Method for preparing ammonium phosphomolybdate from sulfuric acid system phosphorus-containing molybdenum-vanadium mixed solution

Abstract

The invention provides a method for preparing ammonium phosphomolybdate from a sulfuric acid system phosphorus-containing molybdenum-vanadium mixed solution, and relates to the technical field of ammonium phosphomolybdate production. S2, adjusting pH and supplementing an ammonium source; step S3, precipitating ammonium phosphomolybdate; and S4, recovering and reusing the molybdenum and vanadium-containing solution resin. The process flow is short, the whole process is simple and easy to industrialize, three wastes are basically avoided, and the method is an efficient, green, environment-friendly and low-carbon process route.

Description

Technical Field

[0001] The invention relates to the technical field of ammonium phosphomolybdate production, and in particular to a method for preparing ammonium phosphomolybdate from a sulfuric acid system phosphorus-molybdenum-vanadium mixed solution. Background Art

[0003] As an important compound of molybdenum, ammonium phosphomolybdate is a multifunctional chemical substance with a wide range of uses. It can not only be used as a fertilizer to increase crop yields, but can also be used in photosensitive materials, catalysts, electronic materials, flame retardant additives, etc., and has important application value. With the continuous development of science and technology, the application field of ammonium phosphomolybdate will continue to expand, providing more possibilities for the development and progress of various fields.

[0004] In the literature reports on the preparation of ammonium phosphomolybdate, most of them are prepared by reacting ammonium molybdate and phosphate in a nitric acid system. The nitrate ion content in the wastewater produced by the preparation of ammonium phosphomolybdate in the nitric acid system is relatively high, and the wastewater treatment is difficult, which is not conducive to industrial production. There are very few reports on the preparation of ammonium phosphomolybdate in a sulfuric acid system. Summary of the invention

[0005] The present invention aims at the problem of a large amount of nitric acid wastewater generated in the existing method for preparing ammonium phosphomolybdate, and provides a new method for preparing ammonium phosphomolybdate. The preparation method is completed in a sulfuric acid system, avoiding the problem of treating nitric acid-containing wastewater, reducing production costs, producing products with high added value and wide application, and the production process is green and environmentally friendly, and suitable for large-scale production. Specifically:

[0006] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution, comprising:

[0007] S1, add sulfuric acid to the phosphorus-molybdenum-vanadium mixed solution to adjust the solution pH, heat and add ammonium sulfate, stir and fully react for a certain period of time, stop heating and let stand, filter to obtain crude ammonium metavanadate and vanadium precipitation liquid, and wash and dry the crude ammonium metavanadate to obtain an ammonium metavanadate byproduct;

[0008] S2, adding sulfuric acid to the solution after vanadium precipitation to adjust the solution pH, then adding ammonium source, and stirring thoroughly to completely dissolve the ammonium source;

[0009] S3, heating the solution obtained in S2, then adding a phosphorus source and sulfuric acid, controlling the reaction to a certain pH range, and standing and filtering after a certain reaction time to obtain crude ammonium phosphomolybdate and a precipitated molybdenum mother liquor, and washing and drying the crude ammonium phosphomolybdate to obtain an ammonium phosphomolybdate product;

[0010] S4, after collecting and mixing the wash water and the platinum precipitation mother liquor of steps S1-S3, recover the platinum element and a small amount of vanadium element by resin adsorption, then parse the adsorption saturated resin to obtain a molybdenum-vanadium solution, return the molybdenum-vanadium solution to the next phosphorus-containing molybdenum-vanadium mixed solution of S1, continue, and recycle.

[0011] Preferably, the pH of the phosphorus-molybdenum-vanadium mixed solution in step S1 is about 13, the molybdenum content of the phosphorus-molybdenum-vanadium mixed solution is 30-70 g / L, the phosphorus content is 2-10 g / L, and the vanadium content is 10-20 g / L.

[0012] Preferably, in step S1, sulfuric acid is used to adjust the pH to 10-12, the heating temperature is 30-70° C., the amount of ammonium sulfate used is 5.0-8.0 times the theoretical amount, and the reaction time is 2-5 hours. By using a large theoretical amount of ammonium sulfate, there are enough ammonium ions in the solution to promote the formation of precipitation and accelerate the precipitation rate.

[0013] Preferably, in step S2, the pH of the solution is adjusted to 1.0-3.0, the ammonium source is one or both of ammonium sulfate and ammonia water, and the amount of the ammonium source is 0.5-2.0 times the theoretical amount.

[0014] Preferably, in step S3, the phosphorus source is one or more of sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, etc., and the added amount is 1.1-2.0 times the difference of the phosphorus source required to form ammonium phosphomolybdate, the sulfuric acid used is concentrated sulfuric acid, the pH range of the reaction is controlled to be 0-1.5, the reaction time is 1.5-4.0h, and the reaction temperature is 20-70°C.

[0015] Preferably, in step S3, the phosphorus source and sulfuric acid are added simultaneously.

[0016] Preferably, the resin used to adsorb molybdenum and a small amount of vanadium in step S4 is D314 resin.

[0017] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0018] Compared with a nitric acid system, the method for preparing ammonium phosphomolybdate using a sulfuric acid system of the present invention does not introduce nitrate ions, and thus does not involve the problem of discharging or recycling a large amount of nitrate-containing wastewater in a traditional nitric acid system process.

[0019] The process of the invention fully utilizes the molybdenum and phosphorus elements in the solution to form the ammonium phosphomolybdate product, and directly synthesizes the ammonium metavanadate product with the vanadium element, and efficiently recovers the molybdenum, phosphorus and vanadium in the solution, thereby achieving the purpose of comprehensive utilization of resources.

[0020] The technical solution of the invention is simple, the equipment requirement is low, the materials used are all common industrial products, which are easy to purchase and cheap, the recovery rate of the target element is high, the production cost is low, and basically no three wastes are generated. The process is green and environmentally friendly. Therefore, the application of the technology will provide a new method for preparing ammonium phosphomolybdate in the field of ammonium phosphomolybdate production technology, which has great economic and social value.

[0021] The present invention can obtain a high-value-added ammonium phosphomolybdate product by regulating pH, temperature, phosphate, sulfate and reaction process. Finally, the washing water and molybdenum precipitation mother liquor of the previous step can be mixed together, and resin adsorption and analysis can further improve the recovery rate of molybdenum and vanadium, which is conducive to large-scale industrial production and promotion.

[0022] In summary, compared with other traditional methods, the method of the present invention selects a sulfuric acid system that is avoided as much as possible in the prior art to prepare ammonium phosphomolybdate, fully utilizes the molybdenum and phosphorus elements in the solution to synthesize ammonium phosphomolybdate, reduces production costs, synergistically improves product yield and the comprehensive recovery rate of molybdenum and vanadium elements, and efficiently recovers molybdenum, phosphorus and vanadium in the solution, thereby achieving the purpose of comprehensive resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 The present invention is a process flow chart for preparing ammonium phosphomolybdate from a phosphorus, molybdenum and vanadium mixed solution in a sulfuric acid system. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The composition analysis results of the phosphorus-molybdenum-vanadium mixed solution used in the following examples are shown in Table 1

[0027] Table 1 Composition analysis results of phosphorus-molybdenum-vanadium mixed solution

[0028] Mo P V pH 58.72g / L 2.33g / L 14.77g / L 13.5

[0029] Example 1

[0030] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution, such as Figure 1 As shown, the method comprises the following steps:

[0031] S1, vanadium removal: add sulfuric acid to the phosphorus, molybdenum and vanadium mixed solution to adjust the solution pH to 10, heat to 50 ° C and add ammonium sulfate according to 5 times the theoretical amount, stir and react for 4 hours, stop heating and let stand, filter to obtain crude ammonium metavanadate and vanadium precipitation liquid, the crude ammonium metavanadate is washed and dried to obtain ammonium metavanadate byproduct. The vanadium precipitation rate of this step is 93.89%;

[0032] S2, pH adjustment and ammonium source supplement: add sulfuric acid to the vanadium precipitation solution of S1 to adjust the solution pH to 1.0, then add ammonium sulfate according to 0.8 times the theoretical amount, and stir thoroughly to completely dissolve the ammonium source;

[0033] S3, ammonium phosphomolybdate precipitation: the solution obtained in S2 is heated to 30°C, and then sodium phosphate is added according to 1.1 times the difference of the phosphorus source required to form ammonium phosphomolybdate, and concentrated sulfuric acid is added at the same time as the sodium phosphate, and the reaction pH is controlled to be 1.0. After reacting for 2 hours, the crude ammonium phosphomolybdate and molybdenum precipitation mother liquor are obtained by standing and filtering. The crude ammonium phosphomolybdate is washed and dried to obtain the ammonium phosphomolybdate product. The molybdenum precipitation rate of this step is 92.44%;

[0034] S4, recovery and reuse of resin containing molybdenum and vanadium solution: the washing water and molybdenum precipitation mother liquor of the above steps are collected and mixed. After mixing evenly, D314 resin is used to adsorb and recover molybdenum element and a small amount of vanadium element, and then the adsorption saturated resin is analyzed to obtain molybdenum-vanadium solution, and the molybdenum-vanadium solution is returned to the phosphorus-molybdenum-vanadium mixed solution of S1 to continue.

[0035] In the method described in this embodiment, the comprehensive recovery rate of molybdenum element is 99.31%, and the comprehensive recovery rate of vanadium element is 99.72%.

[0036] Example 2

[0037] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution is implemented according to the method described in Example 1, except that:

[0038] In the step S2, sulfuric acid is added to the vanadium precipitation solution of S1 to adjust the solution pH to 1.5, and the amount of ammonium sulfate added is 1.0 times the theoretical amount;

[0039] In step S3, the heating temperature is 50°C, the amount of sodium phosphate added is 1.5 times the difference in phosphorus source required to form ammonium phosphomolybdate, the reaction pH is controlled to 0.5, and the reaction time is 2.5h. The molybdenum precipitation rate in this step is 95.29%;

[0040] In the method described in Example 2, the comprehensive recovery rate of molybdenum element is 99.76%, and the comprehensive recovery rate of vanadium element is 99.63%.

[0041] Example 3

[0042] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution is implemented according to the method described in Example 1, except that:

[0043] In the step S2, sulfuric acid is added to the vanadium precipitation solution of S1 to adjust the solution pH to 2.0, and the amount of ammonium sulfate added is 1.5 times the theoretical amount;

[0044] In step S3, the heating temperature is 60°C, the amount of sodium phosphate added is 2.0 times the difference in phosphorus source required to form ammonium phosphomolybdate, the reaction pH is controlled to 1.2, and the reaction time is 3.5 hours. The molybdenum precipitation rate in this step is 93.81%;

[0045] In the method described in Example 3, the comprehensive recovery rate of molybdenum element is 99.84%, and the comprehensive recovery rate of vanadium element is 99.73%.

[0046] Comparative Example 1

[0047] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution is implemented according to the method described in Example 1, except that:

[0048] In step S3, the amount of sodium phosphate added is 0.7 times the difference in phosphorus source required to form ammonium phosphomolybdate. The molybdenum precipitation rate in this step is 59.71%;

[0049] The molybdenum element precipitation rate in the method described in Comparative Example 1 is relatively low, only 59.71%.

[0050] Comparative Example 2

[0051] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution is implemented according to the method described in Example 1, except that:

[0052] In step S2, the pH is controlled to be 2;

[0053] In step S3, the pH is controlled to be 2.5. The molybdenum precipitation rate in this step is 37.12%.

[0054] It can be seen that when the pH in S3 is not within the range of the present invention, it has a greater impact on the precipitation rate of the molybdenum element, which is only 37.12%.

[0055] Comparative Example 3

[0056] A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution is implemented according to the method described in Example 1, except that:

[0057] In step S3, a phosphorus source is first added, and then concentrated sulfuric acid is gradually added; the molybdenum precipitation rate in this step is 77.43%.

[0058] The precipitation rate of molybdenum element in the method described in this comparative example 3 is relatively low, only 77.43%.

[0059] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing ammonium phosphomolybdate from a sulfuric acid system containing phosphorus, molybdenum and vanadium mixed solution, characterized in that: include: S1, add sulfuric acid to the phosphorus-molybdenum-vanadium mixed solution to adjust the solution pH, heat and add ammonium sulfate, stir and fully react for a certain period of time, stop heating and let stand, filter to obtain crude ammonium metavanadate and vanadium precipitation liquid, and wash and dry the crude ammonium metavanadate to obtain an ammonium metavanadate byproduct; S2, adding sulfuric acid to the solution after vanadium precipitation to adjust the solution pH, then adding ammonium source, and stirring thoroughly to completely dissolve the ammonium source; S3, heating the solution obtained in S2, then adding a phosphorus source and sulfuric acid, controlling the reaction to a certain pH range, and standing and filtering after a certain reaction time to obtain crude ammonium phosphomolybdate and a precipitated molybdenum mother liquor, and washing and drying the crude ammonium phosphomolybdate to obtain an ammonium phosphomolybdate product; S4, after collecting and mixing the wash water and the molybdenum precipitation mother liquor of steps S1-S3, the molybdenum element and a small amount of vanadium element are recovered by resin adsorption, and then the adsorption saturated resin is parsed to obtain a molybdenum-vanadium solution, and the molybdenum-vanadium solution is returned to the phosphorus-containing molybdenum-vanadium mixed solution of S1 for recycling.

2. The method according to claim 1, characterized in that The molybdenum content of the phosphorus-molybdenum-vanadium mixed solution in step S1 is 30-70 g / L, the phosphorus content is 2-10 g / L, and the vanadium content is 10-20 g / L.

3. The method according to claim 1, characterized in that In step S1, sulfuric acid is used to adjust the pH to 10-12, the heating temperature is 30-70° C., the amount of ammonium sulfate used is 5.0-8.0 times the theoretical amount, and the reaction time is 2-5 hours.

4. The method according to claim 1, characterized in that: In step S2, the pH of the solution is adjusted to 1.0-3.0, the ammonium source is one or both of ammonium sulfate and ammonia water, and the amount of the ammonium source is 0.5-2.0 times the theoretical amount.

5. The method according to claim 1, characterized in that In step S3, the phosphorus source is one or more of sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, and ammonium phosphate, and the added amount is 1.1-2.0 times the difference of the phosphorus source required to form ammonium phosphomolybdate, the sulfuric acid used is concentrated sulfuric acid, the pH range of the reaction is controlled to be 0-1.5, the reaction time is 1.5-4.0h, and the reaction temperature is 20-70°C.

6. The method according to claim 1, characterized in that In step S3, the phosphorus source and sulfuric acid are added simultaneously.

7. The method according to claim 1, characterized in that The resin used for adsorbing molybdenum and a small amount of vanadium in step S4 is D314 resin.

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