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CN-121974433-A - Regeneration method of molybdenum removal extractant for contaminated acid system

CN121974433ACN 121974433 ACN121974433 ACN 121974433ACN-121974433-A

Abstract

The invention discloses a regeneration method of a molybdenum-removing extractant for a dirty acid system, and belongs to the technical field of extractant regeneration. Adding 0.05-0.1 wt.% of polycarboxylate, organic phosphonate or hydroxy carboxylate complexing agent into 5-8 wt.% carbonate buffer system, mixing the water phase with an aging extractant according to the ratio of O/A=1:1, reacting for 8-12 min at 20-35 ℃, and separating an organic phase from a weak base phase. Washing the organic phase with 0.5-1.0 mol/L sulfuric acid according to the ratio of O/A=1:1, separating, washing with water, and separating the organic phase from the water phase again. And dehydrating the organic phase until the water content is less than or equal to 150ppm, and enabling the organic phase to be in contact with a pre-equilibrium liquid containing sulfuric acid and/or sulfate according to the ratio O/A=1:1, so that the acid value of the organic phase is 0.10-0.35 mg KOH/g, and recovering the TBP.H 2 SO 4 addition ratio to be 0.05-0.20 mol/mol. Adding 50-200 ppm of hindered phenol antioxidant into the organic phase, filtering, and hermetically aging at room temperature. The regenerated extractant has low water content, stable acid value, high interfacial tension, elimination of metal poisoning, good phase behavior, extraction capacity recovery degree of more than 90%, stable long-term circulation performance and no generation of emulsification and third phase.

Inventors

  • YANG FU
  • YE PUHONG
  • ZHANG JIANXIN
  • XU YUAN
  • ZHU BOYUAN
  • SHI HUIXIAN
  • YUAN YE

Assignees

  • 昆明冶金研究院有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (10)

  1. 1. The method for regenerating the molybdenum-removing extractant for the contaminated acid system is characterized by comprising the following steps of: Weak base complexation treatment, namely adding any one of polycarboxylate, organic phosphonate and hydroxycarboxylic acid salt complexing agent with the mass fraction of 0.05-0.1 wt.% into a carbonate buffer system with the mass fraction of 5-8 wt.% to form a water phase, mixing the water phase with an aging extractant according to the ratio of O/A=1:1, reacting for 8-12 min at room temperature, and separating an organic phase from a weak base phase after standing; Washing and impurity removal, namely washing an organic phase with sulfuric acid with the concentration of 0.5-1.0 mol/L according to the ratio of O/A=1:1, standing for separation, washing the organic phase with water, standing again, and separating the organic phase from a water phase; Dewatering the organic phase to reduce the water content to less than or equal to 150ppm, then enabling the organic phase to contact with pre-equilibrium liquid containing sulfuric acid and/or sulfate according to the ratio O/A=1:1, stabilizing the acid value of the organic phase to be 0.10-0.35 mg KOH/g, and recovering the TBP.H 2 SO 4 addition ratio to be 0.05-0.20 mol/mol; and (3) performing antioxidation fine adjustment, namely adding 50-200 ppm of hindered phenol antioxidants into the organic phase, filtering to remove impurities, and hermetically aging at room temperature to finish the regeneration of the extractant.
  2. 2. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein in the weak base complexation treatment step, the carbonate buffer system is ammonium bicarbonate and/or ammonium carbonate solution.
  3. 3. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein in the weak base complexation treatment step, the complexing agent is any one of citrate, polyphosphonate, and tartrate.
  4. 4. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein the total number of times of washing is not less than 2 in the washing and impurity removing process, wherein the number of times of washing with sulfuric acid is not less than 1 and the number of times of washing with pure water is not less than 1.
  5. 5. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein the acid value of the organic phase is reduced to 0.20mg KOH/g or less in the washing and impurity-removing process.
  6. 6. The method for regenerating a molybdenum-removing extractant for a contaminated acid system according to claim 1, wherein the dehydration is dehydration with a molecular sieve or membrane in the addition specific gravity step.
  7. 7. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein the pre-equilibrium liquid contains 0.8 to 1.0mol/L H 2 SO 4 and/or 0.1 to 1.0mol/L Na 2 SO 4 in the addition specific gravity step.
  8. 8. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein the number of times of the contacting is not less than 1 in the addition specific gravity step, and the mixing is performed for 10 minutes each time.
  9. 9. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein in the antioxidant fine adjustment step, the hindered phenol antioxidant is 2, 6-di-t-butyl-4-methylphenol.
  10. 10. The method for regenerating a molybdenum-removed extractant for a contaminated acid system according to claim 1, wherein the aging temperature is 25 to 35 ℃ and the time is 2 to 4 hours in the antioxidant fine adjustment process.

Description

Regeneration method of molybdenum removal extractant for contaminated acid system Technical Field The invention belongs to the technical field of extractant regeneration, and particularly relates to a regeneration method of a molybdenum-removing extractant for a dirty acid system. Background The sulfuric acid waste acid generated in the copper smelting flue gas acid making process has the characteristics of high acidity, high sulfate radical, high iron and aluminum impurity content and low concentration of scattered metals (such as rhenium). In industrial treatment, in order to improve the recovery rate of valuable elements such as rhenium, a compound extraction system consisting of TBP (tri-n-butyl phosphate) -D2EHPA (di (2-ethylhexyl) phosphate) -fatty alcohol-diluent is generally adopted, so that effective removal of Mo (VI) and enrichment of rhenium are realized. However, during the cyclic operation of extraction-stripping, the composite extractant can gradually age, including aggregation poisoning of metal ions in an organic phase, hydrolysis and degradation of TBP, polymerization or oxidation of D2EHPA, continuous increase of water content, and reduction of interfacial tension. These changes not only lead to a decrease in extraction capacity, but also cause very high liabilities to emulsion, viscous phase, third phase, etc., so that the extractant must be periodically regenerated. In the prior art, a regeneration method of alternating washing of strong acid and strong alkali is generally adopted. For example, acid-base washing operation is performed by oxalic acid, ammonia water, sodium carbonate, or the like, in an attempt to remove metal ions, degradation products, or microparticles adsorbed in the organic phase. However, the phosphate extractant is easy to generate saponification reaction under the strong alkali condition, so that the loss of the extractant is large, the phase behavior is poor, even the organic phase is disintegrated, and the regeneration effect is seriously affected. In addition, existing extraction systems often employ di (2-ethylhexyl) phosphoric acid (P204) or 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) as the acidic extractant. At present, the regeneration method of phosphoric acid extractant such as P507, P204 and the like can remove metal poisoning substances by a complexation precipitation mode, but the application of the method is mainly implemented by organic phosphonate extractant of vanadium, tungsten and molybdenum systems, and the method is not applicable to TBP-D2 EHPA-fatty alcohol composite systems. Meanwhile, the method generally does not quantitatively regulate key parameters such as water content, acid value, an addition structure of TBP.H 2SO4 and the like, so that the optimal interface state of the extractant cannot be recovered. At present, when a composite extractant is used for co-extraction in a copper smelting acid pollution system, the extractant generally has performance degradation phenomena such as water content increase, addition ratio decrease, interface behavior degradation, metal poisoning accumulation and the like along with the increase of the recycling times, and the extraction efficiency and the phase separation performance are seriously influenced. Therefore, a regeneration method suitable for a contaminated acid system and used for TBP+D2EHPA+fatty alcohol composite extractant is urgently needed, and meanwhile, moisture control, addition ratio recovery, interface behavior adjustment and metal poisoning elimination are realized, so that the problem of comprehensive performance reduction of the extractant after long-term cyclic use is solved, efficient cyclic utilization of the extractant is realized, production cost is reduced, and dangerous waste is reduced. Disclosure of Invention Aiming at the comprehensive aging problems of metal poisoning, unbalanced acidification, water content rise, interfacial tension drop, antioxidant consumption and the like of the acid-polluted system extractant in long-term use, the method for regenerating the extractant is mild, efficient, low in loss and repeatable. The aim is to recover the extraction capacity, interface stability and long-term circulation performance of the extractant, so that the extractant can meet the requirements of industrial continuous operation performance again. The invention aims at realizing the regeneration method of the molybdenum removal extractant for the contaminated acid system, which comprises the following steps: Weak base complexation treatment, namely adding any one of polycarboxylate, organic phosphonate and hydroxycarboxylic acid salt complexing agent with the mass fraction of 0.05-0.1 wt.% into a carbonate buffer system with the mass fraction of 5-8 wt.% to form a water phase, mixing the water phase with an aging extractant according to the ratio of O/A=1:1, reacting for 8-12 min at room temperature, and separating an organic phase from a weak base phase