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Статті в журналах з теми "Bauxite Diffraction"
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Cvetkovic, Zeljko, and Pavle Tancic. "Mineralogical and crystallographic characteristics of bauxites from some Grebnik’s (Metohija, Serbia) ore deposits." Annales g?ologiques de la Peninsule balkanique 80, no. 1 (2019): 45–61. http://dx.doi.org/10.2298/gabp19010045c.
Повний текст джерелаАнотація:
Five typical bauxite samples from three ore deposits from the wider area of Grebnik Mt. (Metohija, Serbia) were examined with the optical microscopic, X-ray powder diffraction (XRPD) and chemical methods. The occurrences in bauxites were studied and described and the presence of major minerals was determined: diaspore, boehmite and hematite; minor minerals: quartz, goethite, rutile, kaolinite and hydro-hematite; as well as anatase, brookite, magnetite and chromite, which occur only sporadically. According to the quantity of main Al-bearers, three types of bauxite ore were recognized: diaspore, boehmite and boehmite-diaspore. Unit cell dimensions of major minerals were determined, mostly with values within reference data. However, all of the studied hematites have smaller a0 and V0 values, most probably due to the substitution of Fe3+ by Al3+. All samples are further classified as iron-rich and ferritic bauxites. It was found that there were changes in origin conditions between major Al-hydroxides minerals and hematite, as well as between the diaspore and boehmite. Determined chemical compositions put this raw material into high-quality raw materials for obtaining the electro corundum and alumina. The synthesis of the obtained data indicate that Grebnik?s bauxites have some unique characteristics, more or less different from most of the World?s known bauxite ore deposits.
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Atakoglu, Ozge Ozer, and Mustafa Gurhan Yalcin. "Geochemical characterization of the Sutlegen bauxite deposit, SW Antalya." Mining of Mineral Deposits 15, no. 3 (September 2021): 108–21. http://dx.doi.org/10.33271/mining15.03.108.
Повний текст джерелаАнотація:
Purpose.The purpose is to determine geological and geochemical characteristics of the Sutlegen (Antalya, Turkey) bauxites, to identify the elements that played a major role in their formation. Methods. X-ray diffraction (XRD) mineral phase analysis, X-ray fluorescence (XRF) elemental analysis, plasma-mass spectrometry (ICP-MS), the petrographic and mineralogical analyses, and multivariate statistical methods were used. Findings. The major element content of the ore was determined as Al2O3 (60-35.2 wt%), SiO2 (39.5-0.2 wt%), Fe2O3 (48.4-19.5 wt%), TiO2 (36.9-16 wt%), and P2O5 (0.5-0.1 wt%). The Sutlegen region, which shows epirogenetic action with the uplift of the earth's crust, is generally rich in neritic carbonates. It was revealed that the bauxite ores have undergone moderate and strong laterization as a result of the deferruginization in the environment, and they were classified into four groups as lateritic, ferritic, kaolinitic, and bauxite. The increase in the aluminosilicate minerals, which were formed during the formation of bauxite in the environment was found to be directly proportional to the laterization processes. In this context, it was considered that the lateritic material that was firstly formed in the environment filled the cavities and pores of the karst-type limestones and sedimentary units in the region by superficial transfer phenomena. The bivariate diagrams of Log Cr vs. Log Ni revealed that the bauxite that formed in the region had an ultrabasic source. Originality. In literature, no scientific studies have been found on bauxite mineralization in the Sutlegen deposits that have been operated for a long period. Practical implications. In this context, the geochemical characteristics of bauxites revealed that the source of the laterization process in the region was the ultrabasic igneous rocks. The lateritic material moved by superficial transfer was accumulated on sandstone, claystone, siltstone, and limestone and in karstic cavities; then, it formed karstic bauxite (kaolinitic and bauxite) of different classifications due to the effect of metamorphism.
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Fang, Bin Zheng, Hui Li, Jian Wei Cao, Jian Feng Wu, Xiao Hong Xu, and Xi Dong Wang. "Structure and Performance of Calcined Bauxite." Advanced Materials Research 887-888 (February 2014): 305–8. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.305.
Повний текст джерелаАнотація:
In order to further broaden the application field of calcined bauxite, using differential thermal analysis-thermo-gravimetry (DTA-TG), X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) and other testing technology to study and analysis on the high temperature performance of calcined bauxite in this paper. The results show that the main crystal phases of calcined bauxite are corundum and mullite, appearance is layered, granular distribution. Due to the thermal performance of calcined bauxite is optimal, and is expected to be used for the field of high temperature solar thermal heat storage material.
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Melo, Caio C. A., Rômulo S. Angélica, and Simone P. A. Paz. "A Method for Quality Control of Bauxites: Case Study of Brazilian Bauxites Using PLSR on Transmission XRD Data." Minerals 11, no. 10 (September 28, 2021): 1054. http://dx.doi.org/10.3390/min11101054.
Повний текст джерелаАнотація:
Available Alumina (AvAl2O3) and Reactive Silica (RxSiO2), the main parameters of bauxite controlled in the beneficiation process are traditionally measured by laborious, expensive, and time-consuming wet chemistry methods. Alternative methods based on XRD analysis, capable to provide a reliable estimation of these parameters and valuable mineralogical information of the ore, are being studied. In this work, X-ray diffraction data in transmission mode was used to estimate AvAl2O3 and RxSiO2 from Brazilian bauxites using the Partial Least Square Regression (PLSR) statistical tool. The proposed method comprises a routine of sample classification according to their similarities by Principal Component Analysis (PCA) and K-means, calibration of the PLSR model for each group of samples, grouping new bauxite samples according to the generated clustering model, and subsequent estimation of the parameters AvAl2O3 and RxSiO2 using the PLSR models for these samples. The results showed good accuracy and precision of the models generated for samples of the main ore lithology. The quality and pre-processing of the XRD data required for this method are discussed. The results demonstrated that this method has the potential to be industrially applied to quality control of bauxites as a rapid and automated procedure.
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Nong, Liangqin, Xiying Yang, Lingmin Zeng, and Jingping Liu. "Qualitative and quantitative phase analyses of Pingguo bauxite mineral using X-ray powder diffraction and the Rietveld method." Powder Diffraction 22, no. 4 (December 2007): 300–302. http://dx.doi.org/10.1154/1.2790941.
Повний текст джерелаАнотація:
X-ray powder diffraction technique and the Rietveld refinement method have been used successfully for the qualitative and quantitative analyses of Pingguo bauxite from Guangxi, China. Qualitative phase analysis shows that the Pingguo bauxite contains diaspore (AlOOH), hematite (Fe2O3), goethite (FeOOH), anatase (TiO2), and kaolinite (Al2(Si2O5)(OH)4). Quantitative Rietveld refinement shows that the weight concentrations of diaspore, goethite, hematite, anatase, and kaolinite for the Pingguo bauxite are 71.9(4)%, 7.0(8)%, 11.3(7)%, 6.5(6)%, and 3.3(9)%, respectively.
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van Chanh, Nguyen, Mitsuhiro Shigeishi, and Tran Quoc Tho. "Inorganic Composite Material Based on Fly Ash, Red Residue from Bauxite Ore for Road Building Projects in Vietnam." Advanced Materials Research 383-390 (November 2011): 2774–81. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.2774.
Повний текст джерелаАнотація:
The paper present solidifying technology based on geopolymer theory of inorganic composite materials from bauxite, red residue from bauxite ore, fly ash and activators for road building projects in Vietnam. This study describes physical properties and chemical compositions of bauxite, red residue, fly ash and the effects of bauxite-red residue-fly ash-activator mixes on the geotechnical properties of inorganic composite materials. Mixture design and testing procedures for inorganic composite materials. New inorganic composite materials have high durability and ability to water resistance. The presentation also show microstructure analysis of inorganic composite materials based on bauxite residue, fly ash and activators by X-ray diffraction, Infrared spectroscopy (IR), transmission electron microscopy (TEM) display high density, and modified microstructure of inorganic composite materials. Construction method of road using inorganic composite materials is also presented.
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Jafar, N., S. R. Nurhawaisyah, S. Widodo, C. A. Chalik, and M. H. Wakila. "Mineralogical Study of Bauxite of Kenco Area, Landak District, West Kalimantan Province, Indonesia." IOP Conference Series: Earth and Environmental Science 1134, no. 1 (January 1, 2023): 012025. http://dx.doi.org/10.1088/1755-1315/1134/1/012025.
Повний текст джерелаАнотація:
Abstract Indonesia is a country with a tropical climate that allows for high levels of weathering. Bauxite is the result of weathering rocks that have high aluminum content, low iron content, and little quartz content. The formation of bauxite deposits is controlled by source rock which is rich in Al element, tropical climatic conditions, and geomorphological conditions that allow the formation of the accumulation of weathered source rock products. The altered silicate minerals due to weathering result in the silica element being released from the crystal bonds and some iron are released so that the aluminum element is concentrated as a residual precipitate. X-ray diffraction (XRD) analysis on 16 bauxite samples which are estimated to represent the overburden horizon, bauxite ore horizon, clay horizon, and source rock to establish the mineral composition of bauxite. Mineral groups in the overburden horizon, bauxite ore horizon, and clay horizon are alumina, iron, titanium, silicates, carbonates, sulfides, and sulfates, while mineral groups in source rock are iron, titanium, silicate, sulfide, and sulfate. The type of bauxite in the study area is gibbsite bauxite based on the dominant appearance frequency of gibbsite compared to mineral corundum as an alumina group.
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Yang, Fa, Bowen Guan, Jingyi Liu, Jiayu Wu, Jianan Liu, Chao Xie, and Rui Xiong. "An Investigation of the Polishing Behavior of Calcined Bauxite Aggregate." Coatings 9, no. 11 (November 15, 2019): 760. http://dx.doi.org/10.3390/coatings9110760.
Повний текст джерелаАнотація:
The application of top-grade calcined bauxite to improve the skid resistance of pavement surface coatings increases construction costs and causes excessive tire wear. Therefore, it is necessary to investigate the polishing behavior of different grades of calcined bauxite aggregate. The polished stone value of calcined bauxite was measured after the standard polishing time and the extended polishing time. The Los Angeles (L.A.) abrasion and the crushing value, profile roughness, hardness, X-ray diffraction, and micromorphology were also tested. The results showed that the calcined bauxite above 75# (the ratio of corundum to mullite by weight, C/M > 1) satisfied the requirement of the ultra-thin friction course. Compared with basalt, the calcined bauxite above 80# (C/M > 3) has better long-term skid resistance, even though the pavement surface is subject to heavier traffic. Due to the higher cohesion of lower porosity, more hard minerals to keep the surface roughness, and less soft minerals to smooth the surface roughness, calcined bauxite with a higher corundum content has the better skid resistance. There is a power law relationship between C/M and Polished Stone Value (PSV). Considering the diminishing returns of higher-grade calcined bauxite, it is necessary to accurately select the appropriate C/M of calcined bauxite before use in pavement surface coatings.
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Ma, Cong, Yuehu Tan, Erbing Li, Yinsuo Dai, and Meng Yang. "High-Performance Grouting Mortar Based on Mineral Admixtures." Advances in Materials Science and Engineering 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/425456.
Повний текст джерелаАнотація:
A study on high-performance grouting mortar is reported. The common mortar was modified by mineral admixtures such as gypsum, bauxite, and alunite. The effects of mineral admixtures on the fluidity, setting time, expansion, strength, and other properties of mortar were evaluated experimentally. The microstructure of the modified mortar was characterized by X-ray diffraction, scanning electron microscopy, and mercury intrusion porosimetry. Moreover, the expansive performance and strength of the grouting mortar were verified by anchor pullout test. The results show that the best conditions for gypsum-bauxite grouting mortar are as follows: a water-to-binder ratio of 0.3, a mineral admixture content of ~15%, and a molar ratioKof 2. The ultimate bearing capacity of the gypsum-bauxite grouting mortar anchor increased by 39.6% compared to the common mortar anchor. The gypsum-bauxite grouting mortar has good fluidity, quick-setting, microexpansion, early strength, and high strength performances.
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Dai, Yong-Ming, Cheng-Hsuan Hsieh, Jia-Hao Lin, Fu-Hsuan Chen, and Chiing-Chang Chen. "Biodiesel Production Using Bauxite in Low-Cost Solid Base Catalyst Precursors." Catalysts 9, no. 12 (December 13, 2019): 1064. http://dx.doi.org/10.3390/catal9121064.
Повний текст джерелаАнотація:
Investigation was conducted on bauxite mixed with Li2CO3 as alkali metal catalysts for biodiesel production. Bauxite contains a high percentage of Si and Al compounds among products. Because of the high expense of commercial materials (SiO2, Al2O3) that makes them not economical, the method was very recently improved by replacing commercial materials with Si and Al from bauxite. This is one of the easiest methods for preparing heterogeneous transesterification catalysts, through one-pot blending, grinding bauxite with Li2CO3, and heating at 800 °C for 4 h. The prepared solid-base alkali metal catalyst was characterized in terms of its physical and chemical properties using X-ray powder diffraction and field-emission scanning electron microscopy (FE-SEM). The optimal conditions for the transesterification procedure are to mix methanol oil by molar ratio 9:1, under 65 °C, with catalyst amount 3 wt.%. The procedure is suitable for transesterifying oil to fatty acid methyl ester in the 96% range.
Дисертації з теми "Bauxite Diffraction"
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Antoniassi, Juliana Lívi. "A difração de raios X com o método de Rietveld aplicada a bauxitas de Porto Trombetas, PA." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3134/tde-23112010-090249/.
Повний текст джерелаАнотація:
O projeto enfocou a aplicação da difração de raios X (DRX) associada ao método de Rietveld na determinação quantitativa da composição mineralógica de bauxitas de Porto Trombetas, PA. Os resultados obtidos foram comparados com aqueles de outras ferramentas de determinação mineralógica, especificamente métodos tradicionais de caracterização de minérios e espectroscopia Mössbauer, além da correlação direta com dados de análises químicas que, atualmente, são utilizados no controle de pesquisa e processamento de bauxita. Preliminarmente, definiram-se tipos mineralógicos de minério com o recurso de análise por agrupamento de dados de difração de raios X para um conjunto de 60 amostras, englobando materiais da pesquisa mineral e do beneficiamento de bauxita pela Mineração Rio do Norte (MRN). Esse recurso permitiu otimizar o conjunto de amostras para o estudo e facilitar a definição de seqüências específicas de refinamento pelo método de Rietveld para grupos de amostras com composição mineralógica similar. A DRX-Rietveld mostrou-se relevante e eficiente no estudo de bauxitas, sendo obtidos satisfatórios valores de indicadores estatísticos de refinamento (GOF e Rwp), além de elevada correlação linear com as demais metodologias aplicadas, particularmente no que se refere aos maiores constituintes das amostras, essencialmente gibbsita e argilominerais. No caso de óxi-hidróxidos de ferro (basicamente hematita, goethita e uma fase de Fe3+ de baixa cristalinidade), com proporções inferiores a 20% nas amostras, verificou-se que parte desses minerais praticamente não foi detectada por DRXRietveld visto o grau de cristalinidade dessas fases, conforme observado por microscopia eletrônica de varredura e espectroscopia Mössbauer.This research concerns the application of X-ray diffraction (XRD) with Rietveld method in order to determinate the mineralogical composition of bauxites from Porto Trombetas, PA. The results were compared with the mineralogical composition obtained by mineral separations supported by chemical analysis and Mössbauer spectroscopy, as well as correlated with XRF chemical analysis and selective dissolution chemical analysis, that routinely support bauxite mineral research, mining operation as well as mineral processing. Previously, a definition of mineralogical types was provided by cluster analysis of a 60 samples set of diffractograms, corresponding to geological research and beneficiation products from Mineração Rio do Norte (MRN). This tool simplified the analysis of a large number of data for the study and helped to establish the Rietveld refinement strategies for clusters of samples with similar mineralogical compositions. XRD with Rietveld method showed to be relevant and efficient for bauxite study, giving satisfactory statistical evaluation parameters (GOF and Rwp), besides high linear correlation with the others mineralogical methods for the major minerals, essentially gibbsite and clay minerals. For oxi-hydroxides minerals (basically hematite, goethite and a low crystallinity Fe3+ phase), with proportions bellow 20 percent of the samples, it could be seen that part of these minerals was not detected by XRD and so not evaluated by Rietveld quantification method, since they present low crystallinity as observed by scanning electron microscopy and Mössbauer spectroscopy.
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VIEIRA, HEVELINE. "Obtenção e caracterização de vidros a base de lama vermelha visando a imobilização de rejeitos nucleares." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23654.
Повний текст джерелаАнотація:
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T14:26:55Z
No. of bitstreams: 0Made available in DSpace on 2015-04-10T14:26:55Z (GMT). No. of bitstreams: 0
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Palmer, Sara Jane. "Stability of hydrotalcites formed from Bayer refinery environmental control processes." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/48672/1/Sara_Palmer_Thesis.pdf.
Повний текст джерелаАнотація:
Bauxite refinery residues (red mud) are derived from the Bayer process by the digestion of crushed bauxite in concentrated sodium hydroxide at elevated temperatures and pressures. This slurry residue, if untreated, is unsuitable for discharge directly into the environment and is usually stored in tailing dams. The liquid portion has the potential for discharge, but requires pre-treatment before this can occur. The seawater neutralisation treatment facilitates a significant reduction in pH and dissolved metal concentrations, through the precipitation of hydrotalcite-like compounds and some other Mg, Ca, and Al hydroxide and carbonate minerals. The hydrotalcite-like compounds, precipitated during seawater neutralisation, also remove a range of transition metals, oxy-anions and other anionic species through a combination of intercalation and adsorption reactions: smaller anions are intercalated into the hydrotalcite matrix, while larger molecules are adsorbed on the particle surfaces. A phenomenon known as ‘reversion’ can occur if the seawater neutralisation process is not properly controlled. Reversion causes an increase in the pH and dissolved impurity levels of the neutralised effluent, rendering it unsuitable for discharge. It is believed that slow dissolution of components of the red mud residue and compounds formed during the neutralisation process are responsible for reversion.
This investigation looked at characterising natural hydrotalcite (Mg6Al2(OH)16(CO3)∙4H2O) and ‘Bayer’ hydrotalcite (synthesised using the seawater neutralisation process) using a variety of techniques including X-ray diffraction, infrared and Raman spectroscopy, and thermogravimetric analysis. This investigation showed that Bayer hydrotalcite is comprised of a mixture of 3:1 and 4:1 hydrotalcite structures and exhibited similar chemical characteristic to the 4:1 synthetic hydrotalcite. Hydrotalcite formed from the seawater neutralisation of Bauxite refinery residues has been found not to cause reversion. Other components in red mud were investigated to determine the cause of reversion and this investigation found three components that contributed to reversion: 1) tricalcium aluminate, 2) hydrocalumite and 3) calcium hydroxide. Increasing the amount of magnesium in the neutralisation process has been found to be successful in reducing reversion.
Частини книг з теми "Bauxite Diffraction"
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Vogrin, John, Harrison Hodge, Talitha Santini, Hong Peng, and James Vaughan. "Quantitative X-Ray Diffraction Study into Bauxite Residue Mineralogical Phases." In Light Metals 2019, 93–99. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05864-7_13.
Повний текст джерела
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"Crystallite size of kaolinites as indicator of different geochemical types of bauxite." In Eleventh European Powder Diffraction Conference, 441–46. Oldenbourg Wissenschaftsverlag, 2009. http://dx.doi.org/10.1524/9783486992588-069.
Повний текст джерела