The effect of calcite and dolomite on the oxidation of pyrite was studied using batch-leaching experiments complemented with chemical modeling, solution analysis and solid characterization techniques. Leaching tests c...The effect of calcite and dolomite on the oxidation of pyrite was studied using batch-leaching experiments complemented with chemical modeling, solution analysis and solid characterization techniques. Leaching tests conducted at 80℃ and p(O2)=1.013×105 Pa and pH〉13 showed that pyrite alkaline oxidation rate decreased in the presence of both calcite and dolomite, while more detrimental effect was observed in the case of calcite. FE-SEM/EDS analysis exhibited a surface layer containing Ca(in the case of calcite) and Mg(in the case of dolomite) on the pyrite surface, which justified the slowdown in pyrite leaching rate. This surface layer was formed due to partial dissolution of carbonate minerals, which was affected dominantly by the p H and temperature of the leaching solution based on the chemical modeling data. The surface layer was characterized as Ca or Mg hydroxide using XRD and FTIR analysis. It was also found that this layer was thin and continuous in the case of calcite while it was thick and discontinuous in the presence of dolomite.展开更多
The western Tianshan high-pressure(HP) metamorphic belt represents the paleosubduction mélange of paleozoic south Tianshan ocean between the Yili-central Tianshan and Tarim plates. High-pressure veins are extensi...The western Tianshan high-pressure(HP) metamorphic belt represents the paleosubduction mélange of paleozoic south Tianshan ocean between the Yili-central Tianshan and Tarim plates. High-pressure veins are extensively developed in this HP belt. Compared with normal mid-ocean ridge basalt(N-MORB), the high-pressure veins and host rocks are enriched in light rare earth elements(LREE) and incompatible elements. But high-pressure veins show a larger variation than host rocks in total REE abundance. On the trace element spidergram, all the samples are enriched in incompatible elements and show strong positive Pb anomaly relative to N-MORB. The array tendency lines of plots of the HP rocks have apparent slopes on diagram of m(Sr) vs m(Sr)/m(Zr), m(Li) vs m(Li)/m(Y) and (m(Ce)) vs m(Ce)/m(Pb), which indicates that the enrichment in LREE and incompatible elements relative to N-MORB of the HP-metamorphic rocks from western Tianshan is not attributed to magma evolution process of the protolith. High field strength elements, such as Nb, Ta, Ti, Zr and Hf, do not show negative anomaly relative to N-MORB, which is dissimilar to that of island arc basalts. Therefore, the enrichment in LREE and incompatible elements of the HP rocks is not attributed to the enrichment of the source of the protolith. The mass ratios of Rb to Ba, Ce to Pb, Nb to U and Ta to U of high-pressure veins and host rocks are intermediate of mid-ocean ridge basalt or oceanic island basalt and continental crust. The fluids in western Tianshan paleosubduction zones are mixtures of two sources, dehydration or devolatilization of host rocks and of subducted sediments.展开更多
Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency ...Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency of processing is caused by gold ore characterization and evaluation of gold ore preparation process is not implemented. In this study, the conditions of gold ore deposits have a thin thickness (vein). These gold ore deposits have an economic value if they are developed by traditional gold mining. The objective of the research is to identify and characterize gold ore as well as to analyze the optimum condition to obtain the perfect gold mineral liberation degree. Research methods include characterization of gold ore geology, sampling for test preparation using rod mill (amalgamation), gold mineral liberation using time variables and number of rods. After the grinding process, grain size analysis is performed with various mesh sizes, and the analysis of each fraction uses a polarization microscope. The results show that gold ore minerals are associated with pyrite, chalcopyrite, galena and gangue minerals. Gold minerals are fully liberated at a certain size. The results of this research are very useful for the gold ore grinding process to obtain an efficient gold processing.展开更多
Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and ...Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.展开更多
The pulsed power is a potential means for energy saving and presents an alternative to the conventional mechanical communication for minerals.The effect of magnetic pulse treatment on grindability of a magnetite ore w...The pulsed power is a potential means for energy saving and presents an alternative to the conventional mechanical communication for minerals.The effect of magnetic pulse treatment on grindability of a magnetite ore was investigated by grindability tests.The results of the investigation show that the pulsed treatment has little effect on the particle size distribution of the magnetite ore.Significant micro-cracks or fractures are not found by SEM analysis in magnetic pulse treated sample.Magnetic separation of magnetic pulse treated and untreated magnetite ore indicates that iron recovery increases from 81.3% in the untreated sample to 87.7% in the magnetic pulse treated sample,and the corresponding iron grade increases from 42.1% to 44.4%.The results demonstrate that the magnetic pulse treatment does not significantly weaken the mineral grain boundaries or facilitate the liberation of minerals,but is beneficial to magnetic separation.展开更多
Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 13g in the concentrate so that it became satisfactory for use in the paper or rubber ...Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 13g in the concentrate so that it became satisfactory for use in the paper or rubber industries. The limestone sample was crystalline and constituted primarily of calcite that contained quartz, feldspar, pyroxene, and biotite as gangue minerals. Quartz is the major silicate gangue whereas feldspar, pyroxene, and biotite exist in minor to trace quantities. Traces of pyrite were also observed within the sample. A reverse flotation process was adopted where the silicate gangue minerals were floated using two different commercial cationic collectors: Chem-750 F or Floatamine-D. The studies clearly suggest it is possible to produce a limestone concentrate assaying around 96-97% CaCO3 containing less than 1 % Si02. The effect of feed flow rate, percent solids, froth depth, and wash water on the grade and recovery of the CaC03 concentrate is discussed.展开更多
Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effect...Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.展开更多
Batch experiments tively evaluate the inhibition were conducted to compara- effects and mechanisms of a low-concentration (1%) proline solution cover on the release of pollutants from high-sulfur coal gangue. High- ...Batch experiments tively evaluate the inhibition were conducted to compara- effects and mechanisms of a low-concentration (1%) proline solution cover on the release of pollutants from high-sulfur coal gangue. High- sulfur coal gangue was continuously immersed in a proline solution and in deionized water (as a control treatment) for 540 days. The results showed that the coal gangue in the control treatment was oxidized and generated leachate with poor water qualities, i.e., the leachate exhibited lower pH values, higher redox potential values, higher pollutant concentrations (804^2-, Fe, Mn, Cu, and Zn), and high levels of acidophilic sulfur-oxidizing bacteria. However, compared to the control treatment, the addition of the proline solution (1%) significantly improved the water quality of the leachate by significantly reducing the Eh values, the pollutant concentrations (804^2-, Fe^2+, Fe, Mn, Cu, and Zn), and the activity of acidophilic sulfur-oxidiz- ing bacteria and by significantly increasing the pH value to neutral. The proline treatment significantly inhibited the oxidation of coal gangue and the release of pollutants, mainly by inhibiting the activity of acidophilic sulfur-ox- idizing bacteria and by altering the heavy metal fractions and the mineralogical characteristics. Therefore, in engi- neering practice, workers should consider using an envi- ronmental friendly aqueous proline solution cover to achieve the in-situ control of pollutant releases from coal gangue dumps.展开更多
An innovative technology of high-voltage pulse discharge(HVPD)was proposed to investigate the comminution characteristics of galena ore.The optimal experiment parameters were determined as follows:spark gap spacing of...An innovative technology of high-voltage pulse discharge(HVPD)was proposed to investigate the comminution characteristics of galena ore.The optimal experiment parameters were determined as follows:spark gap spacing of 25 mm,pulse number of 120,and voltage of 25 k V.The mass fraction with size<0.074 mm in ground products was improved by the HVPD.Meanwhile,the relative grindability declined with the increase of the grinding time,which indicated that the superiority of HVPD was weakened.The ground products of HVPD were distributed more homogeneously than those of mechanical crushing.The liberation of breakage products was improved by 24.57%via the HVPD.Moreover,the Brunauer–Emmett–Teller(BET)specific surface area,pore volume,and average pore size were increased via the HVPD.Scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)analyses suggested that obvious grain-boundary breakage and several stomatal traces were observed in the HVPD products.展开更多
Based on the geology and geochemistry of gold-bearing quartz veins in the Jiudian gold deposit of Pingdu,Shandong Province,the geological and geochemical indicators of occurrence of deep-seated ore bodies in the Jiudi...Based on the geology and geochemistry of gold-bearing quartz veins in the Jiudian gold deposit of Pingdu,Shandong Province,the geological and geochemical indicators of occurrence of deep-seated ore bodies in the Jiudian gold deposit have been summarized.Extent occurrence of wide,intensive,varied alteration zones around the gold-bearing quartz veins and continual presence of diorite porphyrite and lamprophyry indicate the probable occurrence of deep-seated ore bodies at depth of gold lodes.As,Sb and Hg belong to the head halo elements, and their anomalies could reveal the probable occurrence of the deep-seated ore bodies below.展开更多
Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was...Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.展开更多
Being as an example of Fuxin, gangue abandoned place was classified gangue hill and dump. It was built 68 piece of temporary standard fields, which physical and chemical character of soil were researched and analyzed....Being as an example of Fuxin, gangue abandoned place was classified gangue hill and dump. It was built 68 piece of temporary standard fields, which physical and chemical character of soil were researched and analyzed. The quality of district site was estimated, and five type abandoned place were gotten. Stopping draining cash less than 7 a and draining cash gangue hill was regarded as I gangue hill. Stopping draining gangue age limit 7-15 a and herbage abundance being COlp level was regarded as II gangue hill. Stopping draining gangue age limit 15-25 a and herbage abundance CO2p level was regarded as III gangue hill. Stopping draining cash gangue age limit over 25 a and herbage abundance CO3p level was regarded as IV gangue hill. Dump being formed the underground layer dug up and stacked in the course of mining was regarded asVgangue hill. The results show that every typical abandoned place can plant vegetable.展开更多
The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted thr...The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted three-phase inclusions. The fluid inclusions are characterized by low salinity (5%-9% NaCl eqv) , low density (0.66-0.72 g/cm^3 ) and medium temperature (210℃-250℃). The pressure of ore-forming is 60-95 MPa and the metallogenic depth is about 5.49-7.56 km. During the mineralizing process, ore-forming fluid under- went fluid unmixing in CO2-H2O-NaCl system. The stable isotope resuhs indicate that the ore-forming fluids mainly generated from mantle, with the participation of a small amount of atmospheric water. Comprehensive studies have suggested that Qiangsheng gold deposit belongs to the type of mesothermal hydrotherm with mantlederived fluid participating in mineralization.展开更多
The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating...The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating results of zircons from the diorites indicate that the rocks were formed in the Middle Jurassic (171 ±2 Ma, MSWD = 1. 19). Geochemically, these rocks have Si02 concentrations of 52. 52%-54. 90%,K20 of 2. 14%-3.84% , Na20 of 3. 17%-3. 35% , MgO of 7. 43%-9. 34% and high Mg# of 68. 57-72. 57. These rocks are characterized by enrichment in large ion lithophile elements( LILE,such as K, Ba, Rb and Sr) and light rare earth elements ( LREE) , relatively depletion in high field strength elements ( HFSE, such as Ta, Nb, Ti and Zr) , and heavy rare earth elements (HREE). These characteristics suggest that primary magma of the rocks were derived from the partial melting of mantle with miner crustal contamination, which may related to partial melting of mantle wedge by addition of sediment melt from subducting oceanic crust. Based on former and present studies, the authors consider that the Nancha ore deposit high-Mg diorites were formed in compres- sional structural setting which is similar to volcanic arc. It could be related to the subduction of the Paleo-Paci- fic plate beneath the Eurasian continent.展开更多
An ultra-wideband impulse radar was studied for the detection of buried life in coal mines. An improved Empirical Mode Decomposition (EMD) method based on a cross-correlation filter was proposed for reduction of multi...An ultra-wideband impulse radar was studied for the detection of buried life in coal mines. An improved Empirical Mode Decomposition (EMD) method based on a cross-correlation filter was proposed for reduction of multipath and noise interference. Multipath interference was first removed by cross-corre- lation filtering. Then the delays of each pulse in every echo were summed. An EMD algorithm was used for noise reduction for the total delay of each echo. The corresponding EMD results of every echo were then summed and averaged. Finally, evidence for the existence of buried life and their position were obtained from amplitude-frequency curves of the averaged EMD results. Detailed simulation experi- ments are presented to validate the effectiveness of this proposed method. The experimental results show that this method can efficiently eliminate multipath interference and reduce noise interference in echoes, which makes detection and location of buried life in coal mines more accurate.展开更多
Based on research conducted by the author in the last thirty-five years, this article presents the physicochemical mechanisms of the osteoporosis process, transport of substances created as its result, and the phenome...Based on research conducted by the author in the last thirty-five years, this article presents the physicochemical mechanisms of the osteoporosis process, transport of substances created as its result, and the phenomena of tissue mineralization resulting from osteoporosis. Examination of bones, joint cartilage, arteries, veins, parts of heart, thyroid, salivary glands, various tumors and others was conducted with the use of biological and polarizing microscopy, SEM, EDS, ASA, IR, Raman spectroscopy, and X-ray diffraction. Several devices of the same kind, e.g. different types of SEM, were used. Specimens used for examination were obtained from post-surgery and post rnortem materials. Examination of human bones focused on their mineralization and demineralization (osteoporosis). Examination of the mineralization of other tissues was conducted in terms of the ageing of human body. Obtained results show that the process of osteoporosis leads not just to mechanical degradation of bones, but through the transport of ions (mainly Ca and P), it also causes mineralization of soft tissue. Such mineralization occurs in mineralization centers that have been classified in regard to genetics. Tissue mineralization in its first stage is latent and consists of including atoms, mainly Ca and P, into the biological structures of compounds that build the tissues. Latent mineralization may evolve into the next stage--apparent mineralization. Both types of mineralization cause many health issues and may lead to death. This article also presents initial results of research on dissolution of aortic mineralization.展开更多
Aims Pulse effects of precipitation cause soil organic matter to rapidly decompose and release CO2 in a short period.The pulse effects of precipitation are important for ecosystem C cycling and soil C balance,although...Aims Pulse effects of precipitation cause soil organic matter to rapidly decompose and release CO2 in a short period.The pulse effects of precipitation are important for ecosystem C cycling and soil C balance,although their spatial variation in forest soils and the underlying mechanisms remain unclear.Methods Soil samples(0–10 cm)from 22 typical forest ecosystems in eastern China were used,to investigate the effects of simulated pulse precipitation on soil microbial respiration rates(Rs).We simulated pulsed precipitation to reach 65%water-holding capacity,the Rs was measured on a minute scale for 48 h.Important Findings Precipitation pulses can cause a rapid 1.70–38.12-fold increase in the rate of mineralized decomposing organic matter.Maximum Rs(_(Rs-soil-max)),cumulative Rs(A_(Rs-soil))and the time taken to arrive at the maximal Rs(T_(Rs-soil-max))were significant differences among different soil samples.Furthermore,the pulse effects in different climate zones were significantly different.R_(s-soil-max)(11.701μg C g^(-1)soil h^(-1))and A_(Rs-soil)(300.712μg C g^(-1) soil)were the highest in the mid-temperate zone.Soil chemical properties(total C and,N,pH and oxidation–reduction potential)and soil fractions were strongly correlated with the pulse effects in forest soils,but soil microbes contributed less.Our findings demonstrated that the pulse effects increase forest soil carbon emissions in the short term at a regional scale,and identified the factors with the greatest influence on this change.These findings help guide future studies on the C cycles of forest ecosystems and regulating ecosystem C cycles.展开更多
Objective:We investigated whether disturbance of calcium and phosphate metabolism is associated with the presence and severity of calcific aortic valve disease (CAVD) in patients with normal or mildly impaired rena...Objective:We investigated whether disturbance of calcium and phosphate metabolism is associated with the presence and severity of calcific aortic valve disease (CAVD) in patients with normal or mildly impaired renal function. Methods:We measured serum levels of calcium, phosphate, alkaline phosphatase (AKP), intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25-OHD), and biomarkers of bone turnover in 260 consecutive patients with normal or mildly impaired renal function and aortic valve sclerosis (AVSc) (n=164) or stenosis (AVS) (n=96) and in 164 age- and gender-matched controls. Logistic regression models were used to determine the association of mineral metabolism parameters with the presence and severity of CAVD. Results:Stepwise increases were observed in serum levels of calcium, phosphate, AKP, and iPTH from the control group to patients with AVS, and with reverse changes for 25-OHD levels (al P〈0.001). Similarly, osteocalcin, procol agen I N-terminal peptide, andβ-isomerized type I col agen C-telopeptide breakdown products were significantly increased stepwise from the control group to patients with AVS (al P〈0.001). In patients with AVS, serum levels of iPTH were positively, in contrast 25-OHD levels were negatively, related to trans-aortic peak flow velocity and mean pressure gradient. After adjusting for relevant confounding varia-bles, increased serum levels of calcium, phosphate, AKP, and iPTH and reduced serum levels of 25-OHD were in-dependently associated with the presence and severity of CAVD. Conclusions: This study suggests an association between mineral metabolism disturbance and the presence and severity of CAVD in patients with normal or mildly impaired renal function. Abnormal bone turnover may be a potential mechanism.展开更多
Supergene Mn-oxide deposits are commonly related to thick weathering profiles and form as a result of intense and prolonged weathering of Mn-bearing precursor rocks, processes facilitated by a combination of multiple ...Supergene Mn-oxide deposits are commonly related to thick weathering profiles and form as a result of intense and prolonged weathering of Mn-bearing precursor rocks, processes facilitated by a combination of multiple factors including warm and wet climate, relatively quiescent tectonic environment, and favorable geomorphic setting. Precise age constraints of supergene Mn-oxides may provide valuable information on the climatic, tectonic, and geomorphic conditions prevailing in the geological past. 4~Ar]39Ar laser incremental heating analysis of cryptomelane from the Baye manganese deposit, western Yunnan-Guizhou Plateau, SW China, was conducted to provide numerical constraints on the ages of supergene Mn enrichment and growth rates of Mn-oxide veins. In this study, two Mn-oxide veins of 3-6 cm thickness, termed as Vein A and B, respectively, were col- lected for 4~Ar/39Ar dating. Vein A is subhorizontal and present in fractures parallel to schistosity of the Proterozoic spessartine schists, whereas Vein B is filled in nearly vertical fractures penetrating the schistosity. A combination of optical microscopy, XRD, SEM, and EMP analyses demonstrate that mineral grains extracted from both veins consist of pure, well-crystallized cryptomlane, which has acicular crystal forms and contains 0.96%4.70% K2O. Fourteen cryptomelane subsamples extracted from different growth bands of Vein A yield well-defined plateau ages ranging from 1.35 ± 0.05 to 1.16 ± 0.04 Ma (2or), whereas seven subsamples obtained from Vein B have plateau ages ranging from 1.23 ±0.05 to 1.01 ± 0.04 Ma (20). The age results permit estimation for the growth rates of both veins at ca. 115-153 and 34-67 mm Ma-1, respectively. Distinct growth rates between Veins A and B are likely reflective of different fluid pressures during their formation governed by the orientation of the fractures hosting the veins. The growth rates calculated for both veins are 1-2 orders of magnitude higher than the val- ues (〈1-10 mm Ma-l) estimated for Mn-oxide nodules in supergene Mn deposits elsewhere. The high growth rates obtained for the Baye samples are consistent with direct precipitation of tetravalent Mn-oxides from weathering solution in open cavities or fractures, characterized by incremental growth of Mn-oxide bands from the margin to the center of the cavities or fractures. In contrast, Mn-oxide nodules with low growth rates from other deposits formed through self-oxidation and self-catalization, and grow outwards from the nuclei. In addition, prevalence of warm and humid climate and prolonged tectonic uplift in the Yunnan Plateau may have also partly contributed to the rapid growth of Mn-oxides in the Baye deposit.展开更多
基金the support of IMIDRO,Iranian Mines & Mining Industries Development & Renovation,for providing the financial support to carry out this research
文摘The effect of calcite and dolomite on the oxidation of pyrite was studied using batch-leaching experiments complemented with chemical modeling, solution analysis and solid characterization techniques. Leaching tests conducted at 80℃ and p(O2)=1.013×105 Pa and pH〉13 showed that pyrite alkaline oxidation rate decreased in the presence of both calcite and dolomite, while more detrimental effect was observed in the case of calcite. FE-SEM/EDS analysis exhibited a surface layer containing Ca(in the case of calcite) and Mg(in the case of dolomite) on the pyrite surface, which justified the slowdown in pyrite leaching rate. This surface layer was formed due to partial dissolution of carbonate minerals, which was affected dominantly by the p H and temperature of the leaching solution based on the chemical modeling data. The surface layer was characterized as Ca or Mg hydroxide using XRD and FTIR analysis. It was also found that this layer was thin and continuous in the case of calcite while it was thick and discontinuous in the presence of dolomite.
基金Preoject(2001CB409803) supported by the National Key Fundamental Research and Development Program of China
文摘The western Tianshan high-pressure(HP) metamorphic belt represents the paleosubduction mélange of paleozoic south Tianshan ocean between the Yili-central Tianshan and Tarim plates. High-pressure veins are extensively developed in this HP belt. Compared with normal mid-ocean ridge basalt(N-MORB), the high-pressure veins and host rocks are enriched in light rare earth elements(LREE) and incompatible elements. But high-pressure veins show a larger variation than host rocks in total REE abundance. On the trace element spidergram, all the samples are enriched in incompatible elements and show strong positive Pb anomaly relative to N-MORB. The array tendency lines of plots of the HP rocks have apparent slopes on diagram of m(Sr) vs m(Sr)/m(Zr), m(Li) vs m(Li)/m(Y) and (m(Ce)) vs m(Ce)/m(Pb), which indicates that the enrichment in LREE and incompatible elements relative to N-MORB of the HP-metamorphic rocks from western Tianshan is not attributed to magma evolution process of the protolith. High field strength elements, such as Nb, Ta, Ti, Zr and Hf, do not show negative anomaly relative to N-MORB, which is dissimilar to that of island arc basalts. Therefore, the enrichment in LREE and incompatible elements of the HP rocks is not attributed to the enrichment of the source of the protolith. The mass ratios of Rb to Ba, Ce to Pb, Nb to U and Ta to U of high-pressure veins and host rocks are intermediate of mid-ocean ridge basalt or oceanic island basalt and continental crust. The fluids in western Tianshan paleosubduction zones are mixtures of two sources, dehydration or devolatilization of host rocks and of subducted sediments.
文摘Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency of processing is caused by gold ore characterization and evaluation of gold ore preparation process is not implemented. In this study, the conditions of gold ore deposits have a thin thickness (vein). These gold ore deposits have an economic value if they are developed by traditional gold mining. The objective of the research is to identify and characterize gold ore as well as to analyze the optimum condition to obtain the perfect gold mineral liberation degree. Research methods include characterization of gold ore geology, sampling for test preparation using rod mill (amalgamation), gold mineral liberation using time variables and number of rods. After the grinding process, grain size analysis is performed with various mesh sizes, and the analysis of each fraction uses a polarization microscope. The results show that gold ore minerals are associated with pyrite, chalcopyrite, galena and gangue minerals. Gold minerals are fully liberated at a certain size. The results of this research are very useful for the gold ore grinding process to obtain an efficient gold processing.
文摘Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.
基金Projects(N140108001,N150106003)supported by the Fundamental Research Funds for National University of China
文摘The pulsed power is a potential means for energy saving and presents an alternative to the conventional mechanical communication for minerals.The effect of magnetic pulse treatment on grindability of a magnetite ore was investigated by grindability tests.The results of the investigation show that the pulsed treatment has little effect on the particle size distribution of the magnetite ore.Significant micro-cracks or fractures are not found by SEM analysis in magnetic pulse treated sample.Magnetic separation of magnetic pulse treated and untreated magnetite ore indicates that iron recovery increases from 81.3% in the untreated sample to 87.7% in the magnetic pulse treated sample,and the corresponding iron grade increases from 42.1% to 44.4%.The results demonstrate that the magnetic pulse treatment does not significantly weaken the mineral grain boundaries or facilitate the liberation of minerals,but is beneficial to magnetic separation.
文摘Pilot scale column flotation studies were conducted on a low grade siliceous limestone ore. Silica content was reduced to less than 13g in the concentrate so that it became satisfactory for use in the paper or rubber industries. The limestone sample was crystalline and constituted primarily of calcite that contained quartz, feldspar, pyroxene, and biotite as gangue minerals. Quartz is the major silicate gangue whereas feldspar, pyroxene, and biotite exist in minor to trace quantities. Traces of pyrite were also observed within the sample. A reverse flotation process was adopted where the silicate gangue minerals were floated using two different commercial cationic collectors: Chem-750 F or Floatamine-D. The studies clearly suggest it is possible to produce a limestone concentrate assaying around 96-97% CaCO3 containing less than 1 % Si02. The effect of feed flow rate, percent solids, froth depth, and wash water on the grade and recovery of the CaC03 concentrate is discussed.
文摘Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.
基金funded by a grant from the United Fund of Guizhou Province GovernmentNational Natural Science Foundation of China(No.U1612442-3)the Project of the Education Department of Guizhou Province(Nos.KY 2016011,GZZ201607,and ZDXK201611)
文摘Batch experiments tively evaluate the inhibition were conducted to compara- effects and mechanisms of a low-concentration (1%) proline solution cover on the release of pollutants from high-sulfur coal gangue. High- sulfur coal gangue was continuously immersed in a proline solution and in deionized water (as a control treatment) for 540 days. The results showed that the coal gangue in the control treatment was oxidized and generated leachate with poor water qualities, i.e., the leachate exhibited lower pH values, higher redox potential values, higher pollutant concentrations (804^2-, Fe, Mn, Cu, and Zn), and high levels of acidophilic sulfur-oxidizing bacteria. However, compared to the control treatment, the addition of the proline solution (1%) significantly improved the water quality of the leachate by significantly reducing the Eh values, the pollutant concentrations (804^2-, Fe^2+, Fe, Mn, Cu, and Zn), and the activity of acidophilic sulfur-oxidiz- ing bacteria and by significantly increasing the pH value to neutral. The proline treatment significantly inhibited the oxidation of coal gangue and the release of pollutants, mainly by inhibiting the activity of acidophilic sulfur-ox- idizing bacteria and by altering the heavy metal fractions and the mineralogical characteristics. Therefore, in engi- neering practice, workers should consider using an envi- ronmental friendly aqueous proline solution cover to achieve the in-situ control of pollutant releases from coal gangue dumps.
基金financial supports from the National Natural Science Foundation of China(No.51974063)the Fundamental Research Funds for the Central Universities of China(No.N180104016)the China Postdoctoral Science Foundation(No.2020M670783)。
文摘An innovative technology of high-voltage pulse discharge(HVPD)was proposed to investigate the comminution characteristics of galena ore.The optimal experiment parameters were determined as follows:spark gap spacing of 25 mm,pulse number of 120,and voltage of 25 k V.The mass fraction with size<0.074 mm in ground products was improved by the HVPD.Meanwhile,the relative grindability declined with the increase of the grinding time,which indicated that the superiority of HVPD was weakened.The ground products of HVPD were distributed more homogeneously than those of mechanical crushing.The liberation of breakage products was improved by 24.57%via the HVPD.Moreover,the Brunauer–Emmett–Teller(BET)specific surface area,pore volume,and average pore size were increased via the HVPD.Scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)analyses suggested that obvious grain-boundary breakage and several stomatal traces were observed in the HVPD products.
基金Supported by Project of China Geological Survey(No.1212011085480 )Key Scientific and Technological Development Project of Jilin Province (No.20090479)
文摘Based on the geology and geochemistry of gold-bearing quartz veins in the Jiudian gold deposit of Pingdu,Shandong Province,the geological and geochemical indicators of occurrence of deep-seated ore bodies in the Jiudian gold deposit have been summarized.Extent occurrence of wide,intensive,varied alteration zones around the gold-bearing quartz veins and continual presence of diorite porphyrite and lamprophyry indicate the probable occurrence of deep-seated ore bodies at depth of gold lodes.As,Sb and Hg belong to the head halo elements, and their anomalies could reveal the probable occurrence of the deep-seated ore bodies below.
文摘Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.
文摘Being as an example of Fuxin, gangue abandoned place was classified gangue hill and dump. It was built 68 piece of temporary standard fields, which physical and chemical character of soil were researched and analyzed. The quality of district site was estimated, and five type abandoned place were gotten. Stopping draining cash less than 7 a and draining cash gangue hill was regarded as I gangue hill. Stopping draining gangue age limit 7-15 a and herbage abundance being COlp level was regarded as II gangue hill. Stopping draining gangue age limit 15-25 a and herbage abundance CO2p level was regarded as III gangue hill. Stopping draining cash gangue age limit over 25 a and herbage abundance CO3p level was regarded as IV gangue hill. Dump being formed the underground layer dug up and stacked in the course of mining was regarded asVgangue hill. The results show that every typical abandoned place can plant vegetable.
基金Supported by projects of Geological Exploration of Jilin Province(No.22201300111)Shanhou Gold Deposit of Laixi of Shandong Province(SDLX2012-3-28)
文摘The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted three-phase inclusions. The fluid inclusions are characterized by low salinity (5%-9% NaCl eqv) , low density (0.66-0.72 g/cm^3 ) and medium temperature (210℃-250℃). The pressure of ore-forming is 60-95 MPa and the metallogenic depth is about 5.49-7.56 km. During the mineralizing process, ore-forming fluid under- went fluid unmixing in CO2-H2O-NaCl system. The stable isotope resuhs indicate that the ore-forming fluids mainly generated from mantle, with the participation of a small amount of atmospheric water. Comprehensive studies have suggested that Qiangsheng gold deposit belongs to the type of mesothermal hydrotherm with mantlederived fluid participating in mineralization.
文摘The authors presented geochronology and geochemical data of diorites from Nancha gold deposit in Tonghua region, with the aim to constraining its formation age, magma source and tectonic setting. LA-ICP-MS U-Pb dating results of zircons from the diorites indicate that the rocks were formed in the Middle Jurassic (171 ±2 Ma, MSWD = 1. 19). Geochemically, these rocks have Si02 concentrations of 52. 52%-54. 90%,K20 of 2. 14%-3.84% , Na20 of 3. 17%-3. 35% , MgO of 7. 43%-9. 34% and high Mg# of 68. 57-72. 57. These rocks are characterized by enrichment in large ion lithophile elements( LILE,such as K, Ba, Rb and Sr) and light rare earth elements ( LREE) , relatively depletion in high field strength elements ( HFSE, such as Ta, Nb, Ti and Zr) , and heavy rare earth elements (HREE). These characteristics suggest that primary magma of the rocks were derived from the partial melting of mantle with miner crustal contamination, which may related to partial melting of mantle wedge by addition of sediment melt from subducting oceanic crust. Based on former and present studies, the authors consider that the Nancha ore deposit high-Mg diorites were formed in compres- sional structural setting which is similar to volcanic arc. It could be related to the subduction of the Paleo-Paci- fic plate beneath the Eurasian continent.
基金support forour work by the National Science and Technology Support Project of China (No. 2006BAK03B00)
文摘An ultra-wideband impulse radar was studied for the detection of buried life in coal mines. An improved Empirical Mode Decomposition (EMD) method based on a cross-correlation filter was proposed for reduction of multipath and noise interference. Multipath interference was first removed by cross-corre- lation filtering. Then the delays of each pulse in every echo were summed. An EMD algorithm was used for noise reduction for the total delay of each echo. The corresponding EMD results of every echo were then summed and averaged. Finally, evidence for the existence of buried life and their position were obtained from amplitude-frequency curves of the averaged EMD results. Detailed simulation experi- ments are presented to validate the effectiveness of this proposed method. The experimental results show that this method can efficiently eliminate multipath interference and reduce noise interference in echoes, which makes detection and location of buried life in coal mines more accurate.
文摘Based on research conducted by the author in the last thirty-five years, this article presents the physicochemical mechanisms of the osteoporosis process, transport of substances created as its result, and the phenomena of tissue mineralization resulting from osteoporosis. Examination of bones, joint cartilage, arteries, veins, parts of heart, thyroid, salivary glands, various tumors and others was conducted with the use of biological and polarizing microscopy, SEM, EDS, ASA, IR, Raman spectroscopy, and X-ray diffraction. Several devices of the same kind, e.g. different types of SEM, were used. Specimens used for examination were obtained from post-surgery and post rnortem materials. Examination of human bones focused on their mineralization and demineralization (osteoporosis). Examination of the mineralization of other tissues was conducted in terms of the ageing of human body. Obtained results show that the process of osteoporosis leads not just to mechanical degradation of bones, but through the transport of ions (mainly Ca and P), it also causes mineralization of soft tissue. Such mineralization occurs in mineralization centers that have been classified in regard to genetics. Tissue mineralization in its first stage is latent and consists of including atoms, mainly Ca and P, into the biological structures of compounds that build the tissues. Latent mineralization may evolve into the next stage--apparent mineralization. Both types of mineralization cause many health issues and may lead to death. This article also presents initial results of research on dissolution of aortic mineralization.
基金This study was financially supported by the NationalNatural Science Foundation of China(31988102,31770655,31800368).
文摘Aims Pulse effects of precipitation cause soil organic matter to rapidly decompose and release CO2 in a short period.The pulse effects of precipitation are important for ecosystem C cycling and soil C balance,although their spatial variation in forest soils and the underlying mechanisms remain unclear.Methods Soil samples(0–10 cm)from 22 typical forest ecosystems in eastern China were used,to investigate the effects of simulated pulse precipitation on soil microbial respiration rates(Rs).We simulated pulsed precipitation to reach 65%water-holding capacity,the Rs was measured on a minute scale for 48 h.Important Findings Precipitation pulses can cause a rapid 1.70–38.12-fold increase in the rate of mineralized decomposing organic matter.Maximum Rs(_(Rs-soil-max)),cumulative Rs(A_(Rs-soil))and the time taken to arrive at the maximal Rs(T_(Rs-soil-max))were significant differences among different soil samples.Furthermore,the pulse effects in different climate zones were significantly different.R_(s-soil-max)(11.701μg C g^(-1)soil h^(-1))and A_(Rs-soil)(300.712μg C g^(-1) soil)were the highest in the mid-temperate zone.Soil chemical properties(total C and,N,pH and oxidation–reduction potential)and soil fractions were strongly correlated with the pulse effects in forest soils,but soil microbes contributed less.Our findings demonstrated that the pulse effects increase forest soil carbon emissions in the short term at a regional scale,and identified the factors with the greatest influence on this change.These findings help guide future studies on the C cycles of forest ecosystems and regulating ecosystem C cycles.
基金Project supported by the Science and Technology Commission of Shanghai Municipality(No.114119a8800),China
文摘Objective:We investigated whether disturbance of calcium and phosphate metabolism is associated with the presence and severity of calcific aortic valve disease (CAVD) in patients with normal or mildly impaired renal function. Methods:We measured serum levels of calcium, phosphate, alkaline phosphatase (AKP), intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25-OHD), and biomarkers of bone turnover in 260 consecutive patients with normal or mildly impaired renal function and aortic valve sclerosis (AVSc) (n=164) or stenosis (AVS) (n=96) and in 164 age- and gender-matched controls. Logistic regression models were used to determine the association of mineral metabolism parameters with the presence and severity of CAVD. Results:Stepwise increases were observed in serum levels of calcium, phosphate, AKP, and iPTH from the control group to patients with AVS, and with reverse changes for 25-OHD levels (al P〈0.001). Similarly, osteocalcin, procol agen I N-terminal peptide, andβ-isomerized type I col agen C-telopeptide breakdown products were significantly increased stepwise from the control group to patients with AVS (al P〈0.001). In patients with AVS, serum levels of iPTH were positively, in contrast 25-OHD levels were negatively, related to trans-aortic peak flow velocity and mean pressure gradient. After adjusting for relevant confounding varia-bles, increased serum levels of calcium, phosphate, AKP, and iPTH and reduced serum levels of 25-OHD were in-dependently associated with the presence and severity of CAVD. Conclusions: This study suggests an association between mineral metabolism disturbance and the presence and severity of CAVD in patients with normal or mildly impaired renal function. Abnormal bone turnover may be a potential mechanism.
基金supported by National Natural Science Foundation of China(Grant Nos.41202053&40573021)Fok Ying Tong Education Fund(Grant No.101017)+1 种基金Fundamental Research Funds for the Central Universities(Grant No.CUG120102)Program for New Century Excellent Talents in University(Grant No.NCET-05-0665)
文摘Supergene Mn-oxide deposits are commonly related to thick weathering profiles and form as a result of intense and prolonged weathering of Mn-bearing precursor rocks, processes facilitated by a combination of multiple factors including warm and wet climate, relatively quiescent tectonic environment, and favorable geomorphic setting. Precise age constraints of supergene Mn-oxides may provide valuable information on the climatic, tectonic, and geomorphic conditions prevailing in the geological past. 4~Ar]39Ar laser incremental heating analysis of cryptomelane from the Baye manganese deposit, western Yunnan-Guizhou Plateau, SW China, was conducted to provide numerical constraints on the ages of supergene Mn enrichment and growth rates of Mn-oxide veins. In this study, two Mn-oxide veins of 3-6 cm thickness, termed as Vein A and B, respectively, were col- lected for 4~Ar/39Ar dating. Vein A is subhorizontal and present in fractures parallel to schistosity of the Proterozoic spessartine schists, whereas Vein B is filled in nearly vertical fractures penetrating the schistosity. A combination of optical microscopy, XRD, SEM, and EMP analyses demonstrate that mineral grains extracted from both veins consist of pure, well-crystallized cryptomlane, which has acicular crystal forms and contains 0.96%4.70% K2O. Fourteen cryptomelane subsamples extracted from different growth bands of Vein A yield well-defined plateau ages ranging from 1.35 ± 0.05 to 1.16 ± 0.04 Ma (2or), whereas seven subsamples obtained from Vein B have plateau ages ranging from 1.23 ±0.05 to 1.01 ± 0.04 Ma (20). The age results permit estimation for the growth rates of both veins at ca. 115-153 and 34-67 mm Ma-1, respectively. Distinct growth rates between Veins A and B are likely reflective of different fluid pressures during their formation governed by the orientation of the fractures hosting the veins. The growth rates calculated for both veins are 1-2 orders of magnitude higher than the val- ues (〈1-10 mm Ma-l) estimated for Mn-oxide nodules in supergene Mn deposits elsewhere. The high growth rates obtained for the Baye samples are consistent with direct precipitation of tetravalent Mn-oxides from weathering solution in open cavities or fractures, characterized by incremental growth of Mn-oxide bands from the margin to the center of the cavities or fractures. In contrast, Mn-oxide nodules with low growth rates from other deposits formed through self-oxidation and self-catalization, and grow outwards from the nuclei. In addition, prevalence of warm and humid climate and prolonged tectonic uplift in the Yunnan Plateau may have also partly contributed to the rapid growth of Mn-oxides in the Baye deposit.