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BACKGROUND Tin is widely distributed in the crust, and more than 20 kinds of tin minerals are known, mainly in the form of cassiterite SnO2.Cassiterite is insoluble in hydrochloric acid, nitric acid and aqua regia.Even when sulfuric acid is heated for a long time or treated with hydrofluoric acid-sulfuric acid, only a small part of it is dissolved.Therefore, for the analysis of tin ore, the alkali fusion method is usually used for sample pretreatment.The determination methods of tin in ore include polarography, spectrophotometry, hydride generation atomic fluorescence spectrometry, emission spectrometry, inductively coupled plasma-optical emission spectrometry (ICP-OES), and inductively coupled plasma-mass spectrometry (ICP-MS).The selection of these methods mainly depends on the characteristics of the ore itself and the content of tin, but also depends on the operating conditions, the selection of reagents and other objective factors.The ICP-OES has high sensitivity, a wide linear range and low matrix effect, which can not only be used to simultaneously determine the main and secondary elements of tin ore, but also has good precision and reproducibility, and can greatly improve the test efficiency.However, when the elemental contents are determined by ICP-OES, traditional sodium peroxide or other oxidizing fluxes introduce a large amount of salts, and the solution after acidification and extraction needs to be further separated or diluted, which not only affects the accuracy of the analysis and the determination limit of lower content elements, but also causes the signal to decrease and cause damage to the instrument during the long-term determination.Lithiummetaborate is a non-oxidizing flux with high melting point and has strong resolution.Since Ingamells reported in 1964 that lithium metaborate is a good flux, it has been successfully applied in the decomposition of soil, silicate rocks, and even some refractory rock and mineral samples.In this study, the analysis of the elemental contents of tin ores are attempted, which are fused by lithium metaborate and measured by ICP-OES. OBJECTIVES To develop a method for simultaneous determination of Sn, W, Zn, Cu, Fe and Mn in tin ores which is decomposed by lithium metaborate and determined by ICP-OES. METHODS Lithium metaborate, a non-oxidizing flux with a high melting point, was used to replace the traditional sodium peroxide and other oxidizing fluxes to melt the sample.After ultrasonic water treatment, Sn, W, Zn, Cu, Fe and Mn of tin ores were determined by ICP-OES.Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) was used to observe the morphological characteristics of the sample molten beads under different flux amounts and analyze the elemental content in the molten beads.It was found that the surface structure of molten beads changed from loose and brittle to fine and compact with the proportion of flux to sample from small to large.When the ratio of flux to sample reached 7:1, the surface morphology of the molten bead had no obvious change.When the ratio of flux to sample was 8:1, the Boron element was detected on the surface of the molten bead, indicating that the flux was excessive at this time.In this way the optimal ratio of flux and sample was finally determined. RESULTS The optimal ratio of flux to sample was 7:1, the sample was melted at 1000℃ and extracted by 5% nitric acid solution.The method precision (RSD) was 1.20%-8.06% by determination of tin ore standard substance GBW07281.The method detection limit was 0.0012%-0.0098%.Each element was compared by this method with classical chemical analysis methods and the relative error was within 7%. CONCLUSIONS The content of tin, tungsten, zinc, copper, iron and manganese in tin ore is determined by ICP-OES method by means of matrix matching.There is no obvious interference between the elements to be measured.The sample pretreatment is simple, the molten salt extraction is fast, the analysis cost is low, and the environmental pollution is small.The method meets the requirement of content analysis of tin, tungsten, zinc, copper, iron and manganese in tin ore.Compared with the traditional chemical analysis method, this method is more convenient, saves a lot of time and cost, and is easy to master.SEM-EDX is used to observe and analyze the morphology characteristics and composition content of sample residue and bead under different flux amounts, which provides a theoretical basis for determining the optimal ratio of flux and sample.The low result of lead in the experiment may be due to the high melting temperature of lithium metaborate and the low melting point of lead oxide, which can be further studied in future work.The limitations of a single instrument in detection sensitivity, resolution, analysis rate and efficiency can be solved by the combination of a variety of analysis means, to obtain more abundant information and accurate results, which is one of the most important directions in the development of modern instrument technology.

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BACKGROUND Tungsten molybdenum ores are strategic mineral resources. China is a large producer and consumer of tungsten and molybdenum ore. Accurate and efficient analysis of tungsten and molybdenum and its associated beneficial and harmful elements is of great significance for the evaluation and comprehensive utilization of tungsten and molybdenum ore deposits. Acid dissolution and alkali fusion are the general digestion methods in tungsten molybdenum ore analysis. However, the acid solution method cannot be used to overcome the hydrolysis problem when treating samples with high content of tungsten and molybdenum, whereas the alkali fusion method such as sodium peroxide and sodium hydroxide usually introduces a large content of alkali metals, so the determination of potassium and sodium cannot be finished. OBJECTIVES To find an efficient method for the determination of tungsten, molybdenum and 11 other elements in tungsten molybdenum ore. METHODS Lithium metaborate melting-tartaric acid ultrasonic leaching and inductively coupled plasma-optical emission spectrometry (ICP-OES) was used for the simultaneous determination of tungsten, molybdenum, copper, lead, zinc, aluminum, iron, calcium, magnesium, titanium, manganese, potassium and sodium in tungsten-molybdenum ore. The sample was completely digested by lithium metaborate fusion. No other elements were introduced except for B and Li. Tartaric acid was used to inhibit the hydrolysis of tungsten and molybdenum. Ultrasonic leaching speeds up the dissolution of the frit. RESULTS The experiment optimized the analysis spectrum and observation method of each element, compared the amount of flux and instrument conditions to obtain the best conditions, and used the matrix matching method to draw a standard curve to eliminate the influence of the matrix effect. The linear correlation coefficient of the standard curve of each element was greater than 0.9990, the detection limit of the method was 1.34-46.2μg/g, the relative error of measured results was 0.14%-8.7%, the relative standard deviation (RSD, n=10) of the measured results was 1.4%-7.6%. CONCLUSIONS This method can accurately and efficiently complete the simultaneous determination of multiple elements in tungsten and molybdenum ore samples.

Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is a growing demand for the determination of actinides in soil and sediment samples for environmental monitoring and tracing, radiological protection, and nuclear forensic reasons. A total sample dissolution method based on lithium metaborate fusion, followed by sequential column chromatography separation, was developed for simultaneous determination of Pu, Am and Cm isotopes in large-size environmental samples by alpha spectrometry and mass spectrometric techniques. The overall recoveries of both Pu and Am for the entire procedure were higher than 70% for large-size soil samples. The method was validated using 20 g of soil samples spiked with known amounts of 239 Pu and 241 Am as well as the certified reference materials IAEA-384 (Fangataufa Lagoon sediment) and IAEA-385 (Irish Sea sediment). All the measured results agreed very well with the expected values. [ABSTRACT FROM AUTHOR]

Abstract: An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (<8min) was investigated for the complete dissolution of various samples. It could be preceded, if required, by an effective ashing procedure using the M4 fluxer and a newly designed platinum lid. Complete dissolution of the sample was observed and measured using standard reference materials (SRMs) and experimental data show no evidence of cross-contamination of crucibles when LiBO2/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100pgkg−1 for 5–300mg of sample. [Copyright &y& Elsevier]

An improved lithium metaborate fusion technique for inductively coupled plasma mass spectrometric analysis of felsic rocks is proposed. The method involves the dissolution of fused sample material with HF followed by treatment with HNO3. The decomposition method developed was used for the determination of trace elements in ancient felsic volcanic rocks and granites of Southern Siberia and further applied to petrologic modeling and the geodynamic setting of the rock origin. Data for geological reference materials STM-1, G-2, GSP-1, AGV-1 and BCR-1 were used for method validation and experimental results obtained agreed well with certified values. Detection limits determined ranged from 0.021 to 0.24 μg/g for Y, Pr, middle and heavy rare earth elements (REE), Ta, U and from 0.44 to 2.07 μg/g for Rb, Sr, Zr, Nb, Ba, light REE, Hf and Th. [Copyright &y& Elsevier]