Search

Copyright of Journal of Fuzhou University is the property of Journal of Fuzhou University, Editorial Department 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 Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group 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 Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology 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 Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office 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.)

The nickel-rich ternary cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) has excellent discharge capacity, which is the favorite to succeed as the next new cathode materials for lithium-ion batteries. However, it has problems such as serious Li+/Ni2+ mixed discharge, and rapid capacity fading caused by poor structural stability. In order to solve these problems, accelerate the application process of ternary cathode materials in new energy vehicle. LiNi0.8Co0.1Mn0.1O2 (NCM811) ternary cathode material coated with LiZr2 (PO4)3 (LZPO) was obtained by wet coating method, and the structure and electrochemical performance of LZPO coating on NCM811 ternary cathode material were studied in this paper. The results show that the NCM811 coated with 1% LZPO possess the most stable structure, and the best electrochemical performance. The first cycle discharge capacity at 0. 1 C rate is 210. 16 mAh/g, which is much higher than that of the pristine NCM811 material (201. 01 mAh/g); the capacity retention rate after 200 cycles is 79. 4%, which is better than that of pristine NCM811 (60. 0%). [ABSTRACT FROM AUTHOR]

BACKGROUND: Illite is an important mineral resource. It is of great theoretical and practical significance to accurately obtain the mineral composition and content of illite ores. The Rietveld full pattern fitting method uses the whole diffraction pattern for analysis and shows high accuracy. However, due to the lack of pure illite samples, the accuracy and error sources of this method for analyzing the content of illite ores are not clearly known at present. OBJECTIVES: To understand the accuracy and error sources of the Rietveld full pattern fitting method in quantitative analysis of illite ores. METHODS: The Rietveld full pattern fitting method was used to quantitatively analyze artificial and natural illite ore samples. The results of X-ray fluorescence spectrometry (XRF) of natural illite ores were compared with the chemical compositions calculated from the mineral contents by the Rietveld method. RESULTS: The results showed that the maximum absolute error ranges of illite-quartz binary mixtures, illite-quartz-albite ternary mixtures, and illite-quartz-albite-calcite-kaolinite multiple mixtures were-0.9%-0.9%,-1.9%-1.6%, and-2.3%-1.6%, respectively. The chemical compositions of natural illite ores calculated by Rietveld method were in good agreement with the results of XRF. This indicated that the Rietveld method had high accuracy in the quantitative analysis of mineral contents of natural illite ore samples. The error sources were mainly affected by the illite structural model, atomic thermal displacement parameters Uiso, and preferred orientation. CONCLUSIONS: A reasonable structural model of illite should be chosen according to the actual samples. The values of atomic thermal vibration Uiso should be reasonably set according to the references. Preferred orientation should be decreased as much as possible during the sample preparation. [ABSTRACT FROM AUTHOR]

Bismuth trioxide (Bi2O3) is an oxygen ion conductor. In order to obtain its atomic thermal vibration isotropic temperature factor, X-ray diffraction experiments were carried out on the powder crystal, and the crystal structure model was established. The RIETAN-2000 program refined the crystal structure of the obtained experimental results, and obtained the three-dimensional (3D) and two-dimensional (2D) visualization patterns of the powder crystal's iso-high electron density distribution through MEM analysis. The results show that the atomic thermal vibrational isotropic temperature factors of Bi (1), Bi(2), O(1), O(2) and O(3) are 0. 004 938 nm², 0.004 174 nm², 0.007 344 nm², 0.007 462 nm², and 0.007 857 nm², respectively. The three-dimensional and two-dimensional visualization of the electron density distribution at the same height further verifies the accuracy of the crystal structure model and the position of atoms. These parameters have a certain reference significance for studying the thermal properties of crystal materials. [ABSTRACT FROM AUTHOR]

BACKGROUND: The polytype species and the content of synthetic fluorophores have a considerable influence on the physiochemical properties of fluorphlogopites. However, conventional methods ( e. g., front loading and side loading) of sample preparation tend to generate a strongly preferred orientation on the OOl basal plane, limiting the X - ray diffraction ( XRD) analysis of the composition and content of fluorphlogopite polytypes. The conventional spraying method was utilized to prepare samples with random orientations for XRD analysis. However, the sample surface was not flat enough to perform the analysis. OBJECTIVES: To decrease the preferred orientation and develop a method for quantitative analysis of fluorphlogopite polytypes. METHODS: In this study, the conventional spraying method was improved. The sample holder was rotated evenly during the spraying process to obtain a flat surface sample. RESULTS: XRD data suggested that the orientation index ( 0 I = I 00/ / 060 ) obtained by the rotation - spraying method was 3. 9, which was close to the theoretical value ( 4. 5). The Ols of the front and side loading methods were 38. 7 and I8. I, respectively, which were significantly larger than the theoretical value ( 4. 5). The results showed that the rotation - spraying method significantly decreased the preferred orientation of mica along the OOl basal plane compared with the front and side loading methods. Microscopic observations revealed that the surface of the sample prepared by the rotation - spraying method exhibited a canine tooth staggered distribution. This increased the random distribution between the crystal particles and reduced the preferred orientation. Rietveld quantitative phase analyses of fluorphlogopites were successfully performed based on the XRD data for the samples prepared by the rotation - spraying method. In this study, Rietveld refinement showed that the contents of IM and 2M1 polytypes of synthetic fluorphlogopites were 86% and I4%, respectively. The systematic investigations of eight commercial fluorphlogopites revealed that these samples were composed of 28% - 43% 2M1 polytype and 57% -72% IM polytype. In addition, significant stacking faults were observed in these eight commercial samples. CONCLUSIONS: The rotation - spraying method significantly weakened the effect of preferential orientation. This study provides technical support for understanding the mica crystal growth, polymorphism, and structure - performance relationship. [ABSTRACT FROM AUTHOR]

The Rietveld phase quantitative analysis (RQPA) method has been widely applied in geology. In the analysis of evaporite, the evaluation and error control of precision are important factors to improve the quality. The RQPA method was applied to simulated binary mixtures (halite and sylvite), ternary mixtures (halite, sylvite, and calcite), and geological samples (i.e., gypsum and sylvite samples). The contents of each mineral calculated by RQPA were compared with the results of chemical analytical data to evaluate the RQPA's accuracy and the main error sources were analyzed. The results show that the absolute errors between theoretical and calculated values are in the range of 0.4%-0.9% and 0.1%-1.2% for the binary and ternary mixtures, respectively. The mineral contents of geological samples matched very well with the results of the chemical analysis. The standard deviation of binary mixtures is 0.702 for 10 calculated results. The relative standard deviation of the same samples are 1.74%(KCl) and 1.17%(NaCl), respectively. The study indicates that the RQPA method is accurate in the quantitative analysis of mineral contents of evaporite rocks. The error sources arose mainly from the nature of the samples, sample preparation, measuring conditions, and refinement process. Due to the advantages of reducing the preferred orientation, not requiring pure samples, and high utilization of data, the RQPA method has a potentially extensive application in mineral exploration analysis, reserve evaluation, and industries of evaporites, when coupled with the chemical analysis method.

BACKGROUND:The content of minerals in kyanite can be analyzed by chemical phase method, but the analytical process is very tedious. Moreover, the existence of heteromorphism and refractory minerals can affect the accuracy of analysis results. An internal standard method by X-ray diffraction (XRD) for direct determination of kyanite requires the use of pure mineral to draw a standard curve, but it is extremely challenging to purify minerals due to the inclusion. The differences between the mineral components of kyanite in different mining areas makes the above two methods applicable only to the quantitative analysis of minerals in the same mining area. OBJECTIVES:To simplify analysis the process of mineral composition of kyanite and improve efficiency. METHODS:The content of minerals in kyanite was studied by X-ray diffraction. The X-ray diffraction Rietveld refinement method was used to analyze the secondary standard materials and field samples of kyanite, and the results were compared with the diffraction quantitative method and chemical analysis results including RIR method, adiabatic method and K-value method. RESULTS:Rietveld refinement method was simple and effective in correcting the diffraction intensity error caused by the preferred orientation. Accurate results can be obtained by Rietveld refinement method more than other methods of X-ray quantitative phase analysis, such as RIR method, adiabatic method, K-value method. The analytic absolute error of minerals with content greater than 5% was less 1%, and significantly lower than, the allowable error. The results obtained by highscore agree well with results measured by Jade, and the double difference of results was less than 0.8%. The relative standard deviation was less than 2.5%. The spiked recoveries of kyanite were 95%-101%. CONCLUSIONS:X-ray diffraction with Rietveld refinement method is simple, and can be used to determine the content of all minerals in kyanite from different mining areas. [ABSTRACT FROM AUTHOR]

The Rietveld phase quantitative analysis (RQPA) method has been widely applied in geology. In the analysis of evaporite, the evaluation and error control of precision are important factors to improve the quality. The RQPA method was applied to simulated binary mixtures (halite and sylvite), ternary mixtures (halite, sylvite, and calcite), and geological samples (i.e., gypsum and sylvite samples). The contents of each mineral calculated by RQPA were compared with the results of chemical analytical data to evaluate the RQPA's accuracy and the main error sources were analyzed. The results show that the absolute errors between theoretical and calculated values are in the range of 0.4%-0.9% and 0.1%-1.2% for the binary and ternary mixtures, respectively. The mineral contents of geological samples matched very well with the results of the chemical analysis. The standard deviation of binary mixtures is 0.702 for 10 calculated results. The relative standard deviation of the same samples are 1.74%(KCl) and 1.17%(NaCl), respectively. The study indicates that the RQPA method is accurate in the quantitative analysis of mineral contents of evaporite rocks. The error sources arose mainly from the nature of the samples, sample preparation, measuring conditions, and refinement process. Due to the advantages of reducing the preferred orientation, not requiring pure samples, and high utilization of data, the RQPA method has a potentially extensive application in mineral exploration analysis, reserve evaluation, and industries of evaporites, when coupled with the chemical analysis method. [ABSTRACT FROM AUTHOR]