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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.)

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.)

BACKGROUND: The redox potential is a quantitative indicator of the mixed redox potential of all substances in a system, which reflects the relative strength of the redox capacity of the whole system. It is of great significance to delineate the uranium enrichment horizon. The redox potential of sandstone - type uranium deposits controls the geochemical behavior of uranium and other variable valence elements, and is of great significance for accurately delineating uranium-enriched horizons. The potential difference method is used to measure the redox capacity of the sample by means of the oxidant solution, and the magnitude of the potential difference can accurately reflect the reducing ability of the reducing components in the sandstone-type uranium ore sample. OBJECTIVES: To compare the two methods for the determination of the redox potential (ΔEh) of sandstone-type uranium ores. METHODS: ΔEh of sandstone-type uranium ores was determined by two potential drop methods using potassium dichromate and potassium permanganate as oxidants. The effects of the solution medium concentration, oxidant concentration, equilibrium potential time, sample immersion time, and solid - liquid ratio of sample to oxidant solution on the determination of ΔEh were systematically studied. According to the optimal conditions of the two methods, 8 sandstone-type uranium samples were measured. RESULTS: The ΔEh of the potassium dichromate method was between 15mV and 118mV, and the relative standard deviation was between 2. 50% and 7. 44%. The ΔEh of the potassium permanganate method was between 45mV and 89mV, with the relative standard deviation of 0. 89% - 1. 42%. The two methods had significant consistency in determining the relative level of ΔEh of 8 sandstone-type uranium ore samples, and the correlation coefficient was 0. 9882. CONCLUSIONS: The ΔEh of the potassium dichromate potential drop method is more dispersed with a large range, and the difference in reducing ability between samples can be identified more intuitively. The ΔEh of the potassium permanganate potential drop method is more stable. The ΔEh values of sandstone-type uranium deposits measured by two potential drop methods can be used for the division of redox zoning. [ABSTRACT FROM AUTHOR]

BACKGROUND: Studying the characteristics of rare earth elements in uranium ore can determine the source of the ore-forming fluids, the mineralization environment, and the physical and chemical conditions. It is particularly important to accurately determine the content of rare earth elements in uranium ore. At present, rare earth elements are mainly determined by inductively coupled plasma-mass spectrometry (ICP-MS). High-pressure closed aciddissolution is commonly used. The open acid dissolution method is rarely used because perchloric acid is routinely used to dissolve samples, and the temperature is relatively low, which may cause incomplete decomposition of some samples. OBJECTIVES: In order to solve the problem that the rare earth elements have contents lower than real values in open acid dissolution. METHODS: The tetracid system of nitric acid-hydrofluoric acid-perchloric acid-sulfuric acid was used in the open acid dissolution method. ICP-MS with Rh as internal standard was used to determine 15 rare earth elements in uranium ore. RESULTS: The relative standard deviation (RSD) of the 15 rare earth elements was between 0. 54% and 5. 98%, and the recovery was between 96. 0% and 106. 0%. Applying to national rock standard materials (GBW07103, GBW07104, GBW07122), the measured values were consistent with the standard values, and the relative error (RE) was between -8. 33% and 7. 24%, indicating that this method was effective for the determination of rare earth elements. CONCLUSIONS: The method has simple operation, accurate and reliable results, and is suitable for the determination of rare earth elements in large quantities of uranium ore. [ABSTRACT FROM AUTHOR]

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.)

BACKGROUND: Sepiolite is a very important non-metallic mineral, which is widely used in aviation, animal husbandry, the chemical industry, environmental protection and other fields. Sepiolite is in great demand and needs a lot of analysis and testing. However, the existing sepiolite reference materials are inadequate and do not satisfy the needs of sepiolite composition analysis. Furthermore, there are no sepiolite reference materials in China, making it necessary to develop one. OBJECTIVES: To prepare a reference material for composition analysis of sepiolite whose certified value components cover as many elements as possible. METHODS: Sepiolite samples were collected from Xiangtan, Hunan Province. The samples were subjected to primary crushing, coarse-grain sieving, inactivation, fine grinding and fine grain sieving. After passing the initial inspection, samples were bottled and numbered. Random samples were taken for homogeneity test, stability test. 24 components were selected for homogeneity and stability test. RESULTS: The results showed that the RSD of 20 components were less than 3%, and the F value of the variance test was less than the critical value of the list [F0.05（29,60）=1.65], indicating that the homogeneity of the reference material was good. During the investigation period, the contents of 24 components had no significant change, indicating that the standard material was stable. Nine laboratories cooperated with traditional chemical analysis methods and modern instrumental analysis methods to determine the value. The final values were 63 components, covering major, trace and all rare earth elements. The contents of characteristic components MgO and LOI were 18% and 8.55%, respectively. These two components form a certain ladder with the existing reference materials, which can better satisfy the requirements of sepiolite composition analysis. CONCLUSIONS: The developed sepiolite reference material can be used as the quality control standards for geological prospecting, geochemical investigation and testing of geological and mineral products, as well as for other industries to analyze similar materials. Moreover, in the process of developing the reference material, improvements and developments to the new methods will provide technical support for the subsequent development of the sepiolite reference material. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sepiolite is a widely used fibrous magnesium-rich silicate clay mineral. Sepiolite is mainly composed of silicon and magnesium, with minor aluminum, potassium, sodium and other impurities. Determination of the major element of sepiolite usually adopts the classical chemical analytical method. After the alkali melting treatment, the sample is determined by volumetric method, photometry and atomic absorption spectrometry, which is inefficient and time-consuming. Moreover, potassium and sodium cannot be simultaneously determined.OBJECTIVES: To find an efficient method for the determination of seven major elements in sepiolite.METHODS: The samples were digested by hydrofluoric acid, nitric acid, and perchloric acid. Contents of major elements such as Al2O3 were determined by inductively coupled plasma-optical emission spectrometry（ICP-OES）. The dosage of hydrofluoric acid was optimized. The analytical spectral lines were Al 396.153 nm, Ti 334.940 nm, K 766.490 nm, Na 589.592 nm, Ca 422.673 nm, Mg 285.213 nm and Fe 238.204 nm, and elements were determined by axial observation. The content of magnesium in sepiolite was high, and there was a certain matrix effect during ICP-OES analysis. A series of high magnesium mixed standard solutions were prepared to match the matrix.RESULTS: The linear correlation coefficient of the standard curve of each element was greater than 0.9990, the detection limits of the method were 0.53-3.25μg/g, the relative standard deviations（RSD, n=10） of the measured results were 0.66%-5.65%, and the recoveries of each element were 95.3%-108.5%.CONCLUSIONS: Acid dissolution is easy to operate compared with the alkali fusion method. The results are consistent with those obtained by classical chemical analytical methods and thus meet the analytical requirements of sepiolite samples. [ABSTRACT FROM AUTHOR]

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.)

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.)

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.)

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.)

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.)

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.)

Alpha dose matrix effect is the discrepancy of ablation rate and down-hole fractionation induced by the difference of crystal damage degree (alpha dose) between standard zircons and sample zircons. It has been proved to be the cause of systematic bias of zircon U-Pb dating by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Alpha dose is closely related to ablation rate and down-hole fractionation behaviour of zircon. The higher the alpha dose, the faster the ablation rate and more obvious is the down-hole fractionation. However, the correction of alpha dose matrix effect has received little attention thus far. In this study, Laser Raman Spectroscopy and LA-ICP-MS were used to analyze zircons from the Badaling Granitic Complex rocks. Results show that the metamictization degree is low when the actual retained alpha dose (DαP) is no more than 0.75×1018 g-1 and the matrix effect is negligible. However, when the actual retained alpha dose (DαP) is larger than 0.75×1018 g-1, metamictization degree is high and the dating results are obviously affected byalpha dose matrix effect. For this reason, U-Pb data of zircons need to be corrected using the‘Age offset-DαP’empirical equation such as y=347.8×exp(0.260×10-15x). In conclusion, it was found that this is a feasible method to correct alpha dose matrix effect by using Laser Raman Spectroscopy and a full width at half maximum (FWHM)-DαP correction curve to obtain DαP values of analyzed zircons by using age deviations-DαP empiric formula to determine the systematic deviations of LA-ICP-MS. [ABSTRACT FROM AUTHOR]