127 results about "Ammonium citrate" patented technology

The invention discloses a copper-based nano-enzyme, a preparation method thereof and application of the copper-based nano-enzyme in organophosphorus pesticide detection, and belongs to the technical field of pesticide residue detection. The copper-based nano-enzyme has a netted-like structure, a high specific surface area and many active sites, the valence state of a copper element is zero-valence Cu, Cu < + > and Cu < 2 + >, the copper-based nano-enzyme has high peroxidase-like activity and laccase-like activity, the detection limit is low, and glyphosate can be sensitively detected; and glyphosate, glufosinate-ammonium and isazofos can be well distinguished from six organophosphorus pesticides with medium concentration, and the method has high selectivity. The nano enzyme provided by the invention is prepared from ammonium citrate and copper nitrate in an N, N-dimethylformamide (DMF) solution by using a solvothermal method; the preparation process of the nano enzyme is simple.

The invention provides a haematococcus pluvialis culture medium and a culture method thereof. The culture medium comprises a nutrition proliferation culture medium, a stress induction culture medium and an accumulation strengthening culture medium which are used for segmented culture, the nutrition proliferation culture medium comprises sodium nitrate, monopotassium phosphate, potassium chloride, ferric ammonium citrate, sodium citrate and a trace element mixed solution; adding an osmotic stress agent, an oxidation inducer and plant hormones into a stress induction culture medium; and accumulating and strengthening the culture medium to remove sodium nitrate, and adding and supplementing a carbon source, a polymer penetrant and a zwitterionic stabilizer. The culture method comprises the following steps: a nutrition proliferation stage, a stress induction stage and an accumulation strengthening stage. According to the method, through a three-section culture medium and a fine regulation culture process, and through the synergistic effect of a composite stress factor and a dynamic environment signal, on the premise of ensuring relatively high activity of algae cells, bidirectional synergistic efficient improvement of biomass growth and astaxanthin accumulation is realized.

The invention belongs to the technical field of preparation processes of barium metaphosphate, and particularly relates to a preparation method of monodisperse micron-sized barium metaphosphate. The preparation method comprises the following steps: mixing purified barium carbonate slurry and phosphoric acid according to a certain molar ratio, reacting to obtain barium dihydrogen phosphate slurry, adding ethanol and a particle size regulating agent, uniformly mixing, and carrying out spray drying to obtain a crude product; the particle size regulating agent comprises ammonium citrate, polyalcohol and barium metaphosphate; and calcining the crude product to obtain the product monodisperse micron-sized barium metaphosphate. According to the preparation method, a small amount of particle size regulating agent and a certain amount of ethanol are added, a crude product with uniform particle size distribution is prepared under a spray drying process condition, and then calcination is performed to obtain the micron-sized barium metaphosphate with uniform particle size distribution.

The invention discloses a rapid enrichment-atomic absorption spectrum analysis method for low-content gold in gold ore, and relates to the technical field of gold ore analysis and detection.The rapid enrichment-atomic absorption spectrum analysis method comprises the following steps that an ore sample and a solid composite additive are mixed and roasted at the low temperature of 500-650 DEG C, and the additive contains alkali metal carbonate and zinc oxide; sulfur fixation, catalytic oxidation of organic carbon and stabilization of volatile elements can be synchronously realized; the method comprises the following steps: roasting gold-loaded activated carbon, dissolving the gold-loaded activated carbon in aqua regia to obtain a to-be-enriched solution, enabling the solution to pass through an adsorption column filled with modified activated carbon, pretreating the activated carbon with a 1-10% ammonium citrate solution to improve the selective adsorption capacity of the activated carbon on gold chloride complex ions, ashing the gold-loaded activated carbon, dissolving residues, fixing the volume, and measuring by using an atomic absorption spectrometry. According to the rapid enrichment-atomic absorption spectrum analysis method for the low-content gold in the gold ore, through cooperation of low-temperature roasting of the composite additive and selective adsorption of the modified activated carbon, the decomposition efficiency and enrichment selectivity of the ore difficult to treat are improved.

The invention discloses a method for producing mRNA (messenger ribonucleic acid) template plasmids by fermenting escherichia coli. When the recombinant escherichia coli is fermented and cultured, a seed solution of the recombinant escherichia coli is inoculated into a basic culture medium to be fermented and cultured until the OD600 value of fermentation liquor is 18-22, then a fed-batch culture medium is continuously added at the feeding rate of 5-15 mL / L / h to be subjected to continuous fed-batch fermentation culture, the basic culture medium contains 0.05-0.2 mmoL / L of ferric salt compound and 0.05-0.2 mmoL / L of copper chloride dihydrate, and the basic culture medium contains 0.05-0.2 mmoL / L of ferric salt compound and 0.05-0.2 mmoL / L of copper chloride dihydrate. The basal culture medium contains 10-15 g / L of copper chloride dihydrate and 100-300 mg / L of p-hydroxybenzoic acid, the carbon source of the basal culture medium contains 0.1-0.3 mmoL / L of a ferric salt compound, 0.1-0.3 mmoL / L of copper chloride dihydrate and 100-300 mg / L of p-hydroxybenzoic acid, the carbon source of the fed-batch culture medium contains 360-480 g / L of glycerol, and the ferric salt compound is one or more of ferrous citrate, ferric ammonium citrate or ferrous sulfate heptahydrate. According to the method, the yield and superhelix content of the mRNA template plasmids are improved by optimizing the culture medium formula and culture conditions, and large-scale production of the high-quality target mRNA template plasmids is facilitated.

The preparation method comprises the following steps: S1, adding silicon powder, graphite, a carbon source and a pore-forming agent into a solvent to obtain slurry; the pore-forming agent comprises ammonium citrate and polylactic acid; s2, performing spray drying on the slurry to obtain precursor microspheres; s3, the precursor microspheres are subjected to first-stage low-temperature oxidation to form macropores, second-stage medium-temperature melting to form mesopores, third-stage high-temperature carbonization and cooling shaping, the heat preservation temperature of the first-stage low-temperature oxidation is 180-200 DEG C, the heat preservation temperature of the second-stage medium-temperature melting is 340-360 DEG C, the heat preservation temperature of the third-stage high-temperature carbonization is 800-900 DEG C, and the gradient pyrolysis dual-pore-forming silicon-carbon negative electrode material is obtained. Through combined use of ammonium citrate and polylactic acid and control of gradient pyrolysis conditions, synergistic distribution of double-peak gradient pores is formed, and effective improvement of the first effect and the cycle performance can be realized.

The invention discloses a preparation method of an anti-aging lead-acid battery electrolyte, and relates to the technical field of electrolytes. According to the electrolyte, dilute sulphuric acid is adopted as a basic system, and a biological small molecule synergistic inhibitor (sodium glutamate and taurine), organic weak acid salt (triammonium citrate), water-soluble polymer (hydroxypropyl methyl cellulose), a conductive nano material (graphene oxide) and a green deep eutectic solvent (choline chloride-ethylene glycol) are compositely introduced; and a trace amount of aluminum salt and a metal organic catalyst are supplemented. By inhibiting sulfation, relieving grid corrosion, inhibiting gassing and balancing acid concentration, systematic improvement of the cycle life, the charge acceptance and the repair capacity of the lead-acid battery is realized.

The invention belongs to the technical field of biochar immobilized microorganisms, and particularly relates to a preparation method of a biochar-based composite material for efficient immobilization of adaptive microorganisms. The microbial loading capacity is remarkably improved, the chain structure of the attapulgite layer provides a large number of linear adsorption sites, the porous structure of the biochar forms a three-dimensional adsorption space, and the chain structure and the porous structure of the biochar construct a synergistic adsorption mode; when the ammonium ferric citrate is modified, a decomposition product of the ammonium ferric citrate can form new mesopores / micropores in the carrier to enlarge the specific surface area, and the Fe element can be coordinated with an Si-O bond of the attapulgite and a carbon skeleton of the charcoal, so that pore collapse is inhibited, and the cycle stability is improved. And hydroxyl groups on the surface of the attapulgite and oxygen-containing functional groups of the charcoal cooperate with each other, so that electrostatic attraction and hydrogen bond binding force to the microorganisms are enhanced. The microorganism survival microenvironment is optimized, the composite carrier has the ion exchange capacity of the attapulgite and the water and fertilizer retention characteristic of the biochar, and a stable buffer environment and nutrition reserve can be provided for microorganisms.

The invention discloses a preparation method and application of an ammonium citrate modified mesoporous SBA-15 supported Ni catalyst, and belongs to the field of catalytic materials. By adjusting the molar ratio of ammonium citrate to the nickel precursor, the distribution state of nickel species on the carrier is accurately regulated and controlled, so that the weight percentage of nickel is 6%, and the balance is the SBA-15 molecular sieve; under the optimized Ni loading capacity, CA / Ni < 2 + > molar ratio and 800 DEG C reaction conditions, the prepared catalyst shows excellent methane dry reforming performance, the CH4 conversion rate reaches 95%, the CO2 conversion rate reaches 98%, the hydrogen-carbon ratio reaches 0.85, and the catalyst can stably run within 100 h without inactivation signs. The excellent performance is attributed to good nickel dispersibility, small nickel nanoparticles, strong metal-carrier interaction and moderate alkaline site concentration of the catalyst, so that efficient synergy of CH4 dissociation and CO2 activation processes is realized. The method has the advantages of cheap raw materials, simple operation and large-scale industrial application potential through a one-step impregnation synthesis method.

The invention discloses a high-entropy perovskite oxide, a preparation method thereof and application of the high-entropy perovskite oxide as an electrocatalyst, and belongs to the technical field of high-entropy transition metal oxides. A sol-gel method is adopted, various metal nitrates and lanthanum nitrate are dissolved in water and ethylene glycol in an equimolar mode, and an ammonium citrate complexing agent is added. And then heating at 120 DEG C for 10 hours. And heating the obtained gel precursor to 600 DEG C in a muffle furnace at a heating rate of 10 DEG C / min, maintaining the temperature for 2 hours, and cooling to obtain the high-entropy perovskite oxide LaBxO3. The high-entropy perovskite oxide electrocatalyst which is simple in synthesis method, stable in structure and easy in raw material obtaining is obtained, and the electrocatalyst can be applied to electrocatalytic nitrate radical reduction and sulfur ion oxidation; and a foundation is laid for developing other high-entropy transition metal oxides as electrocatalysts for synthesizing value-added chemicals by electrocatalyzing nitrate radicals and sulfur-containing wastewater.

The invention relates to the technical field of ceramic materials, in particular to a preparation method of submillimeter zirconia microspheres. The preparation method comprises the following steps: adding an isobutylene-maleic anhydride copolymer, butyl glycidyl ether and ammonium citrate into water, then adjusting the pH value of the solution to be alkaline by using an alkaline solution, and adding a defoaming agent and yttria-stabilized zirconia powder to obtain a premixed solution; carrying out ball milling on the premixed liquid, and then carrying out vacuum bubble removal to obtain zirconium oxide slurry; injecting the zirconium oxide slurry into an oily medium to obtain a zirconium oxide ceramic microbead green body; cleaning the zirconia ceramic microbead green body, drying, carrying out gradient heating calcination, and carrying out autogenous grinding to obtain the submillimeter zirconia microbead; the gel microspheres can be formed only by adding three organic matters, and the gel microspheres are low in organic matter content and free of toxicity. The method disclosed by the invention is high in yield, simple to operate and low in cost, and the prepared zirconium oxide microbeads are uniform in particle size and have relatively high density and mechanical properties.

The invention relates to the field of complex bone defect treatment, and discloses a nano material with an efficient antibacterial effect and a preparation method thereof.The preparation method comprises the steps that ammonium bismuth citrate and luteolin are mixed and dissolved in formamide, the mixture is put into a reaction kettle to react, a reaction solution is obtained, and Bi-Lu CDs in formamide is obtained after centrifugation and filtration; mixing the MSN-coated Bi-Lu CDs with amino-modified mesoporous silica microspheres, centrifuging, dispersing in deionized water, and drying in vacuum to obtain pure MSN-coated Bi-Lu CDs powder; the preparation method comprises the following steps: preparing a polyurethane dispersion liquid from polyurethane, spraying the polyurethane dispersion liquid on a quartz plate to form a polyurethane film, and spraying MSN and Bi-Lu CDs powder on the polyurethane film to carry out metal spraying treatment; a second precipitate is obtained; drying in vacuum to obtain J-Bi-LuCDs M (at) Au powder; the problems that in the prior art, due to the fact that a pure carbon dot material lacks active diffusion power, the treatment effect on complex tissue defects and bacterial biofilms is still limited, and a precursor material is poor in biocompatibility, not prone to dissolution and low in bioavailability are solved.

The invention discloses a green process method for extracting alkali metal from composite ore, and relates to the field of metal extraction.The green process method comprises the following steps that S1, aluminosilicate composite ore containing alkali metal and ammonium carbonate are mixed and roasted, and activated clinker is obtained; s2, mixing the activated clinker with an ammonium citrate solution, carrying out a leaching reaction at 80-95 DEG C, and carrying out solid-liquid separation after the reaction to obtain a leaching solution and leaching residues; according to the green process method for extracting the alkali metal from the composite ore, through systematic coupling of a low-temperature ammonium carbonate activation-ammonium citrate complexing leaching-manganese system / ammonium phosphomolybdate specific adsorption-bipolar membrane electrodialysis closed-loop regeneration technology chain, a synergistic interaction effect is formed; the activation step significantly improves the leaching efficiency of the subsequent mild leaching agent.

The invention belongs to the technical field of rare earth material analysis, and particularly relates to an ultra-trace analysis method for a copper element in a rare earth material based on an extraction principle, and the analysis method comprises the following steps: dissolving a rare earth oxide sample with 1: 1 hydrochloric acid, and drying by distillation to obtain a sample solution; sequentially adding an ammonium citrate solution, a hydroxylamine hydrochloride solution and a copper reagent solution into the sample solution, stirring for 1-2 minutes at the rotating speed of 150-200rpm, dropwise adding ammonia water with the ratio of 1: 5 to adjust the pH value to be 9-10, and forming a complex by Cu < 2 + > and a copper reagent to obtain a complex solution; adding an extracting agent into the complex solution, oscillating and extracting for 1-2 minutes, standing and layering for 10-15 minutes, and taking a lower layer organic phase; when ultra-trace analysis is carried out on the copper in the rare earth element, through specific chemical treatment, other elements or compounds which may interfere with determination are reduced, and through collaborative optimization of chemical extraction and spectrophotometry, the lower detection limit of the copper in the rare earth element is reduced to 0.1 ppm from traditional 2ppm.

The invention discloses a nickel-cobalt layered double hydroxide for a supercapacitor and a preparation method and application thereof, and belongs to the technical field of energy storage. The preparation method of the nickel-cobalt layered double hydroxide for the supercapacitor comprises the following steps: performing hydrothermal reaction on nickel salt, cobalt salt, ammonium citrate and urea to obtain the nickel-cobalt layered double hydroxide, the temperature of the hydrothermal reaction is 120-150 DEG C, and the time of the hydrothermal reaction is 6-12 hours. According to the invention, ammonium citrate is added to regulate the precipitation rate of the precursor, so that the morphology of the nickel-cobalt layered double hydroxide can be regulated and controlled, and the situation that the nickel-cobalt layered double hydroxide is rapidly combined with hydroxyl ions to cause too fast crystallization and coarse crystal grains is avoided; and meanwhile, the concentration uniformity of metal ions in the solution is regulated and controlled, so that the crystallinity of the nickel-cobalt layered double hydroxide is uniform, and lattice defects are reduced. Therefore, when the material is used as an electrode material of a supercapacitor, the material has relatively high specific discharge capacity.

The invention discloses a manufacturing method of a high-strength low-carbon-residue silicon nitride ceramic green body for electronic ceramics, which achieves the purpose of enhancing strength by increasing the content of PVB (polyvinyl butyral) in tape casting slurry or increasing the molecular weight of PVB because a three-dimensional network structure formed by PVB in the green body can be enhanced by larger addition amount of PVB and PVB with higher molecular weight. The green body defect caused by non-uniform dispersion of silicon nitride powder can be eliminated to a certain extent through PVB with larger molecular weight and more PVB increment, the strength and mechanical property of the green body are improved, meanwhile, the effect of electrostatic repulsion brought by the surface of the coated powder is improved through reasonable proportion matching of ammonium polyacrylate and ammonium citrate, and the strength and mechanical property of the green body are improved. Meanwhile, polyethylene glycol and salmon fish oil are creatively added and reasonably matched, the steric hindrance dispersion effect of large and small molecule matching is provided, the proportion of the four dispersion effect media is adjusted to be optimal, and under the condition that the high strength of the green body is guaranteed, the carbon content of the product obtained after glue discharging is low.

This invention provides a precise method for detecting phosphorus content in high-matrix copper-phosphorus alloys, belonging to the field of chemical analysis technology for metallic materials. The detection method of this invention includes the following steps: S1: Sample pretreatment; S2: Sample dissolution and volume adjustment; S3: Solution pretreatment: Nitric acid, hydrochloric acid, and deionized water are added to the solution and boiled to remove volatile impurities; S4: Precipitation formation: Ammonia water is added to the solution to adjust the pH to 8.5-9.5, and ammonium citrate-EDTA masking agent is added; quinomolybdate-limonene precipitant is slowly added under simmering conditions, and boiling is carried out for 10-15 minutes with intermittent stirring to ensure complete phosphorus precipitation; S5: Filtration, washing, drying, and weighing; S6: Calculation of phosphorus content. Compared with existing technologies, this invention, through a unique combination scheme, suppresses the hydrolysis of copper ions and the interference of coexisting elements, enabling precise detection of phosphorus content in high-matrix copper-phosphorus alloys. It has advantages such as strong resistance to matrix interference, high detection accuracy, good reproducibility, wide applicability, low detection cost, and simple operation.

This invention relates to a β -COF / GA composite adsorbent materials use graphene oxide as a carbon precursor and a reinforcing phase. β -COF blends form an aqueous solution system, and ammonium citrate is added as a reducing agent to carry out a liquid-phase reduction self-assembly reaction. β -COF loading on the surface and pores of reduced graphene aerogel β An adsorbent material with a COF to graphene oxide mass ratio of 1:5 to 15. This invention... β The COF / GA composite adsorbent material has a rich microporous structure and high adsorption activity, and can be used for the efficient adsorption and removal of phenol molecules in aqueous solutions.

This invention discloses a culture medium for manganese-oxidizing bacteria suitable for low-carbon source environments in water supply networks and its application. The culture medium is prepared by mixing ferric ammonium citrate, manganese sulfate, ammonium sulfate, sodium chloride, magnesium sulfate, dipotassium hydrogen phosphate, and sodium nitrate, followed by high-temperature and high-pressure sterilization to obtain a culture solution. Manganese sulfate is added to the culture solution to obtain the manganese-oxidizing bacteria culture medium. Manganese-oxidizing bacteria are screened using this culture medium. Cast iron pipe scale is subcultured in the medium to enrich the manganese-oxidizing bacteria culture solution. The enriched manganese-oxidizing bacteria culture solution is diluted and spread onto agar solid medium, and incubated at a constant temperature to obtain manganese-oxidizing bacteria colonies. This invention solves the problem of altered bacterial physiological metabolism caused by high concentrations of added manganese ions, effectively improving bacterial activity and manganese oxidation capacity.

The application discloses an improved iodine oxidation-dimethylglyoxime spectrophotometry for detecting the content of nickel in steel, which comprises the following steps: obtaining an acidolysis solution by acidolysis of the steel to be detected; then diluting the solution to obtain a mother liquor to be detected; mixing the mother liquor to be detected with an ammonium citrate solution, water, an iodine solution, ammonia water and a dimethylglyoxime solution to obtain a chromogenic solution to be detected; and placing the chromogenic solution to be detected below a critical temperature to perform spectrophotometry to obtain the content of nickel in the steel to be detected. The application controls the adding amount of the ammonium citrate and the dimethylglyoxime in the chromogenic solution to be detected and the chromogenic temperature, so that the stable time of the absorbance of the chromogenic solution to be detected is greater than or equal to 60 minutes, the detection of the content of copper in the steel to be detected is less than or equal to 0.2%, and the probability of the result of the detection of the content of nickel in the steel to be detected (0.10%-50%) exceeding the allowable error of a navigation mark is less than or equal to 5%.

The invention provides a thermal-insulation and flame-retardant bio-based polystyrene composite board and a preparation method thereof, and relates to the field of high polymer materials. The preparation method comprises the following steps: pretreating plant fibers, grafting the plant fibers with styrene, preparing a phytic acid-chitosan compound, preparing a flame retardant and preparing the polystyrene composite board. Grafting the plant fiber with styrene: under the protection of nitrogen, mixing the pretreated fiber, deionized water, styrene, sulfonated oil and potassium persulfate, heating, and stirring for reaction; the preparation method comprises the following steps: preparing a phytic acid-chitosan compound: adding deionized water, chitosan and acetic acid into a reaction kettle, heating and stirring; introducing nitrogen, adding phytic acid, and reacting; the phytic acid-chitosan compound, ammonium citrate and biochar are put into a ball mill to be ground, and mixed powder is obtained; adding the mixed powder into a fluidized bed coating machine, and spraying a coupling agent solution; the board has excellent thermal insulation and flame retardant effects.

This invention belongs to the field of cemented carbide additive manufacturing technology and discloses a method for preparing a high-solids WC-Co water-based slurry for direct-write forming. The invention uses cobalt-coated tungsten carbide powder as the solid phase, which is dispersed in an aqueous solution of ammonium citrate and polyethylene glycol composite additives to obtain a WC-Co water-based slurry with a solid content of 90wt%~93wt%. The slurry of this invention exhibits good shear-thinning properties and extrusion shape retention, with a total dispersant dosage of only 1~1.2wt%. After direct-write 3D printing and debinding sintering, a density ≥99% and a Vickers hardness >1900HV can be obtained. 30 The complex structure of WC-Co cemented carbide components is suitable for the low-cost preparation of high-performance cemented carbide in industrial applications.

The invention belongs to the technical field of hard alloy additive manufacturing, and discloses a preparation method of high-solid-phase WC-Co water-based slurry for direct writing forming. According to the preparation method, cobalt-coated tungsten carbide powder is used as a solid-phase main body and is dispersed in an ammonium citrate and polyethylene glycol composite additive aqueous solution, and WC-Co water-based slurry with the solid-phase content being 90-93 wt% is prepared. The slurry has the good shear thinning characteristic and extrusion shape preserving capacity, the total dosage of the dispersing agent is only 1-1.2 wt%, after direct-writing 3D printing and degreasing sintering, a WC-Co hard alloy component of a complex structure with the density larger than or equal to 99% and the Vickers hardness larger than 1900 HV30 can be obtained, and the slurry is suitable for low-cost preparation of high-performance hard alloy in the industrial field.

The invention relates to the technical field of leavening agents, and discloses a food composite leavening agent, which comprises the following components by mass: 25-30 parts of ammonium bicarbonate; 15 to 23 parts of microencapsulated ammonium citrate; 8 to 16 parts of sodium pyrophosphate; 5 to 9.5 parts of L-potassium hydrogen tartrate; 13 to 17 parts of trehalose; 0.5 to 1.3 parts of surface modified nano silicon dioxide; and 10 to 17 parts of hydroxypropylated cassava starch. The microencapsulated ammonium citrate is formed by coating beta-cyclodextrin, and the thickness of an embedding layer is 16-20 [mu] m. The multi-layer microcapsule structure is constructed by carrying out gradient embedding on ammonium citrate through beta-cyclodextrin, so that staged release of gas production substances is realized. According to the structure, different temperature intervals are accurately matched in the baking process, it is guaranteed that the gas production rate is synchronous with the dough expansion requirement, and the problem of excessive expansion or insufficient gas production caused by concentrated release in the traditional technology is solved.

The invention belongs to the technical field of microorganisms, and discloses a high-density fermentation process of vagina-sourced lactobacillus crispatus. The invention discloses a fermentation medium which comprises glucose, tryptone, beef extract, yeast extract, dipotassium phosphate, ammonium citrate, L-cysteine or salt thereof, magnesium sulfate and manganese sulfate. According to the fermentation culture medium provided by the invention, through scientific compounding of a carbon source, a nitrogen source and key factors, the final viable concentration and thallus activity of vagina-derived lactobacillus crispatus can be remarkably improved. The fermentation culture medium is adaptive to the micro-aerobic metabolism characteristics of vagina-derived lactobacillus crispatus by precisely regulating and controlling the dissolved oxygen level (initial dissolved oxygen is controlled to be 5% or below), and when the fermentation culture medium is used for culturing lactobacillus crispatus, the fermentation delay period can be remarkably shortened to 2-3 h, the final viable bacterium yield is greatly increased to 1 * 10 < 10 > CFU / mL or above, and the production cost is reduced. And an efficient and stable technical support is provided for industrial production of the probiotic preparation.

The present application relates to the field of agricultural chemical analysis, and particularly relates to a method for grading extraction and fluorescent labeling quantitative detection of effective phosphorus forms in organic fertilizer, first, water-soluble phosphorus is extracted by oscillation with deionized water; then, the filter residue is treated with an ammonium citrate-EDTA complexing extraction liquid to obtain citric-soluble phosphorus; finally, the residue is dissolved with a mixed acid extraction liquid to obtain insoluble phosphorus, three kinds of extraction liquids are taken respectively, color developing reagent of ammonium molybdate, ascorbic acid reducing agent are added in turn to carry out color developing reaction, then a fluorescent enhancer is added to amplify the signal, the fluorescence intensity is measured, and the contents of water-soluble phosphorus, citric-soluble phosphorus and insoluble phosphorus are accurately calculated according to a standard curve, a water-ammonium citrate / EDTA-mixed acid three-stage gradient extraction system is adopted to realize efficient separation and extraction of water-soluble phosphorus, citric-soluble phosphorus and insoluble phosphorus in the organic fertilizer, especially, the synergistic complexing system of ammonium citrate and EDTA is introduced in the second-stage extraction, thereby improving the extraction efficiency of citric-soluble phosphorus.

The application discloses a combined depressor for recovering scheelite from ultra-low-grade tungsten-molybdenum associated ore and a method, the combined depressor comprising sodium humate, sodium mercaptoacetate, ammonium citrate, sodium pyrophosphate, sodium fluosilicate and lead nitrate, and the six kinds of substances are configured into the combined depressor in a proportion of 1:1:(2-5):(1-5):(1-3):(2-5). The application aims at recovering scheelite from low-grade refractory ore, improves the separation effect of scheelite and gangue minerals, improves the scheelite recovery rate and the concentrate grade, and improves the economic benefit.

The invention provides a copper-based catalyst and a preparation method and application thereof. The preparation method of the copper-based catalyst comprises the following steps: mixing a copper precursor, a zinc precursor, an aluminum precursor and water to prepare a sol solution or suspension; wherein the copper precursor is copper metal salt, the zinc precursor is zinc metal salt, and the aluminum precursor comprises at least one of aluminum metal salt and activated aluminum oxide particles; adding a first reagent into the sol solution or the suspension, and then adding ammonia water to adjust the pH value of the solution to 7 to obtain a neutral solution; wherein the first reagent comprises at least one of citric acid, ammonium citrate, maleic acid, oxalic acid and ammonium oxalate; the ratio of the molar weight of the first reagent to the total molar weight of copper, zinc and aluminum is (1-3): 1; carrying out heating reaction on the neutral solution to obtain wet gel; then drying the wet gel to obtain dry gel; roasting the dry gel to obtain catalyst powder; and carrying out die-casting molding on the catalyst powder, and roasting to obtain the copper-based catalyst.

A process for producing a nitrogen-doped peony-shaped molybdenum oxide, comprising the following steps: (1) adding a regulator to a molybdenum-containing solution for reacting, concentrating and thermally treating to obtain a peony-shaped molybdenum oxide; and (2) dissolving the peony-shaped molybdenum oxide in a conditioning agent and adding an amine source for standing, centrifuging, washing, and heat-treating, thereby obtaining the nitrogen-doped peony-shaped molybdenum oxide; wherein the regulator is at least one of the following: nitric acid, ammonium nitrate, sodium persulfate, ammonium persulfate, concentrated sulfuric acid, H2O2, ozone, sodium hypochlorite, wherein in step (2), the conditioning agent is at least one of the following: sodium acetate, ammonium acetate, sodium formate, diaminoethane, sodium oxalate, ammonium benzoate, sodium phenylacetate, sodium propionate, sodium tartrate, sodium citrate, ammonium citrate; and wherein in step (2) the amine source is at least one of the following: aniline, dimethylamine, trimethylamine, benzylamine, phenethylamine, ethylamine, diethylamine, propylamine, phenylenediamine, xylylenediamine, amphetamine.

This invention discloses an alkaline, phosphorus-free nano-chelating agent, which, by weight percentage, is composed of the following components: 30%–40% sodium hydroxide, 6%–15% polyethylene terephthalate, 5%–10% polyglutamic acid, 1%–5% polysuccinimide, 11%–18% ammonium citrate, 2%–9% nano-silica, 2%–9% nano-alumina, and the balance being water. This phosphorus-free nano-chelating agent contains no phosphorus and will not cause phosphorus pollution during use. Compared to traditional phosphorus-containing chemicals, it is more environmentally friendly and helps reduce phosphorus content in water bodies, thereby mitigating environmental problems such as eutrophication.