Correlations between mineral composition and mechanical properties of granite using digital image processing and discrete element method

This study investigated the correlations between mechanical properties and mineralogy of granite using the digital image processing(DIP) and discrete element method(DEM). The results showed that the X-ray diffraction(XRD)-based DIP method effectively analyzed the mineral composition contents and spatial distributions of granite. During the particle flow code(PFC2D) model calibration phase, the numerical simulation exhibited that the uniaxial compressive strength(UCS) value, elastic modulus(E), and failure pattern of the granite specimen in the UCS test were comparable to the experiment. By establishing 351 sets of numerical models and exploring the impacts of mineral composition on the mechanical properties of granite, it indicated that there was no negative correlation between quartz and feldspar for UCS, tensile strength(σ_(t)), and E. In contrast, mica had a significant negative correlation for UCS, σ_(t), and E. The presence of quartz increased the brittleness of granite, whereas the presence of mica and feldspar increased its ductility in UCS and direct tensile strength(DTS) tests. Varying contents of major mineral compositions in granite showed minor influence on the number of cracks in both UCS and DTS tests.

Effects of Polishing on Proximate Composition,Physico-Chemical Characteristics,Mineral Composition and Antioxidant Properties of Pigmented Rice

The effects of polishing on proximate compositions,physico-chemical characteristics,mineral compositions and antioxidant properties of the rice flours obtained from three different pigmented rice varieties(Chak-hao Angangba,Chak-hao Amubi and Chak-hao Poireiton) were investigated.The rice varieties were significantly(P < 0.05) different in the contents of the test characteristics.Lipids,ash,minerals,phytochemicals(phenolic acids and flavonoids) and 2,2-diphenyl-1-picrylhydrazyl(DPPH) activity of rice flours were decreased after polishing(9% degree of milling),while amylose content and lightness were increased.X-ray diffraction pattern of rice flours exhibited A-type crystalline pattern with reflections at 15.1o,17.1o,18.2o and 23.0o.Pasting properties and transition temperatures were decreased after polishing treatment.Polishing resulted in changes in the crystallinity,enthalpy and morphology of rice flours.

INFLUENCE OF MINERAL ADMIXTURES ON MECHANICAL PROPERTIES OF HIGH-PERFORMANCE CONCRETE

The improvements of the mechanical properties, including bulk density of fresh mixtures, elastic modulus, and compressive strengths of four high-performance concrete mixtures, made with the addition of fly ash, refined ground blast - furnace microslag (microslag) and silica fume are studied. The concrete mixtures were determined based on the dispersion testing results. The study indicates that the elastic modulus at 28 and 91 days, and compressive strengths of the concretes are improved a lot when fly ash and microslag by 25 percent by weight of cement are added into the mixtures individually. The improvement is especially evident when silica fume by 5 percent and fly ash by 25 percent by weight of cement are added together into the mixture, while the fresh concrete mixture keeps a good workability. Through the analysis of chemically combined water ratios of the four mixtures at various hydration ages, it is found that the addition of all these mineral mixtures are beneficial to the hydration process, especially, at later stages, which might be one of the reasons for the improvement of mechanical properties. (Author abstract) 4 Refs.

Influence of Long Term Fertilization with Different Mineral Fertilizers and Farmyard Manure on Some Soil Chemical Properties and Crop Yields *1

A long term fertilization experiment was carried out in an experimental field in Lyczyn near Warsaw, Poland. Application ofmineral fertilizers, especially N fertilizers with and without farmyard manure accelerated the acidification process of the soil. Application of 1.6 t CaO ha -1 every four years was essential to maintenance of the soil pH KCl at 5.5～6.6 and base saturation degree above 60%. Application of 50 t farmyard manure ha -1 every 4 years, which contained 46 kg P and 240 kg K, was sufficient to maintain both the K and P fertility of the soil. Besides, it was beneficial to alleviating soil acidification. As a result of long term unbalanced fertilization, yield responses to N, P and K fertilizers increased significantly with time. The efficiency of N from farmyard manure was found to be comparable to that of N fertilizer during 1988～1991.

EFFECTS OF DISSOLVED MINERAL SPECIES ON THE SURFACE CHEMICAL CHARACTERISTIC,ELECTROKINETIC PROPERTY AND FLOTATION BEHAVIOR OF FLUORITE AND SCHEELITE

Interactions between the dissolved mineral species and other mineralsurface were investigated using solution chemistry calculation, -potential measurement, AES analysis and flotation tests. It has been indicated that there canbe precipitation of scheelite over fluorite in scheelite supernatant at PH> 4.The conversion of fluorite into scheellte was detected by AES. Fluorite in the supernatant of scheelite exhibits nearly identical electrokinetic property andflotation behavior with those of scheelite. The selective flotatlon separation of fluorite from scheelite or vice vasa may be achieved by using selective amphoteric collector for fluorite at PH<4 to avoid surface conversion.

Spatial distribution and driving factors of sediment net nitrogen mineralization in riparian zone of the Three Gorges Reservoir

Inorganic nitrogen(N)loss through sediment N mineralization is important for eutrophication surrounding riparian zone.Sediment physicochemical properties have been changed at water-level elevation in riparian zone of the Three Gorges Reservoir(TGR)due to differences in hydrological stress and human activity intensity.However,spatial distribution and driving factor of net N mineralization rate(Nmin)and its temperature sensitivity(Q10)based on the changes in sediment physicochemical properties are still unclear at waterlevel elevation in the riparian zone.A total of 132 sediment samples in the riparian zone were collected including 11 transections and 12 water-level elevations on basin scale of the TGR during drying period,to conduct a 28-day incubation at 15℃,22℃,29℃and 36℃.Nmin,total N(TN)and substrate quality(SQ)increased with water-level elevation,while Q10 showed an opposite trend(P<0.001).Results of the structural equation model showed that water-level elevation had direct positive effects on TN and SQ(P<0.01).In addition,TN was the major factor that had a direct positive effect on Nmin,and SQ was the crucial factor that had a direct negative effect on Q10(P<0.001).In conclusion,increases in TN and SQ were major driving factors of Nmin and its Q10 at water-level elevation,respectively,in riparian zone of the TGR during drying period.

Environmental properties of metallic minerals and their applications in environmental protection in China

In terms of environmental mineralogy, the environmental properties of metallic minerals, including chemical activation, adsorption, pore effect and nanometer effect, have been analyzed. On the basis of the analysis of environmental properties of metallic minerals, the applications of iron-bearing sulfides, iron and manganese oxides in the purification of wastewaters containing heavy metal ions (Cr{6+}, Hg{2+}, Pb{2+}, etc.) have been summarized. Moreover, research on the application of metallic minerals in environmental protection has been anticipated. It should be a piece of dominating work for environmental mineralogic researchers in the future to lucubrate systematically the physical and chemical characteristics of the metallic mineral surfaces, further reveal the reciprocity process between metallic minerals and water surface, perfect the theory and model of the metallic minerals to remove contaminants, intensify study on the facilities and techniques of metallic minerals to remove contaminants, and entail well the extension and propagation of achievements.

PREPARATION OF FERROFLUID FOR MINERAL PROCESSING AND ITS PROPERTIES

１ＩＮＴＲＯＤＵＣＴＩＯＮＢｅｃａｕｓｅｏｆｉｔｓｅｓｐｅｃｉａｌｙｈｉｇｈｓｅｐａｒａｔｉｎｇｄｅｎｓｉｔｙａｎｄｓｅｐａｒａｔｉｎｇｐｒｅｃｉｓｉｏｎ，ｔｈｅｆｅｒｏｆｌｕｉｄｉｃｓｅｐａｒａｔｉｏｎｈａｓａｔａｃｔｅｄｓｃｉｅｎｔｉｓｔ’ｓｇｒ...

Charge Properties and Clay Mineral Composition of Tianbao Mountains Soils

The clay mineral association, oxides of clay fraction and surface charge properties of 7 soils, which are developed from granite, located at different altitudes of the Tianbao Mountains were studied. Results indicate that with the increase in altitude, 1) the weathering process and desilicification of soil clay minerals became weaker, whereas the leaching depotassication and the formation process of hydroxy-aluminum interlayer got stronger; 2) the contents of amorphous and complex aluminum and iron, and the activity of aluminum and iron oxides for soil clay fraction increased; and 3) the amount of variable negative charge, anion exchange capacity and the values of PZC and PZNC also increased. The activity of aluminum and iron oxides, the accumulation of aluminum, and surface charge characteristics and their relation to clay oxides of the vertical zone soils were observed and recorded.

Nanoscale mechanical property variations concerning mineral composition and contact of marine shale

Mechanical properties of shales are key parameters influencing hydrocarbon production – impacting borehole stability, hydraulic fracture extension and microscale variations in in situ stress. We use Ordovician shale(Sichuan Basin, China) as a type-example to characterize variations in mineral particle properties at microscale including particle morphology, form of contact and spatial distribution via mineral liberation analysis(MLA) and scanning electron microscopy(SEM). Deformation-based constitutive models are then built using finite element methods to define the impact of various architectures of fracture and mineral distributions at nanometer scale on the deformation characteristics at macroscale.Relative compositions of siliceous, calcareous and clay mineral particles are shown to be the key factors influencing brittleness. Shales with similar mineral composition show a spectrum of equivalent medium mechanical properties due to differing particle morphology and mineral heterogeneity. The predominance of small particles and/or point-point contacts are conducive to brittle failure, in general, and especially so when quartz-rich. Fracture morphology, length and extent of filling all influence shale deformability. High aspect-ratio fractures concentrate stress at fracture tips and are conducive to extension, as when part-filled by carbonate minerals. As fracture spacing increases, stress transfer between adjacent fractures weakens, stress concentrations are amplified and fracture extension is favored. The higher the fractal dimension of the fracture and heterogeneity of the host the more pervasive the fractures. Moreover, when fractures extend, their potential for intersection and interconnection contributes to a reduction in strength and the promotion of brittle failure. Thus, these results provide important theoretical insights into the role of heterogeneity on the deformability and strength of shale reservoirs with practical implications for their stimulation and in the recovery of hydrocarbons from them.

Residual Effect of Long Term Application of Organic and Mineral Fertilizers on Selected Chemical Properties of a Savanna Alfisol

The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was left fallow for fourteen years due to lack of funds. Topsoil was collected from plots that received three levels of cow dung （D）, nitrogen （N） and phosphorus （P） in all possible combinations. The soils were analyzed for selected chemical properties. Except for significant effect of applied P on available P, sole application of cow dung, N or P had no significant effect on all the measured soil properties. The interaction of D and P significantly affected the mean values of exchangeable Ca, Mg, K and ECEC in the range of 1.12-1.96, 0.62-1.11, 0.37-0.64 and 2.82-4.11 cmol/kg respectively. The most important results were the ability of the plot that received neither D nor P to significantly increase these parameters than the plots that received only one of the treatments. The results show that the fallow period has changed the effects of application of organic and mineral fertilizers on the soil chemical properties under continuous cultivation by modifying them towards those of a native savanna Alfisol.

Study the Physical, Chemical, Mineralogical, and Geo-technical Properties of Soils Used in Pottery Industries, Kurdistan-lraq

The study area is located in Duhok and Sulaimania province in Kurdistan region, lraq. Study soils developed from parent material that has derived from limestone. Randomize, composed and disturbed surface soil samples were collected. The bulk soils were air dried, crushed and passed through 2 mm sieve. Standard methods were used for chemical, physical, geotechnical and mineralogical analyses of soil samples. The results indicated that the study soils texture were clay to loam clay, this texture was considered as suitable for ceramic and pottery industries as a result of increasing clay contents that ranged between 301 g/kg and 676 g/kg. Soil consistence depending on geotechnical properties increased the ability of study soils for resistance rapture and deformation. Existence the high amount of cementing agents in study soils such as organic matter, iron oxides and particularly total carbonate （247.2-308.8 g/kg） act to reduce the bad effect of the smectite minerals group （high shrinkage） in soils of study locations through increasing the resistance of these soils for rupture and deformation. The existing of Kaolinite, palygorskite and chlorite allows clay to be dried in ceramic and pottery industries without cracking from shrinkage. Study soils were different in their colors as a result of existence, different pigmentation materials that led to coloring soils with different colors in turn caused coloring of pottery and ceramic materials. Since, there are no available academic studies or researches about this subject in Kurdistan region in addition the clay pottery and ceramic sector still has a good market at the same time using this type of soils for arts, therefore, this study was conducted.

Effect of Mineral Oil on the Mechanical Properties and Fractographs of Fe_3(Al,Cr,Zr) Intermetallic Alloy

The effect of mineral oil on the mechanical properties and fractographs of Fe3(Al,Cr,Zr) in termetallic alloy has been investigated. The results show that the tensile ductility of the Fe3(Al,Cr,Zr) alloy tested in oil is comparable with the results obtained in oxygen and is in sensitive to strain rate. The fracture mode of the Fe3(Al,Cr,Zr) alloy treated at 700℃/1.5 h and tested in oil, is cleavage and with dimples in some areas.

Effect of Substitution of Cement by Mineral Powders on the Physico-mechanical Properties and Microstructure of Sand Concretes

The approach that contributes to the development of eco-materials in construction is the use of mineral powders,which can improve mechani­cal properties and reduce cement consumption.This article aims to study the effect of substitution by mass of cement with mineral powders on the physicomechanical properties and microstructure of sand concretes.The used mineral powders are A:the limestone,B:the natural pozzolan,C:the hydraulic lime,D:(1/3 limestone+1/3 natural pozzolan+1/3 hydraulic lime),and E:(1/2 natural pozzolan+1/2 hydraulic lime).The studied percentages are 5%,10%and 15%,in both separated and combined states.The studied properties are workability,compressive strength,the elastic­ity modulus in compression,shrinkage and microstructure analysis.The objective is to target the optimal percentage of the substitution of cement with mineral powders,which ensures the best compromise between the main properties of the studied sand concretes.The obtained results show that the optimal percentage is in favor of the substitution of cement by 10%D(1/3 limestone,1/3 natural pozzolan and 1/3 hydraulic lime).Even the 15%of mineral powder D,presented similar performances compared to the sand concrete(without mineral powders).Finally,in the context of the development of eco-materials,it should be noted that the 10%D and 15%D(1/3 limestone,1/3 natural pozzolan and 1/3 hydraulic lime)contribute to decrease the use of cement and consequently to reduce of CO2 emissions.

A DYNAMIC EVALUATION MODEL OF MINERAL RESOURCE PROPERTY

Based on the value theory of mineral resource, a dynamic evaluation model of mineral resource property is erected, which not only takes the factors of extractions into consideration but also those of explorations. The solution process of the model is described and the differential solution is presented. Then the paper comes to the conclusion that the differential solution is also the optimal depletion path of the resource.

Application of 3-D Geoscience Modeling Technology for the Estimation of Solid Mineral Reserves

Applying new approaches, methods, and technologies for the estimation of reserves can effectively improve the efficiency and accuracy of assessments of solid mineral resources. After analyzing the development of 3-D geoscience modeling technology （3-D GMT）, this paper discusses the application of 3-D GMT for the estimation of solid mineral reserves, emphatically introducing its workflow and two key technologies, 3-D orebody surface modeling, and property modeling. Moreover, the paper analyzes the limitations of traditional methods, such as the section method and geological block method, and points out the advantages of 3-D GMT： building more accurate 3-D orebody models, expressing the internal inhomogeneous attributes of an orebody, reducing the potential for errors in the estimation of reserves, and implementing dynamic estimations of reserves.

Characteristics of soil organic carbon mineralization and influence factor analysis of natural Larix olgensis forest at different ages

Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial ecosystem.Natural stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10,>10–20,>20–40 and>40–60 cm.The results showed that compared with a mid-aged forest,the SOC stock in the young forest was 32%higher.Potentially mineralizable soil carbon(C0)in the young forest was 1.1–2.5 g kg^-1,accounting for 5.5–8.1%of total SOC during the 105 days incubation period and 0.3–1.5 g kg^-1 in the mid-aged forest at different soil depths,occupying 2.8–3.4%of total SOC.There was a significant difference in C0 among the soil depths.The dynamics of the SOC mineralization was a good fit to a three-pool(labile,intermediate and stable)carbon decomposition kinetic model.The SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 days.Correlation analysis revealed that the C0 was significantly positively related with SOC content,soil total N(TN)and readily available K(AK)concentration.The labile soil carbon pool was significantly related to SOC and TN concentration,and significantly negatively correlated with soil bulk density.The intermediate carbon pool was positively associated with TN and AK.The stable carbon pool had negative correlations with SOC,TN and AK.

Growth and mineral nutrient analysis of teak (Tectona grandis) grown on acidic soils in south China

Teak （Tectona grandis L.f.） is widely planted in the world due to its high market demand, economic, ecological and social value. Its plantations have mostly been established and expanded into sites that are acidic to severely acidic in southern China. But, there are no available and specific evidence-based nutrient management techniques. To better recognize and understand the relationship between teak tree growth and nutrient content in the foliage and soil and establish nutrient norms are critical to optimally manage these young plantations. We studied the foliar nutrient and soil chemistry in 19 representative teak plantations aged 5-8 years. Regression analysis indicated that the mean annual increment of teak volume was linearly and positively correlated with foliar N, Ca, Fe and B concentrations, with soil base saturation percentage, available P and Zn concentrations, and negatively correlated with soil Al concentration. Only if the Ca and Mg contents in soil were enhanced, could the increase in soil base saturation percentage benefit teak growth. A revised classification of low-and high-yielding stands was established by using a sorting method of principal components over 6 foliar macro and 8 micro elements in a Diagnosis and Recommendation Integrated System （DRIS）. Specific DRIS norms for teak plantations in acid soils were derived. The nutrient balance of N, P, K Ca, Mg, Zn, B with Fe or A1, Ca with Mg, and Fe with AI provided a key to promote the growth of teak in acid soils. Meanwhile, soil Zn was also found as a primary trace element that affected teak growth in this study.

Geology and mineralization of the Sanshandao supergiant gold deposit(1200 t)in the Jiaodong Peninsula,China:A review

The Jiaodong Peninsula in Shandong Province,China is the world’s third-largest gold metallogenic area,with cumulative proven gold resources exceeding 5000 t.Over the past few years,breakthroughs have been made in deep prospecting at a depth of 500‒2000 m,particularly in the Sanshandao area where a huge deep gold orebody was identified.Based on previous studies and the latest prospecting progress achieved by the project team of this study,the following results are summarized.(1)3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield,which was previously considered to consist of several independent deposits,is a supergiant deposit with gold resources of more than 1200 t(including 470 t under the sea area).The length of the major orebody is nearly 8 km,with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction.(2)Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined,forming a stepped metallogenic model from shallow to deep level.The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults,the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed.Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure,these sections along the fault plane serve as the target areas for deep prospecting.(3)Thermal uplifting-extensional structures provide thermodynamic conditions,migration pathways,and deposition spaces for gold mineralization.Meanwhile,the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks.This further led to the reactivation of ore-forming elements,which provided rich materials for gold mineralization.(4)It can be concluded from previous research results that the gold mineralization in the Jiaodong gold deposits occurred at about 120 Ma,which was superimposed by nonferrous metals mineralization at 118‒111 Ma.The fluids were dominated by primary mantle water or magmatic water.Metamorphic water occurred in the early stage of the gold mineralization,while the fluid composition was dominated by meteoric water in the late stage.The S,Pb,and Sr isotopic compositions of the ores are similar to those of ore-hosting rocks,indicating that the ore-forming materials mainly derive from crustal materials,with the minor addition of mantle-derived materials.The gold deposits in the Jiaodong Peninsula were formed in an extensional tectonic environment during the transformation of the physical and chemical properties of the lithospheric mantle,which is different from typical orogenic gold deposits.Thus,it is proposed that they are named“Jiaodong-type”gold deposits.

DFT calculation on relaxation and electronic structure of sulfide minerals surfaces in presence of H_2O molecule

First-principles calculations are performed to investigate the relaxation and electronic properties of sulfide minerals surfaces(MoS2, Sb2S3, Cu2 S, ZnS, PbS and FeS2) in presence of H2 O molecule. The calculated results show that the structure and electronic properties of sulfide minerals surfaces have been influenced in presence of H2 O molecule. The adsorption of the flotation reagent at the interface of mineral-water would be different from that of mineral surface due to the changes of surface structures and electronic properties caused by H2 O molecule. Hence, the influence of H2 O molecule on the reaction of flotation reagent with sulfide mineral surface will attract more attention.