草酸盐质量法测定铁矿石中稀土总量

Determination of total rare earth in iron ore by oxalate gravimetric method

准确测定铁矿石中稀土总量,对于有效控制铁矿石的生产技术及产品质量具有重要意义。由于目前铁矿石的产品品类及含量和成分与过去存在差异,有必要对固有的试验方法进行优化。采用氢氧化钠、过氧化钠熔融试样,以三乙醇胺溶液浸取,在盐酸羟胺和抗坏血酸存在下,采用EDTA络合分离铁、锰、铝、钙等干扰元素,于pH 1.8~2.0的弱酸性介质中,用草酸沉淀稀土和钍,于900℃将草酸沉淀物灼烧成为氧化物,称其质量。所得氧化物质量减去二氧化钍量为稀土氧化物量。按照试验方法对铁矿石样品中的稀土总量进行测定,结果的相对标准偏差(RSD,n=11)均小于2.0%,加标回收率为99%~101%。草酸盐质量法测定铁矿石中稀土总量,在参考一系列同类分析方法的前提下,充分试验了各种条件对稀土总量测定的影响,确定了此方法。此方法具有准确性好,适用产品检测范围大、干扰元素影响小等优点。

Accurate determination of the total amount of rare earth in iron ore is of great significance to effectively control the production technology and product quality of iron ore. Because the product category, content and composition of iron ore are different from those of the past, it is necessary to improve the inherent experimental methods. Sodium hydroxide and sodium peroxide were used to melt samples, which were leached with triethanolamine solution. With the presence of hydroxylamine hydrochloride and ascorbic acid, interference elements such as iron, manganese, aluminum and calcium were separated by EDTA complexation. Rare earth and thorium were precipitated with oxalic acid in weakly acidic medium with pH 1.8~2.0, and the oxalic acid precipitate was burned into oxide at 900 ℃, and its mass was weighed. The amount of rare earth oxide is obtained by subtracting the amount of thorium dioxide from the mass of oxide. According to the experimental method, the total amount of rare earth in iron ore samples was determined, and the relative standard deviation(RSD,n=11) of the results were all less than 2.0%, and the recovery rate was 99%~101%. Oxalate gravimetric method was used to determine the total amount of rare earth in iron ore. On the premise of referring to a series of similar analysis methods, the influence of various conditions on the determination of total amount of rare earth was fully tested, and this method was determined. This method has the advantages of good accuracy, wide applicable product detection range and small influence of interference elements.