Determination of Rare Earth Elements in Phosphate Ores by Inductively Coupled Plasma-Mass Spectrometry with Mixed Acid Dissolution
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摘要: 磷矿石中伴生的大量稀土,是继离子型稀土矿后重要的稀土后备资源。对磷矿石稀土元素分析测定方法的研究具有重要意义。本实验采用盐酸-硝酸-氢氟酸-硫酸体系消解、王水提取,建立了应用电感耦合等离子质谱法(ICP-MS)测定磷矿石中15种稀土元素的分析方法。经优化实验选取了合适的称样量以保证分析结果的准确可靠。选择合适的分析同位素及采用干扰校正方程以消除质谱干扰,利用103Rh为内标元素,有效抑制了分析信号的动态漂移,用于测定磷矿石国家标准物质中的15种稀土元素,方法的检出限为0.001~0.021 μg/g,精密度均小于6.0%(n=12),加标回收率在95.7%~108.0%。适合推广运用于大批量磷矿石中稀土分量的快速分析
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关键词:
- 磷矿石 /
- 稀土元素 /
- 干扰校正 /
- 电感耦合等离子体质谱法
Abstract: It is known that a large amount of rare earth elements (REEs) is contained in phosphate rock, making it an important reserve of REEs after ion-type REEs ores. Therefore, it is significant to analyze and study the determination method for REEs in phosphate rock. Phosphate ore samples were digested with HF-HNO3-HCl-H2SO4-aqua regia. A method for the determination of 15 REEs in phosphate ores by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) was established. Some parameters affecting the determination, such as sample weight, sample digestion method, selected determination isotopes and interference correction were investigated. Matrix effect and sensitivity drift were monitored and corrected by an interior isotope of 103Rh. The recoveries of the method are 95.7%-108.0%, detection limits are 0.001-0.021 μg/g and precision (RSD) is less than 6% (n=12). The method is suitable for analysis of rare earth elements in phosphate ores. -
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表 1 ICP-MS仪器工作参数
Table 1. Operating parameters of the ICP-MS instrument
工作参数 设定条件 工作参数 设定条件 功率 1300 W 蠕动泵泵速 40 r/min 冷却气(Ar)流量 13 L/min 测量方式 跳峰 辅助气(Ar)流量 0.7 L/min 通道数/质量 3 雾化气(Ar)流量 0.9 L/min 扫描次数 30 采样锥(Ni)孔径 1.0 mm 驻留时间/通道 10 ms 截取锥(Ni)孔径 0.7 mm 总采集时间 15 s 采样深度 120 mm 表 2 标准溶液浓度
Table 2. Concentration of the element calibration standard solutions
稀土元素 ρ/(μg·L-1) 稀土元素 ρ/(μg·L-1) Y 100 Tb 5.00 La 100 Dy 50.0 Ce 100 Ho 5.00 Pr 50.0 Er 10.0 Nd 100 Tm 5.00 Sm 50.0 Yb 5.00 Eu 10.0 Lu 1.00 Gd 50.0 表 3 称样量对测定结果的影响
Table 3. Analytical results of REEs with different sampling mass
标准物质编号 称样量m/g w/(μg·g-1) La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Y GBW 07212 (硅镁质磷矿) 0.0500 20.10 30.20 5.71 25.20 5.38 1.27 5.17 0.99 5.69 1.15 3.11 0.44 2.31 0.40 42.30 0.1000 19.70 29.80 5.63 24.20 5.21 1.25 5.16 0.96 5.67 1.16 3.03 0.43 2.30 0.37 40.60 0.2000 17.90 25.42 5.38 22.30 5.03 1.15 4.98 0.85 5.29 1.10 2.79 0.38 2.12 0.33 35.90 0.3000 15.80 23.50 5.18 20.40 4.89 0.95 4.79 0.75 4.98 0.89 2.43 0.30 1.87 0.30 32.70 表 4 测定元素和干扰校正方程
Table 4. Determination isotopes and correction equations for interfering ions
稀土元素 校正方程 151Eu -0.00045×135Ba 157Gd -0.0015×140Ce-0.019×141Pr 159Tb -1.47×(161Dy-0.76×161Dy) 165Ho -0.0002×140Nd-0.0034×147Sm 表 5 方法检出限
Table 5. Detection limits of the method
稀土元素 同位素m/z 检出限/(μg·g-1) 稀土元素 同位素m/z 检出限/(μg·g-1) La 139 0.013 Dy 161 0.006 Ce 140 0.021 Ho 165 0.001 Pr 141 0.012 Er 166 0.039 Nd 146 0.010 Tm 169 0.002 Sm 147 0.008 Yb 172 0.005 Eu 151 0.002 Lu 175 0.001 Gd 157 0.005 Y 89 0.016 Tb 159 0.015 表 6 加标回收率
Table 6. Recovery tests of the method
稀土元素 ρ/(μg·mL-1) 回收率/% 本底值 加入量 本法测定值 La 19.7 20.0 40.1 102.0 Ce 29.8 20.0 51.2 107.0 Pr 5.63 10.0 15.2 95.7 Nd 24.2 20.0 43.5 96.5 Sm 5.21 10.0 15.1 98.9 Eu 1.25 2.00 3.31 103.0 Gd 5.16 10.0 14.9 97.4 Tb 0.96 1.00 2.01 105.0 Dy 5.67 10.0 15.4 97.3 Ho 1.16 1.00 2.24 108.0 Er 3.03 5.00 8.15 102.0 Tm 0.43 1.00 1.50 107.0 Yb 2.3 2.00 4.42 106.0 Lu 0.37 0.50 0.90 106.0 Y 40.6 20.0 59.8 96.0 表 7 两种分析方法的结果比较
Table 7. Analytical results of REEs by two methodsw/(μg·g-1)
稀土元素 GBW 07210(磷块岩) GBW 07211(磷块岩) GBW 07212(硅镁质磷矿) 本法(ICP-MS) 国标法(ICP-AES) 本法(ICP-MS) 国标法(ICP-AES) 本法(ICP-MS) 国标法(ICP-AES) La 11.3 10.7 29.5 30.4 19.7 19.6 Ce 21.0 21.8 26.9 25.4 29.8 31.1 Pr 2.70 2.68 6.00 6.13 5.63 5.79 Nd 12.4 12.5 24.8 25.7 24.2 23.6 Sm 2.80 2.71 5.00 5.22 5.21 5.33 Eu 0.80 0.85 1.10 1.25 1.25 1.13 Gd 3.10 3.21 5.40 5.26 5.16 5.24 Tb 0.60 0.57 1.00 1.13 0.96 1.04 Dy 4.00 4.09 7.00 7.15 5.67 5.57 Ho 0.90 0.94 1.50 1.61 1.16 1.23 Er 2.80 2.63 4.70 4.81 3.03 3.14 Tm 0.40 0.44 0.70 0.67 0.43 0.41 Yb 2.50 2.42 4.20 4.11 2.30 2.21 Lu 0.40 0.44 0.70 0.66 0.37 0.41 Y 37.4 38.9 69.2 71.2 40.6 41.7 表 8 方法精密度
Table 8. Precision tests of the method
稀土元素 GBW 07210(磷块岩) GBW 07211(磷块岩) GBW 07212(硅镁质磷矿) w/(μg·g-1) RSD/% w/(μg·g-1) RSD/% w/(μg·g-1) RSD/% La 11.3 2.6 29.5 6.0 19.7 2.1 Ce 21.0 2.4 26.9 5.6 29.8 3.0 Pr 2.70 1.6 6.00 2.4 5.63 2.7 Nd 12.4 2.5 24.8 5.5 24.2 2.5 Sm 2.80 3.6 5.00 4.4 5.21 2.6 Eu 0.80 1.6 1.10 2.6 1.25 2.6 Gd 3.10 3.7 5.40 5.5 5.16 5.4 Tb 0.60 0.4 1.00 3.5 0.96 3.9 Dy 4.00 1.5 7.00 5.2 5.67 4.6 Ho 0.90 1.4 1.50 5.4 1.16 4.0 Er 2.80 1.6 4.70 3.3 3.03 4.2 Tm 0.40 0.6 0.70 1.1 0.43 1.9 Yb 2.50 1.7 4.20 3.1 2.30 4.8 Lu 0.4 1.7 0.70 1.2 0.37 3.4 Y 37.4 2.3 69.2 2.4 40.6 3.9 -
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] GB/T 17417.1—2010,稀土矿石化学分析方法第1部分:稀土分量的测定[S].
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