Non-ammoniation preparation process of high-purity molybdic acid and non-ammoniation preparation process of high-purity molybdenum trioxide

Abstract

The invention particularly relates to a non-ammoniation preparation process of high-purity molybdic acid and high-purity molybdenum trioxide, which is used for treating a molybdenum salt solution and comprises the following operation steps: (1) preliminary chemical impurity removal; (2) precisely filtering; (3) deeply removing impurities by an ion exchange method; (4) adsorbing molybdenum; (5) washing; (6) analyzing; (7) deacidification; (8) preparing high-purity molybdic acid; after deacidification, heating the solution to 60-70 DEG C and becoming turbid, keeping the temperature for 3-6 hours to enable crystals to grow, and then continuously heating to 90-95 DEG C to enable molybdenum to be completely precipitated; filtering to obtain high-purity molybdic acid; and dehydrating the high-purity molybdic acid to obtain high-purity molybdenum trioxide. The high-purity molybdic acid prepared by adopting the process is extremely low in impurity content, high-purity molybdenum trioxide can be directly obtained after drying and dehydration, and compared with an existing method for preparing high-purity molybdenum oxide through decomposition of ammonium molybdate, the process is simple, and no pollutant is generated.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of high-purity molybdic acid and high-purity molybdenum trioxide, and specifically relates to a non-ammoniation preparation process of high-purity molybdic acid and a non-ammoniation preparation process of high-purity molybdenum trioxide. Background Art

[0002] Residue oil, the most difficult heavy component of petroleum to utilize, has an extremely high sulfur content and contains a certain amount of metals (primarily nickel and vanadium). It is typically used only as asphalt or refined petroleum coke, resulting in low economic value. Furthermore, the use of high-sulfur petroleum coke, a highly polluting product, is significantly limited, while the fuel industry is shifting towards low-sulfur petroleum coke or alternative fuels. To reduce pollution during the oil refining process and increase refining profits, hydrogenation of residue oil into economical products such as gasoline and diesel is the optimal production route, and residue oil hydrogenation catalysts play a key role in this process. Molybdic acid is the main active ingredient in the preparation of residue oil hydrogenation catalysts. It appears as white or slightly yellowish monoclinic columnar crystals or powder. The main components of molybdenum acid can be understood as molybdenum trioxide and water. The molybdenum-based catalyst prepared with this acid catalyzes the hydrogenation of residue oil to produce hydrogenated heavy oil. This hydrogenated heavy oil can then be used as a feedstock for catalytic units and processed into high-value-added lighter components such as gasoline, coal, and diesel. Residue oil hydrogenation catalysts have extremely high purity requirements for the molybdenum acid used, and control up to 26 impurity elements, including 19 metal impurities, including sodium, potassium and aluminum, and 7 non-metallic impurities, including sulfur, phosphorus and chlorine.

[0003] The preparation of ordinary molybdic acid primarily involves acidifying a molybdate solution. The resulting molybdic acid has a high impurity content, a fine particle size, and is difficult to filter, making it unsuitable for the raw material requirements of residue oil hydrogenation catalyst production. While the dehydration of molybdic acid to produce molybdenum trioxide is simple and contaminant-free, the resulting molybdenum trioxide does not meet the quality standards for high-purity molybdenum trioxide due to excessive impurities in the molybdic acid.

[0004] Patent CN104445411 adopts platinum calcining water washing wastewater as raw material, adds sodium carbonate solution thereto, utilizes sodium carbonate solution to precipitate the foreign ions such as copper, iron, calcium and magnesium in platinum calcining water washing wastewater, simultaneously sodium carbonate solution can dissolve tiny molybdic acid in platinum calcining water washing wastewater, make filtrate clear after filtration, then adopt the molybdate ion in nitric acid precipitation filtrate, crystallize and grow up to generate large-particle molybdic acid at high temperature.The scanning electron microscope figure of the molybdic acid prepared by its embodiment shows as hexagonal prism, octahedral shape, size is uniform, interface is clear, uniformly dispersed, but it is raw material with platinum calcining water washing wastewater, and applicable face is little, is not suitable for large-scale production, simultaneously Na, K content are 0.X%, Ca, Mg, Fe content are 0.0X%, and high-purity requirement is not reached completely, and other impurity situations are not described.The scanning electron microscope figure of the molybdic acid prepared by the direct acid precipitation of ammonium molybdate solution in its comparative example, crystal is tiny, reunion, interface fuzzy. A scanning electron microscope image of molybdic acid prepared by heating a molybdenum trioxide hydrochloric acid solution shows small, elongated crystals with a relatively clear interface. A scanning electron microscope image of molybdic acid prepared by acid precipitation by adding ammonium nitrate and molybdic acid seed crystals to an ammonium molybdate solution shows a relatively clear interface at 3000x magnification, with hexagonal and octahedral crystals appearing, but the crystals are small.

[0005] Patent CN106698517 adds flaky sodium hydroxide to molybdate solution and evaporates after pre-treatment, dissolves with pure water after crystal appears, then adds solid-liquid separation and oven dry after nitric acid acidification to obtain high-purity molybdic acid. Utilize flaky sodium hydroxide to pre-treat molybdate solution, hope that ammonium ion and ammonia in the solution are all replaced, and simultaneously some metallic impurity ions are carried out impurity removal such as calcium ion. But ammonia odor is serious, need to properly dispose and increase waste gas treatment cost, add alkali decalcification effect not good in addition, adopt fuming nitric acid to precipitate molybdic acid, use process heat release is serious, along with heat release increase, the molybdic acid separated out is sticky, caking is serious after drying, can not form powder. In embodiment, product sodium salt content is higher at 2.0%, and other anionic impurity elements such as chloride ion, phosphorus etc. are not described, and product crystal form has certain improvement.

[0006] Patent CN107915256 uses waste oil hydrogenation catalyst as raw material. After deoiling, sodium roasting and leaching, pure sodium hydroxide or pure calcium hydroxide is used to remove calcium, aluminum, silicon and phosphorus. After vanadium precipitation in the purified liquid, the molybdenum liquid after ion exchange adsorption of vanadium is extracted and stripped to obtain sodium molybdate solution. Concentrated sulfuric acid is added to obtain molybdic acid precipitate. The method does not clearly describe the composition and crystal form of the resulting molybdic acid product. However, based on descriptions in other patents and actual production conditions, the Na and S contents in the product should be relatively high, making it difficult to ensure high purity.

[0007] Patent CN112875753 uses high-purity molybdenum trioxide as the raw material. After slurrying, sodium hydroxide is dissolved to obtain a sodium molybdate solution. Nitric acid solution is slowly added until acidic, and the temperature is increased until molybdic acid crystals precipitate. The molybdic acid obtained by this method has a sodium salt content of 0.2%. The eight impurities measured meet the requirements for high-purity molybdenum acid, and other impurities are not described. However, the high-purity molybdenum trioxide used is expensive, exceeding the price of molybdic acid, making it economically unfeasible.

[0008] Patent CN118026261 and its paper "Research on a New Process for Preparing High-Purity Molybdic Acid from Crude Sodium Molybdate Solution" use crude sodium molybdate as raw material, and deeply remove impurities in molybdate through precipitation and ion exchange methods. The obtained pure sodium molybdate solution is passed through a bipolar membrane electrolysis system to form a molybdic acid solution, and then a high-purity molybdic acid product is prepared by adding a crystallization aid or heating crystallization. Removing P, As, Si, W, and V only through calcium precipitation has limited effect and a large amount of molybdenum loss. Cationic resin is used to remove impurity ions such as calcium and magnesium, and desalination is carried out through a bipolar membrane electrodialysis system. The end point of the sodium molybdate solution is controlled at 0~1.5 and then heated to precipitate. However, the electrodialysis desalination efficiency gradually decreases with the extension of operating time and the decrease of pH. In order to ensure the desalination effect, the voltage must be increased and the time must be extended, resulting in increased costs. When high-purity molybdenum trioxide is added as a seed crystal, the crystals are relatively perfect, but the composition after XRD analysis is H2MoO 10 , and it is not the common molybdic acid expression MoO3▪H2O or H2MoO4.

[0009] Patent CN116397100 uses an oil hydrogenation catalyst as raw material. After crushing, deoiling, sodiumization, roasting, and leaching, calcium oxide is added to the leachate to precipitate calcium vanadate and calcium molybdate, respectively. The calcium molybdate is added to an ammonium solution, thoroughly mixed, and filtered. The filtered solution is crystallized to produce solid ammonium molybdate. The ammonium molybdate is then ground and refined, neutralized with nitric acid, and washed and dried to produce molybdic acid. The resulting molybdic acid is consistent with that produced by direct acid precipitation from an ammonium molybdate solution. The resulting crystals are small, agglomerated, and have a fuzzy interface. Furthermore, the NH4+ content exceeds the standard.

[0010] Patent CN113981251 pulverizes and calcines a waste heavy oil hydrogenation catalyst, mixes it with ammonium bicarbonate water, and then hydrothermally treats it to produce a molybdenum-containing solution. Concentrated nitric acid is then added to precipitate molybdic acid. Simple precipitation and washing alone cannot effectively remove impurity ions and ensure purity.

[0011] Patent CN115710018 calcines and pulverizes the catalyst, dissolving it with ammonia and hydrogen peroxide. After solid-liquid separation, the resulting solution should be an ammonium molybdate solution, not the molybdic acid solution described. Adding sodium hydroxide, filtering, and evaporating at normal pressure actually expel the ammonia gas. Nitric acid precipitation is then added to obtain molybdic acid. The resulting product is consistent with nitric acid precipitation of a sodium molybdate solution, and the process is simple, but the impurity content cannot be guaranteed.

[0012] CN114275816 treats a molybdenum source with an alkali solution to obtain a sodium molybdate leachate, which is then subjected to adsorption and impurity removal to obtain an adsorption leachate. The leachate is heated, hydrochloric acid is added, and stirred, followed by filtration, washing, and drying to obtain molybdic acid particles. Using an anion exchange resin alone for impurity removal is effective for cationic impurities but ineffective for anionic impurities, resulting in a high sodium salt content in the precipitate.

[0013] CN114349050 uses calcium molybdate as a raw material, adds a leaching solvent, and obtains a sodium molybdate leachate, which is then subjected to gas stripping and deammoniation to obtain a deaminated molybdenum-containing solution. Hydrogen peroxide is then added for oxidation, and nitric acid is added to adjust the pH. The reaction is then heated to precipitate molybdic acid crystals. This process does not involve any impurity removal process, and the resulting molybdic acid crystals are poorly shaped, lacking hexagonal or octahedral shapes.

[0014] In summary, in view of the shortcomings of the above-mentioned treatment processes in the prior art, the present invention provides a non-ammoniation preparation process for high-purity molybdic acid and a non-ammoniation preparation process for high-purity molybdenum trioxide. Summary of the Invention

[0015] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0016] To this end, the present invention proposes a non-ammoniation preparation process for high-purity molybdic acid and a non-ammoniation preparation process for high-purity molybdenum trioxide. The high-purity molybdic acid prepared by this process has an extremely low impurity content. After drying and dehydration, high-purity molybdenum trioxide can be directly obtained. Compared with the current method of preparing high-purity molybdenum oxide by decomposing ammonium molybdate, the process is simple and free of pollutants.

[0017] A non-ammoniation process for preparing high-purity molybdic acid comprises treating a molybdenum salt solution and comprising the following steps: (1) Preliminary chemical impurity removal Adjust the solution pH to 8-10, add magnesium salt, and heat to boil for 0.5-2h.

[0018] In this step, silicon is removed by precipitation in the form of H2SiO3 and MgSiO3, phosphorus is removed by precipitation in the form of MgHPO4, and arsenic is removed by precipitation in the form of MgHAsO4. In the ammonium salt solution, the phosphorus and arsenic precipitates are further converted into MgNH4PO4 and MgNH4AsO4 precipitation forms. At the same time, the amphoteric metals aluminum and tin are hydrolyzed to form Al(OH)3 and Sn(OH)4, which are removed. Filter to remove the precipitate, and the silicon, phosphorus and arsenic content in the filtrate can be reduced to 30~50mg / L; The pH of the filtrate was further adjusted to 10-14, and calcium chloride was added to form calcium sulfate precipitation, and silicon, phosphorus and arsenic were further removed to <30 mg / L; (2) Precision filtration After filtering the above solution, the filtrate is readjusted to pH 6-10 and then finely filtered through a filter membrane with a pore size of 0.1-1 μm to remove tiny colloidal precipitates such as silica gel and aluminum hydroxide; (3) Deep impurity removal by ion exchange method (4) Adsorption of molybdenum (5) Washing Wash the ion exchange resin with pure water until the sodium ion concentration is less than 10 mg / L, then wash with dilute acid at a concentration of 1% to 10% to further remove cations precipitated in the resin due to inclusions and pH changes, and wash until the cation concentration in the washing solution is less than 1 mg / L; (6) Analysis (7) Deacidification The acidity of the high-acid analytical solution is too high to directly precipitate molybdic acid; Excess acid is recovered.

[0019] Diffusion dialysis, cathode membrane electrolysis, and bipolar membrane electrodialysis are used to reduce the acidity in the analytical solution. After treatment, the acidity of the solution drops to 0.5~1mol / L. Diffusion dialysis is no longer effective for further reduction. The voltage of membrane electrolysis and electrodialysis has increased significantly, increasing the power consumption cost. The recovered acid can be reused to adjust the pH of the solution.

[0020] (8) Producing high-purity molybdic acid After deacidification, the solution is heated to 60-70°C and begins to become turbid. Keep warm for 3-6 hours to allow crystal growth, and then continue to heat to 90-95°C to complete the precipitation of molybdenum. After filtration, high-purity molybdic acid is obtained.

[0021] As a further improvement of this solution, the specific operating steps of the (3) ion exchange method for deep impurity removal are as follows: The filtrate is passed through a macroporous resin with active rare earth element groups and the pH is controlled to be 3-7 for column adsorption, which can reduce silicon, phosphorus and arsenic to <1 mg / L.

[0022] In this step, the macroporous resin with active rare earth element groups has a high specific surface area and porosity. Advanced active component introduction technology is used to introduce the zirconium inorganic polymer into the porous resin with high specific surface area and porosity, which has high selectivity for silicate, phosphate and arsenate in the solution. If the column liquid contains tungsten and vanadium impurities, first remove the vanadium through a macroporous strong alkaline anion exchange resin.

[0023] In this step, vanadium is mainly in the form of V3O9 3- Molybdenum exists mainly in the form of MoO4 2- Form exists, V3O9 3- Because it carries more charges, it can be preferentially adsorbed by strong base macroporous chloride anion exchange resin.

[0024] The column liquid then passes through the weakly alkaline anion resin to remove tungsten. Tungsten is mainly in the form of W7O 24 6- The morphology exists, and the radius is larger than MoO4 2- In a solution with high molybdenum and low tungsten, the polytungstate ions have a larger nucleophilic potential and are preferentially adsorbed.

[0025] As a further improvement of this solution, The specific steps of (4) molybdenum adsorption are as follows: After impurity removal, the pH of the solution is adjusted to 1.5~4. After the adjustment, the solution passes through a macroporous weakly basic anion resin to adsorb molybdenum, and most of the cationic impurities are removed with the column liquid.

[0026] In this step, molybdenum is mainly in the form of Mo8O 26 4- and Mo7O 21 (OH) 3- In the sodium molybdate solution obtained by alkali leaching, except for amphoteric metals, other metals such as copper and nickel are not leached. In the ammonium molybdate solution obtained by ammonia leaching, there are impurities such as copper, nickel, and zinc, such as ammonium complex ions [Me(NH3)4]. 2- , by adjusting the pH to Me 2+ exists in the form of .

[0027] As a further improvement of this solution, In the (1) preliminary chemical impurity removal, the magnesium salt is any one or more of magnesium chloride, magnesium sulfate, and basic nickel carbonate.

[0028] As a further improvement of this solution, The dilute acid in the washing (5) is any one or more of hydrochloric acid, sulfuric acid, and nitric acid.

[0029] As a further improvement of this solution, The specific steps of (6) analysis are as follows: using high concentration acid for analysis; Wherein, the high-concentration acid is any one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the acidity is 4-9 mol / L.

[0030] As a further improvement of this solution, the molybdenum salt solution is sodium molybdate or ammonium molybdate solution.

[0031] As a further improvement of this solution, the molybdenum salt solution is an alkaline leaching solution or an ammonia leaching solution after molybdenum roasted sand or a molybdenum-containing catalyst is sodium-roasted.

[0032] A non-ammoniation preparation process for high-purity molybdenum trioxide comprises the following preparation steps: directly roasting and dehydrating high-purity molybdenum acid to obtain high-purity molybdenum trioxide; Wherein, the high-purity molybdic acid is prepared by the non-ammoniation preparation process of high-purity molybdic acid.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) Anionic impurity removal method: First, the chemical impurity removal method currently in industrial application is used to perform preliminary impurity removal on silicon, phosphorus, and arsenic. However, the removal capacity of this method is limited and can generally only be reduced to 15~50 mg / L. The introduction of excessive magnesium salts and calcium salts will also cause the precipitation loss of molybdenum. After the impurity content is detected by the original solution, a precise amount of chemical reagents (MgCl2, CaCl2) is added to remove most of the silicon, phosphorus, arsenic, sulfur and other impurities. After filtration, the filtrate does not directly enter the ion exchange link, and precision filtration is added. By selecting the pore size of the filter membrane, fine colloidal impurities in the solution that cannot be observed by the naked eye are further removed. The filtrate further enters the ion exchange deep impurity removal. Through the selected special functional group resin and precise control of pH, the resin further adsorbs the impurities to <1 mg / L.

[0034] (2) Molybdenum desorption: The use of anion exchange resin to adsorb molybdenum has been widely used in industrial production. After passing through the resin, most cationic impurities can be removed. The cations entrained in the resin can be further removed by washing with water. However, there are still very small amounts of amphoteric metal ions such as aluminum and tin that cannot be removed by simple water washing. The acid washing process is added, the pH of the acid washing solution is controlled, and the cationic impurities are further washed to remove them. At present, the conventional desorption method is to use sodium hydroxide or ammonia water for desorption, which reintroduces sodium and ammonium ions. When acid precipitation of molybdenum acid occurs, it is easy to enter the molybdenum acid precipitate and is difficult to remove by washing (the washing effect is poor and it cannot be washed multiple times. After multiple washings, the molybdenum acid will lose its original crystal form and become sticky and difficult to filter). The innovative use of acid solution desorption has a high acid concentration requirement. Low-concentration acid desorption has poor or no effect. Molybdenum exists in the form of cations in the high-acid desorption solution. If the molybdenum acid is precipitated by neutralization to reduce the acidity, impurity ions such as sodium or ammonium ions introduced by the alkali will be reintroduced. There is no essential difference from direct alkaline solution or ammonia solution desorption and the cost is increased. Diffusion dialysis and electrodialysis have been widely used in waste acid recovery in recent years. This technology can be used to recover acid from high-acid analytical solutions. The recovered acid, which contains tens of milligrams per liter of molybdenum, can be used in the initial pH adjustment process, allowing the acid to be reused without losing the small amount of molybdenum it contains. When the acidity of the analytical solution drops to 0.5-1 mol / L, diffusion dialysis is essentially ineffective. Electrodialysis can further reduce the acidity, but this increases the cell voltage and power consumption, making these conditions the preferred method for molybdate precipitation.

[0035] (3) Molybdic acid crystallization process: After the solution with reduced acidity is heated to 60-70 degrees, the solution becomes turbid. In order to ensure that the precipitated molybdic acid has a regular hexagonal shape, the temperature is controlled and kept warm for 3-6 hours to allow crystal growth. The temperature is then continued to rise to 90-95 degrees to allow the molybdenum to precipitate completely. After filtration, high-purity molybdic acid is obtained. If the temperature is too high during the process, a large number of crystal nuclei will burst out, agglomeration will occur, and the precipitated molybdic acid will be of poor crystal form, which is difficult to filter and sticky.

[0036] (4) Molybdenum trioxide process: The high-purity molybdic acid prepared by this process has an extremely low impurity content. After drying and dehydration, high-purity molybdenum trioxide can be directly obtained. Compared with the current method of preparing high-purity molybdenum oxide by decomposing ammonium molybdate, the process is simple and free of pollutants. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a process flow chart for the non-ammoniation preparation of high-purity molybdenum trioxide according to the present invention; Figure 2 This is a scanning electron microscope image of the high-purity molybdic acid product in Example 1 of the present invention; Figure 3 This is the XRD analysis diagram of high-purity molybdic acid in Example 1 of the present invention; Figure 4 This is a screenshot of the XRD software analysis of high-purity molybdic acid in Example 1 of the present invention; Figure 5 This is a scanning electron microscope image of the sodium molybdic acid product in Comparative Example 2 of the present invention; Figure 6 This is the XRD analysis diagram of sodium molybdic acid in Comparative Example 2 of the present invention; Figure 7 This is a screenshot of the XRD software analysis of sodium molybdate in Comparative Example 2 of the present invention; Figure 8 This is a scanning electron microscope image of the high-acid precipitated molybdic acid product in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0038] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0039] The non-ammoniation preparation process of high-purity molybdenum trioxide of the present invention is as follows: The molybdenum salt solution is sodium molybdate or ammonium molybdate solution, which is generally the alkaline leachate or ammonia leachate after molybdenum roasted sand or molybdenum-containing catalyst sodium roasting, and contains anions such as silicon, phosphorus, arsenic and a certain amount of sulfate and cationic impurities.

[0040] Preliminary chemical impurity removal Adjust the solution's pH to 8-10, then add a magnesium salt (such as magnesium chloride, magnesium sulfate, or basic nickel carbonate). Heat and boil for 0.5-2 hours. Silicon is precipitated as H2SiO3 and MgSiO3, phosphorus as MgHPO4, and arsenic as MgHAsO4. In the ammonium salt solution, the phosphorus and arsenic precipitates are further converted to MgNH4PO4 and MgNH4AsO4. Simultaneously, the amphoteric aluminum and tin are hydrolyzed to form Al(OH)3 and Sn(OH)4, which are removed. Filter and remove the precipitate. The silicon, phosphorus, and arsenic levels in the filtrate can be reduced to 15-50 mg / L. The pH of the filtrate is then adjusted to 10-14, and calcium chloride is added to form a calcium sulfate precipitate. This further removes silicon, phosphorus, and arsenic to <30 mg / L.

[0041] Precision filtration After filtering the above solution, the filtrate is readjusted to pH 6-10 and then finely filtered through a filter membrane with a pore size of 0.1-1 μm to remove tiny colloidal precipitates such as silica gel and aluminum hydroxide.

[0042] (3) Deep impurity removal by ion exchange method The filtrate passes through a macroporous resin with active rare earth element groups. The resin has a high specific surface area and porosity. Advanced active component introduction technology is used to introduce zirconium inorganic polymers into the porous resin with high specific surface area and porosity. It has high selectivity for silicate, phosphate, and arsenate in the solution. By controlling the pH to 3~7 and adsorbing through the column, silicon, phosphorus, and arsenic can be reduced to <1mg / L. If the column liquid contains tungsten and vanadium impurities, it is first removed by a macroporous strong alkaline anion exchange resin. At this time, the vanadium is mainly in the form of V3O9 3- Molybdenum exists mainly in the form of MoO4 2- Form exists, V3O9 3- Because it carries a higher charge, it is preferentially adsorbed by a strong-base macroporous chloride-type anion exchange resin (preferably D231yt or D231II). The column liquid then passes through a weakly basic anion resin to remove tungsten. Tungsten exists primarily in the form of W7O246-, which has a larger radius than MoO42-. In a solution with high molybdenum and low tungsten content, the polytungstate ion has a greater nucleophilic potential and is preferentially adsorbed (preferably D630 resin).

[0043] (4) Adsorption of molybdenum After removing impurities, the solution pH was adjusted to 1.5~4, and the molybdenum was mainly in the form of Mo8O 26 4- and Mo7O 21 (OH) 3- In the sodium molybdate solution obtained by alkali leaching, except for amphoteric metals, other metals such as copper and nickel are not leached. In the ammonium molybdate solution obtained by ammonia leaching, there are impurities such as copper, nickel, and zinc, such as ammonium complex ions [Me(NH3)4]. 2-, by adjusting the pH to Me 2+ After adjustment, the solution passes through a macroporous weakly alkaline anion resin to adsorb molybdenum, and most of the cationic impurities are removed with the column liquid.

[0044] (5) Washing Wash the ion exchange resin with pure water until the sodium ion concentration is <10 mg / L, then wash it with dilute acid (which can be hydrochloric acid, sulfuric acid, or nitric acid) at a concentration of 1% to 10% to further remove cations precipitated in the resin due to inclusions and pH changes. Wash until the cation concentration in the washing liquid is <1 mg / L.

[0045] (6) Analysis Use high concentration acid (such as hydrochloric acid, sulfuric acid, or nitric acid) for analysis, with an acidity of 4~9 mol / L.

[0046] (7) Deacidification The high-acid solution has too high an acidity to directly precipitate molybdic acid. To recover the excess acid, diffusion dialysis, cathodic membrane electrolysis, or bipolar membrane electrodialysis can be used to reduce the acidity in the solution. After treatment, the solution acidity drops to 0.5-2 mol / L. Further reduction by diffusion dialysis is ineffective, and the membrane electrolysis and electrodialysis voltages increase significantly, increasing power consumption and costs. The recovered acid can be reused to adjust the solution pH.

[0047] (8) Producing high-purity molybdic acid After deacidification, the solution is heated to 60-70°C until it becomes turbid. Keep warm for 3-6 hours to allow crystal growth, and then continue to heat to 90-95°C to completely precipitate the molybdenum. After filtration, high-purity molybdic acid is obtained.

[0048] (9) High-purity molybdenum trioxide is obtained by direct roasting and dehydration of high-purity molybdic acid.

[0049] The embodiments and comparative examples of the present invention are described in detail below: Example 1 The sodium-calcined molybdenum-containing spent catalyst was leached at a solid-to-liquid ratio of 1:3, controlling the pH to 9 at 60-80°C. The theoretical amount of MgCl2 was added to remove silicon and phosphorus. The reaction was heated and stirred for 60 minutes before filtration. The filtrate was adjusted to pH 10, and 1.1 times the theoretical amount of CaCl2 was added to further remove silicon and phosphorus. Filtration through a 0.22μm membrane yielded a sodium molybdate solution containing 15.02g / L molybdenum, 23.45mg / L silicon, 18.77mg / L phosphorus, 3.07mg / L tungsten, 5.44mg / L vanadium, and 1.95mg / L vanadium. The filtrate was collected as 1#, a portion of which was used in this example and a portion in Comparative Example 1.

[0050] The filtrate was adjusted to pH 7 and passed through a macroporous resin with active rare earth element groups (adsorption rate of 0.5 VB·h−1). The adsorption effluent yielded a solution with silicon, phosphorus, and arsenic concentrations <0.5 mg / L, W 3.20 mg / L, and V 1.06 mg / L, with molybdenum adsorption loss <2%. After sequential passage through a vanadium-absorbing resin (adsorption rate of 0.2 VB·h−1) and a tungsten-absorbing resin (adsorption rate of 0.5 VB·h−1), tungsten and vanadium concentrations were <0.5 mg / L. The column liquid was collected as 2#, a portion of which was used in this example and a portion in Comparative Example 2.

[0051] The column liquid was adjusted to pH 2.5 with hydrochloric acid and adsorbed with D314 resin (adsorption rate was 0.5 VB·h −1 After adsorption saturation, the column was washed with pure water until the sodium content in the washing water reached 8.6 mg / L. After washing with 0.1 mol / L HCl for 2 column volumes, the column was decomposed with 6 mol / L HCl (decomposition rate was 2 VB·h −1 ), the molybdenum concentration in the analytical solution was 85.62 g / L, and the acidity was 4.64 mol / L. After collection, it was 3#, part of which was used in this embodiment and part was used in Comparative Example 3.

[0052] The high-acid analytical solution was passed through a diffusion dialysis device until the acidity dropped to 1.62 mol / L. The solution was heated to 60°C and became turbid. After adding hydrogen peroxide with a volume ratio of 1‰, the reaction was kept warm for 6 hours. The temperature was further raised to 95°C and the reaction was continued for 1 hour. The product was cooled and filtered to obtain a high-purity molybdic acid product. The molybdenum content in the filtered tail liquid was <5 g / L. The product analysis results are shown in Table 1 below. The high-purity molybdic acid was dehydrated at 300°C to obtain high-purity molybdenum trioxide. The product analysis results are shown in Table 2. The electron microscopy analysis of the high-purity molybdic acid product is shown in Table 2. Figure 3 As shown, the XRD analysis of high-purity molybdic acid products is as follows Figure 2 and Figure 3 shown.

[0053] Table 1 Analysis results of high-purity molybdic acid

[0054] Table 2 Analysis and test results of high-purity molybdenum trioxide

[0055] Figure 2 This is a scanning electron microscope image of the high-purity molybdic acid product in Example 1. Figure 3 This is the XRD analysis diagram of high-purity molybdic acid in Example 1 Figure 4 Screenshot of the XRD software analysis of high-purity molybdic acid in Example 1 Comparative Example 1: In Example 1, the filtrate was adjusted to pH 3 and passed through a macroporous resin with active rare earth element groups (adsorption rate was 0.5 VB·h −1 After adsorption, silicon, phosphorus, and arsenic were <0.5 mg / L, but molybdenum was also adsorbed at the same time, and the molybdenum content in the column liquid was only 33.55 mg / L.

[0056] Comparative Example 2: The column liquid in Example 2# was re-adjusted to pH 2.5 with hydrochloric acid and adsorbed with D314 resin for molybdenum (adsorption rate was 0.5 VB·h −1 ), after adsorption saturation, it was washed with pure water for 2 column volumes and then analyzed with 12% NaOH (analysis rate was 2 VB·h −1 ), the molybdenum concentration in the analytical solution was 105.64 g / L, heated to 60°C, added hydrogen peroxide with a volume ratio of 1‰ and continued to heat to 90°C, added hydrochloric acid to pH 0.5 and kept warm for 2 hours, cooled and filtered to obtain molybdic acid product, and the molybdenum content in the filtered tail liquid was <5g / L. The product analysis results are shown in Table 3, and the scanning electron microscopy analysis results are shown in Figure 5 As shown: Table 3 Analysis results of sodium-containing molybdic acid

[0057] Molybdic acid contains a large amount of sodium.

[0058] Figure 5 This is the scanning electron microscope image of the sodium molybdate product in Comparative Example 2. Figure 6 XRD analysis diagram of sodium molybdic acid in comparative example 2 Figure 7 Screenshot of XRD software analysis of sodium molybdate in Comparative Example 2 Comparative Example 3: In the embodiment 3# high acid desorption liquid was heated to 60°C, and hydrogen peroxide with a volume ratio of 1‰ was added. The solution was clear and continued to be heated to 90°C. A precipitate was precipitated. The reaction was kept warm for 2h, cooled and filtered to obtain a molybdate product. The molybdenum content in the filtered tail liquid was >30g / L, and the recovery rate was low. The results of scanning electron microscopy analysis were as follows: Figure 8 As shown: Figure 8 This is the scanning electron microscope image of the high acid precipitation molybdic acid product in Comparative Example 3 The molybdic acid product crystals are not hexagonal and are slow to filter.

[0059] Comparative Example 4: The molybdenum-containing spent catalyst, calcined with sodium, was leached at a solid-liquid ratio of 1:3, with a pH of 9 at 60-80°C. A theoretical amount of MgCl2 was added to remove silicon and phosphorus. The reaction was stirred and heated for 60 minutes before filtration. The filtrate was adjusted to pH 10, and 1.1 times the theoretical amount of CaCl2 was added to further remove silicon and phosphorus. Filtering with slow quantitative filter paper yielded a sodium molybdate solution containing 14.33 g / L molybdenum. The solution was adjusted to pH 2.5, and the solution turned from clear and transparent to slightly turbid and opaque. Molybdenum was adsorbed on D314 resin (at an adsorption rate of 0.5 VB·h). −1 ), after adsorption saturation, it was washed with pure water for 2 column volumes and then analyzed with 12% NaOH (analysis rate was 2 VB·h −1 ), the molybdenum concentration in the analytical solution was 105.64 g / L, heated to 60°C, added with hydrogen peroxide at a volume ratio of 1‰ and continued to heat to 90°C, added with hydrochloric acid to pH 0.5 and kept warm for 2 hours, cooled and filtered to obtain molybdic acid product, and the molybdenum content in the filtered tail liquid was <5 g / L. The product analysis results are shown in Table 4: Table 4 Analysis results of sodium-containing molybdic acid

[0060] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A process for preparing high-purity molybdic acid without ammoniation, characterized in that: The molybdenum salt solution is treated, comprising the following steps: (1) Preliminary chemical impurity removal Adjust the solution pH to 8-10, add magnesium salt, and boil for 0.5-2h; Filter to remove the precipitate, and the silicon, phosphorus and arsenic content in the filtrate can be reduced to 15~50mg / L; The pH of the filtrate is further adjusted to 10-14, and calcium chloride is added to form calcium sulfate precipitation, and silicon, phosphorus and arsenic are further removed to <15 mg / L; (2) Precision filtration After filtering the above solution, the filtrate is readjusted to pH 6-10 and then finely filtered through a filter membrane with a pore size of 0.1-1 μm to remove tiny colloidal precipitates such as silica gel and aluminum hydroxide; (3) Deep impurity removal by ion exchange method (4) Adsorption of molybdenum (5) Washing Wash the ion exchange resin with pure water until the sodium ion concentration is less than 10 mg / L, then wash with dilute acid at a concentration of 1% to 10% to further remove cations precipitated in the resin due to inclusions and pH changes, and wash until the cation concentration in the washing solution is less than 1 mg / L; (6) Analysis (7)Deacidification (8) Producing high-purity molybdic acid After deacidification, the solution is heated to 60-70°C and begins to become turbid. Keep warm for 3-6 hours to allow crystal growth, and then continue to heat to 90-95°C to complete the precipitation of molybdenum. After filtration, high-purity molybdic acid is obtained.

2. The non-ammoniation preparation process for high-purity molybdic acid according to claim 1, wherein: The specific operation steps of the (3) ion exchange method for deep impurity removal are as follows: The filtrate passes through a macroporous resin with active rare earth element groups, controls the pH to 3-7, and then undergoes column adsorption to reduce silicon, phosphorus, and arsenic to <1 mg / L. If the column liquid contains tungsten and vanadium impurities, first remove vanadium through macroporous strong alkaline anion exchange resin. At this time, vanadium is mainly in the form of V3O9 3- Molybdenum exists mainly in the form of MoO4 2- Form exists, V3O9 3- Because it carries more charges, it is preferentially adsorbed by strong base macroporous chloride anion exchange resin; The column liquid then passes through weakly alkaline anion resin to remove tungsten.

3. The non-ammoniation preparation process for high-purity molybdic acid according to claim 1, wherein: The specific steps of (4) molybdenum adsorption are as follows: After impurity removal, the pH of the solution is adjusted to 1.5~4. After adjustment, the solution passes through a macroporous weakly basic anion resin to adsorb molybdenum, and most of the cationic impurities are removed with the column liquid.

4. The process for preparing high-purity molybdic acid without ammoniation according to claim 1, wherein: In the (1) preliminary chemical impurity removal, the magnesium salt is any one or more of magnesium chloride, magnesium sulfate, and basic nickel carbonate.

5. The process for preparing high-purity molybdic acid without ammoniation according to claim 1, wherein: The dilute acid in the washing (5) is any one or more of hydrochloric acid, sulfuric acid, and nitric acid.

6. The process for preparing high-purity molybdic acid without ammoniation according to claim 1, wherein: The specific steps of (6) analysis are as follows: using high concentration acid for analysis; Wherein, the high-concentration acid is any one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the acidity is 4-9 mol / L.

7. The process for preparing high-purity molybdic acid without ammoniation according to claim 1, wherein: The molybdenum salt solution is sodium molybdate or ammonium molybdate solution.

8. The process for preparing high-purity molybdic acid without ammoniation according to claim 7, wherein: The molybdenum salt solution is an alkaline leaching solution or an ammonia leaching solution obtained after molybdenum calcined sand or a molybdenum-containing catalyst is sodium-treated and calcined.

9. A process for preparing high-purity molybdenum trioxide without ammoniation, characterized in that: The method comprises the following preparation steps: directly roasting and dehydrating high-purity molybdenum acid to obtain high-purity molybdenum trioxide; The high-purity molybdic acid is prepared by the non-ammoniation preparation process of the high-purity molybdic acid according to any one of claims 1 or 8.

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