China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in rece...China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in recent years.Silver deposits include different types,such as submarine volcanism and continental volcanism related type,intrusion related type,and sedimentary related type.This study summarized the metallogenic regularity of China＇s silver deposits systematically based mainly on the data from 490 silver deposits.It is shown that submarine volcanic sedimentary type,continental volcanic or sub-volcanic type,skarn type,hydrothermal type（including vein type and stratabound type）,sedimentary metamorphic type,sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit.A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated.The map of ＂Spatial distribution of silver mineralization belts in China＂ and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China.展开更多
Gold leaching was influenced in association with silver and polymetal sulphide minerals.A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals:pyrite?silica,chalcopyrite...Gold leaching was influenced in association with silver and polymetal sulphide minerals.A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals:pyrite?silica,chalcopyrite?silica,sphalerite?silica and stibnite?silica.Pyrargyrite enhanced Au recovery to 77.3%and 51.2%under galvanic and passivation effects from pyrite(vs 74.6%and 15.8%).Pyrargyrite in association with sphalerite also enhanced Au recovery to 6.6%and 51.9%(vs 1.6%and 15.6%)under galvanic and passivation effects from sphalerite.Pyrargyrite associated with chalcopyrite retarded gold recovery to 38.0%and 12.1%(vs 57%and 14.1%)under galvanic and passivation effects.Accumulative silver minerals enhanced Au recovery to 90.6%and 81.1%(vs 74.6%and 15.8%)under galvanic and passivation impacts from pyrite.Silver minerals with sphalerite under galvanic and passivation effects enhanced Au recovery to 71.1%and 80.5%(vs 1.6%and 15.6%).Silver minerals associated with chalcopyrite retarded Au recovery to 10.2%and 4.5%under galvanic and passivation impacts(vs 57%and 14.1%).Stibnite retarded Au dissolution with pyrargyrite and accumulative silver minerals.Pyrargyrite and accumulative silver enhanced gold dissolution for free gold and gold associated with pyrite and sphalerite.Gold dissolution was retarded for gold and silver minerals associated with chalcopyrite and stibnite.展开更多
The paleosol samples from the fifth layer of the loess profile at Renjiapo in the eastern suburb of Xi'an are observed and analyzed using electron microscope and energy spectrum. Minerals such as AgSO4 and molybde...The paleosol samples from the fifth layer of the loess profile at Renjiapo in the eastern suburb of Xi'an are observed and analyzed using electron microscope and energy spectrum. Minerals such as AgSO4 and molybdenum, which are rare to find and can indicate typical dry climate environment, are found in this layer of paleosol. Secondary mineral is usually granular form of ellipsoidal and crystallization, and has the characteristics of chemical precipitating crystallization of apertures and fracture. Molybdenum minerals have the characteristics of colloidal substances. There are two kinds of secondary minerals. One is silver sulfate mineral and the other is silver oxide mineral. The movement of secondary silver, molybdenum and cobalt minerals, new clay mineral, Fe2O3 and Al2O3 indicates that S5 has experienced strong chemical weathering and mineral dissolution during its development. Silver, molybdenum, and cobalt can be released from primary minerals. During that period, the precipitation was abundant in Xi'an where soil reached an acidity stage of chemical weathering. At the later development stage of paleosol in the lowest part of S5, warm and wet monsoon climate had changed to dry and non-monsoon climate. In the period of the formation of AgSO4, which is easier to dissolve than CaSO4, a dry and non-monsoon climate was present in the Guanzhong Plain. Strong evaporation resulted in the accumulation of SO42-in the soil water solution and the formation of AgSO4. At that time, summer monsoon of East Asia was weak and did not cross Qinling Mountains to reach Guanzhong Plain. And at that time, the precipitation in Xi'an was less than 300 mm, and it was drier then in Xi'an than at present in Lanzhou.展开更多
基金funded by the Chinese Geological Survey(Grant no.12120114039601,1212011121037,1212011220369)
文摘China has widely distributed silver deposits,and is rich in silver resources.Although silver deposits are mainly associated with Pb-Zn deposits,a number of independent silver deposits have also been discovered in recent years.Silver deposits include different types,such as submarine volcanism and continental volcanism related type,intrusion related type,and sedimentary related type.This study summarized the metallogenic regularity of China＇s silver deposits systematically based mainly on the data from 490 silver deposits.It is shown that submarine volcanic sedimentary type,continental volcanic or sub-volcanic type,skarn type,hydrothermal type（including vein type and stratabound type）,sedimentary metamorphic type,sedimentary type and regolith type should be regarded as the most important prediction types of silver deposit.A total of 32 silver mineralization belts and 111 silver concentration areas have been delineated.The map of ＂Spatial distribution of silver mineralization belts in China＂ and other series of maps finished in this study may provide a theoretical basis for the evaluation and prognosis of silver resources potential in China.
基金Financial support from the Natural Sciences and Engineering Research Council through its Cooperative Research & Development grants program
文摘Gold leaching was influenced in association with silver and polymetal sulphide minerals.A packed bed was adopted to single out the galvanic and passivation effects with four sets of minerals:pyrite?silica,chalcopyrite?silica,sphalerite?silica and stibnite?silica.Pyrargyrite enhanced Au recovery to 77.3%and 51.2%under galvanic and passivation effects from pyrite(vs 74.6%and 15.8%).Pyrargyrite in association with sphalerite also enhanced Au recovery to 6.6%and 51.9%(vs 1.6%and 15.6%)under galvanic and passivation effects from sphalerite.Pyrargyrite associated with chalcopyrite retarded gold recovery to 38.0%and 12.1%(vs 57%and 14.1%)under galvanic and passivation effects.Accumulative silver minerals enhanced Au recovery to 90.6%and 81.1%(vs 74.6%and 15.8%)under galvanic and passivation impacts from pyrite.Silver minerals with sphalerite under galvanic and passivation effects enhanced Au recovery to 71.1%and 80.5%(vs 1.6%and 15.6%).Silver minerals associated with chalcopyrite retarded Au recovery to 10.2%and 4.5%under galvanic and passivation impacts(vs 57%and 14.1%).Stibnite retarded Au dissolution with pyrargyrite and accumulative silver minerals.Pyrargyrite and accumulative silver enhanced gold dissolution for free gold and gold associated with pyrite and sphalerite.Gold dissolution was retarded for gold and silver minerals associated with chalcopyrite and stibnite.
基金supported by National Natural Science Foundation of China(Grant No. 40672108)State Key Laboratory of Chinese Academy of Sciences (Grant No. SKLLQG0916)
文摘The paleosol samples from the fifth layer of the loess profile at Renjiapo in the eastern suburb of Xi'an are observed and analyzed using electron microscope and energy spectrum. Minerals such as AgSO4 and molybdenum, which are rare to find and can indicate typical dry climate environment, are found in this layer of paleosol. Secondary mineral is usually granular form of ellipsoidal and crystallization, and has the characteristics of chemical precipitating crystallization of apertures and fracture. Molybdenum minerals have the characteristics of colloidal substances. There are two kinds of secondary minerals. One is silver sulfate mineral and the other is silver oxide mineral. The movement of secondary silver, molybdenum and cobalt minerals, new clay mineral, Fe2O3 and Al2O3 indicates that S5 has experienced strong chemical weathering and mineral dissolution during its development. Silver, molybdenum, and cobalt can be released from primary minerals. During that period, the precipitation was abundant in Xi'an where soil reached an acidity stage of chemical weathering. At the later development stage of paleosol in the lowest part of S5, warm and wet monsoon climate had changed to dry and non-monsoon climate. In the period of the formation of AgSO4, which is easier to dissolve than CaSO4, a dry and non-monsoon climate was present in the Guanzhong Plain. Strong evaporation resulted in the accumulation of SO42-in the soil water solution and the formation of AgSO4. At that time, summer monsoon of East Asia was weak and did not cross Qinling Mountains to reach Guanzhong Plain. And at that time, the precipitation in Xi'an was less than 300 mm, and it was drier then in Xi'an than at present in Lanzhou.
