Simultaneous Determination of Major Elements, Si, Al, Ca, Mg, Fe, Ti, Mn and P in Graphite by Inductively Coupled Plasma-Optical Emission Spectrometry with Sodium Carbonate Fusion
-
摘要:
石墨化学性质稳定, 需采用高温碱熔(1000℃)才可使样品分解完全, 已有分析方法在样品前处理不同的阶段使用不同材质的坩埚。基于石墨性质和坩埚熔样情况, 本文采用预先已均匀铺垫0.50 g碳酸钾的高熔点铂坩埚灼烧石墨样品, 样品灼烧后直接在原坩埚中加入0.80 g碳酸钠碱熔, 熔融物用稀盐酸提取后用电感耦合等离子光谱法(ICP-OES)实现了石墨中8种常量元素(硅铝钙镁铁钛锰磷)的同时测定。方法检出限为13~228 μg/g, 方法精密度(RSD, n=12) 为0.7%~7.2%;全流程加标回收率为90.5%~105.0%;实际土状和鳞片石墨样品的测定结果与化学分析法无显著差异。本方法避免了铂坩埚的损毁和样品在前处理过程中的损失, 分析过程简单、分析速度快。
-
关键词:
- 石墨 /
- 常量元素 /
- 铂坩埚 /
- 碳酸钾-碳酸钠碱熔 /
- 电感耦合等离子体发射光谱法
Abstract:Graphite is a stable nonmetal and must be decomposed completely by alkali fusion at high temperature (1000℃). In previous methods, different crucibles were used in different phases in order to shorten the utility time of the platinum crucible and avoid damage to the platinum crucible and sample loss. Based on the nature of graphite ore and the character of the crucible, a new method has been developed. The sample was firstly ignited at high temperature in a platinum crucible, which was prepared with 0.50 g potassium carbonate at the bottom. The sample was then directly digested by 0.80 g sodium carbonate in the former platinum crucible. Lastly the melt was dissolved by diluting hydrochloric acid. Eight major elements (Si, Al, Ca, Mg, Fe, Ti, Mn, P) were simultaneously determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The proposed method has a detection limit of 13-228 μg/g, precision (RSD, n=12) of 0.7%-7.2%, and whole-process recoveries of 90.5%-105.0%. The analytical results of flake graphite and amorphous graphite by this method are in agreement with those by chemical method. This method avoids sample loss and platinum crucible damage. The whole process of treatment is simple and rapid.
-
-
表 1 元素分析谱线和方法检出限
Table 1. Analytical spectral lines and detection limit of the elements
元素分析谱线
(nm)方法检出限
(μg/g)元素 分析谱线
(nm)方法检出限
(μg/g)SiO2 251.611 228 Fe2O3 259.940 60 Al2O3 396.152 60 TiO2 336.122 13 CaO 317.933 66 MnO 257.610 17 MgO 280.270 18 P2O5 213.618 200 表 2 方法准确度和精密度
Table 2. Accuracy and precision tests of the method
标准物质
编号元素 含量(%) 相对误差
(%)RSD
(%)标准值
(参考值)测定值 GBW03120
(石墨矿)SiO2 10.34 10.40 0.58 2.4 Al2O3 5.60 5.66 1.07 0.8 CaO 0.74 0.75 1.35 3.1 MgO 0.50 0.54 8.00 1.7 Fe2O3 1.48 1.46 -1.35 0.9 TiO2 0.55 0.56 1.82 1.0 MnO 0.022 0.021 -4.55 3.9 P2O5 0.16 0.15 -6.25 7.2 Z-1 SiO2 44.64 44.61 -0.06 1.7 Al2O3 13.83 13.76 -0.49 1.4 CaO 8.81 8.88 0.82 3.1 MgO 7.77 7.69 -1.00 2.6 Fe2O3 13.40 13.37 -0.20 2.5 TiO2 2.37 2.39 0.91 1.8 MnO 0.169 0.17 -1.16 2.9 P2O5 0.95 0.94 3.34 6.1 Z-2 SiO2 44.64 44.60 -0.09 1.6 Al2O3 13.83 13.76 -0.48 0.7 CaO 8.81 8.91 1.09 3.0 MgO 7.77 7.83 0.75 3.7 Fe2O3 13.40 13.62 1.67 1.8 TiO2 2.37 2.44 3.01 1.8 MnO 0.169 0.16 -3.23 4.4 P2O5 0.95 0.97 3.00 6.0 表 3 方法加标回收率
Table 3. Recovery tests of the method
元素 GBW03120 Y-2 标准值
(%)加标量
(%)加标后
测定值回收率
(%)本底值
(%)加标量
(%)加标后测
定值(%)回收率
(%)SiO2 10.34 10.00 19.39 90.5 3.23 3.50 6.620 96.9 Al2O3 5.60 6.00 11.22 93.67 1.09 1.50 2.460 91.3 CaO 0.74 1.00 1.696 95.6 0.37 0.50 0.833 92.6 MgO 0.50 1.00 1.436 93.6 0.67 1.00 1.704 103.4 Fe2O3 1.48 2.00 3.580 105.0 1.15 1.50 2.56 94.0 TiO2 0.55 1.00 1.461 91.1 0.015 0.03 0.044 96.7 MnO 0.022 0.04 0.0603 95.8 0.0078 0.015 0.023 101.3 P2O5 0.16 0.20 0.352 96.0 0.043 0.050 0.0893 92.6 表 4 不同样品分析方法测定结果对比
Table 4. Comparison of the analytical results
样品 测试方法 含量(%) SiO2 Al2O3 CaO MgO Fe2O3 TiO2 MnO P2O5 Z-1 化学法 44.48 13.81 8.82 7.75 13.39 2.43 0.18 0.93 本法测定 44.61 13.76 8.88 7.69 13.37 2.39 0.17 0.94 Z-2 化学法 44.72 13.88 8.76 7.90 13.43 2.35 0.17 0.94 本法 44.60 13.76 8.91 7.83 13.62 2.44 0.16 0.97 Y-1 化学法 14.51 8.23 1.27 0.44 0.70 0.35 0.017 0.11 本法 14.50 8.48 1.30 0.46 0.67 0.35 0.016 0.12 Y-2 化学法 3.23 1.09 0.37 0.67 1.15 0.015 0.0078 0.043 本法 3.27 1.11 0.38 0.69 1.16 0.016 0.0078 0.042 -
[1] [2] [3] [4] [5] [6] [7] [8] [9] doi: 10.1039/an9931800827
[10] doi: 10.1039/AN9962100623
[11] doi: 10.1039/b001608j
[12] [13] [14] [15] [16] [17] -