碱熔预处理对废旧稀土荧光粉中稀土提取的影响
Effect of alkaline fusion pre-treat on extraction rate of rare from waste rare earth fluorescent powder
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摘要: 针对废旧稀土荧光粉的特性,采用高温碱熔与酸浸相结合的方法处理废旧稀土荧光粉,考察碱熔温度、氢氧化钠用量、碱熔时间对稀土浸出率和铝的回收率的影响,并对碱熔过程中的物相及形貌变化进行分析。结果表明,在碱熔温度为1050 ℃、氢氧化钠与废粉质量比为2.5:1、碱熔时间为2 h的条件下,其稀土浸出率可达98%以上,铝的回收率可达98%。通过对碱熔产物物相和形貌分析表明,废粉晶体结构被有效破坏,其中稀土以稀土氧化物形式存在,碱熔产物变成无定型云絮状。Abstract: The method of combining high-temperature alkaline fusion and acid leaching was used to pre-treat waste rare earth fluorescent powder according to its characters to investigate the effect of alkaline fusion temperature, sodium hydroxide dosage and alkaline fusion time on rare earth extraction rate and aluminum deprivation rate, and to analyze the phase structure and surface morphology during the process of alkaline fusion. The results show that alkaline fusion can be achieved at temperature of 1 050 & for 2 h when the mass of the ratio of sodium hydroxide to waste rare earth fluorescent is 25:1 with the leaching rate of the total rare earth more than 98 %, and aluminum deprivation rate being 98 %. The phase and morphology analysis of the alkaline fusion indicates that the structure of waste crystal structure is destroyed effectively, rare earth is in form of rare earth oxide, and alkaline fusion product becomes amorphous cotton-like.