Xiaoyun Qiu,Zhaochu Hu,Tao Luo,Tao He,Wen Zhang,Ming Li,Zhenli Zhu,Lijin Huang,Mingxing Gong
Preparation of homogeneous and mechanically resistant targets is essential for representative bulk analysis using laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS). Fused glasses are preferred (for LA-ICP-MS) over pressed powder pellets owing to their greater homogeneity. However, their use is often limited by the loss of Pb and Zn during the fusion process. In this study, a novel and rapid (NH4)2HPO4–LiBO2 fusion technique using a homemade fusion furnace and graphite crucibles was established for determining major and trace elements in silicate rocks by LA-ICP-MS. Homogenous glasses were produced by fusing a mixture of ~50 mg of silicate rock powders, 10 mg of (NH4)2HPO4, and 100 mg of LiBO2 at 950 °C for 5 min in a closed fusion system. This approach ensures the complete dissolution of refractory minerals such as zircon and effectively suppresses the loss of volatile elements such as Pb and Zn. The use of a 100% oxide normalization calibration strategy provided accurate results, enabling the direct analysis of unknown samples without any prior determination of internal standard element mass fractions. Analytical results for most elements in five silicate rock reference materials generally agreed with the reference values, within 10% deviation. Precision was achieved within 5% relative standard deviation (RSD) for major elements and 10% RSD for most trace elements. The developed method is simple, rapid, and efficient, addressing the challenges of volatile element loss and incomplete dissolution of refractory minerals, which significantly benefits the application of LA-ICP-MS for bulk silicate rock analysis.
Lan Yang,Lele Chen,Tao Zhang,Dan Li,Lingzong Meng,Tianlong Deng,Yafei Guo
The solubilities and the refractive indices in the ternary system LiBO 2 −Li 2 B 4 O 7 −H 2 O at 298.15 K and 323.15 K were determined with the isothermal dissolution method. The phase diagrams and refractive index diagrams were drawn with the experimental values. The phase diagrams at 298.15 K and 323.15 K consist of one invariant point, two univariant curves and two crystallization regions corresponding to Li 2 B 4 O 7 ·3H 2 O, LiBO 2 ·8H 2 O (at 298.15 K) and LiBO 2 ·2H 2 O (at 323.15 K). Based on the Pitzer model, the mixing ion-interaction parameters ( θ B ( O H ) 4 − , B 4 O 5 ( OH ) 4 2 − and Ψ L i + , B ( O H ) 4 − , B 4 O 5 ( O H ) 4 2 − ) at 298.15 K and 323.15 K were fitted with the solubility data. A comparison shows that the calculated solubilities in the ternary system at 298.15 and 323.15 K agree well with the experimental data. The phase diagram and Pitzer model for the ternary system were then used to conduct isothermal evaporation simulation. Different salt will be obtained if the original solution point in different unsaturated regions.
Tao Zhang,Liwei Zhuang,Dan Li,Lingzong Meng,Tianlong Deng,Yafei Guo,Yong Ma
The solubilities of salts, refractive indices, and pH values of the equilibrium liquid phases in the quaternary system LiCl–LiBO2–Li2B4O7–H2O at 323.15 K were investigated by the isothermal dissolution method for the first time. The dry-salt diagram of the quaternary system consisted of one invariant point, three univariant curves and three crystallization fields corresponding to LiCl·H2O, LiBO2·2H2O, and Li2B4O7·3H2O. The solution refractive indices and pH values change regularly with the changing of concentration. Combining the equilibrium constants for different boron species, the distributions of six boron species in the mixed solution in the systems LiCl–LiBO2–H2O, LiBO2–Li2B4O7–H2O, and LiCl–Li2B4O7–LiBO2–H2O were calculated with the total boron concentration and pH values. The main boron species in the mixed solution of the quaternary system are B3O3(OH)4–, B4O5(OH)42–, B(OH)3, and B5O6(OH)4–. The boron species distributions are mainly affected by the pH values and the concentration of total boron and LiCl in the solution. The results of phase diagram and boron species distribution in the quaternary system can supply foundation data for separating lithium borate from brines.
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