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CN-122010171-A - Closed loop recovery method for disqualified zirconium sponge

CN122010171ACN 122010171 ACN122010171 ACN 122010171ACN-122010171-A

Abstract

The invention discloses a closed-loop recovery method of unqualified zirconium sponge, which relates to the technical field of nuclear fuel circulation and materials, and comprises the following steps of S1, converting irregular and porous unqualified zirconium sponge into zirconium oxide blocks or particles with stable chemical components and uniform physical morphology through high-temperature oxidation reaction; S3, mixing the qualified zirconia powder after ball milling with a carbonaceous reducing agent according to a set proportion, placing the mixed material in a reaction device for chlorination reaction, and condensing the product to realize the high-efficiency recovery of ZrCl 4 . The method provided by the invention can solve the treatment difficulty of the unqualified zirconium sponge caused by the porous and irregular physical properties of the zirconium sponge, ensure the consistency of the high purity and quality of the final product, and can be directly embedded into the recovery process of the existing production flow to realize the high-value reutilization of the unqualified zirconium sponge.

Inventors

  • SUN YANDONG
  • CAO ZHI
  • ZHAO ZIQIAN
  • CHEN QI
  • CHEN YING
  • ZHENG WEIFANG
  • YUAN ZHONGWEI
  • YAN TAIHONG
  • LIU FANG
  • JIA YANHONG
  • TANG HONGBIN

Assignees

  • 中国原子能科学研究院

Dates

Publication Date
20260512
Application Date
20260105

Claims (10)

  1. 1. A closed loop recovery method of unqualified zirconium sponge comprises the following steps: s1, converting irregular and porous unqualified zirconium sponge into zirconium oxide blocks or particles with stable chemical components and uniform physical forms through high-temperature oxidation reaction; S2, processing zirconia blocks or particles obtained after oxidation into powder meeting the feeding requirement of a chlorination process through a ball milling process; S3, mixing the qualified zirconia powder after ball milling with a carbonaceous reducing agent according to a set proportion, placing the mixed material into a reaction device for chlorination reaction, and condensing the product to realize high-efficiency recovery of ZrCl 4 .
  2. 2. The method for recycling the disqualified zirconium sponge according to claim 1, wherein the oxidizing atmosphere in the step S1 is a mixed gas of nitrogen and oxygen, and the volume concentration of the oxygen is 20% -80%.
  3. 3. The method for recycling the disqualified zirconium sponge according to claim 2, wherein the oxidation temperature in the step S1 is 500-1000 ℃.
  4. 4. The method for recycling the disqualified zirconium sponge according to claim 3, wherein the oxidation temperature in the step S1 ranges from 700 ℃ to 1000 ℃.
  5. 5. The method for closed-loop recovery of off-specification zirconium sponge according to claim 4, wherein the oxidation reaction time in step S1 is 1 to 8 hours.
  6. 6. The method for closed-loop recovery of unqualified zirconium sponge according to any one of claims 1 to 5, wherein in step S2, a ball mill is adopted, and the optimal combination of ball milling process parameters is determined by systematically adjusting the rotation speed, the ball milling time, the material quality, the size ratio and the filling amount of the grinding medium of the ball mill.
  7. 7. The method for recycling the unqualified zirconium sponge according to claim 6, wherein the optimal ball milling process parameter combination determined in the step S2 is that the rotation speed of a ball mill is 300 revolutions per minute, the ball milling time is 2 hours, and the material of the grinding balls is zirconium oxide.
  8. 8. The method for closed-loop recovery of off-specification zirconium sponge according to claim 7, wherein the ball-milled product in step S2 has a particle fraction of-200 mesh of 95% or more and wherein the particle fraction of-400 mesh of 65% or more.
  9. 9. The method for recycling the disqualified sponge zirconium in the closed loop is characterized in that in the step S3, the mixed material is placed in a fixed bed or a fluidized bed chlorination furnace to react with chlorine, wherein a reaction formula is ZrO 2 +2Cl 2 +2C→ZrCl 4 +2CO, and the high-efficiency separation and deep impurity removal are realized by precisely controlling the chlorination temperature, the chlorine flow and the carbon ratio and utilizing the obvious difference of the volatility of the target product and the impurity element chloride.
  10. 10. The method for closed loop recovery of off-specification zirconium sponge according to claim 9, wherein the chlorination reaction temperature in step S3 is set to 800-1000 ℃.

Description

Closed loop recovery method for disqualified zirconium sponge Technical Field The invention belongs to the technical field of nuclear fuel circulation and materials, and particularly relates to a method for recycling unqualified products (mainly comprising surface oxides and filtering matters) generated in a nuclear grade zirconium sponge production process. Background Zirconium is a key material for nuclear reactor fuel cladding due to its excellent thermal neutron transparency and corrosion resistance. With the rapid development of the nuclear power industry in China, the demand for nuclear grade zirconium sponge is continuously growing. In the domestic nuclear grade zirconium sponge production process, about 20% of unqualified products can be produced in the zirconium ingot peeling and filtering links. At present, the unqualified products can only be disposed at a low price of about 8.5 ten thousand yuan/ton, which is far lower than the market price of 48 ten thousand yuan/ton of qualified sponge zirconium and even lower than the purchasing cost of raw material ZrO 2. The current 200 tons/year yield can be counted, the annual direct economic loss reaches 245 ten thousand yuan, and if the yield is increased to 2000 tons/year in the plan, the annual loss reaches 2450 ten thousand yuan, thus forming a huge value depression of enterprises. At present, the main idea of the recovery research of the disqualified zirconium sponge is to return the disqualified zirconium sponge to the starting point of the chlorination purification of zircon sand, but the recovery research faces the challenges of long process flow, high energy consumption and poor economy. And the method is simple, and the crushed product is directly returned to the chlorination process, so that the non-uniform chlorination process and low reaction efficiency are easily caused due to irregular shape and large difference between physical properties and main raw materials of unqualified products, and the enriched metal impurities such as Cr, ni, mn and the like are difficult to effectively remove, so that dyeing and finishing batch products are polluted, and the quality of main line products is influenced. Even if part of the materials are recovered, the recovery rate and the product purity are difficult to ensure stably, so that the whole recovery process is lack of feasibility in economy and technology. Therefore, there is an urgent need to find a recycling process which is economical and efficient and can be directly embedded into the existing production flow, so as to realize high-value recycling of the unqualified sponge zirconium. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide the closed-loop recovery method of the unqualified sponge zirconium, by using the method, the treatment difficulty of the unqualified sponge zirconium caused by the porous and irregular physical properties of the unqualified sponge zirconium can be solved, the high purity and quality consistency of a final product are ensured, and the unqualified sponge zirconium can be directly embedded into the recovery process of the existing production flow, so that the high-value reutilization of the unqualified sponge zirconium is realized. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A closed loop recovery method of unqualified zirconium sponge comprises the following steps: s1, converting irregular and porous unqualified zirconium sponge into zirconium oxide blocks or particles with stable chemical components and uniform physical forms through high-temperature oxidation reaction; S2, processing zirconia blocks or particles obtained after oxidation into powder meeting the feeding requirement of a chlorination process through a ball milling process; S3, mixing the qualified zirconia powder after ball milling with a carbonaceous reducing agent according to a set proportion, placing the mixed material into a reaction device for chlorination reaction, and condensing the product to realize high-efficiency recovery of ZrCl 4. Further, according to the disqualified sponge zirconium closed-loop recovery method, in the step S1, the oxidizing atmosphere is a mixed gas of nitrogen and oxygen, wherein the volume concentration range of the oxygen is 20% -80%. Further, according to the method for recycling the disqualified zirconium sponge in a closed loop mode, the oxidation temperature range in the step S1 is 500-1000 ℃. Further, according to the method for recycling the disqualified zirconium sponge in a closed loop mode, the oxidation temperature range in the step S1 is 700-1000 ℃. Further, according to the method for recycling the disqualified zirconium sponge in a closed loop, the oxidation reaction time in the step S1 is 1-8 hours. Further, in the above-mentioned disqualified zirconium sponge closed-loop recovery method, in step S2, a ball mill is adopted, and the rotation speed