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Basic studies for in-situ leaching project: Leaching of polished and powdered natural ore samples
Published in Vladimir Litvinenko, Innovation-Based Development of the Mineral Resources Sector: Challenges and Prospects, 2018
A. Korda, J. Heinrich, G. Heide
The crushed material as well as the McCrone milled material were investigated via X-ray powder diffraction (XRD) before the leaching experiment (TEST 2) using a Seifert-FPM URD6 (Bragg-Brentano geometry) with a step width of 0.02� (40 kV, 30 mA, measurementrange 5-60 2?, counting time per step 2 sec.). The X-ray apparatus was equipped with a Meteor0D detector and an automatic divergence slit. Furthermore, cobalt radiation was chosen to avoid iron fluorescence by the samples. In addition, the solid leaching residues were recovered from the dried filters and briefly homogenized in an agate mortar. A small amount of each sample was prepared with a few drops of ethanol in the form of a thin film on a silicon single crystal slide. After the ethanol has dried, this specimen was measured by XRD as well (identical parameters except for fixed divergence slit). The evaluation of the XRD results was done with the program ANALYZE from the software package RayfleX (GE Sensing & Inspection Technologies GmbH; Version 2.501) based on the PDF-4/Minerals Database (PDF - Powder Diffraction File) from the ICDD (International Centre for Diffraction Data). Rietveld refinements were done using the graphical user interface (GUI) Profex for the Rietveld refinement program BGMN developed by J. Bergmann (Doebelin & Kleeberg, 2015). Furthermore, a representative part of each sampled ore was further analyzed for major and trace elements by Activation Laboratories Ltd. (Actlabs), Ontario Canada.
Characterisation of historical fired clay bricks with small angle neutron scattering
Published in Claudio Modena, F. da Porto, M.R. Valluzzi, Brick and Block Masonry, 2016
A. Viani, K. Sotiriadis, P. Šašek, R. Ševčík, A. Len
A sample of clay raw material has been collected, on the basis of historical documents, from the place of the original clay pit. Quantitative phase analysis was conducted on the dried and hand milled sample with X-ray powder diffraction method, recording the data in the angular range 4-82° 20 with a Bragg-Brentano 0-0 diffractom- eter (Bruker D8 Advance pro) and Cu Ka radiation. Rietveld refinement was accomplished with the software TOPAS 4.2 (Bruker).
Rietveld Refinement of Powder X-Ray Diffraction Patterns
Published in Dong ZhiLi, Fundamentals of Crystallography, Powder X-ray Diffraction, and Transmission Electron Microscopy for Materials Scientists, 2022
In this chapter, we have discussed the intensity of a diffracted beam for a polycrystal sample. In the case where there are two or more phases present, the peak intensities from each phase can also be calculated. The Rietveld refinement is a whole-pattern-fitting least-squares technique that uses the entire pattern rather than a few selected reflections to extract the crystallographic information.
Automatic Rietveld refinement by robotic process automation with RIETAN-FP
Published in Science and Technology of Advanced Materials: Methods, 2022
Ryo Tamura, Masato Sumita, Kei Terayama, Koji Tsuda, Fujio Izumi, Yoshitaka Matsushita
Rietveld analysis is an indispensable technique in materials research [1–6]. Because the crystal structure can be determined from powder diffraction data, it has been widely used for structural analysis of all crystalline materials, including those for which single crystals cannot be obtained. Rietveld refinement is completed by refining various parameters, such as lattice constants, peak profile functions, and backgrounds. However, the refinement of these various parameters necessitates tedious manual trial and error, which consumes significant human resources and time. In many instances, Rietveld analysis specialists are required to accomplish this refinement. To automate this refinement process, we present a robotic process automation (RPA) system that can automate the estimation of parameters in Rietveld analysis on a personal computer.
Formation of surface defects by thermal shock method for the improved photocatalytic activity of ZnO nanoparticles
Published in Journal of Asian Ceramic Societies, 2020
Tien Khoa Le, The Luan Nguyen, Chau Ngoc Hoang, Dieu Khanh An Nguyen, Torben Lund, Huu Khanh Hung Nguyen, Thi Kieu Xuan Huynh
Besides, the surface atomic composition and chemical environment of unmodified ZnO and surface-modified ZnO samples were also studied by X-ray photoelectron spectroscopy (XPS) on a Kratos Axis Ultra DLD spectrometer (Kratos Analytical Ltd, UK) using the Al-Kα source (1486.6 eV) and the pressure of 10−7 mbar. All binding energies of elements in different chemical environments on the surface of catalysts were referenced to the C1s line at 285 eV, corresponding to the surface contamination carbon. The Rietveld refinement was carried out by using the Fullprof 2009 structure refinement software [25].
Phase analysis and hydration behavior of fine and coarse particle fractions contained in a commercial Portland cement
Published in Journal of Sustainable Cement-Based Materials, 2023
Therefore, Rietveld refinement was performed using TOPAS Version 4 software (Bruker, Karlsruhe/Germany). Background (Chebychev, 5th order), sample displacement, scale factors, unit cell parameters, crystal size L and strain L (only for C3S) were refined, but constrained. Furthermore, Brindley correction was applied and as peak type the fundamental parameter (FP) approach was used for all structures. Preferred orientation correction (March-Dollase function) was done for all clinker phases, free lime, anhydrite, gypsum, calcite, portlandite and dolomite.