什么是钠电池的干法回收工艺？

What is the dry recycling process for sodium-ion batteries?

干法回收又称高温冶金回收，全程无需大量酸碱水溶液，依靠隔绝空气高温煅烧实现活性材料、金属、碳的分解分离，工艺短、废水产生极少，适合大批量平价废旧钠电池快速粗再生，分为预处理、高温煅烧、熔融分相、冷凝收集、简单合成五步流程。预处理环节与湿法统一：放电拆解、氮气破碎分选，分离铝塑膜、铝箔、隔膜塑料，得到干燥正负极粉体。高温煅烧：粉体送入惰性气氛回转窑 600~900℃煅烧，粘结剂 PVDF/CMC、电解液有机成分完全气化分解，硬碳部分保留，金属氧化物、钠盐形成熔融混合熔体。熔融分相：高温熔体梯度降温分层，钠盐低密度上浮，钒 / 铁金属氧化物高密度下沉，自动两相分离。冷凝回收：气化的碳氢、氟化物冷凝收集做危废处理，分层固相分别出料得到粗钠盐、过渡金属氧化物粗粉。简易合成：粗原料简单提纯调整配比，再生低中端正极材料，硬碳直接筛分回收复用。干法核心优势：工艺流程短、单批次处理量大，无复杂废水系统，设备投资更低，生产周期仅湿法 1/3；短板是再生材料杂质含量偏高，纯度不及湿法，仅适配户储、低速车低端电池循环再生，高端储能废旧电池需搭配湿法深度提纯。

Dry recycling, also called high-temperature metallurgical recycling, requires no massive acid/alkali aqueous solutions throughout the process. It realizes decomposition and separation of active materials, metals and carbon via air-isolated high-temperature calcination. The process is short with minimal wastewater generation, suitable for rapid crude regeneration of mass low-cost waste sodium batteries, divided into five steps: pretreatment, high-temperature calcination, melt phase separation, condensation collection and simple synthesis. The pretreatment stage is consistent with wet process: discharge, disassembly, nitrogen crushing and sorting separate aluminum plastic films, aluminum foil and separator plastic to obtain dry cathode/anode powder. High-temperature calcination: Powder is calcined at 600~900℃ in inert atmosphere rotary kilns. Binders (PVDF/CMC) and organic electrolyte components fully gasify and decompose, partial hard carbon remains, and molten mixed melts of sodium salts & metal oxides form. Melt phase separation: Gradual cooling stratifies high-temperature melts. Low-density sodium salts float upward while high-density vanadium/iron metal oxides sink for automatic two-phase separation. Condensation recovery: Gasified hydrocarbons and fluorides are condensed for hazardous waste disposal. Layered solids are discharged separately to obtain crude sodium salts and transition metal oxide powder. Simple synthesis: Crude raw materials are slightly purified and proportioned to regenerate low-to-mid-end cathode materials, and hard carbon is directly screened for reuse. Core strengths of dry process: Short flow, large single-batch capacity, no complex wastewater systems and lower equipment investment with production cycle only 1/3 of wet process. Drawbacks include higher impurity content of regenerated materials and lower purity than wet products, only applicable for recycled manufacturing of low-end household storage and low-speed vehicle batteries. High-end energy waste cells require supporting wet deep purification.