Method for efficiently extracting vanadium element in vanadium wastewater

Abstract

The invention provides a method for efficiently extracting a vanadium element in vanadium wastewater, and belongs to the technical field of chemical engineering. The method comprises the following steps: firstly, mixing the vanadium wastewater with a coolant, carrying out blowing treatment, and adding a coolant in the blowing process to obtain a vanadium waste residue crude product; solid obtained after the vanadium waste residue crude product is filtered is crushed, and crushed waste residues are obtained; carrying out magnetic separation on the crushed waste residues to obtain a vanadium-containing magnet crude product; roasting the vanadium-containing magnet crude product, and carrying out acid leaching to obtain metavanadic acid, so as to obtain a vanadium-containing solution; mixing the vanadium-containing solution with ammonium salt, and carrying out vanadium precipitation treatment to obtain ammonium metavanadate precipitate; and roasting the ammonium metavanadate precipitate to obtain a mixed gas of ammonia gas and V2O5, condensing and collecting to obtain liquid ammonia gas and a V2O5 solid, and sequentially filtering and cleaning the V2O5 solid to obtain the V2O5 solid. According to the method, the vanadium pentoxide product with the purity of 96% can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for efficiently extracting vanadium element from vanadium waste water. Background Art

[0002] At present, most of the vanadium wastewater treatment processes use the reduction neutralization precipitation method. The reduction neutralization precipitation method refers to mixing the vanadium wastewater with additives, roasting it at high temperature, and then grinding it and mixing it with water. Then, sodium pyrosulfite (Na2S2O5), sodium bisulfite (NaHSO3) and other reducing agents are added, and then ammonium polyvanadate is obtained by precipitation. Finally, V2O5 or V2O3 is obtained by dehydration melting.

[0003] The reduction and neutralization precipitation method will produce a large number of by-products during the process, such as sulfur-containing gas and ore mud. The utilization rate of these by-products is low, which not only occupies a large amount of land resources, but also may cause secondary pollution to the environment. A large amount of waste gas will also be produced during the smelting process, which contains harmful substances such as sulfides and nitrides, causing serious pollution to the atmospheric environment. Moreover, the reagents added in this method require precise control, the reagent consumption is large, and the processing cost is high.

[0004] Chinese patent CN102220498A discloses a method for preparing fine vanadium slag, which specifically discloses: (1) crushing the raw vanadium slag, and then magnetically separating iron to obtain iron slag and vanadium slag after iron separation; (2) ball milling the vanadium slag after iron separation; (3) selecting powder (iron content is less than 5wt%) on the ball-milled vanadium slag to obtain fine vanadium slag; (4) mixing the obtained fine vanadium slag with sodium carbonate and water according to the stoichiometric ratio of sodium method roasting, and roasting to generate sodium vanadate. Since sodium vanadate is soluble in water, water leaching can be performed to dissolve sodium vanadate in water to obtain a leaching solution containing sodium vanadate; (5) after obtaining the leaching solution containing sodium vanadate, polyvanadate can be obtained by reacting sodium vanadate with ammonium sulfate, and then heating and decomposing and oxidizing ammonium vanadate to obtain vanadium pentoxide. However, the purity of vanadium pentoxide obtained by this method needs to be further improved.

[0005] Therefore, it is necessary to provide a method for extracting vanadium from vanadium wastewater and waste residue with low cost, higher product purity and basically no pollution. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for efficiently extracting vanadium from vanadium wastewater. The method can obtain high-purity vanadium pentoxide products, reduce costs, and meet green environmental protection standards.

[0007] The technical solution of the present invention is as follows:

[0008] The present invention provides a method for efficiently extracting vanadium from vanadium wastewater, comprising the following steps:

[0009] (1) mixing vanadium waste water and a cooling agent, and performing a blowing treatment, and adding a coolant during the blowing process to obtain a crude vanadium waste slag;

[0010] (2) crushing the solid obtained after filtering the crude vanadium waste slag to obtain crushed waste slag;

[0011] (3) subjecting the crushed waste slag to magnetic separation to obtain a crude vanadium-containing magnet;

[0012] (4) roasting the crude vanadium-containing magnetite and then leaching it with acid to obtain a vanadium-containing solution;

[0013] (5) mixing the vanadium-containing solution with an ammonium salt and performing vanadium precipitation treatment to obtain ammonium metavanadate precipitate;

[0014] (6) The ammonium metavanadate precipitate is roasted to obtain a mixed gas of ammonia and V2O5, which is then condensed and collected to obtain liquid ammonia and V2O5 solid. The V2O5 solid is filtered and washed in turn to obtain V2O5 solid.

[0015] In a specific embodiment, in step (1), the heat dissipator includes ethylene glycol; the coolant includes at least one of Fe2O3 and FeO, and the molar ratio of the coolant to the vanadium in the vanadium wastewater is 3 to 5:1.

[0016] In a specific embodiment, in step (1), the blowing temperature is 500° C. to 600° C., the blowing treatment time is 3 to 4 hours, and the coolant is added after 1 hour of blowing.

[0017] In one embodiment, in step (2), the solid needs to be cooled to 20-30° C. before crushing.

[0018] In a specific embodiment, the crude vanadium-containing magnet needs to be finely ground to 200-300 meshes before roasting.

[0019] In a specific embodiment, in step (4), the calcination temperature is 600-700° C. and the calcination time is 0.5-1 h.

[0020] In one specific embodiment, in step (5), the molar ratio of vanadium ions to ammonium ions is 1:1-2.

[0021] In one specific embodiment, in step (5), chlorine is also recovered during the vanadium precipitation treatment.

[0022] In a specific embodiment, in step (6), the calcination temperature is 500-550° C. and the calcination time is 2 h.

[0023] In one specific embodiment, in step (6), the condensation temperature is -60°C to -30°C, and the condensation time is 1 to 2 hours.

[0024] In the present invention, in step (6), the condenser during condensation is a plate condenser; in step (6), the filter during filtration is a vacuum filter.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention provides a method for efficiently extracting vanadium from vanadium wastewater, which produces almost no environmental pollutants in each step and can obtain a high-purity vanadium pentoxide product. The method reduces costs and meets green environmental protection standards. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] The specific components of vanadium wastewater include: vanadium ions, heavy metal ions such as: Fe 2+ , Fe 3+ Cr 3+ etc., soluble impurity ions such as SiO3 2- PO4 3- , other ions such as Na + , SS (suspended solids), etc. The source of vanadium wastewater is produced by the treatment of vanadium-titanium magnetite and vanadium-containing slag.

[0029] Example 1

[0030] This embodiment provides a method for efficiently extracting vanadium from vanadium wastewater, the method comprising the following steps:

[0031] (1) The vanadium wastewater and ethylene glycol are placed in a vacuum steelmaking furnace for a 3-hour blowing process to separate the slag and liquid. The temperature is 500°C. After reacting for 1 hour, a coolant Fe2O3 is added. The molar ratio of Fe2O3 to the vanadium content in the vanadium wastewater is 3:1.

[0032] (2) The crude vanadium waste slag is centrifugally filtered for 1 hour using a centrifugal filter, cooled to 20° C., and then crushed using a crusher for 2 hours to obtain crushed waste slag.

[0033] (3) The crushed waste slag is loaded into an electromagnetic separator and magnetically separated at room temperature (magnetic field strength 50-80 mT) for 5 hours to obtain a crude vanadium-containing magnet.

[0034] (4) The crude vanadium-containing magnet is placed in a grinder and finely ground for 2 h at room temperature to obtain 200-mesh iron vanadate.

[0035] (5) The ferrous vanadate is placed in a roaster and roasted at 600° C. for 0.5 h to obtain vanadium element soluble in acid form.

[0036] (6) The vanadium element soluble in acid form is placed in a centrifugal filter and solid leached with sulfuric acid to obtain a vanadium-containing solution.

[0037] (7) The vanadium-containing solution is mixed with NH4CI to carry out vanadium precipitation treatment for 1 hour, and the CI2 is recovered by activated carbon cooling adsorption method to obtain ammonium metavanadate solution precipitate.

[0038] (8) The ammonium metavanadate precipitate is placed in a calciner at 500°C and calcined for 2 hours to obtain a mixed gas of ammonia and V2O5 vapor.

[0039] (9) The mixed gas of ammonia and V2O5 vapor is condensed at -33.3°C using a plate condenser for 1 h to obtain liquid ammonia and V2O5 solid.

[0040] (10) The V2O5 solid was filtered using a vacuum filter and then washed with distilled water for 5 times to obtain a high-purity V2O5 solid.

[0041] Example 2

[0042] This embodiment provides a method for efficiently extracting vanadium from vanadium wastewater, the method comprising the following steps:

[0043] (1) The vanadium wastewater and ethylene glycol were placed in a vacuum steelmaking furnace for a 3.5-hour blowing process to separate the slag and liquid. The temperature was 550°C. After reacting for 1 hour, a coolant FeO was added. The molar ratio of FeO to the vanadium content in the vanadium wastewater was 4:1.

[0044] (2) The crude vanadium waste slag was centrifugally filtered for 1.5 hours using a centrifugal filter, cooled to 20° C., and then crushed with a crusher for 2 hours to obtain crushed waste slag.

[0045] (3) The crushed waste slag is loaded into an electromagnetic separator and magnetically separated at room temperature (magnetic field strength 50-80 mT) for 5 hours to obtain a crude vanadium-containing magnet.

[0046] (4) The crude vanadium-containing magnet is placed in a grinder and finely ground at room temperature for 3 hours to obtain 250-mesh iron vanadate.

[0047] (5) The ferrous vanadate is placed in a roaster and roasted at 650° C. for 0.6 h to obtain vanadium element soluble in acid form.

[0048] (6) The vanadium element soluble in acid form is placed in a centrifugal filter and solid leached with sulfuric acid to obtain a vanadium-containing solution.

[0049] (7) The vanadium-containing solution was mixed with NH4CI for vanadium precipitation for 1.5 h, and the CI2 was recovered by activated carbon cooling adsorption method to obtain ammonium metavanadate solution precipitate.

[0050] (8) The ammonium metavanadate solution was placed in a roaster at 525°C and roasted for 2 hours to obtain a mixed gas of ammonia and V2O5 vapor.

[0051] (9) The mixed gas of ammonia and V2O5 vapor is condensed at -44.4°C using a plate condenser for 1.5 h to obtain liquid ammonia and V2O5 solid.

[0052] (10) The V2O5 solid was filtered using a vacuum filter and then washed with distilled water for 6 times to obtain a high-purity V2O5 solid.

[0053] Example 3

[0054] This embodiment provides a method for efficiently extracting vanadium from vanadium wastewater, the method comprising the following steps:

[0055] (1) The vanadium wastewater and ethylene glycol are placed in a vacuum steelmaking furnace for a 4-hour blowing process to separate the slag and liquid. The temperature is 600°C. After reacting for 1 hour, a coolant Fe2O3 is added. The molar ratio of Fe2O3 to the vanadium content in the vanadium wastewater is 5:1.

[0056] (2) The crude vanadium waste slag is centrifugally filtered for 2 hours using a centrifugal filter, cooled to 20° C., and crushed with a crusher for 2 hours to obtain crushed waste slag.

[0057] (3) The crushed waste slag is loaded into an electromagnetic separator and magnetically separated at room temperature (magnetic field strength 50-80 mT) for 5 hours to obtain a crude vanadium-containing magnet.

[0058] (4) The crude vanadium-containing magnet is placed in a grinder and finely ground at room temperature for 4 hours to obtain 300 mesh iron vanadate.

[0059] (5) The ferrous vanadate is placed in a roaster and roasted at 700° C. for 1 hour to obtain vanadium element soluble in acid form.

[0060] (6) The vanadium element soluble in acid form is placed in a centrifugal filter and solid leached with sulfuric acid to obtain a vanadium-containing solution.

[0061] (7) The vanadium-containing solution is mixed with NH4CI to carry out vanadium precipitation treatment for 2 hours, and the CI2 is recovered by activated carbon cooling adsorption method to obtain ammonium metavanadate solution precipitate.

[0062] (8) The ammonium metavanadate solution was placed in a roaster at 550°C and roasted for 2 hours to obtain a mixed gas of ammonia and V2O5 vapor.

[0063] (9) The mixed gas of ammonia and V2O5 vapor is condensed at -55.5°C for 2 h using a plate condenser to obtain liquid ammonia and V2O5 solid.

[0064] (10) The V2O5 solid was filtered using a vacuum filter and then washed with distilled water for 5 times to obtain a high-purity V2O5 solid.

[0065] Comparative Example 1

[0066] The present comparative example provides a method for efficiently extracting vanadium from vanadium wastewater, comprising: mixing the ferrous vanadate in step (5) of Example 1 with sodium carbonate and water, and roasting (700-850°C), leaching with water to obtain a leachate containing sodium vanadate, and adjusting the pH to a pH value of 1.5-2, and then heating at a temperature of 90-100 degrees Celsius to generate a mixed solution containing an ammonium polyvanadate precipitate; filtering and washing the mixed solution containing the ammonium polyvanadate precipitate to obtain an ammonium polyvanadate precipitate and a vanadium precipitation mother liquor; heating the ammonium polyvanadate precipitate at a temperature of 400-500 degrees Celsius to decompose and oxidize to generate vanadium pentoxide, and the remaining steps are the same as those in Example 1.

[0067] Comparative Example 2

[0068] This comparative example provides a method for efficiently extracting vanadium from vanadium wastewater. Except for replacing the plate condenser in step (9) with a water-cooled condenser, the rest is the same as Example 2.

[0069] Comparative Example 3

[0070] This comparative example provides a method for efficiently extracting vanadium from vanadium wastewater. Except for replacing the vacuum filter in step (10) with a membrane filter, the rest is the same as Example 3.

[0071] The vanadium content in the intermediate product ferrous vanadate and the purity of V2O5 in the final product are detected to obtain a purity comparison table of the vanadium content in the intermediate product ferrous vanadate and the purity of V2O5.

[0072] Comparison table of vanadium content in intermediate product iron vanadate and purity of V2O5:

[0073]

[0074] In summary, in view of the problems left over from the prior art, the present invention makes technical improvements with the aim of providing a method for efficiently extracting vanadium from vanadium wastewater. This method can obtain high-purity products, reduce costs, and meet green environmental protection standards.

[0075] The specific examples described above are detailed descriptions of the objectives, techniques and beneficial effects of the present invention. It should be understood that the above descriptions are only specific examples of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for efficiently extracting vanadium from vanadium wastewater, characterized in that: The steps include: (1) mixing vanadium waste water and a cooling agent, and performing a blowing treatment, and adding a coolant during the blowing process to obtain a crude vanadium waste slag; (2) crushing the solid obtained after filtering the crude vanadium waste slag to obtain crushed waste slag; (3) subjecting the crushed waste slag to magnetic separation to obtain a crude vanadium-containing magnet; (4) roasting the crude vanadium-containing magnetite and then leaching it with acid to obtain a vanadium-containing solution; (5) mixing the vanadium-containing solution with an ammonium salt and performing vanadium precipitation treatment to obtain ammonium metavanadate precipitate; (6) The ammonium metavanadate precipitate is roasted to obtain a mixed gas of ammonia and V2O5, which is then condensed and collected to obtain liquid ammonia and V2O5 solid. The V2O5 solid is filtered and washed in turn to obtain V2O5 solid.

2. A method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (1), the heat dissipating agent includes ethylene glycol; the coolant includes at least one of Fe2O3 and FeO, and the molar ratio of the coolant to the vanadium in the vanadium wastewater is 3 to 5:

1.

3. A method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (1), the blowing temperature is 500° C. to 600° C., and the blowing treatment time is 3 to 4 hours; the time for adding the coolant is after 1 hour of blowing.

4. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (2), the solid needs to be cooled to 20-30°C before crushing.

5. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: The crude vanadium-containing magnet needs to be finely ground to 200-300 mesh before roasting.

6. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (4), the calcination temperature is 600-700° C. and the calcination time is 0.5-1 h.

7. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (5), the molar ratio of vanadium ions to ammonium ions is 1:1-2.

8. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (5), chlorine is also recovered during the vanadium precipitation treatment.

9. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (6), during calcination, the calcination temperature is 500-550° C. and the calcination time is 2 h.

10. The method for efficiently extracting vanadium from vanadium wastewater according to claim 1, characterized in that: In step (6), the condensation temperature is -60°C to -30°C, and the condensation time is 1 to 2 hours.

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