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CN-122013324-A - Calcium fluoride whisker recovery method

CN122013324ACN 122013324 ACN122013324 ACN 122013324ACN-122013324-A

Abstract

The invention relates to the technical field of inorganic reinforced materials and discloses a calcium fluoride whisker recovery method, which comprises the following steps of S1, mixing pretreated calcium fluoride whiskers with a composite functional treatment liquid for reaction to obtain slurry, wherein the composite functional treatment liquid comprises the following raw material components of 5% -12% of stripping agent, 0.5% -2.5% of structure protective agent, 0.1% -0.8% of surfactant and 1% -3% of oxidant, and the balance of water, S2, carrying out solid-liquid separation on the slurry to obtain a solid product, and S3, washing, floatation and drying the solid product to obtain the recovered calcium fluoride whiskers. The recovery method provided by the invention can recover the high-purity calcium fluoride whisker and simultaneously furthest protect the original structure of the calcium fluoride whisker, the average length-diameter ratio of the recovered calcium fluoride whisker is more than or equal to 76, compared with the length-diameter ratio of the original calcium fluoride whisker in the raw material, the retention rate is more than 89%, and the purity and the performance are obviously improved.

Inventors

  • HU WEIJIE
  • WU WEI
  • ZHANG PENGFEI
  • HE JIN

Assignees

  • 上海市政工程设计研究总院（集团）有限公司

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. A method for recovering calcium fluoride whiskers, comprising the following steps: S1, mixing pretreated calcium fluoride whiskers with a composite function treatment liquid for reaction to obtain slurry; The composite functional treatment fluid comprises the following raw material components, by mass, 5% -12% of stripping agent, 0.5% -2.5% of structure protective agent, 0.1% -0.8% of surfactant, 1% -3% of oxidant and the balance of water; S2, carrying out solid-liquid separation on the slurry to obtain a solid product; s3, washing, floating and drying the solid product to obtain the recovered calcium fluoride whisker.
  2. 2. A method of recovering calcium fluoride whiskers according to claim 1, wherein in step S1, said stripping agent is selected from one or more of citric acid, gluconic acid and tartaric acid.
  3. 3. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S1, said structure-protecting agent is sodium hexametaphosphate or sodium tripolyphosphate.
  4. 4. The method for recovering calcium fluoride whiskers of claim 1, wherein in step S1, the surfactant is alkylphenol ethoxylate or fatty alcohol ethoxylate.
  5. 5. The method for recovering calcium fluoride whiskers according to claim 1, wherein in step S1, the mass-to-volume ratio of the pretreated calcium fluoride whiskers to the composite functional treatment liquid is 1 (6-8) kg/L.
  6. 6. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S1, the temperature of said mixing reaction is 50-65 ℃, and the time of said mixing reaction is 90-150min.
  7. 7. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S1, said pretreated calcium fluoride whiskers comprise the following treatment steps: Crushing the raw material containing the calcium fluoride whisker, and then carrying out airflow separation to obtain the pretreated calcium fluoride whisker.
  8. 8. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S3, said washing is a three-stage countercurrent washing, and the temperature of said washing water is 60-70 ℃.
  9. 9. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S3, said foaming agent used for flotation is methyl isobutyl carbinol.
  10. 10. A method for recovering calcium fluoride whiskers according to claim 1, wherein in step S3, the drying is sequentially freeze-drying and vacuum-drying, the freeze-drying temperature is (-30) - (-40) DEG C, the freeze-drying time is 4-6h, the vacuum degree of the vacuum-drying is <10Pa, and the vacuum-drying time is 20-24h.

Description

Calcium fluoride whisker recovery method Technical Field The application relates to the technical field of inorganic reinforced materials, in particular to a method for recycling calcium fluoride whiskers. Background Calcium fluoride (CaF 2) whisker is used as an inorganic reinforcing material with excellent performance, and is widely applied to the fields of polymer composite materials, friction materials, precision ceramics and the like because of good heat resistance, wear resistance, corrosion resistance and electrical insulation, so as to remarkably improve the mechanical property and dimensional stability of a matrix material. The performance of calcium fluoride whiskers, especially the reinforcing performance of composite materials, is extremely dependent on the integrity of the morphology, and the core index is the length-diameter ratio. The calcium fluoride whisker with high length-diameter ratio has more excellent enhancement effect, lower addition amount and more excellent performance retention rate compared with the common calcium fluoride whisker with low length-diameter ratio. Therefore, whether the original length-diameter ratio of the calcium fluoride whisker can be reserved to the maximum limit is a key for measuring the quality and the product value of the recovery method. However, due to inherent mechanical vulnerability, severe chemical environment sensitivity, complicated impurity stripping dilemma and serious secondary agglomeration problems of the calcium fluoride whiskers, the existing calcium fluoride whisker recovery technology has the problems that the efficient recovery process is often accompanied by damage to the bulk structure of the calcium fluoride whiskers, and as a result, the high purity is replaced at the expense of the high length-diameter ratio of the calcium fluoride whiskers, so that the recovered calcium fluoride whiskers can only be used as common fillers and cannot enter the application field of high added value. Therefore, developing a recovery method capable of recovering high-purity calcium fluoride whiskers while protecting the original structure of the calcium fluoride whiskers to the maximum extent has become a technical problem to be solved in the art. Disclosure of Invention The invention provides a recovery method of calcium fluoride whisker, which aims to develop a recovery method capable of recovering high-purity calcium fluoride whisker and protecting the original structure of the calcium fluoride whisker to the maximum extent. The invention provides a method for recovering calcium fluoride whiskers, which adopts the following technical scheme: a method for recovering calcium fluoride whiskers, comprising the following steps: S1, mixing pretreated calcium fluoride whiskers with a composite function treatment liquid for reaction to obtain slurry; The composite functional treatment fluid comprises the following raw material components, by mass, 5% -12% of stripping agent, 0.5% -2.5% of structure protective agent, 0.1% -0.8% of surfactant, 1% -3% of oxidant and the balance of water; S2, carrying out solid-liquid separation on the slurry to obtain a solid product; s3, washing, floating and drying the solid product to obtain the recovered calcium fluoride whisker. Optionally, in step S1, the stripping agent is one or more selected from citric acid, gluconic acid and tartaric acid. Optionally, in step S1, the structure-protecting agent is sodium hexametaphosphate or sodium tripolyphosphate. Optionally, in step S1, the surfactant is alkylphenol ethoxylate or fatty alcohol ethoxylate. Optionally, in step S1, the mass-volume ratio of the pretreated calcium fluoride whisker and the composite function treatment liquid is 1 (6-8) kg/L. Optionally, in step S1, the temperature of the mixing reaction is 50-65 ℃, and the time of the mixing reaction is 90-150min. Optionally, in step S1, the pretreated calcium fluoride whisker includes the following treatment steps: Crushing the raw material containing the calcium fluoride whisker, and then carrying out airflow separation to obtain the pretreated calcium fluoride whisker. Optionally, in step S3, the washing is three-stage countercurrent washing, and the temperature of the washing water is 60-70 ℃. Optionally, in step S3, the foaming agent used in the flotation is methyl isobutyl carbinol. Optionally, in step S3, the drying is sequentially freeze-drying and vacuum-drying, where the temperature of freeze-drying is (-30) - (-40) deg.c, the freeze-drying time is 4-6h, the vacuum degree of vacuum-drying is less than 10Pa, and the time of vacuum-drying is 20-24h. In summary, the present invention includes at least one of the following beneficial technical effects: The invention effectively avoids the original structure of the calcium fluoride whisker from being damaged by reacting the pretreated calcium fluoride whisker with the composite functional treatment liquid to form a dynamic protective film on the surface of the calc