characteristics of the high fructose syrup, so that the high fructose syrup has increased solubility after being heated and cooled, and the condition that use and sales of the high fructose syrup are affected due to crystallization ofthe high fructose syrup at the low temperature is effectively prevented.

The invention relates to a process for coproducing melamine and ammonium sulfate. The process comprises the following steps of: melting urea serving as a raw material in a urea fusion tank to form liquid urea, conveying the liquid urea into a reactor by a liquid urea washing tower, filtering reacted gas to remove impurities, condensing melamine to form a solid by a crystallizer, and conveying the solid into a cyclone separator for a finished product along with the mixed gas, discharging, cooling and packaging to obtain the melamine; and pressurizing tail gas exhausted from the top of the cyclone separator by a cold air fan to enter the liquid urea washing tower, and dividing the tail gas into three paths, wherein the first path of tail gas is pressurized by a gas carrying compressor, is used as fluidized bed carrier gas and enters the reactor; a second path of tail gas returns to the crystallizer circularly to be used as quenching gas; the third path of tail gas is separated from the gas carrying compressor, enters an ammonium sulfate saturator and reacts with sulfuric acid to generate an ammonium sulfate crystal, and the ammonium sulfate crystal is separated by a centrifugal machine to obtain an ammonium sulfate finished product; and an ammonium sulfate mother solution returns to a mother solution circulating tank to be recycled. The ammonium sulfate is large in crystalline particles, and the process is simple, easy to operate and environment-friendly, and has an obvious economic benefit.

The present invention relates to a solder and an insulation container welded by means of same. The solder comprises, in percentage by weight, 5% of zirconium, 9% of nickel, 78% of titanium, and 8% ofcopper. The insulation container comprises a titanium material liner and a stainless steel housing made of SUS304 stainless steel; a welding cavity is formed between the liner and the housing after assembly; the solder as described above is used for vacuum brazing; and the connection of the liner and the housing is implemented after welding. The present invention can implement the welding connection between the titanium liner and the stainless steel housing of the insulation container, is high in tensile strength of welded parts thereof and excellent in compactness, guarantees the quality of the insulation container, and prolongs the service life thereof.

The invention relates to a preparation method of chlorazol benzathine benzylpenicillin, which comprises the following steps of: (a) measuring and taking the following materials of 1.0g of cloxacillin sodium, 2.0-10.0ml of water and 0.5-10.0ml of buffer agent according to the mass volume ratio to prepare solution A; (b) measuring and the taking the following materials of 1.0g of N, N'-DBED, 2.0-10.0ml of water and 1.0-10.0ml of buffer agent according to the mass volume ration to prepare solution B; (c) adding 15-30 percent of the total amount of the solution A into the solution B, reacting under a stirring state to generate crystal, and growing the crystal for 10-30 minutes; and flowing the rest solution A into the solution B within 30 minutes, and carrying out salt forming reaction to obtain chlorazol benzathine injectable suspension; and (d) filtering, washing, leaching, and vacuum drying at 50-80 DEG C to obtain the product. Stable degree of supersaturation is kept during the reaction, and the nucleus formation caused by outbreak of the product is effectively controlled, so that the product quality can be improved.

The invention provides medicine water suspended emulsion containing rebamipide and povidone, wherein rebamipide fine particles dispersed in the water suspended emulsion can maintain a stable dispersed state and can not get together; besides, the invention also provides a method for preparing the medicine water suspended emulsion containing rebamipide and povidone, and the method for preparing the medicine water suspended emulsion comprises the step of mixing povidone and sodium salt compound with rebamipide.