Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,envir...Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,environmental engineering,and biomedicine.There-fore,the obtained research results need to be systematically summarized,and new perspectives on CF and its composite materials need to be analyzed.Based on the presented studies of CF and its composite materials,the types and structures of the crystal are summarized.In addition,the current application technologies and theoretical mechanisms with various properties in different fields are elucidated.Moreover,the various preparation methods of CF and its composite materials are elaborated in detail.Most importantly,the advantages and disadvantages of the synthesis methods of CF and its composite materials are discussed,and the existing problems and emerging challenges in practical production are identified.Furthermore,the key future research directions of CF and its composite materials have been prospected from the potential application technologies to provide references for its synthesis and efficient utilization.展开更多
Generally speaking, the geological topography of coal mine project is complex, which makes coal mining face many safety risks. When coal mining does not pay attention to safety management, it may lead to serious accid...Generally speaking, the geological topography of coal mine project is complex, which makes coal mining face many safety risks. When coal mining does not pay attention to safety management, it may lead to serious accidents and damage the economic and social benefits of enterprises. Safety management helps to prevent and eliminate safety risks in coal projects, reduce accidents and ensure the healthy development of coal enterprises to a certain extent. From the current situation of China's coal project safety management, there are many problems in the future to achieve the transformation and development of the coal industry, and it is necessary to improve the level of safety management.展开更多
Mineral resources play an important role in human society. To make progress, human society must develop and utilize mineral resources. From primitive society to today's information society, from the use of Stone t...Mineral resources play an important role in human society. To make progress, human society must develop and utilize mineral resources. From primitive society to today's information society, from the use of Stone to the use of nuclear energy and atomic energy, the level of use of mineral resources determines the level of development of human society. Metal mineral resources play a very important role in the development of human society and national economy. Therefore, the comprehensive development and utilization of metal mineral resources will, to some extent, have a direct impact on improving people's living standards and will become an important factor in national economic development and human social progress.展开更多
Horsetailing is an important feature to identify the strike-slip structure and indicates the movement mode of the fault.However,the formation mechanism of horsetailing in the extensional regime remains unclear.In this...Horsetailing is an important feature to identify the strike-slip structure and indicates the movement mode of the fault.However,the formation mechanism of horsetailing in the extensional regime remains unclear.In this study,the formation process of horsetailing is reproduced through physical experiment,simulating the Linnan sag in the extensional regime.The results of the physical experiment demonstrates that the formation of the horsetailing in the extensional regime requires two phases of non-coaxial stretching plus the segment of the principal fault.The stretching distance in the early phase is slightly smaller than that in the middle-late phase.The segment point of the principal fault is only the intersection of the horsetailing structure and the principal fault.The horsetailing formed in the extensional regime is different from that in the strike-slip regime.For the formation of structure,the principal fault is dip-slip in the early phase and then becomes an oblique-slip in the middle-late phase,and the horsetailing is composed of the middle-late new tensile faults.The fault properties of the horsetailing in the extensional regime has important guiding significance for the longitudinal fluid migration along the fault in petroliferous basins.展开更多
To evaluate the geotechnical properties of coarse-grained soil affected by cyclic freeze-thaw,the electrical resistivity and mechanical tests are conducted.The soil specimens are prepared under different water content...To evaluate the geotechnical properties of coarse-grained soil affected by cyclic freeze-thaw,the electrical resistivity and mechanical tests are conducted.The soil specimens are prepared under different water contents,dry densities and exposed to 0?20 freeze-thaw cycles.As a result,the stress?strain behavior of the specimen(w=14.0%andρd=1.90 g/cm^3)changes from strain-hardening into strain-softening due to the freeze-thaw effect.The electrical resistivity of test specimen increases with the freeze-thaw cycles change,but the mechanical parameters(the unconfined compressive strength qu and the deformation modulus E)and brittleness index decrease considerably at the same conditions.All of them tend to be stable after 7?9 cycles.Moreover,both the dry density and the water content have reciprocal effects on the freeze-thaw actions.The failure and pore characteristics of specimens affected by freeze-thaw cycles are discussed by using the image analysis method.Then,an exponential function equation is developed to assess the electrical resistivity of specimens affected by the cyclic freeze-thaw.Linear relations between the mechanical parameters and the electrical resistivity of specimens are established to evaluate the geotechnical properties of the soil exposed to freeze-thaw actions through the corresponding electrical resistivity.展开更多
The contents of Fe and Zn in natural sphalerite samples were determined by chemical titration and spectroscopic techniques(portable X-ray fluorescence(P-XRF) spectrometry, electron probe microanalysis with energy disp...The contents of Fe and Zn in natural sphalerite samples were determined by chemical titration and spectroscopic techniques(portable X-ray fluorescence(P-XRF) spectrometry, electron probe microanalysis with energy dispersive spectroscopy(EPMA-EDS), electron probe microanalysis with wavelength dispersive spectroscopy(EPMA-WDS), and time-of-flight secondary ion mass spectrometry(To F-SIMS)). Besides, the distribution of Fe and Zn in sphalerite samples was analyzed by imaging EPMA-WDS and imaging To F-SIMS. The results show that Fe and Zn contents determined by each spectroscopic technique have good linearity with those determined by chemical titration(R^2>0.77), and the R^2 values of Fe are generally greater than those of Zn. The imaging analysis results revealed that Fe and Zn are not uniformly distributed in the sphalerite.展开更多
Coal spontaneous combustion is a great threat to mine safety,and gas is the key index to describe coal spontaneous combustion.Taking the coal samples of different kinds of coal as research object,the temperature progr...Coal spontaneous combustion is a great threat to mine safety,and gas is the key index to describe coal spontaneous combustion.Taking the coal samples of different kinds of coal as research object,the temperature programmed oxidation experiment was carried out,and the gases produced by coal samples at different temperatures were collected and analyzed by gas chromatography.This research studied the variation characteristics of gas species and gas concentrations in different coal samples during heating oxidation.The experimental results show that different coal samples produce different kinds of gases in the process of heating and oxidation.The order of gas production is CO,C2H6,C2H4,C3H8,and the relationship between gas production and temperature is approximately exponential.With the increase of coal metamorphic degree,the turning point temperature of sharp rise in coal sample gas production rate become higher,the oxidation ability of coal sample decreases,and the quantity of gas production decreases during the same time period.展开更多
For the gold locked within hematite in the two- stage calcination, which leads to a low gold leaching rate, the present work is aiming at pretreating the calcination to selectively dissolve hematite. The calcination w...For the gold locked within hematite in the two- stage calcination, which leads to a low gold leaching rate, the present work is aiming at pretreating the calcination to selectively dissolve hematite. The calcination was pre- treated by sulfuric acid with cosolvent B. The factors in- fluencing the hematite dissolution rate were studied, and the pretreatment parameters considered were H2SO4 con- tent, B dosage and added time, leaching temperature and time. Simultaneously, mineralogy analysis of the calcination, H2SO4 pretreatment residue and cyanide leaching residue were also carried out. Results indicate that the hematite dissolution rate is quicker, the dissolution tem- perature is lower and the dissolution time is shorter in the role of cosolvent B than without B. At the same time, the gold locked within hematite is effectively released, so the leaching rate of gold cyanide increases about 10 % than that in actual factory production. The results have an actual significance in guiding industrial production.展开更多
A combined study of magnetic fabrics, zircon U-Pb geochronology and structural deformation was carried out for Late Paleozoic sedimentary and Mesozoic magmatic rocks in the southwestern Fujian rift basin, South China,...A combined study of magnetic fabrics, zircon U-Pb geochronology and structural deformation was carried out for Late Paleozoic sedimentary and Mesozoic magmatic rocks in the southwestern Fujian rift basin, South China, aiming at deciphering the tectonic evolution during Late Mesozoic. Field observations showed that the Late Mesozoic structure deformations in southwestern Fujian were categorized into four phases： NW-SE compression, ENE-WSW extension, NNE-SSW compression and NNW-SSE extension, se- quentially. Zircons picked out from Juzhou granite and WNW-trending diabase dykes showed complete crys- tal shapes and clear oscillatory zonings on their edges, and the U-Pb dating yielded ages of 132 and 141 Ma, respectively. The susceptibility ellipsoid magnitude parameters of the Juzhou granite are characterized by flaser type strain ellipsoid, with pole density center of K3 falling into the first and the third quadrants, these fea- tures revealed that the Juzhou granite formed in ENE-WSW compressional stress field, indicating the early stage of Early Cretaceous extrusion in southwestern Fujian. The late stage of Early Cretaceous NNE-SSW ex- tension was limited by the widespread WNW-trending diabase dykes, which were usually regarded as impor- tant indications for a regional extensional setting. On the basic of the previous researches, structural deforma- tion studies, and the deductions above, it can be concluded that southwestern Fujian experienced five main tectonic stages during Late Mesozoic： Early Jurassic extension, Middie-Late Jurassic thrusting, early stage of Early Cretaceous extension, late stage of Early Cretaceous compression and Late Cretaceous extension.展开更多
Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions.In this study,cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau to ...Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions.In this study,cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau to study the effect of cyclic freeze-thaw on their uniaxial mechanical properties.The soil specimens were remolded with three dry densities and three moisture contents.Then,after performing a series of freeze-thaw tests in a closed system without water supply,the soil specimens were subjected to a uniaxial compression test.The results showed that the stress-strain curves of the tested soils mainly performed as strain-softening.The softening feature intensified with the increasing dry density but weakened with an increase in freeze-thaw cycles and moisture content.The uniaxial compressive strength,resilient modulus,residual strength and softening modulus decreased considerably with the increase of freeze-thaw cycles.After more than nine freeze-thaw cycles,these four parameters tended to be stable.These parameters increased with the increase of dry density and decreased with the increasing moisture content,except for the residual strength which did not exhibit any clear variation with an increase in moisture content.The residual strength,however,generally increased with an increase in dry density.The soil structural damage caused by frozen water expansion during the freeze-thaw is the major cause for the changes in mechanical behaviors of cohesive coarse-grained soils.With results in this study,the deterioration effect of freeze-thaw cycles on the mechanical properties of soils should be considered during the slope stability analysis in high-altitude mountain regions.展开更多
The Tayuan(Cu-Mo)-Pb-Zn deposit is located in the northern part of Daxinganling,NE China.Lenticular ore body occurs in the skarn zone.The skarn minerals mainly include garnet,pyroxene,epidote and wollastonite.Electron...The Tayuan(Cu-Mo)-Pb-Zn deposit is located in the northern part of Daxinganling,NE China.Lenticular ore body occurs in the skarn zone.The skarn minerals mainly include garnet,pyroxene,epidote and wollastonite.Electron microprobe analysis shows that the end member of garnet is mainly andradite(Ad_(62-97)Gr_(11-45),the pyroxene is mainly diopside,and epidote is mainly clinozoisite.These characteristics indicate that the Tayuan polymetallic skarn deposit is mainly calcareous skarn.Sometimes the content zonation can be observed in garnets.With one garnet crystal,content is shifty from the core to the rim.In general,the iron content in the core is higher than in the edge.The content in the garnet shows that the garnet in the Tayuan deposit formed from weak oxidation in alkaline environment with the oxygen fugacity increasing,suggesting that the hydrothermal fluid evolved from an acidic to a slight alkaline state.In the Tayuan polymetallic deposit,the ratio of Mn/Fe in pyroxene is about 1.3,and of Mg/Fe,it is about 2.The components of garnet in the Tayuan deposit plot in the field of the typical skarn Zn,Cu,Mo deposits in the world.展开更多
The technology of in situ immobilization with amendments is an important measure that remediates the soil contaminated by heavy metals, and selecting economical and effective amendments is the key. The effects and mec...The technology of in situ immobilization with amendments is an important measure that remediates the soil contaminated by heavy metals, and selecting economical and effective amendments is the key. The effects and mechanism of steel slag, the silicon-rich alkaline byproduct which can remediate acidic soil contaminated by heavy metal, are mainly introduced in this paper to provide theory reference for future research. Firstly, the paper analyzes current research situation of in situ immobilization with amendments. Then, it introduces the main physicochemical properties of steel slag, and the effect on soil pH value as well as heavy metal activity. Besides, the paper elaborates the promoting effect on silicon-requiring plant and the strengthening mechanism for its resistant capability of heavy metal. According to the analysis, the application of steel slag could be a potential valuable strategy to remediate acidic soil contaminated by heavy metal by modifying the transformation of heavy metals in both soil and plant, so that the translocation of heavy metal in food chain is reduced.展开更多
Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the ...Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the wall slip characteristics using conventional experimental methods is difficult.Therefore,this paper established a noncontact experimental platform for monitoring the microscopic slip layer of CPB pipeline transport independently based on particle image velocimetry(PIV)and analyzed the effects of slurry temperature,pipe diameter,solid concentration,and slurry flow on the wall slip velocity of the CPB slurry,which refined the theory of the effect of wall slip characteristics on pipeline transport.The results showed that the CPB slurry had an extensive slip layer at the pipe wall with significant wall slip.High slurry temperature improved the degree of particle Brownian motion within the slurry and enhanced the wall slip effect.Increasing the pipe diameter was not conducive to the formation of the slurry slip layer and led to a transition in the CPB slurry flow pattern.The increase in the solid concentration raised the interlayer shear effect of CPB slurry flow and the slip velocity.The slip velocity value increased from 0.025 to 0.056 m·s^(-1)when the solid content improved from 55wt%to 65wt%.When slurry flow increased,the CPB slurry flocculation structure changed,which affected the slip velocity,and the best effect of slip layer resistance reduction was achieved when the transported flow rate was 1.01 m^(3)·h^(-1).The results had important theoretical significance for improving the stability and economy of the CPB slurry in the pipeline.展开更多
As a typical orogenic gold deposit in Tibet,Shangxu gold deposit is located at the Bangong Lake–Nujiang River Metallogenic Belt in the south of Qinghai–Tibet Plateau.In this paper,zircon U-Pb dating,trace elements a...As a typical orogenic gold deposit in Tibet,Shangxu gold deposit is located at the Bangong Lake–Nujiang River Metallogenic Belt in the south of Qinghai–Tibet Plateau.In this paper,zircon U-Pb dating,trace elements and Hf isotopic analysis were performed on Au-bearing quartz veins in the Shangxu gold deposit.Zircons from Au-bearing quartz veins can be divided into three types:detrital,magmatic,and hydrothermal zircons.There are two age peaks in detrital zircons:ca.1700 Ma and ca.2400 Ma.There are two groups of concordant ages including 157±4 Ma(MSWD=0.69)and 120±1 Ma(MSWD=0.19)in magmatic zircons,in whichεH f(t)value of ca.120 Ma from the magmatic zircons range from+8.24 to+12.9.An age of 119±2 Ma(MSWD=0.42)was yielded from hydrothermal zircons,and theirεH f(t)values vary between+15.7 and+16.4.According to sericite Ar-Ar age,this paper suggests that an age of 119±2 Ma from hydrothermal zircons represent the formation age of the Shangxu gold Deposit,and its mineralization should be related to the collision between Lhasa Block and Qiangtang Block.The metallogenic age is basically the same as the diagenetic age of Mugagangri granite,andεH f(t)value of hydrothermal zircon is significantly higher than that of the contemporaneous magmatic zircon,which indicates that there is a genetic relationship between the gold mineralization and the deep crust-mantle magmatism.展开更多
A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to re...A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to recover ferric oxide from red mud.The red mud samples were processed by reduction roasting,grinding and magnetic separating respectively.The effects of different parameters on the recovery rate of iron were studied in detail.The optimum techqicalparameters were proposed with 700 ℃roasting for 20 min,as 50wt% carbon and 4wt% additive were added.The experimentalresults indicated that the iron recovery and the grade of totaliron were 91% and 60%,respectively.A novelprocess is applicable to recover ferric oxide from the red mud waste fines.展开更多
This paper discussed current situations of researches about the isolation remediation technology " soil barrier and landfill technology" and " physical isolation remediation technology" for heavy m...This paper discussed current situations of researches about the isolation remediation technology " soil barrier and landfill technology" and " physical isolation remediation technology" for heavy metal contaminated soil in mining areas.In view of defects of current technologies,it introduced a new isolation remediation technology,of which the new isolation materials were mixed by slaked lime,soil,find sand,and clay mineral in certain proportion.The new isolation remediation technology is expected to realize isolation remediation of heavy metal combined pollution of soil through chemical passivation of slaked lime and physical adsorption function of clay minerals or activated carbons.展开更多
The Yangla Copper Ore Field in Northwest Yunnan Province, China, is a large region of deposits dominated by copper-bearing skarns whose origin remains debatable despite numerous studies over the past two decades. We h...The Yangla Copper Ore Field in Northwest Yunnan Province, China, is a large region of deposits dominated by copper-bearing skarns whose origin remains debatable despite numerous studies over the past two decades. We have investigated the geological and geochemical characteristics of the skarns using field and microscopic observations combined with chemical analyses. The results show that the skarns fall into two categories. The first category is metamorphic skarn, which constitute the majority （〉90%） of skarns in the deposit and is characterized by stratiform occurrences conformable to Devonian host strata, anhydrous mineral assemblages such as diopside＋hedenbergite＋quartz, widespread banded structure, fine-grainsize （〈200 μm） and preserved tuff-like textures. Whole-rock major element compositions, REE and trace-element compositions resemble those of the country rock slates or schists. The skarn layers occur at variable distances （0-2 000 m） from Indosinian plutonic bodies. Fracture-filling veins and/or alteration halos are scarce or absent in or near the skarn layers. This category of skarn probably formed by isochemical contact metamorphism of fine calcareous clastic sediments or impure carbonate rocks during emplacement of the plutonic bodies with no significant material migration by hydrothermal fluids involved during the process, in which case metallic enrichment of the skarn layers was present in the protolith of the skarn. The second category is metasomatic skarn with relatively coarse-grained textures （200-〉1 000 μm） and volatile-reach assemblages such as diopside＋tremolite＋scapolite at or near the igneous contact zones, which constitutes only a minor pro-portion of ore compared with metamorphic skarn. Taking into consideration diverse existing opinions about the genetic type of the deposit, we suggest that the geological and whole-rock geochemical characteristics of the skarus are consistent with a metamorphosed and metasomatized SEDEX （sedimentary exhalative deposit） type rather than a hydrothermal metasomatic skarn type.展开更多
Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks ...Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks of the Chagande＇ersi molybdenum deposit consist mainly of medium- to fine-grained monzogranite, medium-to fine-grained rich-K granite, with minor fine-grained K- feldspar granite veins and quartz veins. The rocks are characterized by high silica, rich alkali, high potassium, which are favorable factors for molybdenum mineralization. The rocks have the Rittmann index ranging from 1.329 to 1.961, an average Na20＋K20 value of 7.41, and AI2Oa/（CaO＋Na20＋K^O） 〉1, suggesting that the rocks belong to the high-K calc-alkaline peraluminous granite. The typical rock samples are enriched in Rb, Th, K and light rare earth elements, depleted in Sr, Ba, Nb, P and Ti, and these features are similar to that of the melt granite resulting from collision of plate margins. The JEu of the rocks falls the zone between the crust granite and crust-mantle granite, and are close to that of the crust granite; （La/LU）N indicates the formation environment of granite is a continental margin setting. The Nb/Ta ratios are close to that of the average crust （10）; the Zr/Hf ratios of monzogranite are partly below the mean mantle （34-60）, while the Zr/Hf ratio of K-feldspar granite are close to the mean value in the crust. Comprehensive analyses show that the granite in this area formed during the transition period between tectonic collision and post-collision. During the plate collision and orogeny, the crust and mantle material were mixed physically, remelting into lava and then crystal fractionation, finally gave rise to the formation of the rock body in this area. This has close spatial and temporal relation with the molybdenum mineralization.展开更多
1 Introduction Daxinganling region is one of the most important nonferrous metal metallogenetic province(Wu et al.,2011;Li et al.,2014).The northern Daxinganling was a geological blank area in China formerly(Li et al....1 Introduction Daxinganling region is one of the most important nonferrous metal metallogenetic province(Wu et al.,2011;Li et al.,2014).The northern Daxinganling was a geological blank area in China formerly(Li et al.,2017).However,the region has a huge resource potential.Forty metal deposits have been found in the area recently,with展开更多
Gold-bearing quartz veins of the Taihua Group consisting of Archean metavolcanic rocks are a main gold deposit type in the Xiao Qinling area,one of the three biggest gold production areas in China.The quartz veins exp...Gold-bearing quartz veins of the Taihua Group consisting of Archean metavolcanic rocks are a main gold deposit type in the Xiao Qinling area,one of the three biggest gold production areas in China.The quartz veins experienced strong alteration characterized by a typical mesothermal hydrothermal altered mineral assemblage.The grade of gold is affected by the contents of sulphides,e.g.galena,pyrite and chalcopyrite.Results of minor elements analysis for the of gold-bearing quartz veins indicate higher contents of Au and high contents of Ag,Pb,Cu,Cd,W,and Mo.Abundant fluid inclusions were found in the gold-bearing quartz veins.Three types of fluid inclusions were identified:(1) aqueous inclusions;(2) CO 2-bearing inclusions;and(3) daughter crystal-bearing fluid inclusions.Homogenization temperatures ranged from 110 to 670℃ with low and high peaks appearing at 160 180℃ and 280 300℃,respectively.The salinity of aqueous inclusions varies between 1.8 wt% and 38.2 wt% NaCl.The homogenization temperature and salinity show a positive correlation.The H and O isotopes of fluid inclusions in the gold-bearing quartz veins indicate that magmatic solution and metamorphic hydrothermal solution,together with meteoric water,were involved in the formation of gold-bearing fluid.Mesozoic magma activities related to granite intrusions should be the main source of CO 2 fluid with higher temperature and salinity.展开更多
基金supported by the National Natural Science Foundation of China(No.51574105)the Science and Technology Program of Hebei Province,China(No.23564101D)+2 种基金the Natural Science Foundation of Hebei Province,China(No.E2021209147)the Key Research Project of North China University of Science and Technology(No.ZD-ST-202308)the Postgraduate Innovation Funding Project of Hebei Province,China(No.CXZZBS2024135).
文摘Calcium ferrite(CF)is recognized as a potential green and efficient functional material because of its advantages of magnetism,electrochemistry,catalysis,and biocompatibility in the fields of materials chemistry,environmental engineering,and biomedicine.There-fore,the obtained research results need to be systematically summarized,and new perspectives on CF and its composite materials need to be analyzed.Based on the presented studies of CF and its composite materials,the types and structures of the crystal are summarized.In addition,the current application technologies and theoretical mechanisms with various properties in different fields are elucidated.Moreover,the various preparation methods of CF and its composite materials are elaborated in detail.Most importantly,the advantages and disadvantages of the synthesis methods of CF and its composite materials are discussed,and the existing problems and emerging challenges in practical production are identified.Furthermore,the key future research directions of CF and its composite materials have been prospected from the potential application technologies to provide references for its synthesis and efficient utilization.
文摘Generally speaking, the geological topography of coal mine project is complex, which makes coal mining face many safety risks. When coal mining does not pay attention to safety management, it may lead to serious accidents and damage the economic and social benefits of enterprises. Safety management helps to prevent and eliminate safety risks in coal projects, reduce accidents and ensure the healthy development of coal enterprises to a certain extent. From the current situation of China's coal project safety management, there are many problems in the future to achieve the transformation and development of the coal industry, and it is necessary to improve the level of safety management.
文摘Mineral resources play an important role in human society. To make progress, human society must develop and utilize mineral resources. From primitive society to today's information society, from the use of Stone to the use of nuclear energy and atomic energy, the level of use of mineral resources determines the level of development of human society. Metal mineral resources play a very important role in the development of human society and national economy. Therefore, the comprehensive development and utilization of metal mineral resources will, to some extent, have a direct impact on improving people's living standards and will become an important factor in national economic development and human social progress.
文摘Horsetailing is an important feature to identify the strike-slip structure and indicates the movement mode of the fault.However,the formation mechanism of horsetailing in the extensional regime remains unclear.In this study,the formation process of horsetailing is reproduced through physical experiment,simulating the Linnan sag in the extensional regime.The results of the physical experiment demonstrates that the formation of the horsetailing in the extensional regime requires two phases of non-coaxial stretching plus the segment of the principal fault.The stretching distance in the early phase is slightly smaller than that in the middle-late phase.The segment point of the principal fault is only the intersection of the horsetailing structure and the principal fault.The horsetailing formed in the extensional regime is different from that in the strike-slip regime.For the formation of structure,the principal fault is dip-slip in the early phase and then becomes an oblique-slip in the middle-late phase,and the horsetailing is composed of the middle-late new tensile faults.The fault properties of the horsetailing in the extensional regime has important guiding significance for the longitudinal fluid migration along the fault in petroliferous basins.
基金Project(2016ZGHJ/XZHTL-YQSC-26)supported by the Key Scientific Research Project of China Gold GroupProject(SQ2019QZKK2806)supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program,China+1 种基金Project(300102268716)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(LHKA-G201701)supported by the Science and Technology Project of Yalong River Hydropower Development Company,China。
文摘To evaluate the geotechnical properties of coarse-grained soil affected by cyclic freeze-thaw,the electrical resistivity and mechanical tests are conducted.The soil specimens are prepared under different water contents,dry densities and exposed to 0?20 freeze-thaw cycles.As a result,the stress?strain behavior of the specimen(w=14.0%andρd=1.90 g/cm^3)changes from strain-hardening into strain-softening due to the freeze-thaw effect.The electrical resistivity of test specimen increases with the freeze-thaw cycles change,but the mechanical parameters(the unconfined compressive strength qu and the deformation modulus E)and brittleness index decrease considerably at the same conditions.All of them tend to be stable after 7?9 cycles.Moreover,both the dry density and the water content have reciprocal effects on the freeze-thaw actions.The failure and pore characteristics of specimens affected by freeze-thaw cycles are discussed by using the image analysis method.Then,an exponential function equation is developed to assess the electrical resistivity of specimens affected by the cyclic freeze-thaw.Linear relations between the mechanical parameters and the electrical resistivity of specimens are established to evaluate the geotechnical properties of the soil exposed to freeze-thaw actions through the corresponding electrical resistivity.
基金Projects(51764022,51404119)supported by the National Natural Science Foundation of ChinaProject(161046)supported by Fok Ying Tong Education Foundation,ChinaProject(2018M632810)supported by China Postdoctoral Science Foundation。
文摘The contents of Fe and Zn in natural sphalerite samples were determined by chemical titration and spectroscopic techniques(portable X-ray fluorescence(P-XRF) spectrometry, electron probe microanalysis with energy dispersive spectroscopy(EPMA-EDS), electron probe microanalysis with wavelength dispersive spectroscopy(EPMA-WDS), and time-of-flight secondary ion mass spectrometry(To F-SIMS)). Besides, the distribution of Fe and Zn in sphalerite samples was analyzed by imaging EPMA-WDS and imaging To F-SIMS. The results show that Fe and Zn contents determined by each spectroscopic technique have good linearity with those determined by chemical titration(R^2>0.77), and the R^2 values of Fe are generally greater than those of Zn. The imaging analysis results revealed that Fe and Zn are not uniformly distributed in the sphalerite.
基金National Natural Science Foundation of China(No.51474086)Hebei Province Natural Science Foundation(No.E2014209138)the North China University of Science and Technology Fostering Fund Project(No.GP201511)for the financial supports
文摘Coal spontaneous combustion is a great threat to mine safety,and gas is the key index to describe coal spontaneous combustion.Taking the coal samples of different kinds of coal as research object,the temperature programmed oxidation experiment was carried out,and the gases produced by coal samples at different temperatures were collected and analyzed by gas chromatography.This research studied the variation characteristics of gas species and gas concentrations in different coal samples during heating oxidation.The experimental results show that different coal samples produce different kinds of gases in the process of heating and oxidation.The order of gas production is CO,C2H6,C2H4,C3H8,and the relationship between gas production and temperature is approximately exponential.With the increase of coal metamorphic degree,the turning point temperature of sharp rise in coal sample gas production rate become higher,the oxidation ability of coal sample decreases,and the quantity of gas production decreases during the same time period.
基金financially supported by the Key Laboratory Project of Education Department in Shaanxi Province (No.14JS055)
文摘For the gold locked within hematite in the two- stage calcination, which leads to a low gold leaching rate, the present work is aiming at pretreating the calcination to selectively dissolve hematite. The calcination was pre- treated by sulfuric acid with cosolvent B. The factors in- fluencing the hematite dissolution rate were studied, and the pretreatment parameters considered were H2SO4 con- tent, B dosage and added time, leaching temperature and time. Simultaneously, mineralogy analysis of the calcination, H2SO4 pretreatment residue and cyanide leaching residue were also carried out. Results indicate that the hematite dissolution rate is quicker, the dissolution tem- perature is lower and the dissolution time is shorter in the role of cosolvent B than without B. At the same time, the gold locked within hematite is effectively released, so the leaching rate of gold cyanide increases about 10 % than that in actual factory production. The results have an actual significance in guiding industrial production.
基金supported by the projects the China Geological Survey(Nos.12120113089600,12120114028701 and 1212011085472)the Key Project of Natural Science Foundation of China(No.41530321)the Fundamental Research Funds for the Central University(No.2652017259)
文摘A combined study of magnetic fabrics, zircon U-Pb geochronology and structural deformation was carried out for Late Paleozoic sedimentary and Mesozoic magmatic rocks in the southwestern Fujian rift basin, South China, aiming at deciphering the tectonic evolution during Late Mesozoic. Field observations showed that the Late Mesozoic structure deformations in southwestern Fujian were categorized into four phases： NW-SE compression, ENE-WSW extension, NNE-SSW compression and NNW-SSE extension, se- quentially. Zircons picked out from Juzhou granite and WNW-trending diabase dykes showed complete crys- tal shapes and clear oscillatory zonings on their edges, and the U-Pb dating yielded ages of 132 and 141 Ma, respectively. The susceptibility ellipsoid magnitude parameters of the Juzhou granite are characterized by flaser type strain ellipsoid, with pole density center of K3 falling into the first and the third quadrants, these fea- tures revealed that the Juzhou granite formed in ENE-WSW compressional stress field, indicating the early stage of Early Cretaceous extrusion in southwestern Fujian. The late stage of Early Cretaceous NNE-SSW ex- tension was limited by the widespread WNW-trending diabase dykes, which were usually regarded as impor- tant indications for a regional extensional setting. On the basic of the previous researches, structural deforma- tion studies, and the deductions above, it can be concluded that southwestern Fujian experienced five main tectonic stages during Late Mesozoic： Early Jurassic extension, Middie-Late Jurassic thrusting, early stage of Early Cretaceous extension, late stage of Early Cretaceous compression and Late Cretaceous extension.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1505001)the Key Scientific Research Project of China Gold Group(Grant No.2016ZGHJ/XZHTL-YQSC-26)+1 种基金the funding from the Department of Transportation of Gansu Province(Grant No.2017-008)the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102268716)
文摘Freeze-thaw cycles are closely related to the slope instability in high-altitude mountain regions.In this study,cohesive coarse-grained soils were collected from a high-altitude slope in the Qinghai–Tibet Plateau to study the effect of cyclic freeze-thaw on their uniaxial mechanical properties.The soil specimens were remolded with three dry densities and three moisture contents.Then,after performing a series of freeze-thaw tests in a closed system without water supply,the soil specimens were subjected to a uniaxial compression test.The results showed that the stress-strain curves of the tested soils mainly performed as strain-softening.The softening feature intensified with the increasing dry density but weakened with an increase in freeze-thaw cycles and moisture content.The uniaxial compressive strength,resilient modulus,residual strength and softening modulus decreased considerably with the increase of freeze-thaw cycles.After more than nine freeze-thaw cycles,these four parameters tended to be stable.These parameters increased with the increase of dry density and decreased with the increasing moisture content,except for the residual strength which did not exhibit any clear variation with an increase in moisture content.The residual strength,however,generally increased with an increase in dry density.The soil structural damage caused by frozen water expansion during the freeze-thaw is the major cause for the changes in mechanical behaviors of cohesive coarse-grained soils.With results in this study,the deterioration effect of freeze-thaw cycles on the mechanical properties of soils should be considered during the slope stability analysis in high-altitude mountain regions.
基金supported by the Natural Science Foundation of China(No.41203039)
文摘The Tayuan(Cu-Mo)-Pb-Zn deposit is located in the northern part of Daxinganling,NE China.Lenticular ore body occurs in the skarn zone.The skarn minerals mainly include garnet,pyroxene,epidote and wollastonite.Electron microprobe analysis shows that the end member of garnet is mainly andradite(Ad_(62-97)Gr_(11-45),the pyroxene is mainly diopside,and epidote is mainly clinozoisite.These characteristics indicate that the Tayuan polymetallic skarn deposit is mainly calcareous skarn.Sometimes the content zonation can be observed in garnets.With one garnet crystal,content is shifty from the core to the rim.In general,the iron content in the core is higher than in the edge.The content in the garnet shows that the garnet in the Tayuan deposit formed from weak oxidation in alkaline environment with the oxygen fugacity increasing,suggesting that the hydrothermal fluid evolved from an acidic to a slight alkaline state.In the Tayuan polymetallic deposit,the ratio of Mn/Fe in pyroxene is about 1.3,and of Mg/Fe,it is about 2.The components of garnet in the Tayuan deposit plot in the field of the typical skarn Zn,Cu,Mo deposits in the world.
文摘The technology of in situ immobilization with amendments is an important measure that remediates the soil contaminated by heavy metals, and selecting economical and effective amendments is the key. The effects and mechanism of steel slag, the silicon-rich alkaline byproduct which can remediate acidic soil contaminated by heavy metal, are mainly introduced in this paper to provide theory reference for future research. Firstly, the paper analyzes current research situation of in situ immobilization with amendments. Then, it introduces the main physicochemical properties of steel slag, and the effect on soil pH value as well as heavy metal activity. Besides, the paper elaborates the promoting effect on silicon-requiring plant and the strengthening mechanism for its resistant capability of heavy metal. According to the analysis, the application of steel slag could be a potential valuable strategy to remediate acidic soil contaminated by heavy metal by modifying the transformation of heavy metals in both soil and plant, so that the translocation of heavy metal in food chain is reduced.
基金financially supported by the National Natural Science Foundation of China (Nos.51774137 and 51804121)。
文摘Wall slip is a microscopic phenomenon of cemented paste backfill(CPB)slurry near the pipe wall,which has an important influence on the form of slurry pipe transport flow and velocity distribution.Directly probing the wall slip characteristics using conventional experimental methods is difficult.Therefore,this paper established a noncontact experimental platform for monitoring the microscopic slip layer of CPB pipeline transport independently based on particle image velocimetry(PIV)and analyzed the effects of slurry temperature,pipe diameter,solid concentration,and slurry flow on the wall slip velocity of the CPB slurry,which refined the theory of the effect of wall slip characteristics on pipeline transport.The results showed that the CPB slurry had an extensive slip layer at the pipe wall with significant wall slip.High slurry temperature improved the degree of particle Brownian motion within the slurry and enhanced the wall slip effect.Increasing the pipe diameter was not conducive to the formation of the slurry slip layer and led to a transition in the CPB slurry flow pattern.The increase in the solid concentration raised the interlayer shear effect of CPB slurry flow and the slip velocity.The slip velocity value increased from 0.025 to 0.056 m·s^(-1)when the solid content improved from 55wt%to 65wt%.When slurry flow increased,the CPB slurry flocculation structure changed,which affected the slip velocity,and the best effect of slip layer resistance reduction was achieved when the transported flow rate was 1.01 m^(3)·h^(-1).The results had important theoretical significance for improving the stability and economy of the CPB slurry in the pipeline.
基金financially supported by the National Natural Science Foundation of China(Grant No.91955208)the National Key Research and Development Program of China(Grant nos.2016YFC0600308 and 2018YFC0604103)a program of China Geological Survey(Grant No.DD2021392)。
文摘As a typical orogenic gold deposit in Tibet,Shangxu gold deposit is located at the Bangong Lake–Nujiang River Metallogenic Belt in the south of Qinghai–Tibet Plateau.In this paper,zircon U-Pb dating,trace elements and Hf isotopic analysis were performed on Au-bearing quartz veins in the Shangxu gold deposit.Zircons from Au-bearing quartz veins can be divided into three types:detrital,magmatic,and hydrothermal zircons.There are two age peaks in detrital zircons:ca.1700 Ma and ca.2400 Ma.There are two groups of concordant ages including 157±4 Ma(MSWD=0.69)and 120±1 Ma(MSWD=0.19)in magmatic zircons,in whichεH f(t)value of ca.120 Ma from the magmatic zircons range from+8.24 to+12.9.An age of 119±2 Ma(MSWD=0.42)was yielded from hydrothermal zircons,and theirεH f(t)values vary between+15.7 and+16.4.According to sericite Ar-Ar age,this paper suggests that an age of 119±2 Ma from hydrothermal zircons represent the formation age of the Shangxu gold Deposit,and its mineralization should be related to the collision between Lhasa Block and Qiangtang Block.The metallogenic age is basically the same as the diagenetic age of Mugagangri granite,andεH f(t)value of hydrothermal zircon is significantly higher than that of the contemporaneous magmatic zircon,which indicates that there is a genetic relationship between the gold mineralization and the deep crust-mantle magmatism.
基金Funded by the Fundamental Research Funds for the Central Universities(No.310827151063)the Provincial Training Program of Innovation and Entrepreneurship for Undergraduates(No.201510710134)
文摘A great amount of red mud generated from alumina production by Bayer process was considered as a low-grade iron ore with a grade of 5wt% to 30wt% iron.We adopted the reduction roastingmagnetic separation process to recover ferric oxide from red mud.The red mud samples were processed by reduction roasting,grinding and magnetic separating respectively.The effects of different parameters on the recovery rate of iron were studied in detail.The optimum techqicalparameters were proposed with 700 ℃roasting for 20 min,as 50wt% carbon and 4wt% additive were added.The experimentalresults indicated that the iron recovery and the grade of totaliron were 91% and 60%,respectively.A novelprocess is applicable to recover ferric oxide from the red mud waste fines.
基金Supported by Scientific Research Project of Shaanxi Province Land Engineering Construction Group(DJNY2017-13)
文摘This paper discussed current situations of researches about the isolation remediation technology " soil barrier and landfill technology" and " physical isolation remediation technology" for heavy metal contaminated soil in mining areas.In view of defects of current technologies,it introduced a new isolation remediation technology,of which the new isolation materials were mixed by slaked lime,soil,find sand,and clay mineral in certain proportion.The new isolation remediation technology is expected to realize isolation remediation of heavy metal combined pollution of soil through chemical passivation of slaked lime and physical adsorption function of clay minerals or activated carbons.
基金financially supported by the China Geological Survey(No.12120113079400)
文摘The Yangla Copper Ore Field in Northwest Yunnan Province, China, is a large region of deposits dominated by copper-bearing skarns whose origin remains debatable despite numerous studies over the past two decades. We have investigated the geological and geochemical characteristics of the skarns using field and microscopic observations combined with chemical analyses. The results show that the skarns fall into two categories. The first category is metamorphic skarn, which constitute the majority （〉90%） of skarns in the deposit and is characterized by stratiform occurrences conformable to Devonian host strata, anhydrous mineral assemblages such as diopside＋hedenbergite＋quartz, widespread banded structure, fine-grainsize （〈200 μm） and preserved tuff-like textures. Whole-rock major element compositions, REE and trace-element compositions resemble those of the country rock slates or schists. The skarn layers occur at variable distances （0-2 000 m） from Indosinian plutonic bodies. Fracture-filling veins and/or alteration halos are scarce or absent in or near the skarn layers. This category of skarn probably formed by isochemical contact metamorphism of fine calcareous clastic sediments or impure carbonate rocks during emplacement of the plutonic bodies with no significant material migration by hydrothermal fluids involved during the process, in which case metallic enrichment of the skarn layers was present in the protolith of the skarn. The second category is metasomatic skarn with relatively coarse-grained textures （200-〉1 000 μm） and volatile-reach assemblages such as diopside＋tremolite＋scapolite at or near the igneous contact zones, which constitutes only a minor pro-portion of ore compared with metamorphic skarn. Taking into consideration diverse existing opinions about the genetic type of the deposit, we suggest that the geological and whole-rock geochemical characteristics of the skarus are consistent with a metamorphosed and metasomatized SEDEX （sedimentary exhalative deposit） type rather than a hydrothermal metasomatic skarn type.
基金supported by the National Natural Science Foundation,40073013
文摘Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks of the Chagande＇ersi molybdenum deposit consist mainly of medium- to fine-grained monzogranite, medium-to fine-grained rich-K granite, with minor fine-grained K- feldspar granite veins and quartz veins. The rocks are characterized by high silica, rich alkali, high potassium, which are favorable factors for molybdenum mineralization. The rocks have the Rittmann index ranging from 1.329 to 1.961, an average Na20＋K20 value of 7.41, and AI2Oa/（CaO＋Na20＋K^O） 〉1, suggesting that the rocks belong to the high-K calc-alkaline peraluminous granite. The typical rock samples are enriched in Rb, Th, K and light rare earth elements, depleted in Sr, Ba, Nb, P and Ti, and these features are similar to that of the melt granite resulting from collision of plate margins. The JEu of the rocks falls the zone between the crust granite and crust-mantle granite, and are close to that of the crust granite; （La/LU）N indicates the formation environment of granite is a continental margin setting. The Nb/Ta ratios are close to that of the average crust （10）; the Zr/Hf ratios of monzogranite are partly below the mean mantle （34-60）, while the Zr/Hf ratio of K-feldspar granite are close to the mean value in the crust. Comprehensive analyses show that the granite in this area formed during the transition period between tectonic collision and post-collision. During the plate collision and orogeny, the crust and mantle material were mixed physically, remelting into lava and then crystal fractionation, finally gave rise to the formation of the rock body in this area. This has close spatial and temporal relation with the molybdenum mineralization.
基金supported by the Natural Science Foundation of China(No.41203039)
文摘1 Introduction Daxinganling region is one of the most important nonferrous metal metallogenetic province(Wu et al.,2011;Li et al.,2014).The northern Daxinganling was a geological blank area in China formerly(Li et al.,2017).However,the region has a huge resource potential.Forty metal deposits have been found in the area recently,with
基金supported jointly by the CNSF (No. 41173055)the National Basic Research Program of China (No.2003CB214605)
文摘Gold-bearing quartz veins of the Taihua Group consisting of Archean metavolcanic rocks are a main gold deposit type in the Xiao Qinling area,one of the three biggest gold production areas in China.The quartz veins experienced strong alteration characterized by a typical mesothermal hydrothermal altered mineral assemblage.The grade of gold is affected by the contents of sulphides,e.g.galena,pyrite and chalcopyrite.Results of minor elements analysis for the of gold-bearing quartz veins indicate higher contents of Au and high contents of Ag,Pb,Cu,Cd,W,and Mo.Abundant fluid inclusions were found in the gold-bearing quartz veins.Three types of fluid inclusions were identified:(1) aqueous inclusions;(2) CO 2-bearing inclusions;and(3) daughter crystal-bearing fluid inclusions.Homogenization temperatures ranged from 110 to 670℃ with low and high peaks appearing at 160 180℃ and 280 300℃,respectively.The salinity of aqueous inclusions varies between 1.8 wt% and 38.2 wt% NaCl.The homogenization temperature and salinity show a positive correlation.The H and O isotopes of fluid inclusions in the gold-bearing quartz veins indicate that magmatic solution and metamorphic hydrothermal solution,together with meteoric water,were involved in the formation of gold-bearing fluid.Mesozoic magma activities related to granite intrusions should be the main source of CO 2 fluid with higher temperature and salinity.
