Heather A.W. Kaminsky, Thomas H. Etsell, Douglas G. Ivey, Oladipo Omotoso
Canada: Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta | Natural Resources Canada, CETC – Devon, Alberta
Minerals Engineering, Volume 21, Issue 4, March 2008, Pages 264-271
Abstract:
Heavy minerals such as zircon, rutile, and ilmenite, have been observed to concentrate in the froth during the extraction of bitumen from oil sands. Consequently, the waste solids from this process are a rich source of both zirconium and titanium. While most of the zircon occurs as discrete particles, attempts at generating a high end concentrate of rutile have met with limited success. Thus, there is a need for further characterization of heavy minerals in oil sands. This work uses X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG) analysis, and X-ray fluorescence to analyze the coarse froth solids from an oil sands ore sample. XRD results reveal that the titanium bearing minerals present in the froth are rutile, anatase, brookite, and ilmenite. SEM results indicate the presence of quartz, intergrown with fine titanium-rich and iron-rich structures. Also present are a large variety of iron–titanium compounds, with iron compositions ranging from a few percent to stoichiometric ilmenite.
South Korea: Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, Pohang | Chemical Testing Section, Quality Control Department of POSCO, Pohang
Steel research international, Volume 83, Issue 9, September 2012, pages 896-902
Abstract:
A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was proposed. Homogeneous glass disks were prepared under the following conditions: lithium tetraborate as flux with sample dilution (1:33), with the addition of lithium nitrate (LiNO3) as oxidizer by slow heating from 888 to 1123 K for 45 min followed by fusion at 1273 K for 3 min in an O2-blowing atmosphere. The complete pre-oxidation of FeMo alloys by adding oxidizer and by employing O2-supplying apparatus was ascribed to the reproducible preparation of homogeneous fused glass disks. Nine FeMo standard materials were employed to establish the XRF calibration curves for Mo and Fe. The calibration curves were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory precision and accuracy, considering the matrix effects and line overlap corrections. It is believed that the newly proposed method of preparing fused glass disks of FeMo alloys employing an automated fusion system can replace the conventional preparation requiring the labor intensive and time consuming procedure.
Priyanka Lekhi, D. Cassis, C.M. Pearce, N. Ebell, M.T. Maldonado, K.J. Orians
Canada: Department of Chemistry, University of British Columbia, Vancouver, BC | Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, BC | Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC | Odyssey Shellfish Ltd., Nanoose Bay, BC
Science of The Total Environment, Volume 393, Issues 2–3, 15 April 2008, Pages 309-325
Abstract:
Pacific oysters (Crassostrea gigas) collected on the coast of British Columbia, Canada have occasionally shown cadmium (Cd) concentrations at or above 2 µg g- 1 (wet weight), which has resulted in the loss of some international markets. This study investigated the source and transfer of Cd to oysters by focusing on the role of dissolved and particulate Cd in seawater. Parameters monitored for 1 year at two oyster farm sites on Vancouver Island included: oyster tissue mass and shell length, Cd in oysters, dissolved Cd, particulate Cd, temperature and salinity. Results show that dissolved Cd was the main source of Cd to the oysters and that Cd was mainly concentrated in the gut tissues. A seasonal trend was observed in Cd in oysters, in which levels were lowest during periods of higher temperatures. Results also indicate that the local oceanographic inputs and sediment diagenesis directly affect dissolved Cd and thereby influence the Cd levels in oysters. Particulate matter was not found to be a source of Cd in oysters, and was actually negatively correlated. This was likely due to the uptake of dissolved Cd by phytoplankton and the effect of phytoplankton on oyster tissue mass.
Alexander W. Middleton, Hans-Jürgen Förster, I. Tonguç Uysal, Suzanne D. Golding, Dieter Rhede
Australia: Queensland Geothermal Energy Centre of Excellence, The University of Queensland, Queensland 4072 Germany: Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, D-14473 Potsdam, FR Australia: School of Earth Science, The University of Queensland, Queensland 4072
Chemical Geology, Volume 335, 6 January 2013, Pages 105-117
Abstract:
The metaluminous Soultz-sous-Forêts monzogranite, France, is highly evolved and contains elevated concentrations of rare-earth elements (REE), Y and particularly Th. Primary accessory minerals include fluorapatite, allanite-(Ce) and Th-rich titanite. Primary titanite has been altered to anatase + calcite + quartz + synchysite-(Ce) ± bastnaesite-(Ce) or anatase + calcite + quartz + monazite-(Ce) + xenotime-(Y) ± thorite. Fluorocarbonate-bearing assemblages are restricted to those samples exhibiting minor selective alteration, whereas those containing phosphate-rich assemblages formed in pervasively altered samples that have experienced high fluid/rock ratios. Comparative electron-microprobe analysis of primary and hydrothermally-derived accessory phases found middle REE, Y and Th concentrations depleted in synchysite-(Ce) relative to primary titanite. Such depletions are not seen in phosphate-rich samples containing monazite-(Ce) and xenotime-(Y). Variability in elemental concentrations may be attributed to distinct fluid chemistries and hence, lead to differential mobility during alteration. Following previous experimental work and mineralogical observations, the ingress of CO2-rich solutions was integral for titanite breakdown and the resultant metasomatic assemblage. The influx of CO2-rich fluids concomitantly with chloritisation of biotite produced fluids enriched in FCO3−. We, therefore, hypothesise that after the alteration of titanite, remnant HCO3− or FCO3−-rich fluids were able to mobilise significant proportions of MREE, Y and Th not accommodated into the synchysite-(Ce) structure. Conversely, those samples rich in monazite-(Ce) and xenotime-(Y) retained their REE, Y and Th concentrations due to the presence of aqueous HPO42− derived from apatite dissolution.
Thailand: National Metal and Materials Technology Center, Klong Luang, Pathumthani 12120 United Kingdom: Department of Mechanical Engineering, University of Bath, Bath
Journal of Biomedical Materials Research Part B: Applied Biomaterials, Volume 99B, Issue 2, pages 230-238, November 2011
Abstract:
Dicalcium silicate (Ca2SiO4) has been reported as an interesting candidate for biomaterials use due to its attractive bioactive properties. Here, we report on how dicalcium silicate was prepared by a sol–gel route using calcium nitrate tetrahydrate and tetraorthosilicate as the precursors chemicals for CaO and SiO2, respectively. The synthesized powders were characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). High purity dicalcium silicate at a CaO/SiO2 molar ratio of 2:1 could be formed by the sol–gel method without a washing process and was then calcined at 800°C. The effects of the molar ratio of CaO/SiO2, the washing process, and the calcination temperature have been shown to affect the purity, the formation, and the particle size of the nanoparticles, which have been investigated and discussed.
South Africa: Faculty of Science, University of the Witwatersrand, 2011
Abstract:
The objective of the study was to investigate the preparation of glass beads for base metal analysis of mining samples prior to x-ray fluorescence analysis. The research method used included the investigation of different fluxes, oxidising, non-wetting agents, fusion temperature and time. The experiments were carried out using different fusion instruments: Electrofluxer and Katanax followed by both EDXRF and WDXRF analysis. The x-ray spectrometers were calibrated with standards prepared from pure oxides and the results compared to values determined by alternative techniques. Different statistical methods were used to validate the experiments including factorial designs. Not all the elements and oxides were recovered successfully, however, perfect glass beads were prepared. The two areas of concern were addressed successfully: firstly the loss of copper was overcome by using an alternative heating mechanism of the Katanax and sodium iodide as the non-wetting agent. Secondly, the sulphur was successfully oxidised and retained in the glass beads.
Edna Celina Alberto Chichango,Fung Dai Kin, Moisés Mabui
Mozambique: Universidade Eduardo Mondlane, Maputo
Abstract:
O presente trabalho objectiva avaliar e comparar a qualidade de diferentes amostras de cimento Portland tipo II, classe 32.5, produzido por 3 fábricas de cimento de Moçambique, nomeadamente fábricas da Matola, Beira e Nacala. Para tal 15 amostras de cimento, divididas em 5 amostras por fábrica foram analisadas e os resultados obtidos comparados. Os parâmetros do cimento determinados foram: Fe2O3, CaO, MgO, Na2O, K2O, SiO2, SO3, resíduo insolúvel (RI) e perda ao rubro (PR). Os métodos usados para as análises foram: espectrofotometria de absorção atómica com chama (FAAS), fotometria de chama (FC) e gravimetria. A exactidão dos métodos FAAS e FC foi averiguada através da análise do material de referência, calcário KH, fornecido pelo Laboratório da Direcção Nacional de Geologia (DNG). Verificou-se, a partir dos erros relativos e das taxas de recuperação, que ela variou de boa a muito boa para todos os elementos analisados com excepção de magnésio e ferro. O mesmo se verificou através do test t para comparação da média experimental e teórica cujos resultados, a um nível de confiança de 95%, mostraram evidências de diferenças significativas para o ferro e magnésio. Em termos de precisão, os valores calculados de %RSD demonstram que ela variou de boa a muito boa para quase todas as amostras analisadas por gravimetria, FAAS e FC. Averiguou-se a qualidade das amostras comparando-se os resultados obtidos para cada parâmetro com os teores especificados pelas normas, tendo-se notado que, para grande parte das amostras analisadas os parâmetros determinados cumprem com os requisitos fixados nas normas. Empregando a ANOVA notou-se haver diferenças significativas, entre amostras produzidas em diferentes dias entre os meses de Março a Julho em cada fábrica, para RI, MgO e SO3. Comparou-se a qualidade do cimento das diferentes fábricas através da ANOVA e notou-se que, com excepção do potássio, não há diferença significativa entre os teores dos parâmetros analisados nas amostras das diferentes fábricas testadas. Deste modo, o cimento produzido pelas 3 fábricas pode ser usado para construção civil em estruturas cuja exposição ao ataque de sulfatos seja moderada.
Ivaniza de Lourdes Lazzarotto Cabral, Rogério Junqueira Prado
Brasil: Dep. de Geografia e de Física/ICHS/UFMT - Av. Fernando Corrêa s/n – Coxipó – 78060-900 Cuiabá – MT
Revista Brasileira de Geomorfológia, v.9, n.2
Abstract:
Neste trabalho foi realizada a análise química de níveis concrecionários em três diferentes situações, localizados no interflúvio entre os rios Ibicuí e Jacuí, na Depressão Periférica do Rio Grande do Sul - município de Cacequi. A presença de níveis concrecionários em blocos, pisolíticos e pisolíticos associados a depósitos de cascalheiras, expressa as duas variações do elemento ferro nas morfologias já mencionadas, indicando transformação e evolução não só da estrutura geológica / geomorfológica, mas das próprias condições pedológicas da região, sob a atual conjuntura climática. Utilizando-se das técnicas de Espectrometria de Raios X por Dispersão em Energia (EDX) e Difração de Raios X (XRD), obteve-se a caracterização química e da estrutura cristalina dos principais componentes pertencentes às três situações morfológicas das concreções. As informações apresentadas permitem verificar que há necessidade de estabelecer algumas revisões em relação aos processos transformadores das superfícies na Depressão Periférica do Rio Grande do Sul, principalmente em relação aos pedogenéticos, pois em uma escala relativamente detalhada tudo indica que na região ocorrem eventos de paleolatossolos e que, sob condições climáticas divergentes às de sua gênese, constituem um dos materiais de origem dos Argissolos na região.
