35results about How to "Coarse particles" patented technology

The present invention relates to material technology and is mixed salt process to prepare in-situ reinforced Mg-base composite material. The process includes determining the alloy element components in the composite material, selecting the reinforcing phase based on the wettability between the substrate and the reinforcing phase whith ic controlled in 2-15 wt%, compounding and pretreating mixed salt system, smelting the magnesium substrate material and adding the pretreated mixed salt into the magnesium melt at proper temperature via stirring, and final casting after being let stand to form. The reinforcing phase is fine, homogeneously distributed and excellent in interface bindnig, and the Mg-base composite material has excellent mechanical and physical performance and may be used widely.

A preparation method of a high-stability high-purity extra-coarse tungsten carbide powder contains the following steps of: (1) grinding a high-purity extra-coarse tungsten carbide powdered raw material with its chemical purity being greater than or equal to 99.98 wt%, and carrying out size grading to obtain the required average granularity and a high-purity extra-coarse tungsten powder according to the particle size distribution; (2) carrying out carbon addition by the use of carbon black according to the total carbon content of the obtained tungsten carbide powder being 6.13+/-0.05%, followed by ball milling and mixing to obtain a ball-milling mixture; (3) filling the obtained ball-milling mixture into a graphite boat and a carbide furnace, and carrying out high-temperature carbonization at 1600-2500 DEGC for the carbonization time of 1-10 hours; and (4) carrying out coarse crushing on the obtained carbonized material, followed by grinding and crushing, and carrying out size grading to obtain the high-purity extra-coarse tungsten carbide powder. The method provided by the invention can be adopted to produce the high-purity extra-coarse tungsten carbide powder with good crush resistance, morphology and structure and excellent thermal stability. The high-purity extra-coarse tungsten carbide powder is used to prepare an extra-coarse crystal cemented carbide product with high performance.

The invention belongs to the technical field of rare earth chemical engineering and particularly relates to a method for preparing rare-earth phosphorate. The method for preparing rare-earth phosphorate comprises the following steps that firstly, a rare-earth carbonate or rare-earth oxide suspension with the concentration of 10-1000 g/L is prepared; secondly, a precipitator is added into the suspension under continuous stirring at the room temperature until the pH value is smaller than or equal to 5; thirdly, stirring continues for 5-30 min, the reaction endpoint is reached when it is observed that the pH does not rise any more, if in the stirring process, the pH rises to 2 or above, the precipitator is supplemented until the pH is smaller than or equal to 5, and stirring and observation are carried out until the reaction endpoint is reached; fourthly, precipitation, dehydration and washing are carried out, and rare-earth phosphorate is obtained. According to the method, rare-earth phosphorate obtained through precipitation is large in particle size and easy to filter and wash with water; compared with preparation with a hydrothermal reaction and a solid-phase reaction, the method is relatively easy to implement, and certain industrial popularization meaning is achieved.

The invention discloses a crystallization method of ammonium paratungstate and relates to a production method of ammonium tungstate by adopting hydrometallurgy. The method is characterized in that the invention has a crystallization process that ammonium paratungstate crystal seeds are added into ammonium tungstate solution when the solution is evaporated and concentrated to appear microcrystalline particles for isothermal crystallization under the solution temperature of 90-95 DEG C for 20-40mins; the solution is then heated up to boil and added with weak aqua ammonia to adjust the pH value of the ammonium tungstate solution to 8.0-8.5 and then treated with feeding and filtering when the density of mother liquor reaches 10.8 to 1.10 g/cm <3>; the solution is again washed with the weak aqua ammonia and deionized water and dried to obtain the ammonium paratungstate crystals with large particle size and uniform distribution. The method of the invention effectively controls the crystallization of the ammonium paratungstate through the measures of removing fine crystals through the weak aqua ammonia, adding the crystal seeds, controlling the evaporation speed, etc.; in addition, the produced ammonium paratungstate crystals with large and controllable particle size are uniform and smooth; and the technology is simple and easy to be operated.

The invention relates to a method for converting neodymium oxide into a neodymium acetate crystal. The method is characterized by comprising the following steps of: pumping analytically-pure glacial acetic acid and deionized water into a reaction kettle according to the volume ratio of 1:1, uniformly stirring and heating until the mixture is boiled; rotating a stirring paddle, and slowly adding the weighted neodymium oxide into the reaction kettle, wherein the mole rate of the addition of the neodymium oxide to the addition of acetic acid is 1:3.9; after the reaction is ended completely, heating a liquid material to 110-125 DEG C, and then, stopping heating to enable the liquid material in the reaction kettle to naturally cool and crystallize; when the liquid material is cooled to the temperature below 50 DEG C, enabling the stirring paddle to stop stirring, filtering a liquid through a filter tank, and centrifugally dewatering; and airing the dewatered reactant in a dust-free room to realize natural evaporation. The rare earth neodymium oxide is used for manufacturing the neodymium acetate crystal, so that the method is simple in process flow, high in production efficiency, low in energy consumption and capable of reducing the production cost and environment pollution; and the neodymium acetate crystal product is high in purity and total rare earth quantity, large in crystal particle and pure in color and luster, and the added value of a product can be increased.

The invention belongs to the field of dihydrate gypsum synthesis and relates to a synthetic method of citric acid gypsum. The method comprises the following steps: preparing a suspension from calcium hydrogen citrate, calcium sulphate dihydrate seed crystal and water; heating the suspension until the temperature of the suspension is 20-80 DEG C, stirring the suspension and simultaneously adding a sulfuric acid solution into the suspension until sulfuric acid and calcium hydrogen citrate completely react; standing and taking a bottom solid after the reaction, cooling and washing and drying. By the technical scheme, the problem of low strength of building gypsum powder due to fine citric acid gypsum particles and irregular crystal structure is solved.

The invention discloses a method for decontaminating potassium sub-molten salt soluble crystal liquid and preparing chromic oxide. The method comprises the following steps: (1) introducing CO2 to potassium sub-molten salt soluble crystal liquid, neutralizing potassium hydroxide in the solution, then adding seed crystals, controlling the temperature of the solution at 30-90 DEG C and removing aluminum and silicon; (2) introducing CO2 to the solution obtained in the step (1) to carry out room-temperature pre-carbonation; (3) adding a reducing agent to pre-carbonated feed liquid obtained in the step (2), heating to 120-170 DEG C, and carrying out heat preservation and solid-liquid separation after reaction is ended, so as to obtain a chromium hydroxide filter cake; and (4) drying and calcining the chromium hydroxide filter cake obtained in the step (3), so as to obtain a chromium sesquioxide product. By adopting a pre-acidification mode, the reducing agent is not added in pre-carbonation; no CO2 is introduced after the pre-carbonated feed liquid and the reducing agent are mixed; the method is high in conversion rate of hydrothermal reduction, fewer in intermediate products, high in total yield of chrome, high in purity of the sintered chromic oxide and fewer in impurities by controlling a proper pre-carbonation condition.

The invention discloses a preparation technology of zinc sulfate heptahydrate by a cold liquid hot flushing method. The preparation technology comprises the following steps of quickly cooling a saturated zinc sulfate solution for the first time, crystallizing, quickly cooling for the second time, adding a hot saturated solution, quickly cooling for the third time, cooling by cooling water, and crystallizing, so as to obtain a zinc sulfate heptahydrate product. The preparation technology has the advantages that when the zinc sulfate heptahydrate is applied to the industrial production, the large-particle zinc sulfate crystal can be obtained; the content of free water in the product is obviously reduced, the crystallizing time is shortened, and the production efficiency and the product quality are improved.

The invention belongs to the technical field of sewage treatment in zinc hydrometallurgy process, and provides a method of water treatment process. The method comprises the following steps: (1) addinga neutralizing agent to acidic wastewater containing heavy metals to adjust the pH value to 7.0 to 8.0 till the reaction stops and precipitates are generated, and then filtering to separate the precipitates to obtain first filtrate with residue at the bottom; (2) adding a neutralizing agent to the first filtrate again to adjust the pH value to 8.0 to 9.0 till the reaction stops and precipitates are generated, then adding Na2S to the filtrate till the reaction stops and precipitates are generated, wherein the weight ratio of Na2S added to heavy metals in the first filtrate is (1.2-1.5) to 1, and finally, filtering to separate the precipitates in the first filtrate, so as to obtain second filtrate with residue at the bottom. The method is highly efficient, the consumption of a precipitatingagent is small, the degree of purification is deep, and the amount of residue is small, and thus the method is suitable for large-scale industrial treatment.

The invention relates to a method for producing a holmium acetate crystal. The method is characterized by comprising the following steps of: pumping analytically pure glacial acetic acid and deionized water at the volume ratio of 1:0.5 into a reactor, stirring uniformly, and heating to the temperature of 50 DEG C; rotating a stirring paddle, and adding the weighed holmium carbonate into the reactor slowly, wherein the molar ratio of the added holmium carbonate to the glacial acetic acid is 1:3.3; heating a liquid material to the temperature of 110-125 DEG C after the materials react completely, and stopping heating to naturally cool the liquid material in the reactor to crystallize; cooling the liquid material to the temperature below 50 DEG C, discharging the liquid material into a filtering box, removing liquid by filtering, and dehydrating centrifugally; and airing the dehydrated product of reaction in a dust-free room to evaporate naturally. The method for producing the holmium acetate crystal from the carbonate holmium (rear earth) is simple in technological process, high in production efficiency and low in production cost, consumes less energy and causes less pollution to the environment. In addition, the holmium acetate crystal is high in purity, high in content of rear earth, high in additional value, large in particle size and pure in color.

The invention relates to a method for analyzing lithium ion battery electrolyte salt LiBF4. The method includes steps of preparing and calibrating a Na2S2O3 5H2O standard solution; preparing and calibrating a K13 standard solution; preparing and calibrating a (C6H5) As4Cl standard solution; preparing 1mol/L of a LiBF4 solution; preparing 0.01 mol of mol/L of the LiBF4 solution; determining a main content four fluorine boric acid roots by a weighting method: placing the LiBF4 solution in a water bath thermostatic bath, adding the (C6H5) As4Cl solution dropwise after 15 minutes to 30 minutes, mixing the mixture during dropwise adding, and obtaining sediment (C6H5) 4AsBF4 after dropwise adding; and ageing the sediment (C6H5) 4AsBF4 in a constant temperature water bath for 30 minutes to 60 minutes and then performing leaching, cleaning and drying to a constant weight, and performing content calculation. According to the method, the operation is simple and rapid, and defects that errors are increased for the increase of the sample dilution ratio as the ion selective electrode method is used are effectively overcome.

The invention relates to a method for converting yttrium oxide into an yttrium acetate crystal. The method is characterized by comprising the following steps of: pumping analytically-pure glacial acetic acid and deionized water into a reaction kettle according to the volume ratio of 1:1, uniformly stirring and heating until the mixture is boiled; rotating a stirring paddle, and slowly adding the weighted yttrium oxide into the reaction kettle, wherein the mole rate of the addition of the yttrium oxide to the addition of acetic acid is 1:3.9; after the reaction is ended completely, heating a liquid material to 110-125 DEG C, and then, stopping heating to enable the liquid material in the reaction kettle to naturally cool and crystallize; when the liquid material is cooled to the temperature below 50 DEG C, enabling the stirring paddle to stop stirring, filtering a liquid through a filter tank, and centrifugally dewatering; and airing the dewatered reactant in a dust-free room to realize natural evaporation. The rare earth yttrium oxide is used for manufacturing the yttrium acetate crystal, so that the method is simple in process flow, high in production efficiency, low in energy consumption and capable of reducing the production cost and environment pollution; and the yttrium acetate crystal product is high in purity and total rare earth quantity, large in crystal particle and pure in color and luster, and the added value of a product can be increased.