21 results about "Homogeneous precipitation" patented technology

The invention discloses a preparation method and application of a ferromanganese phosphate hydrate based on sulfate free radicals, and provides the preparation method and application of the ferromanganese phosphate hydrate based on the sulfate free radicals in order to solve the technical problems existing in preparation of the ferromanganese phosphate hydrate (Mn1-xFexPO4.H2O) in an aqueous solution system in the prior art. The invention innovatively provides a technology for preparing a precursor ferromanganese phosphate hydrate of a lithium ion battery positive electrode material based on a three-step synergistic strategy of oxidation, locking and release of sulfate free radicals, and the sulfate free radicals (SO4 <.->) with strong oxidizability are generated in situ through thermal activation of persulfate; the high-quality ferromanganese phosphate hydrate Mn1-xFexPO4.H2O (01t, 01t) which is pure in phase, uniform in composition and controllable in structure is accurately prepared by combining subsequent formation and'locking 'of an intermediate-state complex and final regulation and control'release' and homogeneous precipitation steps; and x < = 0.5). The Mn < 1-x > FexPO4.H2O (0 lt; x is greater than or equal to 1 and less than or equal to 0.5) is used as a precursor for preparing a lithium battery positive electrode material, and the prepared LiMn1-xFexPO4 / C positive electrode material shows excellent electrochemical performance.

The invention discloses a magnesium-aluminum hydrotalcite / carbon nanotube composite material and a preparation method and application thereof, and the preparation method of the magnesium-aluminum hydrotalcite / carbon nanotube composite material comprises the following steps: S1, carrying out acid pretreatment on a carbon nanotube; and S2, preparing the magnesium-aluminum hydrotalcite / carbon nanotube composite material. Compared with the prior art, the preparation method of the magnesium-aluminum hydrotalcite / carbon nanotube composite material has the advantages that Mg (NO3) 2.6 H2O, Al (NO3) 3.9 H2O, CO (NH2) 2 and pretreated carbon nanotubes are adopted, and magnesium-aluminum hydrotalcite grows on the carbon nanotubes through a hydrothermal homogeneous precipitation method; through the synergistic effect of the carbon nanotubes and the magnesium-aluminum hydrotalcite, aggregation among nanoparticles is effectively prevented, the growth size of the particles is limited, and the magnesium-aluminum hydrotalcite / carbon nanotube composite material is good in crystallinity, small in particle size, high in specific surface area and high in adsorption performance. In a radioactive uranium element adsorption experiment, the adsorption efficiency is as high as 95.6%, and the adsorption capacity is as high as 17.32 mg / g.

The application discloses a method for preparing iron phosphate from red mud, which comprises the following steps: A, after drying, grinding and sieving, the red mud is stirred and leached with high-concentration strong acid under high-temperature conditions to obtain an acid leaching solution containing iron, aluminum and sodium; B, cationic resin is added to the acid leaching solution for ion exchange, and solid-liquid separation is performed to obtain resin adsorbing aluminum ions and filtrate a; C, desorption is performed on the resin to release aluminum ions from the resin, and filtration is performed to obtain a desorption solution and desorbed resin, and the desorption solution is subjected to polymerization to prepare aluminum sulfate; D, the filtrate a is cooled and crystallized to obtain a crystallization product sodium salt and filtrate b; E, the content of iron ions in the filtrate b is detected, a phosphorus-containing solution is added to the filtrate b, pH is adjusted, and homogeneous precipitation reaction is performed, and filtration is performed to obtain a precipitate which is iron phosphate, and the filtrate is adjusted to have a pH of 1.0-2.5 and then is sent back to the step A to be used as high-concentration strong acid for recycling.

The application relates to the technical field of VOCs degradation, and discloses a preparation method of spinel / CeO2 / attapulgite ternary composite material and application of the spinel / CeO2 / attapulgite ternary composite material in VOC degradation. The method comprises the following steps: firstly, loading CeO2 on attapulgite by using a homogeneous precipitation method to obtain a CeO2 / ATP; then, manganese salt and cobalt salt are prepared into a solution, oxalic acid solution is added, the CeO2 / ATP composite is added, and a precursor is generated through water bath stirring reaction; and finally, a non-crystalline-crystalline spinel (Mn 1.5 Co 1.5 O4) ternary composite catalyst loaded on CeO2 / ATP is obtained through calcination. The electron transfer between CeO2 and the non-crystalline-crystalline Mn 1.5 Co 1.5 CoO4 at the interface can enhance the low-temperature catalytic oxidation performance of the catalyst. In addition, the dispersion and stability of the spinel particles on CeO2 can enhance the number of active sites, and the low-temperature degradation activity and high-temperature stability of the catalyst to VOCs such as toluene are improved.

The invention relates to the field of abrasives, and in particular to a high-efficiency grinding diamond abrasive and a preparation process thereof. Diamond micropowder is subjected to multiple coating treatments to prepare composite diamond micropowder, which is then blended with electrolytic copper powder, a filler, a wetting agent, and modified polyvinyl alcohol to obtain a slurry. The slurry is formed by freeze-thaw gel formation to prepare a high-efficiency grinding diamond abrasive with good water resistance. A tungsten coating is deposited on the surface of the diamond micropowder, followed by vacuum high-temperature treatment to obtain a pretreated diamond micropowder with a tungsten carbide layer grown in situ on the surface. Tetraethyl orthosilicate is used to generate a silicon oxide layer on the pretreated diamond micropowder, and then a homogeneous precipitation method is used to generate praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micropowder. A prepolymer generated from polytetramethylene ether glycol and 4,4'-dicyclohexylmethane diisocyanate is chain extended using a silicon-containing chain extender to obtain a polyurethane prepolymer, and then the polyvinyl alcohol is modified using the polyurethane prepolymer and a phenolic resin.

The application discloses a silicon-manganese-aluminum composite oxide carrier and a preparation and application thereof. The silicon-manganese-aluminum composite oxide carrier is modified by Si and Mn to Al2O3, and a microwave-assisted homogeneous precipitation method is adopted to load a first active additive Si on a carrier Al2O3, the Si precursor grows slowly in the Al2O3 channel with the Al2O3 particles as crystal nuclei, and then an impregnation method is adopted to load a second active additive Mn on the SiO2 / Al2O3 composite carrier. The silicon-manganese-aluminum composite oxide carrier is loaded with an active metal Pt, and the obtained catalyst can improve the CO catalytic oxidation activity of the Pt-based catalyst, has high sulfur resistance, can still maintain high activity for the catalytic oxidation of CO in a 300ppm SO2 environment, is particularly suitable for the catalytic combustion of CO in steel tail gas, and has great industrial application potential and value.

The invention provides a method for improving the filtering performance of an aluminum precipitation material under a laterite-nickel ore nitric acid system, and relates to the technical field of chemical metallurgy. S2, carrying out homogeneous aluminum precipitation reaction on the iron precipitation mother liquor, a precipitator and an additive at a certain temperature to obtain aluminum hydroxide and aluminum precipitation mother liquor; s3, adding magnesium oxide into the aluminum precipitation mother liquor, and carrying out homogeneous precipitation reaction at a certain temperature to generate MHP and nickel and cobalt precipitation mother liquor; and S4, the nickel and cobalt precipitation mother liquor is applied to a homogeneous aluminum precipitation section through membrane treatment and sulfate circulation. The addition of the additive does not introduce new impurities, and the additive is recycled after sulfate is separated from a nitric acid system through a nanofiltration membrane treatment technology. The whole process realizes cyclic utilization of resources, and has a remarkable effect and a huge economic value.

The invention relates to oxalate high-purity barium titanate powder and a preparation method thereof. The method comprises six steps of preparation of a titanium salt stabilizing solution, preparation of a barium salt solution, preparation of a dispersant modified solution, a dispersant synergistic homogeneous precipitation reaction, microwave drying purification and microwave gradient calcination. The purity of the prepared barium titanate powder is greater than or equal to 99.9%, the average particle size is 30-60nm, the aggregate content is less than or equal to 1.5%, the dielectric property is excellent, the barium titanate powder can be widely applied to high-end electronic components such as multilayer ceramic capacitors, the process is stable and controllable, and industrial production is easy.

The invention discloses silica gel microspheres with high specific surface area and large pore volume and a preparation method thereof, and belongs to the technical field of catalysts and preparation thereof. The preparation method comprises the following steps: dissolving a surfactant and sodium silicate in water to obtain a clear solution; adding ethyl acetate into the obtained clear solution, and standing or stirring for reaction; and after the reaction is finished, sequentially performing centrifugation, washing, pulping, spray drying, calcining and the like to obtain the silica gel microspheres with high specific surface area and large pore volume. The specific surface area of the obtained silica gel microspheres is 380-530 m < 2 > / g, the pore volume is 1.8-2.3 cm < 3 > / g, and the particle size is 40-60 [mu] m. The specific surface area and the pore volume of the silica gel microspheres are remarkably increased by utilizing a homogeneous precipitation method and combining a spray drying technology, the problems that the synthesis conditions of conventional silica gel microspheres are relatively harsh, and high specific surface area and large pore volume are difficult to obtain at the same time are solved, and the method is suitable for the fields of catalysis, adsorption, separation and the like and has a wide application prospect.

The application discloses a bismuth vanadate material with the function of selectively detecting low-concentration hydrogen sulfide gas, and application of the bismuth vanadate material as a high-selectivity light-driven sensor for detecting low-concentration hydrogen sulfide gas, and belongs to the technical field of material preparation and gas-sensitive sensing. The bismuth vanadate material is obtained through homogeneous precipitation by adjusting the pH of a precursor solution to control the growth of a bismuth vanadate crystal face. The simple and easy-to-synthesize bismuth vanadate octahedron can effectively sense low-concentration hydrogen sulfide under light driving, and has a high response value, good selectivity, long-term stability and a low detection limit. The application has the advantages of simple process, low cost, large-scale production, actual production needs, and great application potential.

The invention relates to the technical field of brine extraction, in particular to a method and system for extracting strontium from high-calcium brine. The high-calcium brine contains calcium, magnesium, barium and strontium, and the method comprises the following steps: carrying out first precipitation separation on the high-calcium brine by using an alkaline complexing agent to obtain a separated precipitate containing calcium, barium and strontium; sequentially dissolving and diluting the separated precipitate by using an acid solvent to obtain a dissolved solution; carrying out hot filtration on the dissolved solution by using first sodium hydroxide to obtain a first filtrate containing barium and strontium; performing secondary precipitation separation on the first filtrate by using sodium sulfate to obtain a strontium-containing second filtrate; performing third precipitation separation on the second filtrate by using a composite additive to obtain a strontium carbonate product; wherein the composite additive comprises first sodium carbonate, urea and ethylenediaminetetraacetic acid. The method is based on a dual strategy of cascade deep impurity removal and complexing homogeneous precipitation, and the purity and the extraction rate of strontium carbonate are greatly improved through the synergistic effect of a composite additive.

The invention discloses a Fe3O4-CeO2 magnetic composite abrasive particle as well as a preparation method and application and relates to the technical field of polishing abrasive particle production, the Fe3O4-CeO2 magnetic composite abrasive particle is prepared through a homogeneous precipitation method, a polishing solution prepared from the composite abrasive particle is good in dispersity, and the polishing efficiency and the polishing quality can be remarkably improved when the composite abrasive particle is applied to glass polishing.

The invention relates to basic praseodymium carbonate and a preparation method thereof, and the preparation method comprises the following steps: introducing carbon dioxide gas into a praseodymium salt solution, adding an alkali solution to carry out carbonization reaction, and aging to obtain the basic praseodymium carbonate. The preparation method of the basic praseodymium carbonate is simple to operate, mild in condition and controllable in crystal form by combining a bubble dispersion technology with a carbonization reaction, so that the basic praseodymium carbonate with a good crystal form can be obtained in a relatively short time under a low-temperature condition, and effective regulation and control of the crystal form are realized by utilizing the advantage that homogeneous precipitation can be realized by a carbonization method.

The present application relates to a kind of oxalate high-purity barium titanate powder and its preparation method, which comprises six steps of titanium salt stabilizing liquid preparation, barium salt solution preparation, dispersant modification liquid preparation, dispersant synergistic homogeneous precipitation reaction, microwave drying purification and microwave gradient calcination.The purity of barium titanate powder prepared by the present application is ≥99.9%, the average particle size is 30-60nm, the agglomerate content is ≤1.5%, and the dielectric performance is excellent.The present application can be widely applied to high-end electronic components such as multilayer ceramic capacitor, and the process is stable and controllable, easy to industrial production.

This invention discloses a method for coating SiO with nano-PMMA as the core. 2 / CeO 2 A method for preparing double-shell abrasives relates to the field of composite abrasive technology. The method includes the following steps: First, a soap-free emulsion polymerization method using a boiling system is employed, with methyl methacrylate as the monomer and 3-(methacryloyloxy)propyltrimethoxysilane as the coupling agent. The polymerization reaction is initiated with 2,2'-azobisisobutylamidine dihydrochloride to prepare PMMA microspheres with controllable particle size and good monodispersity. Then, using tetraethyl silicate as the raw material, a strawberry-shaped PMMA / SiO2 microsphere is prepared using the sol-gel method. 2 Composite microspheres; finally, nano-CeO was prepared by homogeneous precipitation using soluble cerium salt as raw material and hexamethylenetetramine as precipitant. 2 Uniformly coated double-shell PMMA / SiO 2 / CeO 2 Composite abrasive; this abrasive has a flexible core and a large number of surface active sites, which can achieve lower surface roughness and higher material removal rate in ultra-precision surface polishing.

This invention belongs to the field of gas-sensitive materials technology, specifically relating to a cobalt tungstate / tin dioxide nanosheet composite gas-sensitive material, its preparation method, and its application. The preparation method includes the following steps: homogeneous precipitation of cobalt salt and tungstate in a precipitant to obtain a CoWO4 precursor; calcination of the CoWO4 precursor in air to obtain CoWO4(P) nanosheets; dispersion of the CoWO4(P) nanosheets and SnO2 powder in an alcohol solvent in a certain proportion; ultrasonication and stirring treatment; and then centrifugation, washing, and drying of the mixture to obtain the final product. This invention employs a homogeneous precipitation-hydrothermal method to synthesize CoWO4 nanosheets with abundant chemically adsorbed oxygen through precipitant regulation, and then composites them with commercial SnO2 through a simple impregnation method to construct a CoWO4 / SnO2 heterojunction gas-sensitive material. The prepared composite material exhibits high sensitivity, excellent selectivity, and stability to triethylamine.

This invention discloses a method for preparing nano-titanium dioxide using hydrochloric acid, a byproduct of the titanium dioxide production process via the chloride process, comprising the following steps: (1) distilling and concentrating the hydrochloric acid to obtain a titanium solution with a concentration of 4–10 mol / L; (2) diluting the titanium solution with water to obtain a diluted titanium solution with a concentration of 1–4 mol / L; (3) slowly adding an alkaline solution to the diluted titanium solution until it approaches the critical deposition point, at which point the addition of the alkaline solution is stopped, resulting in a critical deposition titanium solution; (4) heating and stirring the critical deposition titanium solution to deposit the solution, followed by filtration, washing, drying, calcination, and grinding to obtain rutile nano-titanium dioxide. This invention employs a critical homogeneous precipitation method, where alkali is slowly added at room temperature to neutralize the solution to the critical deposition point. This titanium solution serves as a homogeneous active reaction liquid, and low-temperature heating deposition is used to prepare nano-titanium dioxide with uniform particle size distribution.

The invention provides cobalt-doped iron phosphate and a preparation method thereof, and belongs to the technical field of iron phosphate doping modification. The preparation method of the cobalt-doped iron phosphate comprises the following steps: providing an amorphous iron phosphate material and a mixed solution containing divalent cobalt salt and persulfate; mixing the amorphous iron phosphate material with the mixed solution to obtain mixed slurry; carrying out heating aging treatment on the mixed slurry to obtain cobalt-doped iron phosphate dihydrate; and washing, drying and sintering the cobalt-doped iron phosphate dihydrate to obtain the cobalt-doped iron phosphate. According to the mode, homogeneous precipitation can be carried out while homogeneous oxidation is carried out on divalent cobalt ions, doping of trivalent cobalt ions is achieved, and therefore the cobalt-doped iron phosphate with the high cobalt element content and the iron element and the cobalt element evenly mixed at the molecular level is obtained with the high cobalt precipitation efficiency; the lattice structure of iron phosphate is changed through cobalt doping, and the performance of iron phosphate is effectively improved.

The invention provides a morphology-controllable rare earth oxide and a preparation method thereof.The preparation method comprises the following steps that rare earth salt, a homogeneous precipitation control agent, a dispersing agent and a solvent are mixed, and a mixed solution is obtained; carrying out heating reaction on the mixed solution, carrying out aging treatment, and carrying out solid-liquid separation treatment to obtain a rare earth carbonate precursor; and calcining the rare earth carbonate precursor to obtain the rare earth oxide with controllable morphology. Under a proper reaction system, the morphology of the obtained rare earth oxide can be regulated and controlled by adjusting the adding amount of the raw materials and the aging time, the reaction is simple, the controllability is high, the morphology of the prepared rare earth oxide is uniform, and the yield is high. The obtained rare earth oxide with controllable morphology and stable structure can be widely applied to the fields of catalysis, luminescent substrates and electronic ceramics, and the performance of devices is obviously improved.

Disclosed is a method for using red mud to efficiently prepare ferrous phosphate dihydrate, comprising: mixing red mud and an acid solution to carry out an acid leaching reaction to obtain a red mud leachate; adding a reducing agent into the red mud leachate to carry out a reduction or comproportionation reaction to obtain a reaction solution; selectively adding an organic solvent into the reaction solution, and using an organic phase to extract impurities to respectively obtain a mixed organic solution and a target object solution; and adding an oxidizing agent and a phosphorus source into the target object solution to carry out an oxidation reaction and a homogeneous precipitation reaction, and cleaning and drying a precipitation product to obtain ferrous phosphate dihydrate.

The invention discloses a Pt-Mn / AAO / Al-NAA catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysis. The preparation method comprises the following steps: treating a pretreated aluminum mesh by adopting an asymmetric two-step anodic oxidation method to prepare an AAO / Al-NAA carrier with a hierarchical porous structure; mn is loaded on the AAO / Al-NAA carrier by adopting a homogeneous precipitation method to obtain a Mn / AAO / Al-NAA catalyst; pt is loaded on the Mn / AAO / Al-NAA catalyst by adopting a colloid precipitation method, and the Pt-Mn / AAO / Al-NAA catalyst is obtained. The catalyst can realize efficient catalytic oxidation of CO under the condition that the humidity is 10%, the catalytic life is as long as 300 hours, good stability and moisture resistance are shown, an effective way is provided for removing CO in a high-humidity environment, and possibility is provided for application of related protection equipment such as gas masks.