182 results about "Dilute acid" patented technology

Disclosed herein are methods and systems for the use of extraction chromatography resins to concentrate Ac from dilute solutions that may contain Th isotopes and / or other isotopes, such as Ra. As disclosed herein, at least some extraction chromatography resins strongly retain trivalent actinides between 4 and 6 M HNO3 that can be recovered in good yields with small volumes of dilute acids. These small volumes of acid eluents result in significant concentration of the solution of the trivalent / certain tetravalent ions, such that they can be further processed without requiring lengthy evaporation steps that are utilized in standard Ac concentration methods.

The invention relates to the technical field of wet-process phosphoric acid, and discloses a wet-process phosphoric acid grading and arsenic removal treatment method and system, and the system can be switched between a parallel grading treatment mode and a series depth treatment mode through flow control; in the parallel mode, the two arsenic removal reaction tanks operate independently to respectively treat different raw materials and produce desulfurized acid for industrial monoammonium and low-arsenic dilute phosphoric acid for high-phosphorus compound fertilizer, the low-arsenic dilute phosphoric acid is mixed and blended with untreated dilute acid and then concentrated, qualified products are obtained with the minimum treatment capacity, and the cost is remarkably reduced; in the series connection mode, raw materials sequentially flow through the two tanks to be deeply purified, and single high-quality phosphoric acid is produced; the two modes are both integrated with efficient filter pressing units, solid-liquid separation is carried out on arsenic-containing thick slurry generated by arsenic removal, and phosphorus resource recovery and arsenic pollution control are achieved; the device has production flexibility and deep purification capacity, perfectly meets the requirements of raw material fluctuation and multiple products, and thoroughly solves the problem of arsenic slag disposal.

A production process of electronic grade molybdenum dichloride dioxide comprises the following steps: S1, pretreatment: contacting molybdenum trioxide with a dilute acid solution at a low temperature for pickling to remove alkaline impurities and soluble metal impurities adsorbed on the surface, and drying for later use after washing; s2, wet synthesis: in an inert gas atmosphere, reacting the molybdenum trioxide subjected to acid pickling in the step S1 with concentrated hydrochloric acid of which the mass is 4-5 times of that of the molybdenum trioxide at 80-100 DEG C, and after the reaction is finished, evaporating and concentrating in a high-temperature chlorine atmosphere to generate a crude product of dichloromolybdenum dioxide; s3, primary sublimation purification; s4, complexing and decomplexing purification; and S5, secondary sublimation purification: using a quartz sublimation tower to carry out vacuum sublimation on the secondary decomplexed molybdenum dichloride obtained in the step S34, and collecting sublimation condensate to obtain the electronic grade molybdenum dichloride. The final product purity of the production process is greater than or equal to 6N, and the process can be used for large-scale production.

The present invention discloses high temperature resistant silicon aluminum aerogel composite materials with red mud as raw material, preparation method and applications thereof, relates to a field of safe disposal and resource utilization of red mud. The method comprises step of pretreating the red mud; step of mixing and heating pretreated red mud with dilute acid solution for reaction; step of mixing with ethanol aqueous solution, heating and stirring, exchanging anionic resins, and adding alkaline catalyst for solution catalytic reaction; step of adding a modifier dropwise, heating and stirring, and then adding a chelating agent dropwise for ring opening reaction; Finally, compositing with a fiber substrate, through steps of gelling, aging and drying. The method greatly save preparation cost of aerogels, and also solve problem that current red mud waste cannot be effectively utilized and environmental pollution, and realize comprehensive utilization of the red mud and preparation of low-cost aerogel.

The invention provides a composite flocculant as well as a preparation process and application thereof, and relates to the technical field of waste acid treatment. Comprising 35%-55% wt of an amide flocculant (containing a strong anionic monomer containing a sulfonic acid group), a compound capable of generating high-valence metal ions and 0.2%-1.5% wt of water-soluble silicate. The composite flocculant disclosed by the invention not only contains hydrophilic groups such as sulfo groups and carboxyl groups with relatively strong polarity, but also contains a certain amount of metal ions with relatively high valence state, which is equivalent to crosslinking of the metal ions and amide polymers, so that the characteristic that polyacrylamide flocculants are difficult to hydrolyze under acidic or dilute acid conditions is mainly overcome; therefore, surface charges of suspended particles in a solution can be neutralized under an acidic or dilute acid condition, and destabilization of fine particles is realized. By using the composite flocculant, the dust in the waste sulfuric acid can generate a flocculation effect, the area of a waste sulfuric acid sedimentation tank is reduced, and the sedimentation time is shortened.

The invention relates to the technical field of production of penicillin V potassium, and particularly discloses a preparation method of penicillin V potassium, which comprises the following steps: S1, under the catalysis of penicillin V acylase, enabling 6-APA and methyl phenoxyacetate to react, performing full-water-phase synthesis to obtain a penicillin V solution, filtering out the penicillin V acylase, adding dilute acid into filtrate, and crystallizing to obtain a penicillin V acid crystal; s2, dissolving the penicillin V acid crystal by using an organic solvent I to obtain a solution I, dissolving potassium isooctanoate by using an organic solvent II to obtain a solution II, mixing the solution I and the solution II, reacting and crystallizing to obtain a penicillin V potassium crystal, and filtering, washing and drying to obtain a penicillin V potassium finished product. According to the method, an enzyme method is used for replacing traditional fermentation and extraction methods to produce the penicillin V potassium, so that the process steps and energy consumption can be reduced, and the product quality is effectively improved.

The invention discloses a short-process low-cost continuous and stable gold extraction process adopting a thiosulfate method, and belongs to the field of hydrometallurgy. In a closed reactor, by adjusting the concentration of dissolved O2, thiosulfate and a catalyst to be at a low level, the potential of ore pulp is reduced to a suitable range to leach gold ore, and leaching residues and a leaching pregnant solution are obtained through filtering. And pure nitrogen is introduced into the leaching pregnant solution to completely discharge oxygen in the solution, copper powder is added for replacement, and gold-rich crude copper and a replacement barren solution are obtained through filtering. Crude copper rich in gold is treated through electrolytic refining, pure copper is obtained from a cathode, and gold mud is obtained from an anode. And washing the gold mud with dilute acid to obtain a copper-containing pickling solution and pure gold. After the pH of the copper-containing pickling solution is adjusted, the copper-containing pickling solution and the replacement barren solution supplemented with the leaching agent are combined and used for leaching of fresh ore in the next circulation. The method provided by the invention solves the problems of long technological process, high circulation cost and high environmental protection pressure of a copper ammonia catalysis thiosulfate method, and is suitable for being used in a natural environment.

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 2-sulfydryl-6-chlorobenzoic acid, which comprises the following steps: dissolving chlorobenzoic acid in dimethyl sulfoxide, adding sodium hydrogen sulfite, and stirring at room temperature; the preparation method comprises the following steps: dissolving mercaptobenzoate in dimethyl sulfoxide, adding sodium carbonate and dimethylamino, and reacting at high temperature; cooling to room temperature, and adjusting the pH value to be neutral by using dilute acid; adding into diethyl ether, uniformly mixing, adding into dilute acid, and standing for layering to obtain 2-sulfydryl-6-chlorobenzoic acid; the preparation method of the chlorobenzoic acid comprises the following steps: mixing parachlorotoluene with water, adding a supported catalyst, stirring and heating; after the temperature rises to 80 DEG C, adding potassium permanganate in batches for reaction; and filtering, adjusting the pH value to be acidic by using dilute acid, and then carrying out suction filtration and drying to obtain the chlorobenzoic acid. According to the preparation method disclosed by the invention, chlorobenzoic acid and mercaptobenzoate are subjected to a reaction to obtain 2-mercapto-6-chlorobenzoic acid with high yield; the method has the characteristics of simplified operation, energy consumption reduction, shortened production period and low production cost.

The present invention provides a device and method for mineralizing desalinated seawater, belonging to the technical field of desalination water production. The device of the present invention comprises a concentrated brine device 100, a bipolar membrane device 200 and a mineralization device 300 connected in sequence; wherein the concentrated brine device 100 comprises a sodium sulfate concentrated solution tank 101. The present invention prepares desalinated water into a sodium sulfate solution, and there is no risk of scaling and clogging during bipolar membrane electrodialysis, thereby ensuring the safe operation of the bipolar membrane device 200, and the corrosiveness of sulfate to the pipe network is reduced compared to chloride ions. The mineralization device 300 of the present invention comprises a dilute acid tank 301, which can control the pH value of the acid solution before mineralization; the dilute sulfuric acid solution enters the mineralization tower 302, which can effectively convert the acidity of the solution into alkalinity and increase the hardness; the alkali produced by the bipolar membrane alkali chamber 201 enters the mineralized water mixing tank 303, which can adjust the pH value of the water produced by the mineralization tower, so that the mineralized water produced by the desalinated seawater meets the drinking standard.

The invention discloses a device for recovering monochlorodifluoromethane from a preparation system, which is characterized in that a residual liquid outlet is communicated with a recovery buffer tank (2) through a residual liquid storage tank (1), a liquid phase outlet of the residual liquid storage tank (1) is communicated with an inlet of an alkali liquor desorption tower (6) through a regulating valve (3), a material outlet of a dilute acid storage tank (5) is communicated with an inlet of the alkali liquor desorption tower (6), and a material outlet of the dilute acid storage tank (5) is communicated with a material outlet of the alkali liquor desorption tower (6). An alkali liquor outlet is communicated with a recovery buffer tank (2) through an alkali liquor desorption tower (6), a monochlorodifluoromethane outlet of the recovery buffer tank (2) is communicated with an inlet of a condensation collecting tank (9) through a compressor (8), and the condensation collecting tank (9) is communicated with a finished product storage tank (12) through a recovery pump (4), a water alkali washing system and a rectifying tower (11). The monochlorodifluoromethane stored in the recovery buffer tank (2) is conveyed to a water alkali washing system and then put into a rectifying tower (11) to be refined, and the obtained monochlorodifluoromethane finished product is stored in a finished product storage tank (12).

The present invention relates to the technical field of silica production, and specifically to a method for producing a friction agent with high specific surface area and moderate oil absorption. The method comprises the following steps: adding deionized water, sodium salt, sodium silicate solution and anionic surfactant into a reaction vessel, then simultaneously adding sodium silicate and dilute acid solution into the reaction vessel for parallel reaction, and after acidification is completed, injecting ice water into the reactor with a water temperature of 0-5°C and a material temperature reduced to 50-65°C. The solution in the reaction vessel is allowed to stand for aging, and then sequentially subjected to filter pressing, washing, pulping, high-temperature spray drying at 600-800°C, and pulverization to obtain a silica friction agent for toothpaste. The method comprises the following steps: achieving rapid reaction in a low-pressure and high-temperature environment by highly precise control of the concentration, temperature and time of the reaction materials during the reaction process, shortening the reaction time of the process, and improving production efficiency. The method meets the market requirement for adding a silica friction agent with high specific surface area and moderate oil absorption to toothpaste.

The utility model discloses an evaporator and a pickling facility low-corrosion treatment device thereof. A concentrated acid tank, a first connecting pipe, a diluted acid tank and a second connecting pipe are used for a pickling process and can also be used for alkali neutralization, water washing and blow-drying. After pickling is completed, the acid storage tank can neutralize residual acid, the pipeline is neutralized by alkali and / or flushed by neutralizing liquid, and under the condition that the pump body design is saved, waste acid discharged by pickling of the evaporator can be returned to the tank for treatment, so that environmental acid pollution is avoided; the reduction evaporator and pickling equipment thereof can be further washed and blown off, so that the corrosion risk is greatly reduced; the service life of a tank pipeline is prolonged by more than 50%, the overhaul cost is reduced, the leakage condition is reduced, and the safety coefficient is improved.

The invention relates to the technical field of pesticide production, and particularly discloses a preparation process of glufosinate-ammonium intermediate 3-(methyl hydroxyl phosphonyl) propionaldehyde. The preparation method comprises the following steps: 1, carrying out addition reaction on diethyl methylphosphonite and acrylic acid in absolute ethyl alcohol to generate 3-[ethyoxyl (methyl) phosphonyl] propionate; in the second step, 3-[ethyoxyl (methyl) phosphonyl] propionate is subjected to a hydrosilylation reaction in an oriented mode, and 3-triethyl siloxy-3-ethyoxyl propyl methyl ethyl phosphonate is generated; and 3, carrying out a simple dilute acid hydrolysis reaction to obtain the 3-(methyl hydroxyl phosphonyl) propionaldehyde. According to the method, a three-step reaction route of addition-hydrosilylation-hydrolysis is adopted, and the acrylic acid is used for replacing the traditional high-toxicity raw material acrolein, so that the toxicity risk is avoided from the source, the yield of the target glufosinate-ammonium intermediate is remarkably improved, the total yield of the three-step reaction can reach 95% or above, and the method is suitable for industrial production. And an efficient and green brand-new technical scheme is provided for large-scale production of glufosinate-ammonium.

The utility model provides a dilute sulfuric acid degassing device which comprises a degassing tower shell, a plurality of manholes are formed in the degassing tower shell, a spraying mechanism A and a spraying mechanism B are arranged on the upper portion and the middle portion in the degassing tower shell respectively, one end of the spraying mechanism A and one end of the spraying mechanism B are connected with a dilute acid inlet A and a dilute acid inlet B respectively, and the other end of the spraying mechanism A and one end of the spraying mechanism B are connected with the degassing tower shell. An air inlet A and an air inlet B are formed in the degassing tower shell on one side below the spraying mechanism B, an air outlet is formed in the upper part of the degassing tower shell, and an acid outlet is formed in one side of the bottom of the degassing tower shell. According to the utility model, dilute acid enters the spraying mechanism, air enters the degassing tower through the air inlet, sulfur dioxide is replaced, the air is discharged through the air outlet and enters the flue gas system and the degassing tower acid receiving outlet, and the dilute acid is discharged, so that the discharge standard is further met, and meanwhile, the sulfur dioxide absorption rate and the yield are improved.

The application discloses a cleaning method of a cauldron for preparing aluminum trihydride, which comprises the following steps: (1) under an inert gas atmosphere, adding a polyhalogenated hydrocarbon solvent and an inorganic salt abrasive into the cauldron, and stirring intensively to grind off the wall-bonding substances in the cauldron; (2) emptying the cauldron, and slowly feeding a buffer solution into the cauldron through a bottom pipe in a vacuum-extraction mode, so that the buffer solution is immersed into the cauldron from the bottom of the cauldron; and (3) sequentially using dilute alkali, dilute acid and water to completely immerse the wall-bonding layer, and then washing the cauldron with water. The method can safely and effectively remove the wall-bonding substances on the cauldron.

The invention belongs to the technical field of cellulose preparation, and particularly relates to micro / nano cellulose based on high-shear intramolecular friction dissociation and a preparation method thereof, and the preparation method comprises the following steps: (1) crushing a cellulose raw material; (2) adding the crushed cellulose into a dilute acid solution at a preset temperature, and dissociating under the action of double-helix high-pressure homogenization to obtain a micro / nano cellulose acidic dissociation liquid; and (3) repeatedly centrifuging the micro / nano cellulose acidic dissociation liquid with deionized water until the micro / nano cellulose acidic dissociation liquid is neutral, and freeze-drying to obtain the micro / nano cellulose. According to the method, multi-selectivity natural cellulose is taken as a raw material, and the long-standing triangular problems of uneven size, overhigh energy consumption and chemical pollution in micro / nano cellulose production are solved through directional utilization of intramolecular friction energy by a double-helix high-pressure homogenization method.

The invention provides a method for detecting and analyzing heavy metal chromium in high-aluminum ore and red mud, and belongs to the field of mineral analysis and detection. The method comprises the following steps: melting a mixture of a sample to be detected and a strong alkaline flux to obtain a melt; extracting and dissolving the melt by using a dilute acid solution to obtain a leaching solution; a strong oxidant and a catalyst are added into the leachate, so that chromium ions in the leachate are oxidized into hexavalent chromium ions, and hexavalent chromium conversion liquid is obtained; adding an alkali carbonate solution into the hexavalent chromium conversion solution to adjust the pH value of the hexavalent chromium conversion solution to 8-10 to obtain a mixed solution; filtering the mixed solution to obtain a chromium-containing filtrate; and quantifying the total chromium content in the chromium-containing filtrate by adopting a spectrophotometric method. The detection and analysis method provided by the invention can ensure that chromium existing in lattices of the high-aluminum ore and red mud sample is completely released, and main matrix interference elements such as aluminum, iron, calcium and magnesium in the sample can be effectively separated, so that accurate determination of the total chromium content in the to-be-detected sample is realized.

The application discloses a preparation process of electronic-grade trans-1,2-cyclohexanediaminetetraacetic acid. The preparation process takes industrial-grade 1,2-cyclohexanediamine as raw material, reacts the 1,2-cyclohexanediamine with electronic-grade organic acid to generate a water-soluble salt, crystallizes at 0-30 DEG C, filters out the crystal to reserve the filtrate, adds an alkaline solution to the filtrate, then adds a polar organic reagent to extract, directly adds an aqueous bromoacetic acid solution to the oil phase to react, after the reaction is completed, adds electronic-grade dilute acid to precipitate trans-1,2-cyclohexanediaminetetraacetic acid until the PH of the system is less than or equal to 2, filters and reserves the solid, washes with pure water, and electronic-grade trans-1,2-cyclohexanediaminetetraacetic acid is obtained. The method has a clear process route, can effectively remove metal ion impurities in the synthesis process, the obtained trans-1,2-cyclohexanediaminetetraacetic acid product has high purity, can be used for preparing high-end semiconductor cleaning liquid, and meets the strict requirements of advanced processes on the purity of cleaning chemicals.

The application provides a preparation method of dydrogesterone, which comprises the following steps: performing a selective epoxidation reaction on a compound I in a first solution containing meta-chloroperoxybenzoic acid and hydrogen peroxide to obtain a compound II; the content of the meta-chloroperoxybenzoic acid in the first solution is more than 1 times of the amount of substance of the compound I; performing a reduction reaction on the compound II under the action of hydrogen and a catalyst to obtain a compound III; performing a hydrolysis reaction on the compound III in a dilute acid solution, and then performing a hydroxyl elimination reaction on the compound III in a second solution to obtain the dydrogesterone; the structural formulae of the compound I, the compound II, the compound III and the dydrogesterone are as follows:; and. The preparation method has less by-products and a higher reaction yield.

The present invention provides a method for preparing diamond micropowder for rough grinding of silicon carbide wafers, which specifically comprises the following steps: (1) taking diamond micropowders of different particle sizes and mixing them; (2) adding the diamond micropowders uniformly mixed in step (1) to a reactor containing a dilute acid solution under stirring conditions to react, and at the same time, adding a hydrogen peroxide solution to the reactor during the entire reaction process until the reaction is completed; (3) washing the diamond micropowder treated with acid in step (2) with pure water until the pH value of the supernatant is between 6 and 7; dispersing the diamond micropowder in pure water to obtain a diamond micropowder dispersion; (4) wet sieving the diamond micropowder dispersion in step (3); and obtaining a diamond micropowder abrasive for rough grinding of silicon carbide wafers. The prepared diamond micropowder is used for rough grinding of silicon carbide wafers, and the removal rate of the rough grinding is high, and the surface of the silicon carbide wafer is not damaged, which significantly improves the processing efficiency and quality.

The present application proposes a method for preparing modified graphene, which relates to the field of new material technology. A method for preparing modified graphene, comprising the following steps: taking graphene, adding it to an ethanol solution, adding sodium hydroxide to adjust the pH value to 10, and obtaining a mixed solution; stirring the mixed solution to react, and then filtering to obtain a filter residue; placing the filter residue in a dilute acid solution, reacting until the pH value of the solution is 7, washing with water and draining, and then drying the filter residue; crushing the dried filter residue to obtain a modified graphene finished product. The present application adjusts the pH value of the ethanol solution with sodium hydroxide, and then adds graphene powder to modify it, adjusts the pH value with acid after the modification, and then washes with water to remove the residual sodium hydroxide, and finally dries and crushes it. The obtained modified graphene has good extreme pressure wear resistance, thermal conductivity and electrical conductivity.

The utility model belongs to the field of nitric acid production devices, and particularly relates to a device for producing 65% dilute nitric acid. The device comprises a dilute acid separator (1), a dilute acid tank (2) and an absorption tower (3), wherein the dilute acid separator (1) is connected with the dilute acid tank (2); the dilute acid tank (2) is divided into two branch lines after passing through a dilute acid pump, a liquid level regulating valve (5-1) is arranged on a pipeline of one branch line, and the dilute acid tank (2) is connected with the absorption tower (3) after passing through the liquid level regulating valve (5-1); and the other branch line is provided with a flow meter and a regulating valve (5-2) on the pipeline, and is communicated with a delivery pipeline through the regulating valve (5-2). The device can reduce moisture brought into the absorption tower and does not change the original process flow, so that the double-pressurization dilute nitric acid device not only can produce dilute nitric acid of a common product, but also can produce dilute nitric acid with the concentration of 65% or above, and does not consume a large amount of energy when producing the dilute nitric acid with the concentration of 65%.

The present invention discloses a treatment agent for removing nitric acid from dilute sulfuric acid and a preparation and use method thereof, belonging to the technical field of coking wastewater treatment. The treatment agent for removing nitric acid from dilute sulfuric acid is composed of a carrier and a reactive component; the carrier is an activated corn cob, and the carrier accounts for 50% to 70% of the total mass of the treatment agent; the reactive component is prepared by mixing ammonium thiocyanate, ammonium thiosulfate, and urea in a mass ratio of 6 to 8:1 to 2:1 to 2. The nitric acid treatment agent is used to treat the mixed acid, thereby increasing the utilization rate of the dilute acid and the yield of ammonium sulfate. The present invention effectively solves the problem of increased operating costs caused by the waste of impure dilute sulfuric acid in waste liquid acid production, equipment corrosion, foaming, and destruction of ammonium sulfate crystals.

The present invention relates to the field of organic synthesis, and particularly relates to a new method for synthesizing 2-chloro-6-nitrotoluene. The synthesis method of 2-chloro-6-nitrotoluene provided by the present invention uses 2,3-dichloronitrobenzene (Compound 1) as a raw material, reacts with methyl cyanoacetate or dimethyl malonate under the action of a reaction solvent and an acid-binding agent to form Compound 2, and after filtration and decolorization, a dilute acid solution is added for de-esterification reaction to obtain Compound 3. Finally, the R group is removed in a dilute acid solution to obtain the final product 2-chloro-6-nitrotoluene (Compound 4). The synthesis method of 2-chloro-6-nitrotoluene described in the present invention has the advantages of simple operation, safety, economy, environmental friendliness, and low cost.

A preparation method of an infrared detector chip based on a gold-free electrode relates to the technical field of infrared detection, and comprises the following steps: preparing a required to-be-metallized infrared detector wafer, sputtering and depositing a gold-free electrode film layer on the to-be-metallized infrared detector wafer; depositing a gold-free electrode film layer with a certain thickness on the surface of the wafer by setting parameters of sputtering power, gas flow and heating temperature, and completing preparation of a metal electrode after a stripping process; the infrared detector wafer after electrode preparation is subjected to dilute acid solution post-treatment, an oxide layer and impurities on the surface of the metal electrode are removed through a dilute acid solution, and preparation of the infrared detector wafer is completed; and finally, cutting the infrared detector wafer to complete the preparation of the infrared detector chip. According to the invention, good ohmic contact between the electrode and an infrared focal plane detector wafer and good flip-chip interconnection between the electrode and high-purity indium are realized, and the electrode is used as a low-cost choice for replacing a system taking Au as a core electrode.

The utility model discloses an iron removal device for white corundum, which belongs to the field of white corundum iron removal, and comprises a bottom plate, the top of the bottom plate is fixedly connected with a white corundum iron removal reaction box, one side of the white corundum iron removal reaction box is fixedly connected with a dilute acid solution storage box, and the top of the dilute acid solution storage box is fixedly provided with a pump body; one side of the pump body is fixedly connected with a liquid guide pipe, and one end of the liquid guide pipe extends into the white corundum iron removal reaction box; through the arrangement of the feeding and discharging mechanism, white corundum subjected to iron removal can be automatically fished out from the interior of the white corundum iron removal reaction box, an operator can be effectively prevented from making contact with a dilute acid solution, the operator can conduct discharging more conveniently, and feeding and discharging integration is achieved; and an operator can clean and drain the deironed white corundum more conveniently, and the operator can treat the white corundum more conveniently in the follow-up process.

The invention belongs to the technical field of sugar alcohol production, and particularly relates to a method for preparing mannose by taking palm meal as a raw material. Comprising the following steps: (1) extraction: carrying out subcritical extraction on palm meal to obtain palm oil and degreased meal; (2) steam explosion pretreatment: performing steam explosion on the degreased meal to obtain steam explosion slag; (3) enzymolysis: mixing the steam explosion residues with protease liquid for enzymolysis to obtain enzymolysis residues and enzymolysis liquid; (4) preparing mannose: hydrolyzing the enzymolysis residues with dilute acid to obtain hydrolysate, and performing decoloration, ion exchange, chromatographic separation, concentration, crystallization, centrifugation and drying on the hydrolysate to obtain mannose; and (5) preparing the palm peptide: removing zymoprotein in the enzymatic hydrolysate, filtering through an organic membrane to obtain membrane filtrate, and performing ion exchange, concentration and spray drying on the membrane filtrate to obtain the palm peptide. According to the method, mannose in the palm meal is extracted, and a small amount of by-products palm oil and palm peptide are obtained, so that the comprehensive utilization value of the palm meal is improved.

Provided herein are catheter lock solutions having anticoagulation and antimicrobial properties, the catheter lock solutions including citrate salts. The citrate salt can be trisodium citrate, and the catheter lock solution can further include a diluted acid for adjusting the pH of the catheter lock solution.

The invention belongs to the field of rare earth metallurgy, and discloses a method for recovering and preparing cerium fluoride from bastnaesite, which comprises the following steps: grinding the bastnaesite by a Raymond mill to obtain ground mineral powder; oxidizing and roasting the ground ore powder to obtain oxidized and roasted ore; water is added into the oxidized roasted ore for size mixing, first-time acid dissolution is carried out under the low-acid condition, and first-time acid leaching liquid and first-time acid leaching residues are obtained through filtering; dilute acid is added into the first-time acid leaching residues for size mixing, second-time acid dissolution is carried out under the low-temperature and high-acid condition, and second-time acid leaching liquid and second-time acid leaching residues are obtained through filtering; and adding alkali into the second acid leaching solution to adjust the acidity, controlling the deposition condition to deposit cerium fluoride, and filtering and washing to obtain cerium fluoride. According to the method, the cerium fluoride product with the purity being 99% or above can be recycled and prepared, and comprehensive recycling of rare earth and fluorine resources in bastnaesite is achieved.

The invention discloses an absorbable monofilament suture and a preparation method thereof, and the preparation method comprises the following steps: S1, dissolving chitosan in a dilute acid solution to form a spinning solution; s2, sequentially carrying out filtering treatment and vacuum defoaming treatment on the spinning solution; s3, the spinning solution treated in the step S2 is extruded into a coagulating bath through a spinning component, and nascent fibers are formed; s4, carrying out water washing treatment on the nascent fiber; s5, immersing the nascent fiber treated in the step S4 into a polycarboxylic acid solution to carry out an ionic cross-linking reaction; s6, the fibers subjected to the ionic cross-linking reaction in the step S5 are sequentially subjected to water washing treatment and drying treatment, the absorbable monofilament suture is obtained, the mechanical properties such as dry-state holding stress and the like of the finally obtained monofilament suture are synergistically and remarkably improved, use of a toxic chemical cross-linking agent is avoided, and the production cost is reduced. And the suture is ensured to finally have good biocompatibility and controllable degradation performance.