119 results about "Dilute acid" patented technology

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 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 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.

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.

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.

The invention relates to the technical field of resource utilization of metallurgical and chemical wastes, in particular to a method for neutralizing waste acid and enriching ferrovanadium from vanadium-containing steel slag. The method comprises the following steps: S1, grinding the vanadium-containing steel slag into fine powder, and adding water according to a liquid-solid ratio of 1g: (1-1.5) ml to prepare slurry; s2, preparing the sulfuric acid process titanium dioxide byproduct waste acid and the acid wastewater into dilute acid with the concentration of 5-15%; s3, dilute acid is added into the slurry, the pH is controlled to be 6-8, the reaction temperature is larger than or equal to 50 DEG C, and continuous stirring reaction is conducted; s4, after the reaction is completed, heating to 90 DEG C or above, and keeping boiling for 30-60 minutes; and S5, flotation separation is conducted, and gypsum slag and an iron-rich vanadium material are obtained.

The invention relates to the technical field of copper foil surface treatment, and discloses an electrolysis device for removing copper ions from dilute acid liquid and a processing method.The electrolysis device comprises a containing assembly forming a cavity, and the dilute acid liquid rich in copper ions is placed in the cavity; the electrolysis assembly is in contact with the dilute acid liquid, the electrified electrolysis assembly comprises at least one cathode plate, and the cathode plate provides electrons for copper ions to be reduced into metal copper; and the copper cleaning assembly is arranged in the cavity and comprises a scraper moving relative to the negative plate, and the top end of the scraper makes contact with the negative plate so as to clean the compact copper plating layer. The containing assembly and the electrolysis assembly are arranged to conduct electro-deposition treatment on dilute acid liquid rich in copper ions, the content of the copper ions is reduced, and the dilute acid liquid capable of spraying the conductive roller is formed; in the electrodeposition treatment process, a compact copper plating layer is formed on the side face of the cathode plate, the scraper moves relative to the side face of the cathode plate to scrape the compact copper plating layer, the contact area of the cathode plate and dilute acid liquid is guaranteed, and then the electrodeposition treatment efficiency of the electrolysis assembly on the dilute acid liquid is guaranteed.

The utility model relates to the technical field of drying towers, and discloses a drying tower inlet structure with an acid discharge pipe, which comprises a tower body and a flue gas pipeline, and an inlet pipe is fixed at the top end of the left side of the tower body. According to the drying tower inlet structure with the acid discharge pipe, the fence is fixed to the position, close to the first mounting flange plate, in the flue gas pipeline and can be used for preventing dilute acid from entering the tower body, meanwhile, the discharge outlet is fixed to the right side of the bottom end of the flue gas pipeline, and a large amount of dilute acid solution generated by condensation can directly flow out of the discharge outlet; an acid return pipe can be mounted at the bottom end of the first valve at the bottom of the recovery tank and is used for returning the collected dilute acid to an acid making system, so that corrosion of a pipeline at the bottom of an inlet of the drying tower and a tower body can be reduced, and the service life of the drying tower is prolonged. The problem that a large amount of dilute acid generated at an inlet section of a drying tower cannot be conveniently discharged in an auxiliary mode is solved.

The invention provides a method for extracting scandium oxide based on P507 extraction resin, and particularly relates to a novel method for extracting scandium oxide from titanium white waste acid and a red mud solution. Figure 1 is a product process flow diagram. The method specifically comprises the following steps: adsorbing raw materials, washing with ultrapure water, treating with a potassium hydroxide solution, washing with an acid solution, desorbing and electrolyzing. The concentration of the potassium hydroxide solution is 1N-8N; the P507 extraction-elution enrichment resin comprises P507 extraction-elution resin and silicon-based amidoxime resin; the concentration of the hydrochloric acid solution is 1-3 mol / L; and the resin desorption agent is any one of ultrapure water or a dilute acid solution with the pH value of 1-5. The method is easy to operate and low in cost, and scandium oxide with the purity of 99.99% or above can be obtained through purification.

The invention belongs to the field of biomass energy utilization, and particularly relates to a method for preparing high-value dehydrated sugar through rapid pyrolysis based on extremely dilute acid high-temperature modification. The method comprises the following steps: by taking palm plant seed waste as a raw material, carrying out boiling-washing modification at a temperature close to a boiling point by using an acid aqueous solution with extremely dilute concentration, preferably further carrying out cold plasma discharge modification treatment, and then carrying out rapid pyrolysis under an anaerobic condition at 350-450 DEG C, and condensing the obtained pyrolysis steam to obtain a liquid product rich in levomannan (LM, 1, 6-anhydro-beta-D-mannopyranose). According to the method, ash can be effectively removed, the reaction activity of the raw materials is improved, high-purity enrichment of LM is promoted, and a technical approach is provided for high-value utilization of palm plant seed waste.

The application discloses a device and method for preparing xylose by electric-thermal coupling dilute acid pretreatment of wood fiber, and belongs to the technical field of biomass resource utilization. The device comprises an electric-thermal reaction unit, and a time-varying magnetic field in a magnetic core in the electric-thermal reaction unit is used as an excitation source to spontaneously induce electric effect and thermal effect on reaction liquid in the reaction tube, so that electric-thermal synergic treatment is completed. The method comprises the following steps: mixing wood fiber raw materials with a dilute acid solution, and then performing electric-thermal pretreatment by using the device; and the electric-thermal coupling dilute acid pretreatment can remove a large amount of hemicellulose and a small amount of lignin in the wood fiber. The application reduces energy loss of traditional hydrothermal treatment, pretreats the wood fiber by means of electric effect, reduces pretreatment temperature, and avoids requirements on equipment or devices under a high-temperature and high-pressure environment.

The present invention discloses a method for producing cobalt sulfate and its application. The method comprises the following steps: step (1) dilute acid impurity removal; step (2) acid leaching reduction; step (3) precipitation impurity removal; step (4) deep extraction impurity removal; step (5) further precipitation impurity removal; and step (6) recrystallization. The cobalt sulfate obtained by the production method of the present application meets the requirements of battery-grade cobalt sulfate and can be used for the synthesis of ternary precursors.

A method for producing a leather-like layered composite material (26), comprising the following steps: 1.1 Addition and dissolution of powdered chitosan (4) in dilute acid (5') to produce a solution (25), 1.2 Comminution and mixing of bacterial nanocellulose (7) with water (8) to produce a mixture (10, 10'), 1.3 Stirring of the solution (25) and the mixture (10, 10') to produce a polyelectrolyte complex (11), 1.4 Application of a first portion of the polyelectrolyte complex (11) to a carrier plate (13), 1.5 Application of a nonwoven fabric (15) to the previously applied polyelectrolyte complex (11), 1.6 Addition and stirring of natural fibers (17) into a second portion of the polyelectrolyte complex (11) and stirring to produce a mixture (16, 16') 1.7 Application of the mixture (16, 16') to the upper side of the fleece (15) 1.8 Drying process and 1.9 Removal of the finished composite material (26)

The present invention discloses a method for coating diamond powder on the surface of cemented carbide powder, comprising the following steps: vacuum pressureless sintering of diamond powder with an average particle size of 0.5-1.5 μm to obtain a core-shell structure of diamond@graphite, then oxidizing the surface graphite to graphene oxide to obtain a modified diamond powder with a core-shell structure of diamond@graphene oxide; impregnating cemented carbide powder with an average particle size of 13-15 μm with dilute acid, and then impregnating with an alcohol solution to obtain hydroxylated cemented carbide powder; uniformly dispersing the modified diamond powder and the hydroxylated cemented carbide powder in anhydrous ethanol, and then performing electrophoretic deposition to deposit the diamond powder on the surface of the cemented carbide powder. The method solves the problem of poor film-based bonding ability of coating tool materials prepared by the prior art, while significantly improving the bonding strength between diamond powder and cemented carbide powder, which is expected to further extend tool life and improve various cutting and mechanical properties.

The application belongs to the technical field of water treatment, and particularly discloses an acid recovery device. The acid recovery device comprises an acid separator and acid concentration electrodialysis. The acid separator is sequentially arranged and placed by a positive charge microporous semi-permeable membrane, a negative charge fibrous filler, a positive charge microporous semi-permeable membrane, a raw material chamber separation net and a positive charge microporous semi-permeable membrane. The components arranged in this way can be arranged in multiple ways to realize more efficient treatment. Dilute acid from the acid separator enters the acid concentration electrodialysis component for treatment. The acid recovery device has the advantages of fast diffusion speed, high salt concentration of waste acid, the ability to treat waste acid with high salt concentration, high recovery rate and the like.

The invention belongs to the technical field of oleic acid purification, and provides a preparation method of high-purity oleic acid. The method comprises the following steps: mixing an oleic acid raw material, urea and a solvent, heating and refluxing, cooling a refluxing product, and crystallizing at low temperature to obtain a mixture; carrying out suction filtration on the mixture, removing the solvent from the filtrate, mixing with water, regulating the pH value to 2-4 by adopting dilute acid, heating to separate an oil phase from a water phase, separating the oil phase and the water phase while hot, extracting, combining organic phases, drying, and carrying out reduced pressure distillation to remove the organic solvent, so as to obtain oily liquid; and mixing the oily liquid with a solvent, and sequentially performing low-temperature crystallization and pressure filtration to obtain the high-purity oleic acid. According to the method, the urea adduction method and the solvent crystallization method are combined for use, the dosage of urea is reduced, the ester solvent is used for solvent crystallization for the first time, the oleic acid with the purity larger than or equal to 99% is prepared, and the method can effectively solve the problems of urea residues and low oleic acid yield.

The utility model discloses a diluted acid filtering structure capable of shunting, which comprises a filtering box, a shunting box is arranged in the middle of the top of the filtering box, a feeding pipe is arranged in the middle of the top of the shunting box, fixed pipes are arranged on two sides of the top in the filtering box, and sleeves are sleeved on the outer sides of the two groups of fixed pipes. Springs sleeve the bottoms, close to the sleeves, of the outer sides of the two fixed pipes; through the mutual cooperation of the rack A, the gear, the rack B, the sleeves, the shunting pipe, the sealing plug, the shunting box, the guide rod, the fixed pipe, the spring and the filter plates, when the device is used, dilute acid can be shunted into the two groups of sleeves to be filtered, so that the filtering pressure of the dilute acid is reduced, and when one group of filter plates is blocked, the filtering pressure is reduced. The sealing plugs can be driven by the gravity of blocked dilute acid to block the inlets of the shunt pipes, so that the dilute acid can only circulate from the other group of shunt pipes, and the dilute acid can be prevented from continuously entering the blocking sleeve to influence the subsequent maintenance work on the premise of not influencing the filtration of the dilute acid.