A preparation system and method for improving the color of ammonium tetramolybdate products

Abstract

The present application introduces a preparation system and method for improving the color of ammonium tetramolybdate products, which relates to the field of chemical production technology, including an extraction box, a two-effect concentrator, a purification reactor, a primary acid precipitation reactor, an ammonia dissolution reactor, a secondary acid precipitation reactor, an industrial microwave oven, a hydrogen peroxide high-level tank, a concentrated sulfuric acid high-level tank, and an ammonia high-level tank; the specific steps are: S1: tungsten removal extraction; S2: concentration; S3: purification; S4: primary acid precipitation; S5: ammonia dissolution; S6: secondary acid precipitation; S7: after drying, screening, mixing, and packaging. The preparation system and method of the present invention have a high degree of system coordination. Through the setting of each process step and specific parameters, the amount of hydrogen peroxide added can be accurately controlled to avoid the influence of too much or too little hydrogen peroxide on the product color, ensuring that the color of the final product is white and improving the quality of the product.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a preparation system and method for improving the color of ammonium tetramolybdate products. Background Art

[0002] During the sulfuric acid precipitation process of the ammonium tetramolybdate product, part of the hexavalent molybdenum will be reduced to pentavalent molybdenum due to the influence of the reducing agent in the ammonium molybdate solution, making the product appear blue; when hydrogen peroxide is added to oxidize the pentavalent molybdenum, the redox reaction rate is lower than the acid precipitation reaction rate, resulting in the redox reaction continuing after the ammonium tetramolybdate is precipitated, making the ammonium tetramolybdate finally appear yellow or yellow-green, affecting the product quality. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation system and method for improving the color of an ammonium tetramolybdate product, which can effectively ensure the product quality.

[0004] The technical solution adopted by the present invention is:

[0005] A preparation system for improving the color of ammonium tetramolybdate products, comprising an extraction box, a second-effect concentrator, a purification reactor, a primary acid precipitation reactor, an ammonia dissolution reactor, a secondary acid precipitation reactor, an industrial microwave oven, a hydrogen peroxide high-level tank, a concentrated sulfuric acid high-level tank and an ammonia high-level tank;

[0006] The liquid outlet of the extraction box is connected to the inlet of the second-effect concentrator through the raffinate storage tank, the outlet of the second-effect concentrator is connected to the inlet of the purification reactor through the concentrated liquid storage tank, the outlet of the purification reactor is connected to the inlet of the primary acid precipitation reactor through the purified liquid storage tank, the primary acid precipitation reactor, the ammonia solution reactor and the secondary acid precipitation reactor are connected in series in sequence, and the outlet of the secondary acid precipitation reactor is connected to the feed port of the industrial microwave oven;

[0007] The hydrogen peroxide high-level tank is connected to the dosing port of the purification reactor and the primary acid precipitation reactor through pipelines; the concentrated sulfuric acid high-level tank is connected to the dosing port of the primary acid precipitation reactor and the secondary acid precipitation reactor through pipelines; the ammonia high-level tank is connected to the dosing port of the ammonia solution reactor through pipelines.

[0008] A method for improving the color of ammonium tetramolybdate products, comprising the following steps:

[0009] S1: Tungsten removal and extraction; the WO3 content in the tungsten-rich molybdenum mother liquor is 20-40g / L, and the Mo content is 30-60g / L. The mother liquor is extracted in the extraction box to remove tungsten to obtain a raffinate, i.e., a dilute ammonium molybdate solution, which enters the raffinate storage tank. The WO3 in the dilute ammonium molybdate solution is determined to be less than 0.1g / L, and Mo: 25-45g / L;

[0010] S2: Concentration; the dilute ammonium molybdate solution in the raffinate storage tank enters the second-effect concentrator for evaporation and concentration, so that the Mo content is increased from 25-45g / L to 100-120g / L, and the concentrate enters the concentrate storage tank;

[0011] S3: Purification; the concentrated liquid in the concentrated liquid storage tank enters the purification reactor and adds activated carbon for purification to remove residual extractants and other organic matter. At the same time, hydrogen peroxide is added through the hydrogen peroxide high-level tank to oxidize the reducing organic matter in the concentrated liquid. The main reaction is C=C-R1+H2O2=CC-R2+H2O; after the reaction, the filtrate enters the purified liquid storage tank for static precipitation, and the supernatant is pumped into the primary acid precipitation reactor;

[0012] S4: primary acid precipitation; adding concentrated sulfuric acid to the primary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the pH value of the solution is 1.5-2.5, and at the same time adding hydrogen peroxide through a hydrogen peroxide high-level tank to adjust the color of the solution from blue to colorless, stirring the reaction until a white ammonium tetramolybdate precipitate appears, and when the content of the white ammonium tetramolybdate precipitate is 10%-15% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a primary acid precipitation product;

[0013] S5: Ammonia dissolution; the primary acid precipitation product is added to the ammonia dissolution reactor, and 5 mol / L ammonia water is added to the ammonia dissolution reactor through the ammonia water high-level tank, and stirred and dissolved until the solution is clear and the pH value is 7.5-8.5, and the molybdenum content is measured to 120-140g / L;

[0014] S6: secondary acid precipitation; the ammonia solution in the ammonia dissolution reactor is pumped into the secondary acid precipitation reactor, and concentrated sulfuric acid is added to the secondary acid precipitation reactor through the concentrated sulfuric acid high-level tank until the pH value of the solution is 1.5-2.5, and when white ammonium tetramolybdate precipitate appears, the content of the white precipitate is 15%-20% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a secondary acid precipitation product;

[0015] S7: After the secondary acid precipitation products enter the industrial microwave oven for microwave drying, they are screened, mixed and packaged.

[0016] Specifically, during the tungsten removal extraction in S1, 5 mol / l ammonia water is added to control the pH value of the solution to 8-9.3.

[0017] Specifically, the evaporation temperature in the second-effect concentrator in S2 is 70-90°C, and the vacuum degree is -0.03Mpa to -0.08Mpa.

[0018] Specifically, the activated carbon added to the purification reactor in S3 is coconut shell powdered activated carbon, with a methylene blue decolorization rate of 1800 mg / g, an iodine adsorption value of 800, an ash content of 4.5%, a mesh size of >200 mesh, and an iron salt of <1000 ppm; the concentration of hydrogen peroxide is 28%-30%, and the amount added is 1%-2% of the solution volume; the reaction temperature is 60-70°C, and the reaction time is not less than 1h; after the reaction, vacuum filtration is performed, the filter cloth mesh size is >325 mesh, and the filtrate is allowed to settle for more than 12h.

[0019] Specifically, the primary acid precipitation reaction temperature in S4 is 55-70°C, the concentrated sulfuric acid is industrial sulfuric acid with a concentration of 95%-98%; the concentration of hydrogen peroxide is 28%-30%, and the added amount is 1‰-2‰ of the solution volume; the reaction time is 10-20 minutes.

[0020] Specifically, the ammonia solution reaction temperature in S5 is 40-60° C., and the stirring time is 10 minutes.

[0021] Specifically, the secondary acid precipitation reaction temperature in S6 is 50-65° C., the concentrated sulfuric acid concentration is 95%-98% industrial sulfuric acid, and the reaction time is 10-20 minutes.

[0022] Specifically, the drying in S7 is carried out using an industrial microwave oven, the drying temperature is 70-85° C., and the material stays in the microwave oven for 20-25 minutes; the mixer is a double-cone mixer, and the mixing time is 30-40 minutes for both the forward and reverse directions.

[0023] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages:

[0024] The preparation system and method of the present invention have a high degree of system coordination. Through the setting of various process steps and specific parameters, the addition step and amount of hydrogen peroxide can be accurately controlled, thereby controlling the redox reaction rate, ensuring that the color of the final product is white, and improving the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention.

[0026] Figure 2 These are sample pictures of the yellow ammonium tetramolybdate product produced by the prior art and the white ammonium tetramolybdate product produced by the embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with the accompanying drawings and embodiments, which should not be used to limit the protection scope of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0028] Combined with Figure 1The system for improving the color of ammonium tetramolybdate product shown in the figure comprises an extraction box, a two-effect concentrator, a purification reactor, a primary acid precipitation reactor, an ammonia dissolution reactor, a secondary acid precipitation reactor, an industrial microwave oven, a hydrogen peroxide high-level tank, a concentrated sulfuric acid high-level tank and an ammonia high-level tank.

[0029] The liquid outlet of the extraction box is connected to the inlet of the second-effect concentrator through the raffinate storage tank, the outlet of the second-effect concentrator is connected to the inlet of the purification reactor through the concentrated liquid storage tank, the outlet of the purification reactor is connected to the inlet of the primary acid precipitation reactor through the purified liquid storage tank, the primary acid precipitation reactor, the ammonia solution reactor and the secondary acid precipitation reactor are connected in series in sequence, and the outlet of the secondary acid precipitation reactor is connected to the feed port of the industrial microwave oven.

[0030] The hydrogen peroxide high-level tank is connected to the dosing ports of the purification reactor and the primary acid precipitation reactor through pipelines; the concentrated sulfuric acid high-level tank is connected to the dosing ports of the primary acid precipitation reactor and the secondary acid precipitation reactor through pipelines; the ammonia high-level tank is connected to the dosing port of the ammonia solution reactor through pipelines. Example 1

[0031] A method for improving the color of ammonium tetramolybdate products, comprising the following steps:

[0032] S1: Tungsten removal and extraction; the WO3 content in the tungsten-rich molybdenum mother liquor is 20g / L, and the Mo content is 30g / L. 5mol / l ammonia water is added to control the pH value of the solution at 8; the mother liquor is subjected to tungsten removal extraction in the extraction box to obtain a raffinate, i.e., a dilute ammonium molybdate solution, which enters the raffinate storage tank. The WO3 content in the dilute ammonium molybdate solution is determined to be 0.05g / L, and the Mo content is 25g / L.

[0033] S2: Concentration: The dilute ammonium molybdate solution in the raffinate storage tank enters the second-effect concentrator for evaporation and concentration, so that the Mo content is increased to 100g / L, and the concentrated solution enters the concentrated solution storage tank. The evaporation temperature in the second-effect concentrator is 90℃ and the vacuum degree is -0.03 Mpa.

[0034] S3: Purification; the concentrated liquid in the concentrated liquid storage tank enters the purification reactor, and coconut shell powdered activated carbon is added to the purification reactor. The methylene blue decolorization rate of coconut shell powdered activated carbon is 1800㎎ / g, the iodine adsorption value is 800, the ash content is 4.5%, the mesh size is greater than 200 mesh, and the iron salt is less than 1000ppm; the purification reaction removes organic matter such as the extractant, and at the same time, 28% hydrogen peroxide is added through the hydrogen peroxide high-level tank, and the added amount is 1% of the solution volume. The hydrogen peroxide oxidizes the reducing organic matter in the concentrated liquid, and the main reaction is C=C-R1+H2O2=CC-R2+H2O; the reaction temperature is 60, the reaction time is not less than 1h, and the reaction is vacuum filtered after the reaction. The mesh size of the filter cloth is greater than 325 mesh. The filtrate enters the purified liquid storage tank and is allowed to settle for more than 13h; the supernatant is pumped into the primary acid precipitation reactor.

[0035] S4: primary acid precipitation; add 95% industrial sulfuric acid to the primary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the solution pH is 1.5, and the reaction temperature is 55°C; at the same time, add 28% hydrogen peroxide in an amount of 2‰ of the solution volume through a hydrogen peroxide high-level tank, adjust the solution color from blue to colorless, stir and react for 10 minutes, and when white ammonium tetramolybdate precipitate appears, the content of the white ammonium tetramolybdate precipitate is 15% and the pH value of the solution no longer changes, filter and perform solid-liquid separation to obtain a primary acid precipitation product.

[0036] S5: Ammonia solution; the primary acid precipitation product is added to the ammonia solution reactor, and 5 mol / L ammonia water is added to the ammonia solution reactor through the ammonia water high-level tank. The reaction temperature is 40°C and the stirring time is 10 minutes. When the solution is clear and the pH value is 7.5, the molybdenum content is measured to be 120 g / L.

[0037] S6: secondary acid precipitation; the ammonia solution in the ammonia dissolution reactor is pumped into the secondary acid precipitation reactor, and industrial sulfuric acid with a concentration of 95% is added to the secondary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the pH value of the solution is 1.5, the reaction temperature is 65°C, and the reaction is stirred for 10 minutes. When ammonium tetramolybdate precipitate appears, the content of ammonium tetramolybdate precipitate is 20% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a secondary acid precipitation product.

[0038] S7: The secondary acid precipitation product enters the industrial microwave oven for microwave drying, the drying temperature is 70℃, the drying time is 25 minutes, after drying, the product is screened and mixed, the mixer is a double cone mixer, the mixing time is 30 minutes each, and finally put into ton bags for packaging. Example 2

[0039] A method for improving the color of ammonium tetramolybdate products, comprising the following steps:

[0040] S1: Tungsten removal and extraction; the WO3 content in the tungsten-rich molybdenum mother liquor is 40g / L, and the Mo content is 60g / L. 5mol / l ammonia water is added to control the pH value of the solution at 9.3; the mother liquor is extracted in the extraction box to remove tungsten and obtain the raffinate, that is, the dilute ammonium molybdate solution, which enters the raffinate storage tank. The WO3 in the dilute ammonium molybdate solution is measured to be 0.08g / L and the Mo is 45g / L.

[0041] S2: Concentration: The dilute ammonium molybdate solution in the extract storage tank enters the second-effect concentrator for evaporation and concentration, so that the Mo content is increased to 120g / L, and the concentrated solution enters the concentrated solution storage tank. The evaporation temperature in the second-effect concentrator is 90°C and the vacuum degree is -0.08Mpa.

[0042] S3: Purification; the concentrated liquid in the concentrated liquid storage tank enters the purification reactor, and coconut shell powdered activated carbon is added to the purification reactor. The methylene blue decolorization rate of coconut shell powdered activated carbon is 1800㎎ / g, the iodine adsorption value is 800, the ash content is 4.5%, the mesh size is greater than 200 mesh, and the iron salt is less than 1000ppm; the purification reaction removes organic matter such as the extractant, and at the same time, 30% hydrogen peroxide is added through the hydrogen peroxide high-level tank, and the added amount is 2% of the solution volume. The hydrogen peroxide oxidizes the reducing organic matter in the concentrated liquid, and the main reaction is C=C-R1+H2O2=CC-R2+H2O; the reaction temperature is 70℃, the reaction time is 1.5h, and the reaction is vacuum filtered after the reaction. The mesh size of the filter cloth is greater than 325 mesh. The filtrate enters the purified liquid storage tank and is allowed to settle for 14h; the supernatant is pumped into the primary acid precipitation reactor.

[0043] S4: primary acid precipitation; add 98% industrial sulfuric acid to the primary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the solution pH is 2.5, and the reaction temperature is 70°C; at the same time, add 30% hydrogen peroxide in an amount of 1‰ of the solution volume through a hydrogen peroxide high-level tank, adjust the solution color from blue to colorless, stir and react for 10 minutes, and when white ammonium tetramolybdate precipitate appears, the content of the white ammonium tetramolybdate precipitate is 10% and the pH value of the solution no longer changes, filter and perform solid-liquid separation to obtain a primary acid precipitation product.

[0044] S5: Ammonia solution; the primary acid precipitation product is added to the ammonia solution reactor, and 5 mol / L ammonia water is added to the ammonia solution reactor through the ammonia water high-level tank. The reaction temperature is 60°C and the stirring time is 10 minutes. When the solution is clear and the pH value is 7.5-8.5, the molybdenum content is measured to be 140g / L.

[0045] S6: secondary acid precipitation; the ammonia solution in the ammonia dissolution reactor is pumped into the secondary acid precipitation reactor, and industrial sulfuric acid with a concentration of 98% is added to the secondary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the pH value of the solution is 2.5, the reaction temperature is 65°C, and the reaction is stirred for 20 minutes. When white ammonium tetramolybdate precipitate appears and the content of the white ammonium tetramolybdate precipitate is 15% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a secondary acid precipitation product.

[0046] S7: The secondary acid precipitation product enters the industrial microwave oven for microwave drying, the drying temperature is 85℃, the drying time is 20 minutes, after drying, the product is screened and mixed, the mixer is a double cone mixer, the mixing time is 40 minutes each, and finally put into ton bags for packaging.

[0047] As attached Figure 2 As shown, the yellow powder on the left is a sample of a prior art product, and the white powder on the right is a sample of a final product of the above two embodiments of the present invention. Through the technical solution of the present invention, the product color is significantly improved.

[0048] Parts of the present invention not described in detail are prior art.

[0049] The embodiments selected herein for the purpose of disclosing the invention are currently considered to be suitable, but it should be understood that the invention is intended to include all changes and modifications of the embodiments that fall within the scope of the concept and invention.

Claims

1. A preparation system for improving the color of ammonium tetramolybdate products, characterized in that: It includes extraction box, two-effect concentrator, purification reactor, primary acid precipitation reactor, ammonia dissolution reactor, secondary acid precipitation reactor, industrial microwave oven, hydrogen peroxide high-level tank, concentrated sulfuric acid high-level tank and ammonia high-level tank; The liquid outlet of the extraction box is connected to the inlet of the second-effect concentrator through the raffinate storage tank, the outlet of the second-effect concentrator is connected to the inlet of the purification reactor through the concentrated liquid storage tank, the outlet of the purification reactor is connected to the inlet of the primary acid precipitation reactor through the purified liquid storage tank, the primary acid precipitation reactor, the ammonia solution reactor and the secondary acid precipitation reactor are connected in series in sequence, and the outlet of the secondary acid precipitation reactor is connected to the feed port of the industrial microwave oven; The hydrogen peroxide high-level tank is connected to the dosing ports of the purification reactor and the primary acid precipitation reactor respectively through pipelines; the concentrated liquid in the concentrated liquid storage tank enters the purification reactor and is added with activated carbon for purification to remove residual organic matter such as the extractant; at the same time, hydrogen peroxide is added through the hydrogen peroxide high-level tank to oxidize the reducing organic matter in the concentrated liquid, and the main reaction is C=C-R1+H2O2=CC-R2+H2O; after the reaction, the filtrate enters the purification liquid storage tank for static precipitation, and the supernatant is pumped into the primary acid precipitation reactor; the concentrated sulfuric acid high-level tank is connected to the dosing ports of the primary acid precipitation reactor and the secondary acid precipitation reactor respectively through pipelines; the ammonia high-level tank is connected to the dosing port of the ammonia solution reactor through a pipeline.

2. A method for improving the color of ammonium tetramolybdate products, characterized in that: The specific steps are: S1: tungsten removal and extraction; the WO3 content in the tungsten-rich molybdenum mother liquor is 20-40g / L, and the Mo content is 30-60g / L. The mother liquor is subjected to tungsten removal and extraction in the extraction box to obtain a raffinate, i.e., a dilute ammonium molybdate solution, which enters the raffinate storage tank. The WO3 content in the dilute ammonium molybdate solution is determined to be less than 0.1g / L, and Mo: 25-45g / L; S2: Concentration; the dilute ammonium molybdate solution in the raffinate storage tank enters the second-effect concentrator for evaporation and concentration, so that the Mo content is increased from 25-45g / L to 100-120g / L, and the concentrate enters the concentrate storage tank; S3: Purification; the concentrated liquid in the concentrated liquid storage tank enters the purification reactor and adds activated carbon for purification to remove residual extractants and other organic matter. At the same time, hydrogen peroxide is added through the hydrogen peroxide high-level tank to oxidize the reducing organic matter in the concentrated liquid. The main reaction is C=C-R1+H2O2=CC-R2+H2O; after the reaction, the filtrate enters the purified liquid storage tank for static precipitation, and the supernatant is pumped into the primary acid precipitation reactor; S4: primary acid precipitation; adding concentrated sulfuric acid to the primary acid precipitation reactor through a concentrated sulfuric acid high-level tank until the pH value of the solution is 1.5-2.5, and at the same time adding hydrogen peroxide through a hydrogen peroxide high-level tank to adjust the color of the solution from blue to colorless, stirring the reaction until a white ammonium tetramolybdate precipitate appears, and when the content of the white ammonium tetramolybdate precipitate is 10%-15% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a primary acid precipitation product; S5: Ammonia dissolution; the primary acid precipitation product is added to the ammonia dissolution reactor, and 5 mol / L ammonia water is added to the ammonia dissolution reactor through the ammonia water high-level tank, and stirred and dissolved until the solution is clear and the pH value is 7.5-8.5, and the molybdenum content is measured to 120-140g / L; S6: secondary acid precipitation; the ammonia solution in the ammonia dissolution reactor is pumped into the secondary acid precipitation reactor, and concentrated sulfuric acid is added to the secondary acid precipitation reactor through the concentrated sulfuric acid high-level tank until the pH value of the solution is 1.5-2.5, and when white ammonium tetramolybdate precipitate appears, the content of the white precipitate is 15%-20% and the pH value of the solution no longer changes, suction filtration is performed for solid-liquid separation to obtain a secondary acid precipitation product; S7: After the secondary acid precipitation products enter the industrial microwave oven for microwave drying, they are screened, mixed and packaged.

3. The method for improving the color of ammonium tetramolybdate product according to claim 2, characterized in that: When removing tungsten from S1, 5 mol / l ammonia water is added to control the pH value of the solution to 8-9.

3.

4. The method for improving the color of ammonium tetramolybdate product according to claim 2, characterized in that: The evaporation temperature in the second-effect concentrator in S2 is 70-90°C, and the vacuum degree is -0.03Mpa to -0.08Mpa.

5. The method for improving the color of ammonium tetramolybdate product according to claim 2, characterized in that: The activated carbon added to the purification reactor in S3 is coconut shell powdered activated carbon, with a methylene blue decolorization rate of 1800 mg / g, an iodine adsorption value of 800, an ash content of 4.5%, a mesh size of >200 mesh, and an iron salt of <1000 ppm; the concentration of hydrogen peroxide is 28%-30%, and the amount added is 1%-2% of the solution volume; the reaction temperature is 60-70°C, the reaction time is not less than 1h, vacuum filtration is performed after the reaction, the filter cloth mesh size is >325 mesh, and the filtrate is allowed to settle for more than 12h.

6. The method for improving the color of ammonium tetramolybdate product according to claim 2, characterized in that: The primary acid precipitation reaction temperature in S4 is 55-70°C, the concentrated sulfuric acid is industrial sulfuric acid with a concentration of 95%-98%; the concentration of hydrogen peroxide is 28%-30%, and the added amount is 1‰-2‰ of the solution volume; the reaction time is 10-20 minutes.

7. The method for improving the color of ammonium tetramolybdate product according to claim 2, characterized in that: The ammonia solution reaction temperature in S5 is 40-60° C., and the stirring time is 10 minutes.

8. The method for improving the color of ammonium tetramolybdate products according to claim 2, characterized in that: The secondary acid precipitation reaction temperature in the S6 is 50-65°C, the concentrated sulfuric acid concentration is 95%-98% industrial sulfuric acid, and the reaction time is 10-20 minutes.

9. The method for improving the color of ammonium tetramolybdate products according to claim 2, characterized in that: The drying in S7 is carried out by an industrial microwave oven, the drying temperature is 70-85° C., and the drying time is 20-25 minutes; the mixer is a double cone mixer, and the mixing time is 30-40 minutes for both the forward and reverse directions.

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