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废弃稀土荧光粉的回收利用对我国稀土资源的可持续发展和环境保护有重要意义。目前的回收工艺主要有直接回用和从其中回收稀土元素。直接回用以制造新的荧光粉是最理想的方案,但废弃荧光粉中杂质较多,需提纯分离,然而目前的风力分选和离心分离效率低,直接萃取法步骤多,污染严重。从废弃稀土荧光粉中回收稀土元素主要包括超临界CO2萃取和浸出后回收。前者反应迅速,回收率高,但对反应设备要求高,投资大;后者成本低,市场前景好,难点是荧光粉中的铝镁尖晶石结构难以破坏,导致Ce和Tb浸出率低,且浸出液难以循环使用。已有研究表明碱熔可破坏铝镁尖晶石结构,但由于后期采用酸浸,酸耗会增大。综上所述,今后研究应在浸出后回收工艺的优化方面引起重视,集中于寻找可经济高效破坏铝镁尖晶石结构的试剂,同时解决浸出液的循环使用,以实现废弃三基色荧光粉的绿色高效回收。
Recycling waste rare earth phosphor on the sustainable development of rare earth resources and environmental protection of great significance. The current recycling process is mainly direct reuse and recovery of rare earth elements from them. Direct reuse to create a new phosphor is the best solution, but more waste impurities in the phosphor, the need for purification separation, but the current wind separation and centrifugation efficiency is low, the direct extraction step more serious pollution. Recycling waste rare earth phosphor rare earth elements include supercritical CO2 extraction and recovery after leaching. The former has the advantages of rapid reaction and high recovery rate, but requires high investment in the reaction equipment and high investment. The latter has low cost and good market prospect. The difficulty is that the aluminum-magnesium spinel structure in the phosphor is hard to be destroyed, resulting in low leaching rates of Ce and Tb, And the leachate is difficult to recycle. Studies have shown that alkali fusion can destroy the structure of aluminum magnesium spinel, but acid leaching will increase due to acid leaching later. In summary, the future research should pay attention to the optimization of the recovery process after leaching, focus on looking for reagents that can destroy aluminum-magnesium spinel structure economically and efficiently, meanwhile, solve the recycle of leachate to realize the waste of trichromatic phosphors Green efficient recycling.