稀土火法冶炼回收料中稀土总量的测定

Determination of Total Rare Earth Content in the Recoverd Materials from Rare Earth Pyrometallurgy

稀土火法冶炼回收料是指稀土熔盐电解冶炼工艺产生的电解渣及金属热还原产生的热还原渣。该类物料经除杂加工后可用于再次提取稀土等有价元素,其中稀土总量是其确定回收利用价值的主要依据。试验采用硝酸-过氧化氢-高氯酸分解,氨水沉淀稀土,继以用盐酸溶解氢氧化物沉淀,在pH 1.5~2.0的酸性条件下,加草酸沉淀稀土,分离铁、铝等。将草酸稀土于950℃灼烧成稀土氧化物,称其质量,计算稀土总量。当样品含重稀土元素镝、钬、铒、铥、镱、镥、钇含量时,需用电感耦合等离子发射光谱法测定草酸沉淀滤液中稀土量,对结果进行补正。标准加入回收率为99.41%~103.10%,统一样品测定结果的相对标准偏差(n=11)为0.14%~0.46%,该方法准确可靠。

The rare earth pyrometallurgical recovery material refers to the electrolytic slag produced by the rare earth molten salt electrolytic smelting process and the thermal reduction slag produced by the thermal reduction of rare earth metals.This kind of material can be used to extract rare earth and other valuable elements after impurity removal,Among them,the total amount of rare earth is the main basis for determining the recovery value of the rare earth pyrometallurgical recovered materials.The sample was decomposed by concentrated nitric acid,hydrogen peroxide and perchloric acid respectively,then add ammonia water,rare earth was precipitated by ammonia water.Then dissolved hydroxide precipitation with hydrochloric acid,then oxalic acid was added to precipitate the rare earth again at pH 1.5~2.0 to separate iron,aluminum etc.the rare earth oxalate was burned at 950℃to from rare earth oxide and the rare earth oxide was weighed for determining the total content of the recycled rare earth.For those samples containing Dy,Ho,Er,Tm,Yb,Lu and Y rare earth elements,the rare earth content in oxalic acid precipitation was determined by inductively coupled plasma atomic emission spectrometry and correction of the results.The recoveries were 99.41%~103.10%.The relative standard deviations(n=11)of the uniform sample determination results were 0.14%~0.46%,The method is accurate and reliable.