The results of REE leached by some organic acids with various concentrations and water/rock ratios for different durations from a mixed sample of the weathering crust of a granite in Gonghe, Guangdong, China, showed t...The results of REE leached by some organic acids with various concentrations and water/rock ratios for different durations from a mixed sample of the weathering crust of a granite in Gonghe, Guangdong, China, showed that: 1) the contents of REE leached increase with increasing concentrations of the organic acids; 2) the contents of REE leached by 0.01 mol/L organic acids increase with increasing water/rock ratio; 3) the interaction between the organic acids and the samples enhances the pH value of the medium and the contents of REE leached tend to increase with decreasing pH value; and 4) compared with those leached by ammonia sulfate, the REE leached by the organic acids are characterized by a weaker negative Ce anomaly, a stronger negative Eu anomaly, and lower (La/Sm)\-N and (Gd/Yb)\-N ratios, indicating that the organic acids have made contributions to the fractionation of REE in the weathering crust.展开更多
Microbes were cultured and identified from the samples collected at various depths in 4 weathering profiles of REE\|bearing granites in Gonghe, Guangdong. The microbes were found existing at the depth of 0-5 m in all ...Microbes were cultured and identified from the samples collected at various depths in 4 weathering profiles of REE\|bearing granites in Gonghe, Guangdong. The microbes were found existing at the depth of 0-5 m in all the profiles. The main microbes include coccus (Staphylococcus, Streptococcus), bacillus (Bacillus, Clostridium and Escherichia Coli), actinomyces and fungi (Saccharomycete, Penicillium, Fusarium, Aspergillus Aiger and Mucor). The number of colonies decreases downwards in the profiles. Experimental studies show that all the microbes used in the experiment can accelerate downward migration of REE in the experimental tubes. The ability to accelerate the migration of REE decreases in a sequence of fungi→actinomyces→bacillus→coccus. The microbes can change the modes of occurrence of REE in the weathering crust. The coccus, bacillus and actinomyces can increase the amounts of REE in ion state, whereas the fungi have a stronger ability to form organic compounding REE and accumulate REE than the bacteria do.展开更多
An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experim...An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experiments,column chromatography,ion-exchange chromatography,infrared spectrum.fluorescence spectrum,polarimicroscopic testing and elemental determination by ultraviolet-visible spectrometer and atomic absorption spectrometer.it was proved to be a compound of humic acid and clays which are connected in the form of bridge by heteronuclearpolynuclear complexing ions formed by cations of RE￣(5+),Al￣(3+).Fe￣(3+) etc.The compounding pattern was further proved by the experiment for compounding humic acid,REE and kaolinite.展开更多
Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcent...Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks.展开更多
Five species of bacteria have been found in granite-weathering profiles of Ore District 701.They tend to decrease in varieties and quantities from the upper part down-ward, and no bacterium has been brought up below t...Five species of bacteria have been found in granite-weathering profiles of Ore District 701.They tend to decrease in varieties and quantities from the upper part down-ward, and no bacterium has been brought up below the depth of 10 m.The simulating experiments done by using humic acid of small molecular weight ,and decanedioic acid extracted from the samples and the bacteria mentioned above have shown that:(1)The dissolving rates of REEs from humic acid+original rock or decanedioic acid +original rock are lower than those from humic acid +bacteria +original rock or decanedioic acid +bacteria+original rock.The presence of bacteria may accelerate the formation of REE-organic complexes and make the complexes increase in quantity.Aminoacids in the bacteria are involved in coordination balance.The concentrations of the complexes tend to increase as a result of the formation of the complexes,i.e., the dissolution, complexation, migration and accumulation of REEs from the original rocks will be accelerated.(2)The metabolism of microorganisms has contributed a lot to keeping a pH environment in the weathering crust.展开更多
基金ThisworkwasgrantedbytheNaturalScienceFoundationofGuangdongProvince China (GrantNos.96 0 0 42 990 2 32 )
文摘The results of REE leached by some organic acids with various concentrations and water/rock ratios for different durations from a mixed sample of the weathering crust of a granite in Gonghe, Guangdong, China, showed that: 1) the contents of REE leached increase with increasing concentrations of the organic acids; 2) the contents of REE leached by 0.01 mol/L organic acids increase with increasing water/rock ratio; 3) the interaction between the organic acids and the samples enhances the pH value of the medium and the contents of REE leached tend to increase with decreasing pH value; and 4) compared with those leached by ammonia sulfate, the REE leached by the organic acids are characterized by a weaker negative Ce anomaly, a stronger negative Eu anomaly, and lower (La/Sm)\-N and (Gd/Yb)\-N ratios, indicating that the organic acids have made contributions to the fractionation of REE in the weathering crust.
基金ThisworkwasgrantedbytheNaturalScienceFoundationofGuangdongProvince China !(GrantNo .96 0 0 42 )
文摘Microbes were cultured and identified from the samples collected at various depths in 4 weathering profiles of REE\|bearing granites in Gonghe, Guangdong. The microbes were found existing at the depth of 0-5 m in all the profiles. The main microbes include coccus (Staphylococcus, Streptococcus), bacillus (Bacillus, Clostridium and Escherichia Coli), actinomyces and fungi (Saccharomycete, Penicillium, Fusarium, Aspergillus Aiger and Mucor). The number of colonies decreases downwards in the profiles. Experimental studies show that all the microbes used in the experiment can accelerate downward migration of REE in the experimental tubes. The ability to accelerate the migration of REE decreases in a sequence of fungi→actinomyces→bacillus→coccus. The microbes can change the modes of occurrence of REE in the weathering crust. The coccus, bacillus and actinomyces can increase the amounts of REE in ion state, whereas the fungi have a stronger ability to form organic compounding REE and accumulate REE than the bacteria do.
文摘An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experiments,column chromatography,ion-exchange chromatography,infrared spectrum.fluorescence spectrum,polarimicroscopic testing and elemental determination by ultraviolet-visible spectrometer and atomic absorption spectrometer.it was proved to be a compound of humic acid and clays which are connected in the form of bridge by heteronuclearpolynuclear complexing ions formed by cations of RE￣(5+),Al￣(3+).Fe￣(3+) etc.The compounding pattern was further proved by the experiment for compounding humic acid,REE and kaolinite.
文摘Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, Jiangxi Province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks.
基金National Natural Science Foundation of China and the StateKey Laboratory of Orgamc GeochemistryGuangzhou Institute of GeochemistryChinese Academy of Sciences
文摘Five species of bacteria have been found in granite-weathering profiles of Ore District 701.They tend to decrease in varieties and quantities from the upper part down-ward, and no bacterium has been brought up below the depth of 10 m.The simulating experiments done by using humic acid of small molecular weight ,and decanedioic acid extracted from the samples and the bacteria mentioned above have shown that:(1)The dissolving rates of REEs from humic acid+original rock or decanedioic acid +original rock are lower than those from humic acid +bacteria +original rock or decanedioic acid +bacteria+original rock.The presence of bacteria may accelerate the formation of REE-organic complexes and make the complexes increase in quantity.Aminoacids in the bacteria are involved in coordination balance.The concentrations of the complexes tend to increase as a result of the formation of the complexes,i.e., the dissolution, complexation, migration and accumulation of REEs from the original rocks will be accelerated.(2)The metabolism of microorganisms has contributed a lot to keeping a pH environment in the weathering crust.
