Study on Mineral Composition and Main Mineral Morphology of Bauxite from ZhongXiang, HuBei Province

2012 ◽  
Vol 512-515 ◽  
pp. 648-651
Author(s):  
Yan Li ◽  
Zhao Hui Huang ◽  
Yan Gai Liu

In this paper, the mineral composition and main mineral morphology of bauxite were studied from ZhongXiang deposit, HuBei province. Through Electron Microscope Identification, there are two main rock types, oolitic, bean-like and aphanitic or fine crystalline structure of bauxite. The main mineral morphology is micro-crystalline or flake, crumby forms. The mineral and chemical compositions of samples were investigated by XRD, EPMA analysis tests. The EPMA results showed that Al2O3 content is 47.95% ~ 75.04%, in association with other isomorphous impurities, such as Si, Fe, Ti and Mg in varying proportions. The mineral compositions of bauxite ore are mainly aluminum, iron, silicon minerals, which totally account for from 83.01% to 86.40%. The XRD revealed that diaspore, hematite and kaolinite are the major mineral components in the bauxite ores. The bauxite from ZhongXiang deposits is a type of high diaspore bauxite, partly with clay minerals. Furthermore, the function of bauxite as a good fire-resistant material was discussed.

The article presents the study of processes of structure formation of cement stone and products of hardening of organic-mineral compositions with fibrous filler (shavings) by the electronic scanning microscopy method. It is established that the additive-free cement stone at the age of 28 days has a dense and homogeneous structure, consists of calcium hydro-silicates, Portlandite and calcite - newgrowths characteristic for cement systems. Cellulose fibers, which make up the bulk of the substance of shavings, are sufficiently active, which determines the high adhesion of the hydration products of the cement binder to their surface. It is shown that the introduction of shavings into the organo-mineral composition leads to inhibition of cement hydration processes. Organo-mineral compositions with different shavings content (two compositions) were analyzed. The first composition is characterized by a fairly dense structure, the cement stone consists of globular nanoscale nuclei of hydrosilicates, Portlandite and calcite. The second composition has a loose porous structure, cement stone consists of non-hydrated cement grains, newgrowths are represented by calcite and vaterite. The structure of the contact zone "osprey fiber-cement stone" in the organo-mineral composition of the first composition indicates a good adhesion of the filler surface with the phases of hydrated cement. The use of shavings as a fibrous filler (the first composition) increases the tensile and bending strength, as well as the wear resistance of organo-mineral compositions. The data obtained by scanning electron microscopy are confirmed by the results of studying the processes of structure formation of cement stone by quantitative x-ray phase analysis.


2013 ◽  
Vol 63 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Magdalena Kokowska-Pawłowska ◽  
Jacek Nowak

Abstract Kokowska-Pawłowska, M. and Nowak, J. 2013. Phosphorus minerals in tonstein; coal seam 405 at Sośnica- Makoszowy coal mine, Upper Silesia, southern Poland. Acta Geologica Polonica, 63 (2), 271-281. Warszawa. The paper presents results of research on tonstein, which constitutes an interburden in coal seam 405 at the Sośnica- Makoszowy coal mine, Makoszowy field (mining level 600 m), Upper Silesia, southern Poland. The mineral and chemical compositions of the tonstein differ from the typical compositions described earlier for tonsteins from Upper Silesia Coal Basin area. Additionally, minerals present in the tonsteins include kaolinite, quartz, kaolinitised biotite and feldspars. The presence of the phosphatic minerals apatite and goyazite has been recognized. The presence of gorceixite and crandallite is also possible. The contents of CaO (5.66 wt%) and P2O5 (6.2 wt%) are remarkably high. Analysis of selected trace elements demonstrated high contents of Sr (4937 ppm) and Ba (4300 ppm), related to the phosphatic minerals. On the basis of mineral composition the tonstein has been identified as a crystalline tonstein, transitional to a multiplied one.


2010 ◽  
Vol 158 ◽  
pp. 197-203 ◽  
Author(s):  
Jie Liu ◽  
Yue Xin Han ◽  
Wan Zhong Yin

The process mineralogy of potassium-rich shale from Chaoyang of Liaoning, China, was studied. Research results showed there are much less variety and smaller quantities in mineral compositions. Calculated mineral composition by means of chemical composition analysis combined with XRD, MLA, IR and TG-DSC analyses showed that main minerals with were Potassium-feldspar, muscovite, biotite and illite, and gangue minerals were quartz and small amounts of hematite. Potassium-rich minerals such as potassium-feldspar and muscovite contact smoothly with quartz respectively, and there was the direction arrangement among potassium-feldspar, quartz and muscovite in the shale. And quartz and hematite were main cement in the shale. The influences of the research results on the potassium extraction from potassium-rich shale were distinct.


2011 ◽  
Vol 194-196 ◽  
pp. 201-206
Author(s):  
Guo Ping Luo ◽  
Sheng Li Wu ◽  
Yi Ci Wang ◽  
Guang Jie Zhang ◽  
Zhi Zhong Hao ◽  
...  

The effects of compound silicate gangue on mineral composition and microstructure of sinter produced by Baiyunebo iron ore concentrates was studied by using mini-sintering test device and optical microscope. The result showed that compound silicate gangue has lower melting point, wider melting temperature range, longer melting time and melts easily to form glassiness during the sintering process. It can promote the solution of CaO and CaF2 in glassy phase, which affects viscosity and fluidity of glassy phase as well as the homogeneity of sinter microstructure. The compound silicate gangue intensely inhibits the generation of complex calcium ferrite and cuspidine as well. The major mineral compositions of sinter are hematite and glassy phase. The sinter exhibits multi-cavities and grainy structure when SiO2 exists entirely in the form of compound silicate gangue.


2007 ◽  
Vol 13 ◽  
pp. 45-48 ◽  
Author(s):  
Mark T. Hutchison ◽  
Louise Josefine Nielsen ◽  
Stefan Bernstein

Exploration for diamonds in West Greenland has experienced a major boost within the last decade following the establishment of world-class diamond mines within the nearby Slave Province of the Canadian Arctic. Numerous companies have active programmes of diamond exploration and increasingly larger diamonds have been discovered, notably a 2.392 carat dodecahedral stone recovered by the Canadian exploration company Hudson Resources Inc. in January 2007. The Geological Survey of Denmark and Greenland (GEUS) is currently carrying out several studies aimed at understanding the petrogenesis of diamondiferous kimberlites in Greenland and the physical and chemical properties of their associated mantle source regions (e.g. Hutchison 2005; Nielsen & Jensen 2005). Constraint of the mantle geotherm, i.e. the variation of temperature with depth for a particular mantle volume, is an important initial step in assessing the likelihood of such a volume to grow diamonds and hence the diamond potential of associated deep-sourced magmatic rocks occurring at surface. Cool geotherms are often present within old cratonic blocks such as West Greenland (Garde et al. 2000) and provide a good environment for the formation of diamonds (Haggerty 1986). This study aims to constrain the mantle geotherm for the southern extent of the North Atlantic Craton in Greenland by applying three-phase geothermobarometry calculations using chemical compositions of clinopyroxene, orthopyroxene and garnet from four-phase kimberlite-hosted lherzolite xenoliths. Xenoliths have been sampled from kimberlites from two areas in South-West Greenland: Midternæs and Pyramide- fjeld (Fig. 1). Kimberlites in the Pyramidefjeld area principally occur as sheeted sills hosted in the Pyramidefjeld granite complex of Palaeoproterozoic Ketilidian age. In contrast, Midternæs kimberlites occur as outcrops within a single, extensive and undulating sill hosted within pre-Ketilidian granodioritic gneiss and Ketilidian supracrustal rocks. Pyramidefjeld kimberlites have been shown to be Mesozoic (Andrews & Emeleus 1971), and work is currently being carried out to further constrain the ages of these and the Midternæs kimberlites and also xenoliths using modern methods. No attempt is made herein to provide a correct petrological classification of the rocks hosting the xenoliths; however, the abundance of clinopyroxene reported by Andrews & Emeleus (1971) suggests that further work may more correctly conclude a classification as ‘orangeite’ after Mitchell (1995). Notwithstanding this, the term ‘kimberlite’ is employed throughout in order to be consistent with that adopted by previous authors. The Precambrian Pyramide fjeld granite complex and adjacent Archaean granod ioritic gneisses are host to several kimberlite sheets located at various levels between 400 and 900 m elevation (Fig. 1A; Andrews & Emeleus 1971, 1975). Kimberlites are mainly found as loose blocks in scree; however, these are almost always sourced locally from in situ bodies. Sheets can often be found deep within overhanging clefts, particularly in granitic walls. The kimberlite bodies are gently dipping, typically 20 degrees, and with a range of strikes. The maximum thickness of sills is approximately 2 m but thickness varies significantly over short distances. In many instances, the occurrence of kimberlite is seen to be controlled locally by structures in the country rocks. Field observations of the range of orientations of intrusive bodies do not appear to suggest a particular focal point which could be a likely location for an intrusive centre such as a pipe. This observation is in line with what is seen throughout West Greenland where kimberlite emplacement appears as dykes and sills (Larsen & Rex 1992) rather than the pipes and blows which are common in other world-wide settings. The occurrence of xenoliths amongst Pyramidefjeld kimberlites is highly variable with the most xenolith-rich localities being in the vicinity of Safirsø (Fig. 1A). The majority of xenoliths are dunites with occasional wehrlites and lherzolites (Emeleus & Andrews 1975). Of particular interest from the point of view of thermobarometry is the occurrence of garnet. This is rarely found, even in clinopyroxene-bearing samples, and the two samples chosen for thermobarometry (Fig. 1A) represent the majority of the garnet-bearing xenoliths identified within an estimated total population of 75 xenoliths collected. The Midternæs kimberlites are hosted in Archaean gneisses and Proterozoic supracrustal rocks (Fig. 1B; Andrews & Emeleus 1971, 1975). The style of kimberlite emplacement and occurrence of garnet-bearing xenoliths are closely similar to those of Pyramidefjeld. Contours of elevation between outcrops suggest that the kimberlites form parts of a largely contiguous single body dipping at approximately 30 degrees to the west-south-west. Individual outcrops as in Pyramidefjeld indicate that the body varies in thickness and undulates in response to local structure. The south-western portion of the body which outcrops near the glacier Sioralik Bræ, is considerably thicker than elsewhere (Fig. 2) and in some places is seen to have a true thickness in excess of 4 m. Xenoliths are less abundant on average than in Pyramidefjeld kimberlites, but a similar variety and proportion of rock types and infrequent occurrence of garnet is observed. The kimberlites from both areas were intruded along zones of platy jointing which likely were caused by degassing of the magma and formed just prior to the kimberlite intrusion. In contrast to some kimberlites in other cratons, very few xenoliths of local, lower crustal rock types have been recognised in the kimberlites from Pyramidefjeld and Mid ternæs. The intrusions are therefore believed to have been of a non-explosive nature, perhaps because of host-rock rheol - ogy or due to emplacement at relatively deep crustal levels. Here we report on calculations of equilibrium pressure and temperature using compositions of three-phase assemblages of garnet, orthopyroxene and clinopyroxene from Midternæs and Pyramidefjeld mantle xenoliths.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 324 ◽  
Author(s):  
Piotr Narloch ◽  
Piotr Woyciechowski ◽  
Jakub Kotowski ◽  
Ireneusz Gawriuczenkow ◽  
Emilia Wójcik

Cemented stabilized rammed earth (CSRE) is a building material used to build load bearing walls from locally available soil. The article analyzes the influence of soil mineral composition on CSRE compressive strength. Compression tests of CSRE samples of various mineral compositions, but the same particle size distribution, water content, and cement content were conducted. Based on the compression strength results and analyzed SEM images, it was observed that even small changes in the mineral composition significantly affected the CSRE compressive strength. From the comparison of CSRE compressive strength result sets, one can draw general qualitative conclusions that montmorillonite lowered the compressive strength the most; beidellite also lowered it, but to a lesser extent. Kaolinite lightly increased the compressive strength.


1968 ◽  
Vol 70 (3) ◽  
pp. 299-301 ◽  
Author(s):  
A. Eden

SUMMARYStudies were made of the proximate and mineral compositions of modern strains of both spring· and winter-sown beans. The majority of the winter beans were of the Throws M.S. variety, of the spring beans Minors. On the dry-matter basis spring beans averaged 31·4% crude.protein, winter beans 26·5%—a highly significant difference. The true protein values showed a parallel trend. Winter beans averaged 9% crude fibre, spring beans 8%, again a highly significant difference. The strains confirmed the usually accepted levels of oil and of the principal mineral components, except that modern beans appear to be richer in phosphorus.


2018 ◽  
Vol 85 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Massimo Malacarne ◽  
Giulio Visentin ◽  
Andrea Summer ◽  
Martino Cassandro ◽  
Mauro Penasa ◽  
...  

This Research Communication investigated the potential of mid-infrared spectroscopy to predict detailed mineral composition of bovine milk. A total of 153 bulk milk samples were analysed for contents of Ca, Cl, Cu, Fe, K, Mg, Na, P and Zn. Also, soluble and colloidal fractions of Ca, Mg and P were quantified. For each milk sample the mid-infrared spectrum was captured and stored. Prediction models were developed using partial least squares regression and the accuracy of prediction was evaluated using both cross- and external validation. The proportion of variance explained by the prediction models in cross-validation ranged from 34% (Na) to 77% (total P), and it ranged from 13% (soluble Mg) to 54% (Cl−) in external validation. The ratio of the standard deviation of each trait to the standard error of prediction in external validation, which is an indicator of the practical utility of the prediction model, was low and never greater than 2. Results from the current study supported the limited usefulness of mid-infrared spectroscopy to predict minerals present in low concentration in bulk milk. For major mineral components, results from the present research did not match previous findings demonstrating the need for further studies using larger reference datasets.


1992 ◽  
Vol 56 (384) ◽  
pp. 319-327 ◽  
Author(s):  
Zenaide C. G. Silva

AbstractThe gabbro-anorthosite complex of SW Angola and Namibia (Kunene Complex) is dominated by anorthosite-troctolite cumulates. Other broadly gabbroic rock types are subordinate. An-rich plagioclase (max. An85) and Fo-rich olivine (max. Fo79) are common in the western area of the complex with plagioclase becoming gradually less anorthitic (min. An45) and olivine less forsteritic (min. Fo62) toward the east. This cryptic change is more pronounced in the northern half of the complex where rocks are darker, fresh, and the rhythmic layering is also more conspicuous. Within the white 'massive' anorthosite type, which is largely restricted to the southern half of the intrusion, cryptic layering is less pronounced. Textures indicate that rocks cooled very slowly and the co-existing mineral compositions indicate re-equilibration to usually low temperatures.


2010 ◽  
Vol 148 (1) ◽  
pp. 112-132 ◽  
Author(s):  
D. PRAKASH ◽  
I. N. SHARMA

AbstractThe Karimnagar granulite terrane is an integral part of the Eastern Dharwar Craton (EDC), India, having been the subject of much interest because of the only reported granulite facies rocks in the EDC. It shows a large variety of rock types with a wide range of mineral parageneses and chemical compositions, namely charnockites (Opx+Pl+perthite+Qtz±Bt±Grt), gneisses (Opx+Crd+Bt+Pl+Qtz+perthite±Sil±Grt±Spl; Bt+Qtz+Pl±Crd±Hbl±Spl), mafic granulites (Cpx+Pl+Qtz±Opx±Hbl), quartz-free granulites (Spr+Spl+Bt+Crd+Kfs+Crn; Bt+Crd+Kfs±Crn±Spl±Krn; And+Bt+Kfs+Chl), granites (Qtz+Pl+Kfs±Bt±Hbl), altered ultramafic rocks (Chl+Trem+Tlc), metadolerites (Cpx+Pl±Bt±Qtz±Chl), banded magnetite quartzites and quartzites. Andalusite- and chlorite-bearing assemblages presumably suggest a retrograde origin. Investigation of quartz-free granulites of the area brings out some interesting and important observations, reflecting the presence of refractory phases. These granulites are devoid of sillimanite and contain corundum instead. Reaction textures in the gneisses include breakdown of garnet to form coronas and symplectites of orthopyroxene+cordierite, formation of cordierite from garnet+sillimanite+quartz and late retrograde biotite and biotite+quartz symplectites. In the mafic granulites, inclusions of quartz and hornblende within orthopyroxene are interpreted as being a part of the prograde assemblage. At a later stage orthopyroxene is also rimmed by hornblende. The quartz-free granulites display a variety of spectacular coronas, for example, successive rims on corundum consisting of spinel+sapphirine+cordierite±orthopyroxene, rare skeletal symplectitic intergrowth of sapphirine+cordierite+potash feldspar, and late retrograde formation of chlorite, corundum, spinel and andalusite from sapphirine±cordierite. Based on chemographic relationships and petrogenetic grids, a sequence of prograde, isothermal decompressive and retrograde reactions have been inferred. Quartz-free sapphirine granulites and mafic granulites record the highest P–T conditions (~7 kbar, 850°C), whereas the gneisses were formed at lower P–T conditions (~5 kbar, 800°C). In addition, the presence of andalusite-bearing rocks suggests a pressure of around 2.5 kbar. This change in pressure from 7 kbar to around 2.5 kbar suggests a decompressive path for the evolution of granulites in the study area, which indicates an uplift for the granulite-facies rocks from lower crustal conditions. The implications for supercontinent history are also addressed in light of available geochronological data.


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