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CN-122012923-A - Extraction system and method for preparing lithium phosphate products

CN122012923ACN 122012923 ACN122012923 ACN 122012923ACN-122012923-A

Abstract

The invention belongs to the production or refining of metals, and discloses an extraction system and a method for preparing lithium phosphate products. The invention uses diketone or oxime as main extractant, neutral phosphorus oxide or alkaline amine as auxiliary extractant, modifier and diluent to prepare extraction system, which has high extraction efficiency, good selectivity, low cost, low corrosiveness, no emulsification phenomenon, and small dissolution loss and degradation of extractant; the lithium phosphate product can be prepared by preparing an extraction system, mixing the extraction system with a lithium-containing solution after saponification treatment, and carrying out extraction, washing, back extraction, oil removal, precipitation and crystallization, so that the flow is obviously shortened, and the lithium recovery rate is greatly improved. The invention can avoid the problems of high energy consumption of mother liquor re-concentration and grade reduction caused by mixing, reduces the alkali consumption during saponification or extraction, can directly circulate the organic phase after back extraction, does not need regeneration, has high efficiency and low cost, is easy to control, and provides technical support for battery-level standard lithium phosphate products.

Inventors

  • LIU ZHAOBO
  • DU GUOSHAN
  • WANG YALI
  • LIU ZHE
  • ZHU XIAO
  • ZHOU WENLONG
  • SANG YUAN
  • ZHANG ZHIGANG
  • LIU JUN
  • YANG YONGLIANG

Assignees

  • 中国恩菲工程技术有限公司
  • 中国有色工程有限公司

Dates

Publication Date
20260512
Application Date
20260408

Claims (12)

  1. 1. The extraction system for preparing the lithium phosphate product is characterized by comprising a main extractant, a synergistic extractant, a modifier and a diluent, wherein the main extractant is a diketone extractant or an oxime extractant, and the synergistic extractant is a neutral phosphorus-oxygen extractant or an alkaline amine extractant.
  2. 2. The extraction system for preparing lithium phosphate products according to claim 1, wherein, The main extractant is one or more of dibenzoylmethane, acetylacetone, benzoylacetone, tetramethyl heptanedione, dodecyl phenyl-methyl-beta diketone, 5-nonyl salicylaldoxime, 2-hydroxy-5-nonyl salicylaldoxime and 2-hydroxy-5-nonyl acetophenone oxime; And/or the co-extractant is one or more of trioctyl phosphate, triisobutyl phosphate, dimethyl heptyl methylphosphonate, diphenyl phosphorus oxide, triphenyl phosphorus oxide, trialkyl phosphorus oxide, triethyl phosphorus oxide, trioctyl phosphorus oxide, trimethyl benzoyl-diphenyl phosphine oxide, benzene bis (2, 4, 6-trimethyl benzoyl) phosphine oxide, N1923, primene JMT and N235.
  3. 3. The extraction system for preparing lithium phosphate products according to claim 2, wherein, The main extractant is one or more of dibenzoylmethane, 5-nonylsalicylaldoxime, 2-hydroxy-5-nonylsalicylaldoxime and 2-hydroxy-5-nonylacetophenone oxime; The co-extractant is one or more of trioctyl phosphate, triisobutyl phosphate, dimethylheptyl methylphosphonate, N1923, primene JMT and N235.
  4. 4. The extraction system for preparing lithium phosphate products according to claim 2, wherein, The extraction system comprises 3-30% of main extractant, 2-20% of co-extractant, 5-10% of modifier and 40-90% of diluent by volume fraction; the modifier is a long-chain alcohol compound, and is selected from one or more of heptanol, n-octanol, sec-octanol, isooctanol, nonanol, decanol, undecanol, dodecyl alcohol, isotridecyl alcohol or tetradecyl alcohol; The diluent is selected from one or more of alkane compounds and aromatic compounds, wherein the alkane compounds comprise sulfonated kerosene, 200# solvent oil, n-12 alkane and 260# solvent oil, and the aromatic compounds comprise dimethylbenzene and heavy aromatic hydrocarbon.
  5. 5. A method for preparing a lithium phosphate product, wherein the extraction system for preparing a lithium phosphate product according to any one of claims 1 to 4 is saponified and then extracted, the method comprising: s1, preparing an extraction system by taking a diketone extractant or an oxime extractant as a main extractant, taking a neutral phosphorus-oxygen extractant or an alkaline amine extractant as a synergistic extractant, and taking a modifier and a diluent to form a composite extraction organic phase; step S2, performing saponification treatment on the composite extraction organic phase to obtain a saponified composite extractant; Step S3, mixing the saponified composite extractant with a lithium-containing solution, and extracting to obtain a lithium-extracted organic phase and a raffinate; S4, washing the lithium extraction organic phase by using a washing liquid to obtain an impurity-enriched washing liquid and a purified lithium extraction organic phase; s5, back-extracting the purified lithium extraction organic phase by using back-extracting solution to obtain a lithium-rich solution and a regenerated organic phase; step S6, degreasing the lithium-rich solution to obtain a lithium-rich water phase; and S7, adjusting the pH value of the lithium-rich water phase to prepare a lithium phosphate product.
  6. 6. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S2, the saponification agent is one or more of sodium hydroxide, potassium hydroxide and ammonia water, and the volume ratio of the composite extraction organic phase to the saponification agent is (10-100): 1; And/or in the step S2, the reaction temperature of the saponification treatment is 10-30 ℃, the reaction time is 5-20min, and the saponification degree is controlled to be 60-90%.
  7. 7. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S3, countercurrent extraction is adopted, the countercurrent extraction stage number is 4-10, the extraction ratio is (0.1-2): 1, and the stirring time of each stage is 5-20 min.
  8. 8. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S4, countercurrent washing is adopted, the countercurrent washing stage number is 2-10, the washing ratio is (2-15): 1, and the stirring time of each stage is 5-20 min; And/or in the step S4, the washing liquid is one or more of pure water and H 2 SO 4 、H 3 PO 4 、HCl、HNO 3 、LiCl、Li 2 SO 4 solution, and when the washing liquid is the solution, the concentration is 0.01-8M.
  9. 9. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S5, countercurrent back extraction is adopted, the countercurrent back extraction stage number is 2-10, the back extraction phase is (2-15): 1, and the stirring time of each stage is 5-20 min; the back extraction liquid is H 3 PO 4 , and the concentration of the back extraction liquid is 4-8M.
  10. 10. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S6, nonpolar macroporous styrene-divinylbenzene copolymer resin or activated carbon is adopted to remove oil from the lithium-rich solution, and the oil removal temperature is 15-60 ℃.
  11. 11. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S7 of the process, And heating the lithium-rich water phase to 70-90 ℃, regulating the pH of the lithium-rich water phase to 7-8, precipitating, centrifuging, washing, and drying at 100-120 ℃ to obtain a lithium phosphate product.
  12. 12. The method for producing a lithium phosphate product according to claim 5, wherein, In the step S7 of the process, Adjusting the pH of the lithium-rich water phase to 1-3, concentrating, cooling, crystallizing and drying to obtain a lithium dihydrogen phosphate product; wherein the concentration temperature is 90-135 ℃, the cooling crystallization temperature is 10-60 ℃, and the drying temperature is 100-120 ℃.

Description

Extraction system and method for preparing lithium phosphate products Technical Field The invention belongs to the technical field of metal production or refining, in particular to lithium extraction and lithium battery preparation, and particularly relates to an extraction system and method for preparing lithium phosphate products with short process and low cost. Background Under the driving of global energy structure transformation, the rapid development of new energy automobiles and energy storage industry continuously pulls the lithium battery demand, and drives the comprehensive upgrade of the upstream material industry chain. Among them, lithium iron phosphate has become one of the main positive materials in the market due to its comprehensive performance advantages, while battery grade lithium dihydrogen phosphate is used as an important precursor thereof, which has a key influence on the material performance and the preparation process. From the upstream of the industrial chain, lithium resources are mainly from salt lakes and ores, and the high efficiency and the green of the lithium extraction technology become an important trend in industry. Under the background, the advanced separation technology represented by solution extraction has the characteristics of short flow, strong adaptability, easy continuous production and the like, and shows remarkable advantages in the preparation of lithium extraction and subsequent lithium phosphate products, thereby becoming an important technical direction for realizing high-value conversion of lithium resources and stable supply of lithium iron phosphate precursors. The lithium-containing mother solution refers to a lithium-containing solution which is remained in the production process of lithium salt, such as a lithium deposition mother solution generated by a lithium carbonate/lithium hydroxide production process, a lithium-containing solution generated after lithium extraction of lithium ore, a lithium-containing mother solution generated after lithium extraction of salt lake, and the like, and the lithium-containing solution generally contains residual lithium ions and impurity ions which are not completely extracted, and has the characteristics of complex components and lower lithium concentration. Patent CN 119082495A discloses a lithium extraction method of lithium precipitation mother liquor, the main extractant is one of 2,3,7, 8-tetraminophenazine-1, 4,6, 9-tetraketone and terpyridine, the patent is mainly applied to extraction and recovery of lithium, and the method simply indicates that after extraction, the lithium complex is recovered by solid, how to strip and strip parameters are not provided, the selected extractant and solvent are expensive, the liquid-solid strip method is difficult to continuously carry out in actual operation, and the method is not suitable for industrial scale application. Patent CN 116854060A discloses a process for producing lithium dihydrogen phosphate, in which the main extractant used for preparing lithium dihydrogen phosphate is tributyl phosphate, trioctylphosphine oxide and beta-diketone, wherein the beta-diketone is a mixture obtained by combining beta-diketones with different structures of R1, R2, R3 and R4. The inventor recognizes that the main problems of the patent are that the trioctylphosphine oxide extractant has extremely high market price, is unfavorable for low-cost extraction of lithium dihydrogen phosphate, has higher solubility (0.6 g/100 mL) in water, has larger influence on subsequent products and environmental protection, can not be applied to recovery and extraction of salt lake brine lithium resources, and has higher oil content in the prepared product without an oil removal step, thus being not applicable to subsequent production of new energy battery raw material lithium iron phosphate at all. Patent CN 118241039A discloses an extractant for extracting lithium from alkaline lithium-containing solution, the ketone organic used is mainly fluorine-containing diketone compound, and the phosphine oxide compound is any one or a combination of at least two of tri-n-butyl phosphorus oxide, triphenyl phosphate, tributyl phosphate, tri-n-amyl phosphate, trioctylphosphine oxide, trisnonylphosphine oxide or tridecylphosphine oxide. However, the inventors of the present invention have noted that the improvement of the extraction effect depends on the fluoro-diketone, the extraction effect is deteriorated without adding fluoro-diketone, the influence on the surrounding ecological environment is large after the fluoro-organic phase enters the aqueous phase, the discharge requirement of the aqueous phase is high, and in addition, the saponification treatment is not performed on the organic phase in the extraction process, and the actual extraction performance of lithium is poor. For the existing preparation of battery grade lithium dihydrogen phosphate, the patent CN 102442654A adopts lithium hydroxide as