A lithium battery powder equipment supporting manufacturer encountered a bottleneck during the commissioning stage of a lithium iron phosphate wet grinding production line. The original sand mill chamber used a polyurethane lining. After 72 hours of continuous grinding, the lining showed obvious wear and detachment, debris mixed into the slurry, the magnetic foreign matter index exceeded the standard, and the cell sampling defect rate reached 9.3%. At the same time, the temperature resistance upper limit of the polyurethane material was insufficient. When the slurry was ground for a long time and the temperature rose above 65°C, the aging speed of the lining accelerated, and the equipment had to be shut down for disassembly and replacement every 2 months, affecting continuous production on the production line. The customer needed a lining material that combines high wear resistance and chemical inertness, strictly controls the precipitation of metal impurities, and adapts to the continuous wet grinding working conditions of lithium iron phosphate slurry with a solid content of 45%.

Dongguan Zhongli Nano Ceramics Technology customized an integrated zirconia ceramic lining for this sand mill working condition. The material uses 3Y zirconia, with a Vickers hardness of 12.8GPa and a bending strength of ≥1050MPa; it is integrally sintered and formed, with no splicing gaps, avoiding material getting stuck in seam positions and causing accumulation and contamination. The lining is resistant to acid-base slurry in the pH2~12 range, and will not precipitate metal ions such as iron and chromium during long-term use.

On-site mass production test: the sand mill linear speed was 12m/s, paired with 0.6mm zirconia grinding beads for continuous operation. After 1000 hours of continuous grinding, the lining wear amount was only 0.018mm, and the magnetic foreign matter in the slurry was stably controlled within 18ppb, meeting the purity standard for battery-grade powder. The chamber can withstand a maximum grinding temperature rise of 80°C, without softening or peeling problems. Installation adopts a cold-fit matching process, making disassembly and assembly convenient, without modifying the original main shaft and sealing structure of the sand mill.

After the project was implemented, the defect rate of cells caused by foreign matter dropped to 2.2%, and the lining replacement cycle was extended from 2 months to 18 months, greatly reducing downtime maintenance man-hours. This zirconia ceramic lining solution can also be applied to powder grinding equipment such as silicon-carbon anodes and conductive slurry.

FAQ

Q: Can the zirconia ceramic lining adapt to acidic lithium battery slurry?

A: 3Y zirconia has good chemical stability and can work stably in the pH2~12 range. It is suitable for both lithium iron phosphate and silicon-carbon anode slurry; it is not recommended for use in strong hydrofluoric acid systems.

Q: What is the difference between an integrally formed ceramic lining and a patch-type ceramic lining?

A: The patch type has splicing gaps, and powder easily accumulates. After long-term scouring, the patches easily fall off; the integrally sintered type has no seams, lower impurity risk, longer wear life, and is more suitable for lithium battery cathode materials.

Q: The sand mill chamber size is non-standard. Can it be customized? How long is the delivery time?

A: It can be molded and processed according to the customer's sand mill cylinder drawings, with a dimensional tolerance of ±0.03mm; regular specification samples take 7 days, and mass production orders take 15~20 days.

Q: Is the ceramic lining easy to break, and what should be noted during installation?

A: Zirconia has better toughness than ordinary alumina ceramics, but dry grinding and sudden thermal shock should be avoided; before feeding, ensure that the slurry fully infiltrates the chamber, and check the filling amount of the grinding media before starting. Under normal working conditions, it is not easy to crack.