荧光粉分散——絮凝行为及废弃荧光粉选择性絮凝浮选试验研究

Dispersion and Flocculation Behavior of Phosphors and Floc-flotation Research of the Waste Phosphors

废弃荧光粉中含有大量的稀土氧化物,具有极高的回收利用价值。为实现废弃荧光粉中稀土元素的预富集,对荧光粉中不同颗粒的分散—絮凝行为进行了研究。结果表明,废荧光粉的粒径过细,颗粒之间会发生互凝现象,在碱性条件下加入分散剂可强化荧光粉中不同颗粒的分散效果;碱性条件下,大分子量的阳离子聚丙烯酰胺可选择性地吸附在石英表面,增大粒径并加快其沉降速度,从而实现不同颗粒间的分离。针对含有32.33%稀土氧化物的某废弃荧光粉,在研究分散—絮凝行为的基础上,采用选择性絮凝浮选法进行稀土元素的预富集。结果表明,分别以碳酸钠、阳离子聚丙烯酰胺和十二胺为分散剂、絮凝剂和捕收剂,pH=9、絮凝剂用量和捕收剂用量分别为100 g/t和800 g/t的条件下,选择性絮凝浮选可将稀土氧化品位提高至43.65%,显著提高了稀土元素品位,实现了废弃荧光粉中稀土元素的预富集,为废弃荧光粉的综合回收利用提供了技术依据。

Waste phosphors contains a large amount of rare earth oxides,which has extremely high recycling value.In order to realize the pre-enrichment of rare earth elements in the waste phosphors,the dispersion and flocculation behaviors of different particulars in the phosphors have been studied.The results showed that interflocculation will occur because the particle size of waste phosphor is too fine.Adding dispersant under alkaline conditions can enhance the dispersion effect of different particles in the phosphors.Under alkaline conditions,cationic polyacrylamide with large molecular weight can be selectively adsorbed on the surface of quartz,increasing the particle size and accelerating its sedimentation rate,so as to realize the separation between different particles.For a certain waste phosphor containing 32.33%rare earth oxides,based on the study of dispersion and flocculation behavior,selective flocculation flotation is used to pre-enrich rare earth elements.When sodium carbonate,cationic polyacrylamide and dodecylamine are used as dispersants,flocculants and collectors respectively,the grade of rare earth oxide in the concentrate can increase to 43.65%in the flocculation flotation test under the conditions of p H=9,flocculant dosage and collector dosage of 100 and 800 g/t.The grade of rare earth elements were increased observably,which provides a technical basis for the comprehensive recovery and utilization of waste phosphors.