Method for comprehensive recovery of rectification residual liquid

Abstract

This invention belongs to the field of waste liquid recycling technology and provides a comprehensive recycling method for distillation residues. The method involves fluidizing and decomposing the distillation residues to obtain solid residues and decomposition gases; absorbing the decomposition gases to obtain a nitric acid solution and a ventable gas; mixing the solid residues with a solvent to dissolve molybdenum, tungsten, and aluminum to obtain a molybdenum-tungsten-aluminum solution and a uranium-containing dissolving residue; the solvent includes a strong alkali and a peroxide; mixing the molybdenum-tungsten-aluminum solution with quicklime to obtain a calcium salt precipitate and an aluminum-containing mother liquor; preparing a slurry with the uranium-containing dissolving residue, the aluminum-containing mother liquor, and water; and dissolving uranium under carbon dioxide conditions to obtain a uranium-containing solution and an aluminum-containing dissolving residue; adsorbing the uranium-containing solution with a strong alkali resin to obtain an adsorption tail liquid and a uranium-absorbing resin; and sequentially subjecting the uranium-absorbing resin to a first rinsing, a second rinsing, and desorption elution to obtain a uranium-containing desorbed liquid and a desorption resin, thus achieving comprehensive recycling of uranium, molybdenum, tungsten, and aluminum.

Description

Technical Field

[0001] This invention relates to the field of waste liquid recycling technology, and in particular to a comprehensive method for recycling distillation residues. Background Technology

[0002] In my country, the uranium purification and conversion production line involves processes such as dissolution, extraction, denitrification, reduction, hydrofluorination, and fluorination during the preparation of uranium hexafluoride from uranium ore concentrate. The raffinate after extraction contains a certain amount of nitric acid, which is typically recovered through distillation. After repeated accumulation, this results in a residue containing large amounts of impurities such as uranium, aluminum, iron, molybdenum, tungsten, nitric acid, nitrate, monobutyl phosphate, dibutyl phosphate, and kerosene (this residue is called distillation residue). The distillation residue has high viscosity, is difficult to filter, and is prone to emulsification during extraction, making it difficult to recover valuable components with comprehensive recovery value, such as uranium, molybdenum, and nitric acid.

[0003] Currently, the treatment of distillation residue involves mixing it with other neutral or alkaline waste liquids to dilute impurities and acidity before extracting and recovering uranium. Alternatively, it can be mixed with alkaline wastewater obtained from the washing of conversion tail gas, adjusted to alkalinity, and then subjected to filtration and other methods to remove organic matter before uranium recovery using ion exchange resins. However, both methods only focus on uranium recovery from the distillation residue, neglecting the comprehensive recovery of valuable components such as nitric acid and molybdenum, resulting in resource waste. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a comprehensive method for the recovery of distillation residues. The method provided by this invention can recover uranium, aluminum, molybdenum, magnesium, and tungsten, with high resource utilization.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a comprehensive method for recovering distillation residues, comprising the following steps:

[0007] The distillation residue was subjected to fluidized bed decomposition to obtain solid residue and decomposition gas;

[0008] The decomposed gas is absorbed and reacted to obtain a nitric acid solution and a removable gas.

[0009] The solid residue is mixed with a solvent to dissolve molybdenum-tungsten-aluminum, yielding a molybdenum-tungsten-aluminum solution and a uranium-containing dissolution residue; the solvent includes a strong alkali and a peroxide.

[0010] The molybdenum-tungsten-aluminum solution was mixed with quicklime to obtain calcium salt precipitate and aluminum-containing mother liquor;

[0011] The uranium-containing dissolving residue and aluminum-containing mother liquor are slurried together, and uranium is dissolved under the condition of carbon dioxide introduction to obtain uranium-containing dissolving liquid and aluminum-containing dissolving residue.

[0012] A strong base resin was used to adsorb uranium-containing solution, resulting in adsorption tail liquid and uranium-absorbing resin.

[0013] The uranium-absorbing resin is subjected to a first rinsing, a second rinsing, and desorption elution in sequence to obtain uranium-containing desorption liquid and desorption resin, thereby achieving comprehensive recovery of distillation residue.

[0014] Preferably, the parameters of the fluidized bed decomposition include: the distillation residue is fluidized in the form of atomized droplets with a diameter ≤0.2mm, the fluidizing gas is air with a temperature ≥400℃ and a residence time ≥10min, and the equipment is a fluidized bed; the gas-liquid ratio of the fluidized bed decomposition is 50~200.

[0015] Preferably, the parameters for gas absorption include: the absorbent is water, the equipment is a venturi tube, the absorbent enters from the main pipe of the venturi tube, and the decomposed gas enters from the side pipe of the venturi tube; the flow rate of the absorbent is ≥10m / s.

[0016] Preferably, the nitric acid solution is used as the eluent for desorption and elution.

[0017] Preferably, the strong alkali includes sodium hydroxide and / or potassium hydroxide, and the peroxide includes one or more of sodium peroxide, potassium peroxide, and hydrogen peroxide, wherein the mass of the peroxide is 0.3 to 0.5% of the mass of the solid residue;

[0018] The potential for dissolving the molybdenum-tungsten-aluminum alloy is ≥500mV, the temperature is 40~100℃, and the time is ≥3h.

[0019] The residual amount of strong alkali in the molybdenum-tungsten-aluminum solution is 10-20 g / L.

[0020] Preferably, the amount of quicklime is 100% to 110% of the theoretical total amount of molybdenum and tungsten; the reaction temperature is room temperature and the time is ≥1 hour.

[0021] Preferably, the uranium dissolution is carried out at a pH of 7-8, a temperature of 50-100°C, and a time of ≥3 hours; the uranium dissolution is carried out under stirring conditions.

[0022] Preferably, the strong alkali resin includes one or more of 201×7, D201, D263 or D261;

[0023] The adsorption tail liquid is returned to the uranium dissolution step for pulping.

[0024] Preferably, the rinsing agent for the first rinsing is water, and the total concentration of carbonate and bicarbonate in the resulting rinsing solution after the first rinsing is not higher than 1 g / L;

[0025] The second rinsing agent is a nitric acid solution of 5-10 g / L, and the second rinsing is performed on 1-3 bed volumes;

[0026] The eluent for desorption and elution is a 1-2 mol / L nitric acid solution.

[0027] Preferably, the uranium-containing desorption solution is used in the uranium purification production line; the desorption resin is washed with water until the pH value is 3-3.5, and then used as a strong base resin for adsorption.

[0028] This invention provides a comprehensive recovery method for distillation residues, comprising the following steps: fluidizing the distillation residues to obtain solid residues and decomposition gases; absorbing the decomposition gases to obtain a nitric acid solution and a ventable gas; mixing the solid residues with a solvent to dissolve molybdenum-tungsten-aluminum (MTA) to obtain a MTA solution and a uranium-containing dissolving residue; the solvent includes a strong alkali and a peroxide; mixing the MTA solution with quicklime to obtain a calcium salt precipitate and an aluminum-containing mother liquor; slurrying the uranium-containing dissolving residue and the aluminum-containing mother liquor, and dissolving uranium under carbon dioxide conditions to obtain a uranium-containing solution and an aluminum-containing dissolving residue; adsorbing the uranium-containing solution with a strong alkali resin to obtain an adsorption tail liquid and a uranium-absorbing resin; and sequentially subjecting the uranium-absorbing resin to a first rinsing, a second rinsing, and desorption elution to obtain a uranium-containing desorbed liquid and a desorption resin, thereby achieving comprehensive recovery of the distillation residues.

[0029] In this invention, fluidized bed decomposition transforms organic impurities in the distillation residue, such as monobutyl phosphate, dibutyl phosphate, and kerosene, into carbon dioxide, water, and phosphates, converts nitric acid into nitrogen oxide gas, and nitrates into metal oxides and nitrogen oxides. The resulting decomposition gas contains water vapor, carbon dioxide, and nitrogen oxides. The gas absorption process absorbs the nitrogen oxides in the decomposition gas, forming a dilute acid that is reused, while carbon dioxide escapes. A solvent containing a strong alkali and peroxides is used to dissolve molybdenum, tungsten, and aluminum in the solid residue obtained from fluidized bed decomposition, causing the molybdenum, tungsten, and aluminum to dissolve while uranium remains in the dissolved residue. Quicklime is added to the solution containing molybdenum, tungsten, and aluminum, causing molybdenum and tungsten to form calcium salt precipitates for recovery, while sodium hydroxide is produced. A portion of the aluminum-containing mother liquor is reused. Uranium-containing dissolving residue is mixed with aluminum-containing mother liquor and then purged with carbon dioxide to dissolve uranium, causing aluminum to precipitate and enter the sediment, resulting in efficient uranium dissolution. The uranium-containing solution is adsorbed using a strong-base resin, then eluted with water and low-concentration nitric acid to remove carbonate and bicarbonate ions. High-concentration nitric acid is then used for elution, and the resulting uranium-containing desorbate is returned to the purification process to prepare uranium concentrate solution, achieving efficient uranium recovery. Using the method of this invention, uranium, molybdenum, tungsten, and aluminum are effectively recovered from the distillation residue, and organic impurities are efficiently removed. The recovery rate of uranium reaches 95%, molybdenum 90%, tungsten 90%, and aluminum 85%. The COD value of the treated wastewater is reduced to below 15 mg / L, realizing the transformation of uranium purification distillation residue into a valuable resource and reducing the amount of waste residue stored in the uranium purification process. Attached Figure Description

[0030] Figure 1 A flowchart of the comprehensive recovery method for distillation residues provided by the present invention. Detailed Implementation

[0031] This invention provides a comprehensive method for recovering distillation residues, comprising the following steps:

[0032] The distillation residue was subjected to fluidized bed decomposition to obtain solid residue and decomposition gas;

[0033] The decomposed gas is absorbed to obtain a nitric acid solution and a removable gas.

[0034] The solid residue is mixed with a solvent to dissolve molybdenum-tungsten-aluminum, yielding a molybdenum-tungsten-aluminum solution and a uranium-containing dissolution residue; the solvent includes a strong alkali and a peroxide.

[0035] The molybdenum-tungsten-aluminum solution was mixed with quicklime and reacted to obtain calcium salt precipitate and aluminum-containing mother liquor.

[0036] The uranium-containing dissolving residue, aluminum-containing mother liquor, and water are slurried together, and uranium is dissolved under the condition of carbon dioxide introduction to obtain uranium-containing dissolving liquid and aluminum-containing dissolving residue.

[0037] A strong base resin was used to adsorb uranium-containing solution, resulting in adsorption tail liquid and uranium-absorbing resin.

[0038] The uranium-absorbing resin is subjected to a first rinsing, a second rinsing, and desorption elution in sequence to obtain uranium-containing desorption liquid and desorption resin, thereby achieving comprehensive recovery of distillation residue.

[0039] Unless otherwise specified, all materials used in this invention are preferably commercially available products.

[0040] This invention involves fluidized bed decomposition of distillation residues to obtain solid residues and decomposition gases.

[0041] In this invention, the distillation residue preferably comprises uranium, aluminum, molybdenum, tungsten, nitric acid, nitrate, monobutyl phosphate, dibutyl phosphate, and kerosene. In this invention, the distillation residue comprises: uranium 0.821–1.568 g / L, aluminum 1.38–4.57 g / L, molybdenum 0.476–0.891 g / L, magnesium 2.00–3.74 g / L, tungsten 0.176–0.339 g / L, and COD 723–1526 mg / L.

[0042] In this invention, the parameters of the fluidized bed decomposition include: the distillation residue is preferably fluidized bed decomposition in the form of atomized droplets, the diameter of the atomized droplets is preferably ≤0.2 mm, the fluidizing gas is preferably air, the temperature of the fluidizing gas is preferably ≥400℃, more preferably 400~600℃, and more preferably 450~500℃; the residence time is preferably ≥10 min, more preferably 10~20 min, and more preferably 15 min; the equipment is preferably a fluidized bed; and the gas-liquid ratio of the fluidized bed decomposition is preferably 50~200, and more preferably 100~150.

[0043] In this invention, the decomposition gas preferably includes carbon dioxide, water vapor, and nitrogen oxides.

[0044] In this invention, the particle size of the solid residue is preferably ≤3mm.

[0045] In this invention, during the fluidized bed decomposition process, organic impurities such as monobutyl phosphate, dibutyl phosphate, and kerosene decompose to generate decomposition gas; the decomposition gas escapes from the top of the fluidized bed along with the fluidizing gas; and the remaining solid residue from the fluidized bed decomposition is discharged from the bottom of the fluidized bed.

[0046] After obtaining the decomposed gas, the present invention performs gas absorption on the decomposed gas to obtain nitric acid solution and removable gas.

[0047] In this invention, the parameters for gas absorption include: the absorbent is preferably water, the equipment is preferably a Venturi tube, the absorbent preferably enters from the main pipe of the Venturi tube, and the decomposed gas preferably enters from the side pipe of the Venturi tube; the flow rate of the absorbent is preferably ≥10 m / s, more preferably 10-20 m / s. In this invention, during the gas absorption process, the decomposed gas is preferably naturally inhaled. In this invention, the gas absorption preferably uses a multi-stage Venturi tube, specifically a first-stage Venturi tube, a second-stage Venturi tube...N-stage Venturi tube: the decomposed gas and absorbent first enter the first-stage Venturi tube, where nitrogen oxides in the decomposed gas mix with the absorbent and react to form a nitric acid solution; the nitric acid solution flows back to the first-stage Venturi tube to continue mixing and reacting with the decomposed gas until the concentration of the nitric acid solution obtained in the first-stage Venturi tube is preferably 1-2 mol / L; then the decomposed gas enters the second-stage Venturi tube for gas absorption.

[0048] In this invention, the nitric acid solution is preferably used as the eluent for desorption and elution. The concentration of the nitric acid solution is preferably 1–2 mol / L.

[0049] In this invention, during the gas absorption process, nitrogen oxides and water vapor dissolve in the absorbent to form a nitric acid solution; carbon dioxide in the decomposed gas is discharged as a ventable gas.

[0050] After obtaining the solid residue, the present invention mixes the solid residue with a solvent to dissolve molybdenum-tungsten-aluminum to obtain a molybdenum-tungsten-aluminum solution and a uranium-containing dissolving residue; the solvent includes a strong alkali and a peroxide.

[0051] In this invention, the strong alkali preferably includes sodium hydroxide and / or potassium hydroxide, and the peroxide preferably includes one or more of sodium peroxide, potassium peroxide, and hydrogen peroxide. In this invention, the mass of the peroxide is preferably 0.3% to 0.5% of the mass of the solid residue.

[0052] In this invention, the liquid-to-solid ratio of the solvent and the solid residue is preferably 1.5:1 (mL / g).

[0053] In this invention, the potential for dissolving molybdenum-tungsten-aluminum is preferably ≥500mV, the temperature is preferably 40~100℃, more preferably 50~80℃, and the time is preferably ≥3h, more preferably 3~15h.

[0054] After the molybdenum-tungsten-aluminum is dissolved, the present invention preferably also includes filtration.

[0055] In this invention, the residual amount of strong alkali in the molybdenum-tungsten-aluminum solution is preferably 10-20 g / L.

[0056] In this invention, during the dissolution of molybdenum, tungsten, and aluminum, the molybdenum, tungsten, and aluminum in the solid residue enter the dissolution liquid, while uranium remains in the uranium-containing dissolution residue.

[0057] After obtaining the molybdenum-tungsten-aluminum solution, the present invention mixes the molybdenum-tungsten-aluminum solution with quicklime and reacts it to obtain calcium salt precipitate and aluminum-containing mother liquor.

[0058] In this invention, the amount of quicklime is preferably 100% to 110% of the theoretical total amount of molybdenum and tungsten, that is, the amount of quicklime is preferably equal to or in excess of the theoretical total amount of molybdenum and tungsten.

[0059] In this invention, the reaction temperature is preferably room temperature, requiring neither additional heating nor additional cooling; the reaction time is preferably ≥1 hour.

[0060] In this invention, the calcium salt precipitate includes calcium molybdate and calcium tungstate.

[0061] In this invention, during the reaction process, molybdenum and tungsten react with quicklime to form calcium salt precipitates, which are then recovered.

[0062] After obtaining the uranium-containing dissolving residue, the present invention prepares the uranium-containing dissolving residue and the aluminum-containing mother liquor into a slurry, and then performs uranium dissolution under the condition of introducing carbon dioxide to obtain the uranium-containing dissolving liquid and the aluminum-containing dissolving residue.

[0063] In this invention, water is preferably added during the pulping process. The liquid-to-solid ratio of the pulp is preferably 1.5:1 (mL / g).

[0064] In this invention, the pH value for uranium dissolution is preferably 7-8, the temperature is preferably 50-100℃, more preferably 60-90℃, and even more preferably 70-80℃; the time is preferably ≥3h; and the uranium dissolution is preferably carried out under stirring conditions.

[0065] In this invention, during the uranium dissolution process, uranium enters the dissolving liquid, while aluminum remains in the dissolving residue and is recovered in the form of slag.

[0066] After obtaining the uranium-containing solution, the present invention uses a strong base resin to adsorb the uranium-containing solution, thereby obtaining adsorption tail liquid and uranium-absorbing resin.

[0067] In this invention, the type of the strong alkali resin is preferably including, but not limited to, 201×7, D201, D263 or D261.

[0068] In this invention, the adsorption tail liquid is preferably refluxed to the uranium dissolution step for pulping.

[0069] In this invention, during the adsorption process, uranium in the uranium-containing solution is adsorbed into the strong base resin.

[0070] After obtaining the uranium-absorbing resin, the present invention sequentially performs a first rinsing, a second rinsing, and desorption elution on the uranium-absorbing resin to obtain uranium-containing desorption liquid and desorption resin, thereby realizing a comprehensive recovery method for distillation residue.

[0071] In this invention, the rinsing agent for the first rinsing is preferably water, and the first rinsing is preferably performed until the total concentration of carbonate and bicarbonate ions in the resulting rinsing solution is not higher than 1 g / L. In this invention, the first rinsing can remove carbonate and bicarbonate ions adsorbed in the strong base resin.

[0072] In this invention, the rinsing agent for the second rinsing is preferably a nitric acid solution of 5-10 g / L, and the second rinsing is preferably rinsing 1-3 bed volumes, more preferably rinsing 2 bed volumes. In this invention, the second rinsing can neutralize the remaining carbonate and bicarbonate ions.

[0073] In this invention, the eluent for desorption and elution is preferably a 1-2 mol / L nitric acid solution.

[0074] In this invention, the uranium-containing desorption solution is preferably used in a uranium purification production line. In this invention, the desorption resin is preferably washed with water until the pH value is 3-3.5, and then used as a strong base resin for adsorption.

[0075] The comprehensive recovery method provided by this invention can recover uranium, aluminum, molybdenum and tungsten from distillation residues.

[0076] In this invention, Figure 1 The flowchart of the comprehensive recovery method for distillation residue provided by the present invention is as follows: the distillation residue is subjected to fluidized bed decomposition to obtain decomposition gas and solid residue; the decomposition gas is absorbed to obtain nitric acid; the solid residue is subjected to molybdenum-tungsten-aluminum dissolution under the action of strong alkali and peroxide to obtain uranium-containing dissolution residue and molybdenum-tungsten-aluminum dissolution solution; the molybdenum-tungsten-aluminum dissolution solution is mixed with quicklime and reacted to obtain calcium salt precipitates (calcium molybdate and calcium tungstate, realizing the recovery of molybdenum and tungsten) and aluminum-containing mother liquor; the uranium-containing dissolution solution and aluminum-containing mother liquor are slurried and subjected to uranium dissolution under the condition of carbon dioxide introduction to obtain uranium-containing dissolution solution and aluminum-containing dissolution residue (realizing aluminum recovery); the uranium-containing dissolution solution is adsorbed to obtain adsorption tail liquid (adsorption tail liquid is returned to uranium dissolution), and the resin adsorbing uranium is eluted to obtain uranium-containing desorption solution, which is returned to the production line.

[0077] The following detailed description of the comprehensive recovery method for distillation residues provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0078] Example 1

[0079] The distillation residue contained 1.08 g / L of uranium, 3.46 g / L of aluminum, 0.527 g / L of molybdenum, 2.35 g / L of magnesium, 0.243 g / L of tungsten, and 1245 mg / L of COD.

[0080] (1) The distillation residue is sprayed out in the form of spray droplets with a diameter of 0.2 mm, a fluidizing air temperature of 500 °C, a fluidization time of 10 min, and a gas-liquid ratio of 50 to obtain solid residue (diameter of 2 mm) and decomposition gas.

[0081] (2) The decomposed gas is absorbed in the Venturi tube. The gas absorption is a three-stage absorption. The water jet velocity is 13 m / s. The decomposed gas is naturally absorbed. Nitrogen oxides are absorbed by water. The concentration of nitric acid in the absorption liquid is 1 mol / L. Carbon dioxide is discharged.

[0082] (3) ① Mix sodium hydroxide and hydrogen peroxide to obtain a solvent. The mass of hydrogen peroxide (mass concentration of 30%) in the solvent is 0.5% of the mass of the dissolved residue. The prepared solvent and solid residue with a diameter of 2 mm are slurried at a liquid-solid ratio of 1.5:1 (mL / g). The mixture is dissolved at 70℃ for 3 hours and then filtered to obtain a molybdenum-tungsten-aluminum solution (sodium hydroxide balance of 10 g / L) and a uranium-containing dissolved residue.

[0083] ② Add quicklime to the molybdenum-tungsten-aluminum solution, the amount of quicklime being 100% of the theoretical total amount of molybdenum-tungsten, and react for 1 hour to obtain calcium salt precipitate and aluminum-containing mother liquor.

[0084] (4) The uranium-containing dissolving residue, aluminum-containing mother liquor, and part of the adsorption tail liquid obtained in step (3) are mixed into a liquid-solid ratio of 1.5:1 (mL / g), carbon dioxide is introduced, pH is controlled at 7.5, temperature is 70℃, and the mixture is stirred for 5 hours. After filtration, uranium-containing dissolving liquid and aluminum-containing dissolving residue are obtained.

[0085] (5) The uranium-containing solution obtained in step (4) is adsorbed using 201×7 resin to obtain adsorption tail liquid and uranium-absorbing resin; the uranium-absorbing resin is rinsed with water until the total concentration of carbonate and bicarbonate in the rinsing solution is 1 g / L; then two bed volumes are rinsed with 5 g / L nitric acid solution; then uranium is desorbed with 1 mol / L nitric acid solution, and the desorbed resin is washed with water until pH 3 for recycling.

[0086] Example results: Uranium recovery rate reached 96%, molybdenum recovery rate reached 93%, tungsten recovery rate reached 91%, aluminum recovery rate reached 87%, and the COD value of the treated wastewater was reduced to below 12 mg / L.

[0087] Example 2

[0088] The distillation residue contained 1.568 g / L of uranium, 4.57 g / L of aluminum, 0.891 g / L of molybdenum, 3.74 g / L of magnesium, 0.339 g / L of tungsten, and 1526 mg / L of COD.

[0089] (1) The distillation residue is sprayed out in the form of spray droplets with a diameter of 0.1 mm, the fluidization air temperature is 400℃, the fluidization time is 10 min, and the gas-liquid ratio is 100, resulting in solid residue (diameter of 2 mm) and decomposition gas.

[0090] (2) The decomposed gas is absorbed by the Venturi tube. The gas absorption is a three-stage absorption. The water jet velocity is 15 m / s. The decomposed gas is naturally absorbed. Nitrogen oxides are absorbed by water. The concentration of nitric acid in the absorption liquid is 2 mol / L. Carbon dioxide is discharged.

[0091] (3) ① Sodium hydroxide and hydrogen peroxide are mixed to obtain a solvent. The mass of hydrogen peroxide (mass concentration of 30%) in the solvent is 0.3% of the mass of the dissolved residue. The prepared solvent and solid residue with a diameter of 2 mm are slurried at a liquid-solid ratio of 1.5:1 (mL / g). The mixture is dissolved at 100℃ for 5 hours and then filtered to obtain a molybdenum-tungsten-aluminum solution (sodium hydroxide balance of 15g / L) and a uranium-containing dissolved residue.

[0092] ② Add quicklime to the molybdenum-tungsten-aluminum solution, the amount of quicklime being 110% of the theoretical total amount of molybdenum-tungsten, and react for 2 hours to obtain calcium salt precipitate and aluminum-containing mother liquor.

[0093] (4) The uranium-containing dissolving residue, aluminum-containing mother liquor, and part of the adsorption tail liquid obtained in step (3) are mixed into a liquid-solid ratio of 1.5:1 (mL / g), carbon dioxide is introduced, pH is controlled at 8.0, temperature is 100℃, and the mixture is stirred for 3 hours. After filtration, uranium-containing dissolving liquid and aluminum-containing dissolving residue are obtained.

[0094] (5) The uranium-containing solution obtained in step (4) is adsorbed using D263 resin to obtain adsorption tail liquid and uranium-absorbing resin; the uranium-absorbing resin is rinsed with water until the total concentration of carbonate and bicarbonate in the rinsing solution is 0.8 g / L; then, one bed volume is rinsed with 10 g / L nitric acid solution; then, uranium is desorbed with 2 mol / L nitric acid solution, and the desorbed resin is washed with water until pH 3.5 for recycling.

[0095] Example results: Uranium recovery rate reached 95%, molybdenum recovery rate reached 94%, tungsten recovery rate reached 92%, aluminum recovery rate reached 85%, and the COD value of the treated wastewater was reduced to below 13 mg / L.

[0096] Example 3

[0097] The distillation residue contained 0.821 g / L of uranium, 1.38 g / L of aluminum, 0.476 g / L of molybdenum, 2.00 g / L of magnesium, 0.176 g / L of tungsten, and 723 mg / L of COD.

[0098] (1) The distillation residue is sprayed out in the form of spray droplets with a diameter of 0.15 mm, the fluidization air temperature is 450℃, the fluidization time is 15 min, and the gas-liquid ratio is 200, resulting in solid residue (diameter of 1 mm) and decomposition gas.

[0099] (2) The decomposed gas is absorbed by the Venturi tube. The gas absorption is a four-stage absorption. The water jet velocity is 10 m / s. The decomposed gas is naturally absorbed. Nitrogen oxides are absorbed by water. The concentration of nitric acid in the absorption liquid is 2 mol / L. Carbon dioxide is discharged.

[0100] (3) ① Sodium hydroxide and hydrogen peroxide are mixed to obtain a solvent. The mass of hydrogen peroxide (mass concentration of 30%) in the solvent is 0.5% of the mass of the dissolved residue. The prepared solvent and solid residue with a diameter of 1 mm are slurried at a liquid-solid ratio of 1.5:1 (mL / g). The mixture is dissolved at 40℃ for 10 hours and then filtered to obtain a molybdenum-tungsten-aluminum solution (sodium hydroxide balance of 10 g / L) and a uranium-containing dissolved residue.

[0101] ② Add quicklime to the molybdenum-tungsten-aluminum solution, the amount of quicklime being 110% of the theoretical total amount of molybdenum-tungsten, and react for 2 hours to obtain calcium salt precipitate and aluminum-containing mother liquor.

[0102] (4) The uranium-containing dissolving residue, aluminum-containing mother liquor, and part of the adsorption tail liquid obtained in step (3) are mixed into a liquid-solid ratio of 1.5:1 (mL / g), carbon dioxide is introduced, pH is controlled at 7.0, temperature is 50℃, and the mixture is stirred for 8 hours. After filtration, uranium-containing dissolving liquid and aluminum-containing dissolving residue are obtained.

[0103] (5) The uranium-containing solution obtained in step (4) is adsorbed using D261 resin to obtain adsorption tail liquid and uranium-absorbing resin; the uranium-absorbing resin is rinsed with water until the total concentration of carbonate and bicarbonate in the rinsing solution is 1.0 g / L; then 1.5 bed volumes are rinsed with 10 g / L nitric acid solution; then uranium is desorbed with 2 mol / L nitric acid solution, and the desorbed resin is washed with water until pH 3.0 for recycling.

[0104] Example results: Uranium recovery rate reached 96%, molybdenum recovery rate reached 90%, tungsten recovery rate reached 90%, aluminum recovery rate reached 86%, and the COD value of the treated wastewater was reduced to below 10 mg / L.

[0105] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for integrated recovery of distillation raffinate, characterized by, Includes the following steps: The distillation residue was subjected to fluidized bed decomposition to obtain solid residue and decomposition gas; The decomposed gas is absorbed to obtain a nitric acid solution and a removable gas. The solid residue is mixed with a solvent to dissolve molybdenum-tungsten-aluminum, yielding a molybdenum-tungsten-aluminum solution and a uranium-containing dissolution residue; the solvent includes a strong alkali and a peroxide. The molybdenum-tungsten-aluminum solution was mixed with quicklime and reacted to obtain calcium salt precipitate and aluminum-containing mother liquor. The uranium-containing dissolving residue and aluminum-containing mother liquor are slurried together, and uranium is dissolved under the condition of carbon dioxide introduction to obtain uranium-containing dissolving liquid and aluminum-containing dissolving residue. A strong base resin was used to adsorb uranium-containing solution, resulting in adsorption tail liquid and uranium-absorbing resin. The uranium-absorbing resin is subjected to a first rinsing, a second rinsing, and desorption elution in sequence to obtain uranium-containing desorption liquid and desorption resin, thereby achieving comprehensive recovery of distillation residue; The parameters of the fluidized bed decomposition include: the distillation residue is fluidized bed decomposition in the form of atomized droplets, the diameter of the atomized droplets is ≤0.2mm, the fluidizing gas is air, the temperature of the fluidizing gas is ≥400℃, the residence time is ≥10min, and the equipment is a fluidized bed; the gas-liquid ratio of the fluidized bed decomposition is 50~200. The parameters for gas absorption include: the absorbent is water, the equipment is a Venturi tube, the absorbent enters from the main pipe of the Venturi tube, and the decomposed gas enters from the side pipe of the Venturi tube; the flow rate of the absorbent is ≥10m / s. The strong alkali includes sodium hydroxide and / or potassium hydroxide, and the peroxide includes one or more of sodium peroxide, potassium peroxide, and hydrogen peroxide, wherein the mass of the peroxide is 0.3-0.5% of the mass of the solid residue; The potential for dissolving the molybdenum-tungsten-aluminum alloy is ≥500mV, the temperature is 40~100℃, and the time is ≥3h. The residual strong alkali in the molybdenum-tungsten-aluminum solution is 10~20g / L; The uranium is dissolved at a pH of 7-8, a temperature of 50-100℃, and a time of ≥3h; the uranium is dissolved under stirring conditions.

2. The integrated recovery process of claim 1 wherein, The nitric acid solution is used as the eluent for desorption and elution.

3. The integrated recovery process of claim 1 wherein, The amount of quicklime is 100%~110% of the theoretical total amount of molybdenum and tungsten; the reaction temperature is room temperature and the time is ≥1h.

4. The comprehensive recycling method according to claim 1, characterized in that, The strong alkali resins include models such as 201×7, D201, D263, or D261; The adsorption tail liquid is returned to the uranium dissolution step for pulping.

5. The comprehensive recycling method according to claim 1, characterized in that, The first rinsing agent is water, and the total concentration of carbonate and bicarbonate in the obtained rinsing solution after the first rinsing is not higher than 1 g / L; The second rinsing agent is a nitric acid solution of 5-10 g / L, and the second rinsing is performed on 1-3 bed volumes; The eluent for desorption and elution is a 1-2 mol / L nitric acid solution.

6. The comprehensive recycling method according to claim 1, characterized in that, The uranium-containing desorption solution is used in the uranium purification production line; the desorption resin is washed with water until the pH value is 3~3.5, and then used as a strong base resin for adsorption.

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