Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mi...Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mineralization,whereas others hypothesize that the formation of lamprophyres increases the fertility of mantle sources and ore-forming fluids.K-feldspar veins,with ages between those of lamprophyres and gold deposits,appear in lamprophyres in Zhenyuan.Therefore,K-feldspar veins are ideal for investigating the relationship between lamprophyres and gold deposits.Phlogopite in K-feldspar veins has lower Mg#,Ni,and Cr contents and higher TiO2,Li,Ba,Sr,Sc,Zr,Nb,and Cs contents than phlogopite in lamprophyres.The in-situ Sr isotopic values of apatites(0.7063–0.7066)in K-feldspar veins are within the range for apatites(0.7064–0.7078)from lamprophyres.High large-ion lithophile element concentrations and low Nb and Ta concentrations in phlogopite from lamprophyres,in addition to high(87Sr/86Sr)i values of apatite(0.7064–0.7078),indicate that the magma parental to these phlogopite and apatite crystals is derived from an enriched mantle.Kfeldspar veins are genetically correlated with lamprophyres,whereas sulfide mineral assemblage and trace element compositions of pyrite in K-feldspar veins suggest that K-feldspar veins in lamprophyres are not directly related to gold mineralization of the Zhenyuan deposit.展开更多
Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mi...Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia.展开更多
The effects of BaCl2 on the flotation of K-feldspar using dodecyl amine chloride as the collector under natural pH wereinvestigated by flotation tests, absorption measurements, Fourier transform infrared spectroscopy ...The effects of BaCl2 on the flotation of K-feldspar using dodecyl amine chloride as the collector under natural pH wereinvestigated by flotation tests, absorption measurements, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectronspectroscopy （XPS）. The results indicated that lower BaCl2 concentration can increase the floatability of K-feldspar, whereas higherBaCl2 concentration can significantly inhibit the flotation of K-feldspar. Peaks at 3548.18, 3475.56 and 3414.35 cm？1in the FTIRspectra of K-feldspar adsorbed by dodecyl amine chloride revealed three forms of -OH. XPS analyses of K-feldspar adsorbed byBa2＋ showed that the concentration of K atom was reduced by nearly twice as those of Si, Al, and O. The activation of BaCl2 at a lowconcentration was mainly caused by Ba2＋ in the form of the ion exchange between K＋ and Ba2＋. The inhibitory action of BaCl2 at ahigh concentration is mainly attributed to the physical absorption of Ba2＋ on the surface of K-feldspar and the fact that a highconcentration of Cl？ causes the chemical equilibrium of dodecyl amine chloride to be changed, and the dodecyl amine chloride in theform of RNH2H＋ is reduced.展开更多
By using the 40Ar-39Ar chronological method to date K-feldspar from K-feldspar granite in the Qiaohuote copper district, the authors obtained a plateau age of 274.78±0.44 Ma and an isochron age of 272.7±3.0 ...By using the 40Ar-39Ar chronological method to date K-feldspar from K-feldspar granite in the Qiaohuote copper district, the authors obtained a plateau age of 274.78±0.44 Ma and an isochron age of 272.7±3.0 Ma. Because there is no tectonic deformation overprinted or hydrothermal alteration in the K-feldspar granite intrusion after its emplacement, the 40Ar-39Ar age represents the crystallization age of K-feldspar in K-feldspar granite, i.e. the late crystallization age of the K-feldspar granite intrusion, which indicates that the K-feldspar granite formed in the intraplate extensional stage during the Early Permian. Moreover, based on the spatial relationship between the K-feldspar granite intrusion and copper orebodies, variations of copper ore grade, REE characteristics of K-feldspar granite and copper ores, and H and O isotopic compositions of fluid inclusions in copper ores, the metallogenesis of the Qiaohuote copper deposit is directly related to intrusive activities of the K-feldspar granite, and thus the crystallization age of K-feldspar in the granite approximately approaches the metallogenic epoch of the Qiaohuote copper deposit.展开更多
The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-fe...The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl.As much as approximately 41% of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91% in 40 min, while the extraction was reduced to only 22% at the theoretical mass ratio of 0.2. Optimal process conditions are as follows: ore particle size of 50–75 μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min.The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the conversion reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.展开更多
The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an effic...The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an efficient methodology via the co-reaction of K-feldspar and phosphogypsum for the extraction of soluble potassium salts and recovery of SO_2 with reduced CO_2 emission and energy consumption. The results of characterization and reactivity evaluation indicated that the partial melting of K-feldspar and phosphogypsum in the hightemperature co-reaction significantly facilitated the reduction of phosphogypsum to SO_2 and the exchange of K^+(K-feldspar) with Ca^(2+)(CaSO_4 in phosphogypsum). The reaction parameters were systematically investigated with the highest sulfur recovery ratio of ~ 60% and K extraction ratio of ~ 87.7%. This novel methodology possesses an energy consumption reduction of ~ 28% and CO_2 emission reduction of ~ 55% comparing with the present typical commercial technologies for utilization of K-feldspar and the treatment of phosphogypsum.展开更多
This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim ...This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim of this study was to find an optimum experimental condition for iron(Fe) removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained. The effect of different parameters such as concentration, pH and temperature on the final structure of this mineral was investigated. To find out the chemical composition of powder, XRF was utilized. FTIR, XRD and SEM were employed to study the structure of mineral. Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment. It was found that O—Al—O bond at 647 cm^-1 for H2SO4 and HNO3 treated sample disappeared. However, HCl and C2H2O4 were ineffective at this band. In addition, the results revealed an increase in K-Feldspar content, a decrease in Fe content, an increase in whiteness index and no significant structural change for C2H2O4 leached sample. Whiteness index of 91% was obtained for C2H2O4 leached sample with the pH of 2.5 to 3 at temperature of 50 ℃ and during 1 h.展开更多
The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,re...The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,reaction temperature and time were investigated, respectively. In addition, the optimum condition for this method was determined by a series of condition experiments. What was more, the K-feldspar ore and the leach residue after reaction based on the above optimum condition were analyzed by XRD, SEM and EDS,separately. The results of which indicated that the mechanism of extraction of potassium for this method was according to the ion exchange reaction between sodium ion and potassium ion, and the extraction ratio of potassium had an obvious improvement than that of traditional methods, which could reach up to 96.25%.Therefore, this method can be a feasible solution to extract potassium from K-feldspar ore for its low energy consumption and high efficiency.展开更多
1 Introduction Yangchun basin locates in the west of Guangdong Province,where more than 50 deposits have been discovered to date,including Xishan W-Sn deposit,Shilv Cu-Mo deposits,Tiantang Cu-Pb-Zn polymetallic
The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa i...The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa in a frequency range of 10-1 Hz–106 Hz. The measured electrical conductivity along the ⊥ [001] axis direction decreases with increasing pressure, and the activation energy and activation volume of charge carriers are determined to be 1.04 ± 0.06 e V and 2.51 ± 0.19 cm~3/mole, respectively. The electrical conductivity of K-feldspar is highly anisotropic, and its value along the⊥ [001] axis is approximately three times higher than that along the ⊥ [100] axis. At 2.0 GPa, the diffusion coefficient of ionic potassium is obtained from the electrical conductivity data using the Nernst–Einstein equation. The measured electrical conductivity and calculated diffusion coefficient of potassium suggest that the main conduction mechanism is of ionic conduction, therefore the dominant charge carrier is transferred between normal lattice potassium positions and adjacent interstitial sites along the thermally activated electric field.展开更多
The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the mai...The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the main paleo-Pearl River Delta. The delta developed for a long geological time and formed a superimposed area. Almost all the oil and gas fields of detrital rock reservoir distribute in this delta. Thirty-three oil sandstone core samples in the Zhujiang Formation, lower Miocene （23-16 Ma）, were collected from nine wells. The illite samples with detrital K feldspar （Kfs） separated from these sandstone cores in four sub-structural belts were analysed by the high-precision 40Ar/39Ar laser stepwise heating technique. All 33 illite 40Ar/39Ar data consistently yielded gradually rising age spectra at the low-temperature steps until reaching age plateaus at mid-high temperature steps. The youngest ages corresponding to the beginning steps were interpreted as the hydrocarbon accumulation ages and the plateau ages in mid-high temperature steps as the contributions of the detrital feldspar representing the ages of the granitic parent rocks in the provenances. The ages of the detrital feldspar from the Zhujiang Formation in the four sub-structural belts were different： （1） the late Cretaceous ages in the Lufeng 13 fault structural belt; （2） the late Cretaceous and early Cretaceous-Jurassic ages in the Huizhou 21 buried hill-fault belt; （3） the Jurassic and Triassic ages in the Xijiang 24 buried hill-fault belt; and （4） the early Cretaceous - late Jurassic ages in the Panyu 4 oil area. These detrital feldspar 4~Ar/39Ar ages become younger and younger from west to east, corresponding to the age distribution of the granites in the adjacent Guangdong Province, Southern China.展开更多
In intermediate-acid magmatic rocks,alkaline magmatic rocks,gneisses and migmatitic rocks K-feldspar is a rook-forming rock in which the contents of Pb are highest,just 2-10 times those of the whole rock,3-16 times th...In intermediate-acid magmatic rocks,alkaline magmatic rocks,gneisses and migmatitic rocks K-feldspar is a rook-forming rock in which the contents of Pb are highest,just 2-10 times those of the whole rock,3-16 times those of mica minerals and 6-32 times those of quartz.The lowest contents of K-feldspar are recognized in Early Proterozoic and Achaean rocks,with Pb in the K-feldspar accounting for less than 10% of that in the whole rock;in post-Middle Proterozoic alkaline magmatic rocks,K-feldspar-rich granites and metamorphic rocks the contents of K-feldspar tend to increase,with the proportion of Pb over that in the whole rock being obviously increased.In the alkaline rocks in which K-feldspar accounts for 50%-70%of the total in the whole rock,the contents of Pb in K-feldspar account approximately for 70%-95% of the total lead in the whole rock.Being accessible to hydrothermal alteration in the late periods,K-feldspar was conversed to sericite,calcite,quartz,etc.In the process of such conversion the lead would be leached out and then find its way into fluid phase.This kind of trans-formation can provide sufficent ore-forming material for later Pb metallogenesis.展开更多
Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished acco...Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished according to their telations to the bedding:one is distributed along the bedding and the.other cuts across the bedding.Sn and sulfide orebodies associated with K-feldspare are mostly characterized by laminated ore structure. Microscopic examinations of K-feldspar-bearing rocks,in conjunction with X-ray diffraction,chemical composiion and cathodoluminescence data for K-feldspars,as well as their telations to mineralization,the authors consider that the K-feldspare are of authigenic origin,subordinate to the epigenetic stage of diagenesis,They resulted from the reaction of mixed,deep-seated,circulating underground hot waters rich in K,Al and Si with argillaceous carbonates during the Indo nesian orogenic movement.It is suggested more attention should be paid to the effect of authigenic K-feldspars on Sn mineralization.In the meantime the event related to circulating underground hot waters should also be taken into account so as to provide new clues to blind ore prospecting.展开更多
The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved...The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume. The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmen- ite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate ig- neous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing lherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deep- subduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western China.展开更多
The Hougou gold deposit in northwestern Hebei is a typical K-metasomatism-related gold deposit hosted by K-altered rocks overprinting alkali intrusive rocks. In order to determine the age and pulse intervals of K-meta...The Hougou gold deposit in northwestern Hebei is a typical K-metasomatism-related gold deposit hosted by K-altered rocks overprinting alkali intrusive rocks. In order to determine the age and pulse intervals of K-metasomatism in this gold deposit, some metasomatic K-feldspars from K-altered rocks are selected to measure their formation time by laser probe 40Ar-39Ar dating method. The new analyzing data show that these metasomatic K-feldspar formed during 202.6 Ma and 176.7 Ma, and the corresponding K-metasomatism and associated gold mineralization occurred in the early stage of Mesozoic era. The pulse intervals of K-metasomatism in the Hougou area are estimated to be about 4 Ma.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41973045)Basic Science and Technology Research Funding of the CAGS(Grant No.JKYZD202312)+1 种基金the National Key Research and Development Project of China(Grant No.2022YFF0800903)National Natural Science Foundation of China(Grant Nos.41802113,42073053,42273073 and 42261144669).
文摘Lamprophyres typically appear in hydrothermal gold deposits.The relationship between lamprophyres and gold deposits is investigated widely.Some researchers suggest that the emplacement of lamprophyres triggers gold mineralization,whereas others hypothesize that the formation of lamprophyres increases the fertility of mantle sources and ore-forming fluids.K-feldspar veins,with ages between those of lamprophyres and gold deposits,appear in lamprophyres in Zhenyuan.Therefore,K-feldspar veins are ideal for investigating the relationship between lamprophyres and gold deposits.Phlogopite in K-feldspar veins has lower Mg#,Ni,and Cr contents and higher TiO2,Li,Ba,Sr,Sc,Zr,Nb,and Cs contents than phlogopite in lamprophyres.The in-situ Sr isotopic values of apatites(0.7063–0.7066)in K-feldspar veins are within the range for apatites(0.7064–0.7078)from lamprophyres.High large-ion lithophile element concentrations and low Nb and Ta concentrations in phlogopite from lamprophyres,in addition to high(87Sr/86Sr)i values of apatite(0.7064–0.7078),indicate that the magma parental to these phlogopite and apatite crystals is derived from an enriched mantle.Kfeldspar veins are genetically correlated with lamprophyres,whereas sulfide mineral assemblage and trace element compositions of pyrite in K-feldspar veins suggest that K-feldspar veins in lamprophyres are not directly related to gold mineralization of the Zhenyuan deposit.
基金funded via an Australian Geophysical Observing System grant provided to Au Scope Pty Ltd.the AQ44 Australian Education Investment Fund programpartly funded by the Western Australian Exploration Incentive Scheme
文摘Detrital zircon U-Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia.
基金Project(51764021)supported by the Key Program of the National Natural Science Foundation of China
文摘The effects of BaCl2 on the flotation of K-feldspar using dodecyl amine chloride as the collector under natural pH wereinvestigated by flotation tests, absorption measurements, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectronspectroscopy （XPS）. The results indicated that lower BaCl2 concentration can increase the floatability of K-feldspar, whereas higherBaCl2 concentration can significantly inhibit the flotation of K-feldspar. Peaks at 3548.18, 3475.56 and 3414.35 cm？1in the FTIRspectra of K-feldspar adsorbed by dodecyl amine chloride revealed three forms of -OH. XPS analyses of K-feldspar adsorbed byBa2＋ showed that the concentration of K atom was reduced by nearly twice as those of Si, Al, and O. The activation of BaCl2 at a lowconcentration was mainly caused by Ba2＋ in the form of the ion exchange between K＋ and Ba2＋. The inhibitory action of BaCl2 at ahigh concentration is mainly attributed to the physical absorption of Ba2＋ on the surface of K-feldspar and the fact that a highconcentration of Cl？ causes the chemical equilibrium of dodecyl amine chloride to be changed, and the dodecyl amine chloride in theform of RNH2H＋ is reduced.
文摘By using the 40Ar-39Ar chronological method to date K-feldspar from K-feldspar granite in the Qiaohuote copper district, the authors obtained a plateau age of 274.78±0.44 Ma and an isochron age of 272.7±3.0 Ma. Because there is no tectonic deformation overprinted or hydrothermal alteration in the K-feldspar granite intrusion after its emplacement, the 40Ar-39Ar age represents the crystallization age of K-feldspar in K-feldspar granite, i.e. the late crystallization age of the K-feldspar granite intrusion, which indicates that the K-feldspar granite formed in the intraplate extensional stage during the Early Permian. Moreover, based on the spatial relationship between the K-feldspar granite intrusion and copper orebodies, variations of copper ore grade, REE characteristics of K-feldspar granite and copper ores, and H and O isotopic compositions of fluid inclusions in copper ores, the metallogenesis of the Qiaohuote copper deposit is directly related to intrusive activities of the K-feldspar granite, and thus the crystallization age of K-feldspar in the granite approximately approaches the metallogenic epoch of the Qiaohuote copper deposit.
基金Supported by the Ministry of Science and Technology(State Key Research Plan2013BAC12B03)the National Natural Science Foundation of China(21236004,21336004)
文摘The extraction of potassium from K-feldspar via a calcium chloride calcination route was studied with a focus on the effects of the calcination atmosphere, calcination temperature and time, mass ratio of CaCl2 to K-feldspar ore and particle size of the K-feldspar ore. The results demonstrated that a competing high-temperature hydrolysis reaction of calcium chloride with moisture in a damp atmosphere occurred concurrently with the conversion reaction of K-feldspar with CaCl2, thus reducing the amount of potassium extracted. The conversion reaction started at approximately 600 °C and accelerated with increasing temperature. When the temperature rose above 900 °C, the extraction of potassium gradually decreased due to the volatilization of the product, KCl.As much as approximately 41% of the potassium was volatilized in 40 min at 1100 °C. The mass ratio of CaCl2/K-feldspar ore significantly affected the extraction. At a mass ratio of 1.15 and 900 °C, the potassium extraction reached 91% in 40 min, while the extraction was reduced to only 22% at the theoretical mass ratio of 0.2. Optimal process conditions are as follows: ore particle size of 50–75 μm, tablet forming pressure of 3 MPa, dry nitrogen atmosphere, mass ratio of CaCl2/ore 1.15:1, calcination temperature of 900 °C, and calcination time of 40 min.The XRD analysis revealed that a complex phase transition of the product SiO2 was also accompanied by the conversion reaction of K-feldspar/CaCl2. The SiO2 product formed at the initial stage was in the quartz phase at 900 °C and was gradually transformed into cristobalite after 30 min.
基金Supported by the National Natural Science Foundation of China(21336004)the State Key Research Plan of the Ministry of Science and Technology(2013BAC12B03)
文摘The issues of reducing CO_2 emissions, sustainably utilizing natural mineral resources, and dealing with industrial waste offer challenges for sustainable development in energy and the environment. We propose an efficient methodology via the co-reaction of K-feldspar and phosphogypsum for the extraction of soluble potassium salts and recovery of SO_2 with reduced CO_2 emission and energy consumption. The results of characterization and reactivity evaluation indicated that the partial melting of K-feldspar and phosphogypsum in the hightemperature co-reaction significantly facilitated the reduction of phosphogypsum to SO_2 and the exchange of K^+(K-feldspar) with Ca^(2+)(CaSO_4 in phosphogypsum). The reaction parameters were systematically investigated with the highest sulfur recovery ratio of ~ 60% and K extraction ratio of ~ 87.7%. This novel methodology possesses an energy consumption reduction of ~ 28% and CO_2 emission reduction of ~ 55% comparing with the present typical commercial technologies for utilization of K-feldspar and the treatment of phosphogypsum.
文摘This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C2H2O4, HCl, HNO3 and H2SO4 were employed for this purpose. Another aim of this study was to find an optimum experimental condition for iron(Fe) removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained. The effect of different parameters such as concentration, pH and temperature on the final structure of this mineral was investigated. To find out the chemical composition of powder, XRF was utilized. FTIR, XRD and SEM were employed to study the structure of mineral. Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment. It was found that O—Al—O bond at 647 cm^-1 for H2SO4 and HNO3 treated sample disappeared. However, HCl and C2H2O4 were ineffective at this band. In addition, the results revealed an increase in K-Feldspar content, a decrease in Fe content, an increase in whiteness index and no significant structural change for C2H2O4 leached sample. Whiteness index of 91% was obtained for C2H2O4 leached sample with the pH of 2.5 to 3 at temperature of 50 ℃ and during 1 h.
基金Supported by the National Natural Science Foundation of China(21373252)Fundamental Research Project of Qing Hai Science&Technology Department(2016-ZJ-749)Qinghai Innovation Fund for Technology Based Firms(2014-GX-Q19)
文摘The low temperature molten salt method was used to extract potassium from K-feldspar ore, and some related factors including mass ratio between NaNO_3, NaOH, H_2O and K-feldspar ore, particle size of K-feldspar ore,reaction temperature and time were investigated, respectively. In addition, the optimum condition for this method was determined by a series of condition experiments. What was more, the K-feldspar ore and the leach residue after reaction based on the above optimum condition were analyzed by XRD, SEM and EDS,separately. The results of which indicated that the mechanism of extraction of potassium for this method was according to the ion exchange reaction between sodium ion and potassium ion, and the extraction ratio of potassium had an obvious improvement than that of traditional methods, which could reach up to 96.25%.Therefore, this method can be a feasible solution to extract potassium from K-feldspar ore for its low energy consumption and high efficiency.
基金funded by the projects of the China Geological Survey [grant numbers 12120114005701 and No.DD20160029]
文摘1 Introduction Yangchun basin locates in the west of Guangdong Province,where more than 50 deposits have been discovered to date,including Xishan W-Sn deposit,Shilv Cu-Mo deposits,Tiantang Cu-Pb-Zn polymetallic
基金Project supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(CAS)(Grant No.XDB 18010401)the Key Research Program of Frontier Sciences of CAS(Grant No.QYZDB-SSW-DQC009)+2 种基金the“135”Program of the Institute of Geochemistry of CASthe Hundred-Talent Program of CASthe National Natural Science Foundation of China(Grant Nos.41474078,41774099,and 41772042)
文摘The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa in a frequency range of 10-1 Hz–106 Hz. The measured electrical conductivity along the ⊥ [001] axis direction decreases with increasing pressure, and the activation energy and activation volume of charge carriers are determined to be 1.04 ± 0.06 e V and 2.51 ± 0.19 cm~3/mole, respectively. The electrical conductivity of K-feldspar is highly anisotropic, and its value along the⊥ [001] axis is approximately three times higher than that along the ⊥ [100] axis. At 2.0 GPa, the diffusion coefficient of ionic potassium is obtained from the electrical conductivity data using the Nernst–Einstein equation. The measured electrical conductivity and calculated diffusion coefficient of potassium suggest that the main conduction mechanism is of ionic conduction, therefore the dominant charge carrier is transferred between normal lattice potassium positions and adjacent interstitial sites along the thermally activated electric field.
基金supported by the National Natural Science Foundation of China (40972095)the NationalS & T Major Project (2008ZX05023-03)
文摘The South China Sea began to outspread in the Oligocene. A great quantity of terraneous detritus was deposited in the northern continental shelf of the sea, mostly in Pearl River Mouth Basin, which constituted the main paleo-Pearl River Delta. The delta developed for a long geological time and formed a superimposed area. Almost all the oil and gas fields of detrital rock reservoir distribute in this delta. Thirty-three oil sandstone core samples in the Zhujiang Formation, lower Miocene （23-16 Ma）, were collected from nine wells. The illite samples with detrital K feldspar （Kfs） separated from these sandstone cores in four sub-structural belts were analysed by the high-precision 40Ar/39Ar laser stepwise heating technique. All 33 illite 40Ar/39Ar data consistently yielded gradually rising age spectra at the low-temperature steps until reaching age plateaus at mid-high temperature steps. The youngest ages corresponding to the beginning steps were interpreted as the hydrocarbon accumulation ages and the plateau ages in mid-high temperature steps as the contributions of the detrital feldspar representing the ages of the granitic parent rocks in the provenances. The ages of the detrital feldspar from the Zhujiang Formation in the four sub-structural belts were different： （1） the late Cretaceous ages in the Lufeng 13 fault structural belt; （2） the late Cretaceous and early Cretaceous-Jurassic ages in the Huizhou 21 buried hill-fault belt; （3） the Jurassic and Triassic ages in the Xijiang 24 buried hill-fault belt; and （4） the early Cretaceous - late Jurassic ages in the Panyu 4 oil area. These detrital feldspar 4~Ar/39Ar ages become younger and younger from west to east, corresponding to the age distribution of the granites in the adjacent Guangdong Province, Southern China.
文摘In intermediate-acid magmatic rocks,alkaline magmatic rocks,gneisses and migmatitic rocks K-feldspar is a rook-forming rock in which the contents of Pb are highest,just 2-10 times those of the whole rock,3-16 times those of mica minerals and 6-32 times those of quartz.The lowest contents of K-feldspar are recognized in Early Proterozoic and Achaean rocks,with Pb in the K-feldspar accounting for less than 10% of that in the whole rock;in post-Middle Proterozoic alkaline magmatic rocks,K-feldspar-rich granites and metamorphic rocks the contents of K-feldspar tend to increase,with the proportion of Pb over that in the whole rock being obviously increased.In the alkaline rocks in which K-feldspar accounts for 50%-70%of the total in the whole rock,the contents of Pb in K-feldspar account approximately for 70%-95% of the total lead in the whole rock.Being accessible to hydrothermal alteration in the late periods,K-feldspar was conversed to sericite,calcite,quartz,etc.In the process of such conversion the lead would be leached out and then find its way into fluid phase.This kind of trans-formation can provide sufficent ore-forming material for later Pb metallogenesis.
文摘Sn-polymetallic ores at Dachang,Guangxi Autonomous Region,China,are hosted in Middle-Upper Devonian reef limestones,siliceous rocks,banded and lenticular limestones,etc.Two types of orebodies can be distinguished according to their telations to the bedding:one is distributed along the bedding and the.other cuts across the bedding.Sn and sulfide orebodies associated with K-feldspare are mostly characterized by laminated ore structure. Microscopic examinations of K-feldspar-bearing rocks,in conjunction with X-ray diffraction,chemical composiion and cathodoluminescence data for K-feldspars,as well as their telations to mineralization,the authors consider that the K-feldspare are of authigenic origin,subordinate to the epigenetic stage of diagenesis,They resulted from the reaction of mixed,deep-seated,circulating underground hot waters rich in K,Al and Si with argillaceous carbonates during the Indo nesian orogenic movement.It is suggested more attention should be paid to the effect of authigenic K-feldspars on Sn mineralization.In the meantime the event related to circulating underground hot waters should also be taken into account so as to provide new clues to blind ore prospecting.
基金the National Key Basic Research Program of China(Grant No. 1999075508) the National Natural Science Foundation of China(Grant Nos.40372088,49972063 , 140032010-c)+1 种基金the Cadreman Teacher Foundation of the Ministry of Education of China (Grant No. 40133020) the Open Foundation of the Laboratory of Orogen and Basin of the Ministry of Education of Peking University.
文摘The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume. The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmen- ite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate ig- neous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing lherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deep- subduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western China.
基金This work was supported by the National Natural Science Foundation of China (Grant No.49802021)
文摘The Hougou gold deposit in northwestern Hebei is a typical K-metasomatism-related gold deposit hosted by K-altered rocks overprinting alkali intrusive rocks. In order to determine the age and pulse intervals of K-metasomatism in this gold deposit, some metasomatic K-feldspars from K-altered rocks are selected to measure their formation time by laser probe 40Ar-39Ar dating method. The new analyzing data show that these metasomatic K-feldspar formed during 202.6 Ma and 176.7 Ma, and the corresponding K-metasomatism and associated gold mineralization occurred in the early stage of Mesozoic era. The pulse intervals of K-metasomatism in the Hougou area are estimated to be about 4 Ma.
