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NEW METHOD OF EXTRACTING GOLD AND SILVER FROM HIGH SILVER-GOLD CONCENTRATES

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中国有色金属学会会刊：英文版 1995年第3期5卷 50-53页

作者： Song, Qingshuang Wang, Dequan Cheng, Jinju Northeastern Univ Shenyang China

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关键词： extraction of gold and silver chloride leach sulphur-ammonia leach cementation

Effect of aggressive pH media on peat treated by cement and sodium silicate grout

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Journal of Central South University 2011年第3期18卷 840-847页

作者： S.Kazemian A.Prasad B.B.K.Huat J.Bolouri Bazaz T.A.Mohammed F.N.Abdul Aziz Department of Civil Engineering Bojnourd BranchIslamic Azad University Department of Civil Engineering Banaras Hindu University Department of Civil Engineering University Putra Malaysia Department of Civil Engineering Ferdowsi University

The effects of aggressive peat nature (pH) on the strength of peat treated by cement and cement-sodium silicate grout were investigated by evaluating the changes in unconfined compressive strength,moisture content,and scanning electron microscopy (SEM) of samples with time in different pH *** results indicate that peats treated by cement-silicate have higher strength than peats treated by cement,due to an increase in pH value of the ***,cement and cement-silicate are highly effective in reducing the moisture content and void ratio of the treated *** microstructures of treated peats support the laboratory test results.

关键词： peat aggressive pH media cementation sodium silicate grout microstructure

Sputtering of W Mo alloy under ion bombardment

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中国有色金属学会会刊：英文版 1999年第3期9卷 629-633页

作者： Li Chengming(李成明) Tian Linhai(田林海) Xu Zhong(徐重) Taiyuan Univ Technol Res Inst Surface Engn Taiyuan 030024 Peoples R China

The distribution of plasma density in the vicinity of the W Mo alloy source in the process of double glow discharge plasma surface alloying was diagnosed using the moveable Langmuir probe. The sputtering law, surface composition and morphological variation of the W Mo alloy source was studied. The experimental results show that there exists obvious preferential sputtering on the surface of the W Mo alloy source under the argon ion bombardment; the stable period is reached after a transitional period, and the preferential sputtering occurs in a definite range of composition(mole fraction): 70%～75% Mo, 22%～25% W; there appears segregation on the surface of the W Mo alloy source.

关键词： metallic cementation W Mo alloy preferential sputtering ion bombardment

Impact of polymer mixtures on the stabilization and erosion control of silty sand slope

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Journal of Mountain Science 2019年第2期16卷 470-485页

作者： YANG Qing-wen PEI Xiang-jun HUANG Run-qiu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology

Silty sand can be prone to erosion because it is short of stability cementation materials. In recent years, various emerging soil stabilizers, especially natural organic substance and polymer, have been used to improve soil strength, water stability and ability of erosion resistance. In this study, a new type of soil stabilization additive modified carboxymethyl cellulose(M-CMC), consisting of carboxymethyl cellulose(CMC) and polyacrylamide(PAM), was developed for stabilization treatment of silty sand. A series of laboratory tests were conducted to evaluate the performance of M-CMC application on shear strength, permeability, water susceptibility and microstructure of the silty sand soil treated with additive concentration range of 0%-1.3%. Moreover, rainfall simulation experiments were conducted to evaluate the effect of M-CMC on the erosion control of silty sand which compacted soil in a large-sized runoff(1 m^2) plots. Test plot which treated with 1.1% concentration of soil stabilizer and control plot which treated with same amount of water were cured outdoor for 50 days before rainfall simulation test. Rainfall intensity was applied at 120 mm·h-1 for 60 min. Finally, a field test is performed in order to assess the practical application effect of silty sand with 1.1% M-CMC. In general, the results showed that an increase of the concentration of M-CMC resulted in an improvement in water susceptibility and shear strength but a decrease in the infiltration rate. Internal friction angle of the treated soil remarkably increased under a low M-CMC concentration(less than 0.7%), while cohesion of them sharply increased under a relatively high M-CMC concentration(larger than 0.7%). Water susceptibility of the treated samples was improved remarkably under a relatively high M-CMC concentration(larger than 0.7%). Permeability coefficient of them decreased significantly when the M-CMC concentration was increased from 0 to 0.5% and, then, from 0.9% to 1.3%. Based on the image

关键词： Soil stabilization Water susceptibility permeability Erosion Water retention cementation

Three-dimensional DEM investigation of the stress-dilatancy relation of grain-cementing type methane hydrate-bearing sediment

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Petroleum 2021年第4期7卷 477-484页

作者： An Zhang Mingjing Jiang Wenhao Du School of Civil Engineering Suzhou University of Science and TechnologySuzhouJiangsu215009China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao266000China State Key Laboratory for Disaster Reduction in Civil Engineering Tongji University Shanghai200092China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Department of Civil Engineering Tianjin UniversityTianjin300072China Tongji Architectural Design(Group)Co. Ltd.No.1230 Siping RoadShanghai200092China

In this study,the Discrete Element Method(DEM)was employed to investigate numerically the effects of hydrate cementation and intermediate principal stress on the stress-dilatancy relation of graincementing type methane hydrate-bearing sediment(MHBS)by conducting a series of conventional and true triaxial tests.A novel 3D thermo-hydro-mechanical-chemical(THMC)contact model for MHBS was *** numerical results show that with increasing hydrate saturation and back pressure,or decreasing confining pressure,temperature and salinity,the stress-dilation relation of grain-cementing type MHBS evolves from dilation-dominant to *** the clean sand samples,the relationship between the normalized stress ratio h/Mcr and the dilatancy rate d is close under different intermediate principal stress ***,for the MHBS samples,this relationship is still affected by the intermediate principal stress coefficient b,due to the effect of hydrate cementation.

关键词： Stress-dilatancy cementation Methane hydrate bearing sediment Discrete element method Intermediate principal stress

Formation Mechanism of Beach Rocks and Its Controlling Factors in Coral Reef Area, Qilian Islets and Cays,Xisha Islands, China

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Journal of Earth Science 2019年第4期30卷 728-738页

作者： Na Zhao Dishu Shen Jian-Wei Shen CAS Key L aboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China University of Chinese Academy of Sciences Beijing 100049China Huxi Higher Education Mega Center Chongqing City Management CollegeChongqing 401331China

Beach rock,which forms at the intertidal zone,is a natural barrier to protect beach and island from wave erosion. The formation mechanism of beach rocks is significant in the study of surface carbonate diagenesis and protection of island. Beach rocks in Qilian Islets and Cays were formed about 500–700 a BP,neither its composition nor sedimentary structure experienced intense *** rocks in Qilian Islets and Cays are mainly composed of reef-building skeletal fragments and bioclasts without terrigenous sediments. This study focused on the types and morphologies of cements in beach rocks of Qilian Islets and Cays,and its cementation mechanisms and influencing factors. Biological activities,such as micritization caused by microbial activities and algae binding action,play an important role in the initial stage of bioclast transformation and promote the subsequent early marine and early meteoric cementation. Acicular aragonite induced by early marine cementation is well developed in beach rocks,especially in those samples from Medium Islet. Early meteoric cementation is not common as marine cementation,generally presenting granular and meniscus cements. The main factors affecting the formation and development of beach rocks in Qilian Islets and Cays include sediment source,hydrodynamic condition,climate,sea level change and anthropogenic impacts.

关键词： beach rock cementation micritization coral reef Qilian Islets and Cays the South China Sea

Estimation of thermal conductivity of cemented sands using thermal network models

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 210-218页

作者： Wenbin Fei Guillermo A.Narsilio Department of Infrastructure Engineering The University of MelbourneParkvilleAustralia

Effective thermal conductivity of soils can be enhanced to achieve higher efficiencies in the operation of shallow geothermal *** cementation is a ground improvement technique that can increase the interparticle contact area,leading to a high effective thermal ***,cementation may occur at different locations in the soil matrix,*** contacts,evenly or unevenly around particles,in the pore space or a combination of *** topology of cementation at the particle scale and its influence on soil response have not been studied in detail to ***,soils are made of particles with different shapes,but the impact of particle shape on the cementation and the resulting change of effective thermal conductivity require further *** this work,three kinds of sands with different particle shapes were selected and cementation was formed either evenly around the particles,or along the direction parallel or perpendicular to that of heat *** effective thermal conductivity of each sample was computed using a thermal conductance network *** show that dry sand with more irregular particle shape and cemented along the heat transfer direction will lead to a more efficient thermal enhancement of the soil,i.e.a comparatively higher soil effective thermal conductivity.

关键词： Network cementation Computed tomography Ground improvement Sands

Earth pressure coefficient at rest during secondary compression

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Journal of Central South University 2011年第6期18卷 2115-2121页

作者：赵晓东周国庆商翔宇陈国舟 State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology School of Architecture and Civil Engineering China University of Mining and Technology

In order to obtain the earth pressure coefficient at rest (K0) at higher consolidation pressures during secondary compression, a series of K0 tests for saturated reconstituted clay were conducted. The results indicate that the measured K0 in secondary compression can be described by equations related to internal friction angle, secondary compression coefficient, compression index, recompression index, and sediment time. Effects of consolidation pressures and sediment time on K0 during secondary compression can be attributed to cementation (part of cohesion) increase and internal friction angle decrease. cementation increase leads to nonlinear variation for K0 and internal friction angle decrease results in increase of K0. K0 computed by equations associated with internal friction angle is overestimated at apparent lower consolidation pressures with different sediment time, which agrees with the measured values well at apparent higher consolidation pressures.

关键词： earth pressure coefficient at rest secondary compression internal friction angle cementation

Classification and Diagenetic Characteristics of the Cretaceous Sandstones in the Southern Bredasdorp Basin,Offshore South Africa

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Acta Geologica Sinica(English Edition) 2021年第5期95卷 1695-1713页

作者： Temitope Love BAIYEGUNHI Kuiwu LIU Oswald GWAVAVA Christopher BAIYEGUNHI Department of Geology University of Fort HarePrivate Bag X1314Alice 5700Eastern Cape ProvinceSouth Africa Department of Geology and Mining University of LimpopoPrivate Bag X1106Sovenga 0727Limpopo ProvinceSouth Africa

A systematic petrographic and geochemical studies of 92 representative sandstone samples from exploration wells E-AH1,E-AJ1,E-BA1,E-BB1 and E-D3 in the southern part of the Bredasdorp Basin was undertaken to classify the sandstones as well as unravel the main diagenetic processes and their time *** study shows that the sandstones are largely subarkosic arenite and arkosic litharenite,which have underwent series of diagenetic processes as a result burial,rifting and subsequent *** main diagenetic processes that have affected the reservoir properties of the sandstones are cementation by authigenic clay,carbonate and silica,growth of authigenic glauconite,dissolution of minerals and load *** major diagenetic processes reducing the porosity are calcite cementation in the subarkosic arenite,and compaction and quartz cementation in arkosic *** the other hand,the formation of secondary porosity due to the partial to complete dissolution of early calcite cement,feldspars and minor grain fracturing has improved the reservoir property of the sandstone to some *** clay minerals in the sandstones commonly acts as pore choking cement,which reduces *** general,there is no particular diagenetic process that exclusively controls the type or form of porosity evolution in the sandstones.

关键词： diagenesis cementation reservoir properties sandstones Bredasdorp Basin