264 results about "Calcium oxalate" patented technology

The invention discloses a concrete early-strength agent, which is characterized in comprising the following components according to weight percentage: inorganic salt early-strength component 35-55 percent, organic early-strength component 5-10 percent, water reducing component 15-25 percent, wherein the inorganic salt early-strength component is prepared by at least two among sulfate, carbonate, nitrate, and nitrite; the organic early-strength component selects any one among calcium formate, sodium acetate, calcium oxalate, triethanolamine, tri-iso-propanolamine and carbamide; the water reducing component selects one among naphthalenesulfuric acid type, melamine type and polycarboxylate type. The invention makes the concrete be coagulated and hardened rapidly under the condition of low temperature, so that the early strength of the concrete is greatly improved as well as later strength is ensured.

The invention provides an acid pickling and waste acid treatment process for improving purity of powdery quartz sand. The process includes the steps: putting the powdery quartz sand in an acid pickling purification device, and using an acid pump for pumping acid pickling solution into the acid pickling purification device, wherein the acid pickling solution is composed of hydrofluoric acid, fluorosilicic acid, oxalic acid and water or composed of fluorosilicic acid, oxalic acid and water; removing the acid pickling solution after acid pickling, and collecting; delivering the powdery quartz sand to a washing device by clear water after acid pickling, washing to neutral, and dewatering to obtain a finished product of powdery quartz sand; transferring waste acid into a neutralization tank for neutralization, delivering into a sedimentation tank by the pump, and allowing calcium fluosilicate and calcium oxalate to precipitate; delivering the clear water into a regulation tank after precipitation to realize pH adjustment for precipitation of iron ions; using oxalic acid or fluorosilicic acid to adjust pH, precipitating calcium fluosilicate and calcium oxalate again, filtering to obtain clear water, and delivering the clear water to a workshop for recycling. The acid pickling and waste acid treatment process for improving purity of the powdery quartz sand has the advantages of remarkable purity improvement and impurity reduction and simplicity and convenience in subsequent treatment.

The invention discloses a method for simultaneously treating oxalic acid precipitation waste water and ammonia-nitrogen waste water and recovering rare earth of a rare earth separation plant. The method is characterized by comprising the following steps of: treating the oxalic acid precipitation waste water by using calcium carbonate; precipitating rare earth dissolved in the oxalic acid precipitation waste water; recovering with calcium oxalate together; obtaining a mixture of calcium oxide and rare earth oxide by burning; treating the ammonia-nitrogen waste water generated in a rare earth separating process by using the calcium oxide in the mixture; generating calcium chloride by dissolving the calcium oxide, simultaneously generating ammonia water from ammonia nitrogen in the ammonia-nitrogen waste water, and generating rare earth hydrate from the rare earth; obtaining rare earth-containing filter residue by filtering and separating; returning filtrate to an extraction line for saponifying an organic extractant; obtaining rare earth material liquid by dissolving the filter residue by using an acid; and returning the rare earth material liquid for use. The method of the invention can treat the oxalic acid precipitation waste water and the ammonia-nitrogen waste water generated in various rare earth separation processes and has a simple process. Acidic waste water is treated, resource is saved, environmental pollution is reduced, rare earth is recovered, waste is utilized comprehensively and simultaneously good economic benefit is achieved.

The invention discloses a desulfurization agent, which comprises organic calcium carboxylates and calcium phosphate, and concretely comprises the following components, by mass, 15-20% of calcium formate, 10-16% of EDTA calcium disodium, 10-16% of calcium lactate, 0-10% of calcium phytate, 25-30% of calcium citrate, 0-10% of calcium gluconate, 10-20% of calcium oxalate, and 1-10% of calcium phosphate. According to the desulfurization agent, combination of the organic calcium carboxylates and the calcium phosphate is adopted, solubility in the solution is high, calcium ions can be ionized quickly, a desulfurization reaction speed is rapid, and desulfurization efficiency is high.

The invention discloses an oil well cement low-temperature composite early-strong coagulation accelerator. The coagulation accelerator is prepared by mixing the following inorganic / organic components in parts by weight: 0.5 to 1 part of inorganic salt, 0.5 to 2 parts of organic salt, 0.04 to 0.1 part of organic amine, and 0.1 to 0.5 part of organic acid; wherein the inorganic salt is a mixture of calcium sulfate and sodium silicate; the organic salt is one or two of calcium formate, calcium oxalate, sodium acetate, and iron lactate; the organic amine can be diethanolamine, triethanolamine, or methanamide; and the organic acid is formic acid or oxalic acid. The provided coagulation accelerator has the advantages of low production cost and good early-strong effect, and also has a certain coagulation accelerating effect. The coagulation accelerator is suitable for international A-grade / G-grade oil well cement, and can be co-used with weighting materials (iron ore powder, barite powder, etc.) or lightening materials (fly ash, floating beads, etc.) to prepare cement mortar with different densities according to the needs.

A process for purifying lithium chloride (LiCl) from industry grade LiCl and hydrochloric acid includes mixing the above raw materials, adding barium chloride and lithium hydroxide to PH=9-13, adding lithium oxalate or oxalic acid under normal temperature and stir to get the mixture of precipitation of barium sulfate, calcium oxalate, magnesium hydroxide and ironic hydroxide, passing the mixture through a membranous filter to get rid of the ions of sulfate, calcium, magnesium and iron, adding a reagent LF with a composition of Li1+xAxB2-x(PO4)3 under normal temperature, ordinary pressure, and PH9-13, purifying 6-96 hours with stir, passing it through a membranous filter again, concentrating and drying. The pureness of lithium chloride obtained is higher than 99.9%, and Na<30ppm, K<10ppm, Ca<20ppm, Mg<10ppm, Fe<5ppm.

The invention discloses a technological process for honeyed black-sesame pills. The honeyed black-sesame pills comprise black sesames, black beans and honey. The technological process includes acquiring, by weight, 50% of black sesame powder (with 5-6% of water content), 20% of black bean powder (with 7-10% of water content) steamed and air-dried for nine times and 30% of prepared wild honey (with14-16% of water content); evenly mixing the black sesame powder, the black bean powder and the wild honey after feeding into the a three-dimensional mixing machine; preparing 10g of big honeyed pillsby a traditional Chinese medicinal pelleting machine. The technological process has the advantages that an optimal process for the honeyed black-sesame pills is adopted, the black sesames and the black beans are steamed and air-dried for nine times, internal calcium oxalate are absorbed by human bodies easily, and a good calcium supplement way is provided; the flavors of the black sesames and theblack beans can be improved through low-speed grinding; the black sesames, the black beans and the wild honey are mixed three-dimensionally according to a certain ratio to prepare the big honeyed pills, integration is achieved, the taste is fine and smooth, the shelf life is long, and the honeyed pills are easy to take and have best taste.

The invention provides a high-purity calcobutrol preparing method. Gadolinium ions are extracted from gadobutrol which serves as a starting material under the action of acid, and filtration is conducted; a calcium preparation is added to filtrate, then refluxing reaction is conducted to generate calcobutrol, and excessive calcium carbonate and the byproduct calcium oxalate are filtered out; a nucleation agent is added to obtained calcobutrol solution, and heating, refluxing, crystallization and then filtration are conducted, so that high-purity calcobutrol is obtained. By the adoption of the method, the obtained product is highly pure, the method is simple, purification is easy, and industrial pollution rate is low.

The invention discloses a dust-suppression and haze-reduction bituminous mixture which is a composite material and comprises mineral aggregate and dust-suppression and haze-reduction asphalt, wherein the dust-suppression and haze-reduction asphalt comprises matrix asphalt and a dust-suppression and a haze-reduction asphalt modifier; the dust-suppression and haze-reduction asphalt modifier comprises a dust-suppression component and an anti-stripping component; the dust-suppression component comprises one or more of calcium chloride, ferric chloride, aluminium chloride, calcium oxalate and potassium oxalate; the anti-stripping component comprises one or more of calcium lignosulphonate, sodium lignosulphonate and petroleum resin. The invention further discloses a preparation method of the dust-suppression and haze-reduction bituminous mixture. The preparation method comprises the following steps: preparing the dust-suppression and haze-reduction asphalt and mixing and stirring the dust-suppression and haze-reduction asphalt and mineral aggregate at certain temperature. The dust-suppression and haze-reduction bituminous mixture can absorb moisture in air and forms a water film on a road surface to increase moisture content of dust, so that the dust cannot be raised by passing vehicles easily, and the dual effects of dust-suppression and haze-reduction and water conservation are realized.

The invention relates to the field of recycle treatment of rare earth wet-method smelting waste water, and especially relates to a process of recycling oxalic acid from rare earth wet-method smelting oxalic acid precipitation waste water. The process disclosed in the invention comprises following steps: adding alkaline calcium ion to the rare earth oxalic acid precipitation waste water, performing solid-liquid separation to collect the solid calcium oxalate, adding dilute sulfuric acid to the solid calcium oxalate, performing solid-liquid separation to obtain a liquid, decreasing the liquid to 0-15 DEG C and performing crystallization to obtain high-purity oxalic acid. The method can effectively recycle the oxalic acid from the rare earth wet-method smelting oxalic acid precipitation waste water with the recycle rate being not less than 50% and the purity of the recycled oxalic acid being not less than 95%. Meanwhile, the method is free of products such as ion exchange resin and the like and is also free of a complex column chromatographic process, so that the method is low in treatment cost, is simple and reliable and is suitable for industrial popularization.

The present invention discloses surface bionic protection method of stone material and lithical cultural relic. The protection method includes cleaning the surface with detergent comprising deionized water or organic solvent, treating the surface with biological amphibpatic functional pre-treating liquid, and crystallizing supersaturated calcium oxalate solution on the surface to form fine and compact surface protecting calcium oxalate film. The present invention has the advantages of wide applicable range, excellent compatibility to stone material, high weather resistance, raised corrosion resistance, improved hydrophobicity, firm combination with base stone material and no influence on the outer appearance, color and hand feeling of original stone material.

This is invention provides a method for extracting high purity plant tannin. The method comprises: (1) extracting plants containing tannin with acetone solution, and filtering to obtain the filtrate; (2) adding Yb3+ to the filtrate, reacting with tannin to form a precipitate, centrifuging or filtering to obtain the precipitate, washing, and dispersing in water to obtain a suspension; (3) adding oxalic acid solution to the suspension, reacting to exchange Yb3+ from the precipitate, stripping tannin, filtering or centrifuging to remove ytterbium oxalate precipitate and obtain tannin solution; (4) adding calcium hydroxide solution to the tannin solution to react with residual oxalic acid, filtering or centrifuging to remove calcium oxalate and obtain purified tannin solution, and drying to obtain high purified plant tannin product.

The invention relates to an apparatus for measuring the calcium oxalate scale forming propensity of a continuously flowing solution having a pH of from 2 to 3 which comprises a quartz crystal microbalance having a top side comprising a working electrode for exposure to the solution and a bottom side isolated from the solution, wherein the working electrode is coated with or made of a conductive material on which the intensive evolution of hydrogen gas proceeds at potentials more negative than necessary to achieve a pH of 3.5-9 proximate to the microbalance.

The invention belongs to intensive agricultural production techniques and discloses an aspergillus niger NJDL-12 bacterial strain and application thereof to improvement of coastal saline-alkali soil. The bacterial strain NJDL-12 obtained by separation belongs to aspergillus niger and is preserved in the China General Microbiological Culture Collection Center on October 26, 2015, and a preservation number of the strain is CGMCC NO.11544. The aspergillus niger NJDL-12 is capable of secreting a large quantity of oxalic acid which is combined with Ca<2+> in the saline-alkali soil to form calcium oxalate, so that Ca<2+> in the soil can be consolidated to reduce soil salinity, soil aggregate structure can be improved, and soil porosity is improved. After a biological organic fertilizer prepared from the strain NJDL-12 is applied to soil, soil pH and salinity are declined, and soil aggregate structure improvement, saline-alkali soil improvement, crop growth promotion and remarkable application effects are realized.

The invention provides a method for remedying Cd-As-Cu heavy metal polluted soil. The method comprises the following steps: step 1, uniformly mixing hydrogen peroxide, oxysophocarpine, phosphoric acid, citric acid, palmitic acid, Tween 80 and deionized water to obtain a solution M, uniformly mixing bismuth phosphate, sodium sulfite, ferrous oxide, hydroxypropyl methyl cellulose and deionized water to obtain a solution N, and uniformly mixing bromelain, amylase, glucono-delta-lactone and deionized water to obtain a solution K; step 2, pulverizing the polluted soil, and performing cyclic leaching on the pulverized polluted soil by adopting the solution M; step 3, adding the solution N into the leached soil for uniform mixing; step 4, adding the solution K for uniform mixing and step 5, adding calcium molybdate, calcium oxalate, silkworm shell powder, chicken manure and fly ash for uniform mixing, and performing conservation. According to the method provided by the invention, the remedying effect on the Cd-As-Cu heavy metal polluted soil and the market prospect are good.

Disclosed are silicon-free aluminum paste compositions for forming an aluminum back electrode with large silicon particles, processes to form aluminum back electrode of solar cells, and the solar cells so-produced. The process applys a silicon-free aluminum paste on a back surface of a p-type silicon substrate. The silicon-free aluminum paste compositions have an additive comprising calcium oxide, calcium oxalate, calcium carbonate, calcium phosphate, or mixtures thereof; an aluminum powder; and an organic vehicle. The process also applys a metal paste on a front side of the p-type silicon substrate and firing the p-type silicon substrate after the application of the aluminum paste at a peak temperature in the range of 600-950° C., whereupon firing the additive promotes a growth of silicon particles having an equivalent diameter in the range of 2-15 microns in a particulate layer of the aluminum back electrode.

The invention relates to a thermal-decomposing pore-forming self-heat-insulating bearing sintered product and a preparation method thereof. The thermal decomposing pore-forming self-heat-insulating bearing sintered product mainly comprises the following raw materials of powder solid waste, a binder and a thermal-decomposing pore-forming agent in a mass ratio of 1: (0.5-1.5): (0.1-0.4), wherein thepowder solid waste adopts one of fly ash, coal gangue and tailings; the binder adopts shale or sodium soil; and the thermal-decomposing pore-forming agent adopts one salt or a mixture of calcium oxalate, basic magnesium carbonate, powdered whiting and dolomite which can be decomposed to discharge a great amount of gases at 500-900 DEG C. The preparation method comprises the following steps: adding water to granulate; aging for 1-3 days; forming blank blocks by a porous block mold in a vacuum extruder; drying at a temperature of 45-55 DEG C for 2-4 days; and sintering at 1000-1100 DEG C for 5-8 hours before cooling. The invention has the advantages of solid waste utilization, soil saving, good heat-insulating effect, convenient and rapid construction, and the like.

The invention discloses a method for separating calcium and magnesium in a hydrochloric acid soluble salt system. The method comprises the following steps of: adding oxalic acid which is 1.5 times of the molar content of calcium in a solution by controlling the reaction temperature to be 50 DEG C, the stirring strength to be 250 revolutions / minute, the pH value to be larger than or equal to 1 and the reaction time to be 1.5 hours; and filtering. Compared with the prior art, the method has the advantages of convenience for operation as well as simplicity and easiness for application, and not only successfully realizes the separation of calcium and magnesium in the hydrochloric acid soluble salt system, but also can be used for obtaining a calcium oxalate product with higher purity. By further recovering, a purer magnesium salt product can also be obtained, thus, with the method, the additional value of the product is increased, the waste is recycled and the utilization rate of resources is greatly improved.

The invention discloses dust-suppression and haze-reduction asphalt. The dust-suppression and haze-reduction asphalt is a composite material and comprises matrix asphalt and a dust-suppression and haze-reduction asphalt modifier, wherein the dust-suppression and haze-reduction asphalt modifier comprises a dust-suppression component and an anti-stripping component, the dust-suppression component comprises one or more of calcium chloride, ferric chloride, aluminium chloride, calcium oxalate and potassium oxalate, and the anti-stripping component comprises one or more of calcium lignosulphonate, sodium lignosulphonate and petroleum resin. The invention further discloses a preparation method of the dust-suppression and haze-reduction asphalt. The method comprises steps as follows: the matrix asphalt is heated to the mixing temperature; the dust-suppression and haze-reduction asphalt modifier is added to the matrix asphalt for mixing; a mixture of the mixed matrix asphalt and the dust-suppression and haze-reduction asphalt modifier is placed in an oven for development. The dust-suppression and haze-reduction asphalt has water absorption and moisture retention performance, the preparation method is simple, the production cost is low, the prepared dust-suppression and haze-reduction asphalt has dust suppression and haze reduction effects, and other properties of the asphalt are not affected.

The invention discloses a detection method of a nine-component heart-calming particle. The detection method of the nine-component heart-calming particle can carry out thin-layer chromatography on spina date seed, schisandra chinensis, corydalis tuber, cinnamon, asparagus fern and polygala tenuifolia in the nine-component heart-calming particle, microscopic identification on calcium oxalate in ginseng and determine HPLC (high performance liquid chromatography) content of ginsenoside Rg1 and ginsenoside Re. The detection method of the nine-component heart-calming particle has the characteristics of stability, high precision, good reproducibility, high recovery ratio and good separation effect. By adopting the detection method of the nine-component heart-calming particle, the quality of the nine-component heart-calming particle can be further comprehensively controlled, the provided method for determining the content of ginsenoside Rg1 and ginsenoside Re can realize good baseline separation effect on ginsenoside Rg1 and ginsenoside Re, and a determination result is accurate and the reproducibility is good.

The invention relates to a refining method for glyoxalic acid. The method comprises the following steps: reacting a crude product obtained in a conventional process with a calcification agent so as to produce calcium oxalate deposit insoluble in a reaction system, wherein in the crude product, most oxalic acid is removed through condensation and crystallization and content of glyoxalic acid is 40 to 50%; carrying out filtering so as to remove calcium oxalate; and subjecting an obtained filtrate to reduced pressure concentration, crystallization at a low temperature, centrifugal separation and vacuum drying so to obtain a high-purity solid glyoxylic acid refined product. The method provided by the invention adds a refining process for glyoxylic acid on the base of a conventional production process for glyoxalic acid through nitric acid oxidation of glyoxal to remove oxalic acid and glyoxal in the crude product of an aqueous glyoxalic acid solution and to remove impurities like by-products produced in the process of an oxidation reaction, which enables purity and quality of the glyoxalic acid product to be improved; and the method has the advantages of a simple process, little equipment investment, convenient operation and control and low production cost and is suitable for industrial production.

The invention relates to a process for reclaiming valuable substance from waste water, in particular a process for reclaiming calcium oxalate from waste water containing oxalic acid, characterized in that the process comprises the two steps of lime cream neutralization and calcium sulfate substitution, wherein the step of lime cream neutralization comprises charging lime cream into waste water containing oxalic acid for neutralization reaction, controlling the reaction temperature to be 80-90 deg. C, when the content of oxalic acid roots in the waste water amounts to 22-25 g / L, ceasing the charging of lime cream, while the calcium sulfate substitution step comprises charging calcium sulfate cream exceeding stoichiometric calculation amount into the waste water to be processed for displacement reaction, controlling the reaction temperature to be 95-98 deg. C, thus obtaining calcium oxalate and acid wastewater.

The invention discloses a powder metallurgy gear and a manufacturing method thereof. The gear is composed of the following ingredients, by mass, 12-24 parts of nickel powder, 1 part-13 parts of copper powder, 5-15 parts of aluminum powder, 2-10 parts of zircon sand, 8-19 parts of zinc powder, 4-11 parts of aluminum oxide, 35-51 parts of iron powder, 3-10 parts of boron powder and 2-16 parts of calcium oxalate. The compression resistance and the salt spray resistance are improved while the tooth portion HRC of the gear is high, the manufacturing process is simple, and the gear has the good market prospect.

The invention discloses a method and a system for preparing red mud pellets. The method for preparing the red mud pellets comprises the following steps: drying red mud and calcium oxalate so as to obtain dried material and flue gas; performing wet-mixing treatment on the dried material with a reducing agent and a binder so as to obtain wet-mixed material; and carrying out pellet making treatment on the wet-mixed material so as to obtain the red mud pellets. The calcium oxalate is added into the red mud and then dried, the calcium oxalate is dried and heated to decompose to generate CO gas and CaCO3, wherein CO gas can destroy the stable pore passages in the red mud, so that the pore diameter is increased and the surface area is reduced; meanwhile, the capillary water in the red mud pores is reduced, and furthermore pelletizing is facilitated; moreover, the prepared pellet is large in porosity, and the pelletizing rate and the pelletizing efficiency are remarkably improved; CaCO3 obtained by decomposition of the calcium oxalate can be used as a reducing agent in a pellet reduction process, and the addition of the calcium-based reducing agent in the reduction process is omitted.

The invention relates to a preparation method of a concrete early strength agent, and belongs to the field of building materials. Aiming at the disadvantages that the traditional concrete early strength agent contains free chloride ions, is high in corrosion to buildings and affects human health and poor in effect at low temperature, non-free chloride ions are prepared by crushing montmorillonite, performing acid treatment, adding calcium oxalate to be adhered to treated montmorillonite powder and then adding polyacrylamide, triisopropanolamine and copper sulfate, and the concrete early strength agent is non-corrosive to buildings, and the effect of which is not affected in low-temperature condition. Experiments show that the preparation method is convenient and simple in preparation, and environmentally friendly and pollution-free, raw materials are easy to get, the method is convenient for operation, the use effect is not affected by temperature, the method is harmless for human health, and the concrete strength is improved by more than 98 percent within four days after the concrete early strength agent is used.

The invention relates to the field of pickling of foods and particularly relates to a pickling method of cabbages. The pickling method comprises the following steps: carrying out hot blanching, carrying out early-stage fermentation, carrying out middle-stage fermentation and carrying out post-stage fermentation. The cabbages pickled by adopting the raw materials and the method provided by the invention is unique in taste, short in pickling time and low in nitrite content; and the potential safety hazard to consumers, caused by the fact that calcium oxalate is crystallized and deposited in a urinary system to form calculus, is not caused.

The invention discloses a conditioner for repairing heavy metal contaminated soil and a preparing method for the conditioner. The conditioner comprises, by weight part, 18-33 parts of oyster powder, 11-17 parts of biogas residue, 4-10 parts of cow dung, 3-11 parts of selenium nitrate, 4-9 parts of calcium molybdate, 2-8 parts of barium phosphonate, 5-11 parts of superphosphate, 50-85 parts of calcareous soil, 6-10 parts of calcium oxalate, 7-12 parts of sugarcane ash, 3-10 parts of palygorskite, 2-8 parts of bamboo powder, 1-3 parts of yeast powder and 4-8 parts of poly dimethyl diallyl ammonium chloride and further comprises 0.1-1.5 parts of cellulose decomposition bacterium agent and 0.3-1.8 parts of silicate bacterium. By means of the prepared conditioner, the content of organic matter in the soil, the content of salt in the soil and the content of available nitrogen in the soil are obviously increased, the texture and the structure of the soil are improved, and the conditioner is suitable for agricultural planting.

The invention discloses a bitter aversive agent and a preparation method thereof. The aversive agent can consist of a bitter substance carrier, a bitter substance and additives. According to the bitter aversive agent and the preparation method thereof provided by the invention, a fresh aloe original fluid is taken as the bitter substance carrier and is matched with a small quantity of chondroitin, and the bitter substance, assisted by two materials, namely the aloe and the chondroitin, can easily permeate into fingernails and subcutaneous tissues; and after 5min of washing a hand coated with the bitter aversive agent, bitterness is still quite strong. The aversive agent is convenient to coat; the aversive agent is applicable to both the fingernails and skin, and the aversive agent is washing-resistant, wear-resistant, free from preservatives and free from toxic and harmful materials; such allergic substances as calcium oxalate, rheum emodin and the like in aloe leaves are effectively eliminated in a process of preparing the bitter substance carrier, so that the bitter aversive agent is quite suitable for young people and children. The aloe ingredient and the chondroitin are also conducive to the repair of collagen tissues in nail beds and the skin, so as to promote the growth of the nail beds and the repair of the hand skin.

The invention discloses a process for removing sodium oxalate from a sodium aluminate solution through lime causticization. The process comprises the following steps of: (1) adding a fine aluminum hydroxide crystal seed cleansing solution into part of red mud wash water, adding a lime additive into a diluted cleansing solution (sodium aluminate solution) containing sodium oxalate according to a molecular ratio of CaO to Na2C2O4 of 0.6-2.0, and reacting for 10-90 minutes at 30-70 DEG C under an enhanced mass transfer condition; (2) performing solid-liquid separation on slurry after reaction to obtain the sodium aluminate solution without the sodium oxalate and an underflow containing calcium oxalate; and (3) adding the sodium aluminate solution without the sodium oxalate into a last tank for red mud washing or a penultimate washing tank for red mud washing, and adding the underflow into the last tank for red mud washing or discharging the underflow along with red mud. According to the process, the sodium oxalate in the sodium aluminate solution can be economically and efficiently removed through lime causticization, the lime addition can be significantly reduced, the causticization rate of the sodium oxalate is improved, the reverse causticization of the calcium oxalate is effectively inhibited, and the alkali consumption is reduced.

The invention provides a method for directly preparing vanadium oxide from vanadium-containing liquid. The method comprises the following steps that 1, calcium oxide is added into the vanadium-containing liquid obtained after impurity removal for a calcification molybdenum precipitation reaction, and solid-liquid separation is carried out to obtain calcium orthovanadate solids and molybdenum precipitation mother liquor; 2, after the calcium orthovanadate solids and oxalic acid are mixed to be uniform, water is added, reaction slurry is prepared for a heating reaction, and solid-liquid separation is carried out after reacting to obtain a vanadyl oxalate solution and calcium oxalate solids; 3, an alkali metal hydroxide water solution and / or ammonium hydroxide are / is added into the vanadyl oxalate solution for reacting, and solid-liquid separation is carried out after reacting to obtain vanadium hydroxide solids; 4, the vanadium hydroxide solids are calcined to prepare vanadium oxide. According to the method, the vanadium-containing liquid is utilized, vanadium oxide is directly prepared from oxalic acid, the conversion rate of the raw materials is high, meanwhile, the purity of the obtained product can be guaranteed, the process is simple, and cost is low.