Title:
RECYCLING PROCESS OF LITHIUM IRON PHOSPHATE
Document Type and Number:
WIPO Patent Application WO/2024/060653
Kind Code:
A1
Abstract:
Provided is a recycling process of lithium iron phosphate, which comprises the following steps: S1, dispersing lithium iron phosphate black powder in a solution system, adding a sulfuric acid solution and hydrogen peroxide, and carrying out a reaction and filtration to obtain a filtrate A and a filter residue A; S2, dispersing the filter residue A in a sulfuric acid solution, and carrying out a reaction and filtration to obtain a filtrate B and a filter residue B; S3, dispersing the filter residue B in a sulfuric acid solution, and carrying out a reaction and filtration to obtain a filter residue C and a filtrate C; and S4, adding aqueous ammonia into the filtrate C, carrying out a hydrothermal reaction in a stirring state to obtain a green crystal and a filtrate D, and roasting the green crystal to obtain battery-grade iron phosphate. In S1, the pH value of the filtrate A is adjusted with lithium hydroxide to obtain a filtrate E and a filter residue E, the filtrate E passes through an electrochemical reactor to obtain a lithium sulfate solution, a lithium hydroxide solution and dilute sulfuric acid, and then the described liquid is reused in all the steps. In S1, the pH value is controlled to be 3-7, and the ORP of the solution system is controlled to be maintained at 350-500 mV. In S2, the pH value is controlled to be 0.5-2. In S3, the pH value is controlled to be 0-0.3. In S4, the pH value is controlled to be 1.6-3.5. By means of the process, recycling of iron phosphate and total-recycle utilization of each intermediate in the recycling process are achieved at the same time, and in a total-recycle process, no new substances need to be additionally added, no wastewater is generated, and thus the process is a green and environment-friendly regeneration process.
Inventors:
DAI LINSHAN (CN)
RONG ZHONGYAN (CN)
ZHANG JIUJUN (CN)
KANG DONGXIN (CN)
SUI BANGJIE (CN)
SHI YIFANG (CN)
RONG ZHONGYAN (CN)
ZHANG JIUJUN (CN)
KANG DONGXIN (CN)
SUI BANGJIE (CN)
SHI YIFANG (CN)
Application Number:
PCT/CN2023/095644
Publication Date:
March 28, 2024
Filing Date:
May 23, 2023
Export Citation:
Assignee:
SICHUAN ENERGY INT RES INST TSINGHUA UNIV (CN)
International Classes:
C01B25/37; H01M10/0525; H01M10/54
Foreign References:
| CN115385316A | 2022-11-25 | |||
| CN112331949A | 2021-02-05 | |||
| CN113501510A | 2021-10-15 | |||
| CN111115662A | 2020-05-08 | |||
| US20190207275A1 | 2019-07-04 |
Attorney, Agent or Firm:
CHENGDU RUIDAO PATENT AGENCY (GENERAL PARTNERSHIP) (CN)
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