什么是钠电池的湿法回收工艺？

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

湿法回收是以酸碱浸出、溶剂萃取、结晶提纯为核心的水相再生工艺，是再生材料纯度最高的工业化路线，适配普鲁士蓝、聚阴离子、层状氧化物全品类废旧钠电池，完整工序包含预处理、浸出、除杂、萃取、结晶、材料合成六大阶段。预处理：退役电池放电、拆解、氮气低温破碎、气流分选，分离铝箔、隔膜，收集正负极混合活性粉末。浸出工段：酸性或碱性浸出液密闭反应釜浸泡粉体，将钠、钒、铁、锰等目标金属离子选择性溶解进入液相，碳、不溶性杂质过滤分离固体残渣。深度除杂：调节 pH 值沉淀铜、铝、微量重金属杂质，压滤去除固体滤渣，得到纯净金属离子母液。溶剂萃取：多级有机萃取剂分离不同金属离子，实现钠与过渡金属（钒 / 铁 / 锰）精准分相，各自独立富集。浓缩结晶：钠相溶液蒸发浓缩冷却结晶，提纯工业级钠盐；过渡金属溶液调配配比，合成再生正极前驱体。后端配套：负极硬碳经碱洗过滤、高温活化提纯再生；铝箔熔融回收铝基材；废水中和达标后排入管网，全程可控危废废液排放量。湿法核心优势：金属回收率超 93，再生正极材料纯度接近矿产原生料，可直接重返电芯产线制作高规格电芯；短板为流程长、酸碱药剂消耗大，配套废水处理设备投入高，适合高端长循环废旧钠电池精细化再生。

Wet recycling is an aqueous regeneration technology centered on acid-base leaching, solvent extraction and crystallization purification, delivering the highest regenerated material purity among industrial routes and compatible with all waste sodium battery systems including Prussian blue, polyanions and layered oxides. The complete procedure consists of six stages: pretreatment, leaching, impurity removal, extraction, crystallization and material synthesis. Pretreatment: Retired batteries undergo discharge, disassembly, low-temperature nitrogen crushing and air sorting to separate aluminum foil and separators and collect mixed cathode/anode active powder. Leaching stage: Powder is immersed in acid or alkaline leachate in sealed reactors to selectively dissolve target metal ions such as sodium, vanadium, iron and manganese into liquid phase, with carbon and insoluble impurities filtered as solid residues. Deep impurity removal: Adjust pH to precipitate copper, aluminum and trace heavy metal impurities, filter and press solid residues to obtain pure metal ion mother liquor. Solvent extraction: Multi-stage organic extractants separate different metal ions to accurately phase-separate sodium and transition metals (vanadium/iron/manganese) for independent enrichment. Concentrated crystallization: Sodium phase solution is evaporated, concentrated and cooled to crystallize industrial-grade sodium salts. Transition metal solutions are proportioned to synthesize regenerated cathode precursors. Supporting back-end procedures: Anode hard carbon is regenerated via alkaline washing, filtration and high-temperature activation; aluminum foil is remelted for substrate recovery; wastewater is neutralized to standard before pipeline discharge with controllable hazardous waste liquid output. Core advantages of wet process: Metal recovery rate exceeds 93%, and regenerated cathode purity is close to virgin mineral raw materials, directly reusable for high-standard cell manufacturing. Drawbacks include long processes, large acid & alkali reagent consumption and high investment in wastewater treatment equipment, suitable for refined regeneration of high-end long-cycle waste sodium batteries.