废弃CRT荧光粉中稀土的提取工艺与技术

Recovery of rare earth from waste CRT phosphor

以废弃CRT荧光粉为原料,在前期稀盐酸预处理工艺的基础上,通过进一步深入研究,开发出从废弃CRT荧光粉中提取稀土的完整工艺路线。结果表明:稀酸预处理后,盐酸酸浸剩余荧光粉固体的最佳浓度为5 mol·L1,最佳反应温度为80℃;酸浸后稀土浸出液净化除杂的p H控制为5.5,DDTC最佳用量比为6:1;稀土净化液经草酸沉淀后煅烧的最佳温度为900℃。从废弃CRT荧光粉中提取到稀土产物Y2O3和Eu2O3的总含量为99.2%,其晶粒由若干片状晶体密实堆积成多面体结构,晶粒之间相互嵌入,呈镶嵌式接触。

On the basis of dilute hydrochloric acid pretreatment, recovery of rare earth from waste CRT phosphor was further studied, and a process route was developed. After dilute acid pretreatment, optimum conditions for recovering rare earth from waste CRT phosphor were： concertration of hydrochloric acid for hydrolysis of residual phosphor solids 5 mol·L1, reaction temperature 80℃, p H value of leaching liquor after hydrolysis reaction 5.5, ratio of diethyldithiocarbamate（DDTC） and phosphors dosage 6：1, calcination temperature of rare earth oxalate precipitation 900℃. The total content of rare earth products Y2O3 and Eu2O3 was 99.2%. The crystal particles of rare earth product possessed polyhedral structure built by the accretion of flaky crystals. The particles were embeded in each other with mosaic contact.