Leucite particles were synthesized from feldspar mixed with 0% to 52% potassium nitrate fired from 800 ℃ to 1 200 ℃ by solid state method. The X-ray Diffraction （XRD） patterns show that in the temperature range fr...Leucite particles were synthesized from feldspar mixed with 0% to 52% potassium nitrate fired from 800 ℃ to 1 200 ℃ by solid state method. The X-ray Diffraction （XRD） patterns show that in the temperature range from 800 ℃ to 1 200 ℃, the leucite can be removed as the single crystalline phase. Kalsilite may be crystallized with leucite at 800 ℃, but can be eliminated after prolonged heating. The scanning electron Microscopy （SEM） images clearly display the that crystals of micrometer scale leucite, and the leucite crystals distribute evenly in the matrix. The Thermal expansion coefficient （TEC） of the samples fabricated is as high as 20.52×10^-6 ℃^-1 measured from 20 ℃ to 500 ℃. The mechanism of transformation from feldspar to leucite was proposed.展开更多
A new permanent magnetic separator was introduced to treat the ores with the characteristics of weak magnetic iron minerals and in a fine size range. The new machine was applied to the iron removal from potash feldspa...A new permanent magnetic separator was introduced to treat the ores with the characteristics of weak magnetic iron minerals and in a fine size range. The new machine was applied to the iron removal from potash feldspar. The effects of the magnetic field intensity, pulp density and grinding fineness on the iron removal were investigated. The optimized operation parameters were achieved and listed as follows： the -0.074 mm content is 85%, the pulp density is 45% and the magnetic field strength is 2T. A close test of middles regrinding was also carried out to improve concentrate yield. The data show that the grade of TFe（total iron） in potash feldspar product decreased from 1.31% to 0.21% and the concentrate yield reached 85.32%. All the results indicated that the traditonal high-intensity electromagnetic separators can be betterly substituted by the new permanent magnetic separator. This study may provide the theoretical evidence for iron removal from potash feldspar.展开更多
A novel process was developed for the preparation of ultrafine silica from potash feldspar. In the first step, potash feldspar was roasted with Na_2CO_3 and was followed by leaching using Na OH solution to increase th...A novel process was developed for the preparation of ultrafine silica from potash feldspar. In the first step, potash feldspar was roasted with Na_2CO_3 and was followed by leaching using Na OH solution to increase the levels of potassium, sodium, and aluminum in the solid residue. The leaching solution was then carbonated to yield ultrafine silica. The optimized reaction conditions in the roasting process were as follows： an Na_2CO_3-to-potash feldspar molar ratio of 1.1, a reaction temperature of 875°C, and a reaction time of 1.5 h. Under these conditions, the extraction rate of SiO_2 was 98.13%. The optimized carbonation conditions included a final solution p H value of 9.0, a temperature of 40°C, a CO_2 flow rate of 6 m L/min, a stirring intensity of 600 r/min, and an ethanol-to-water volume ratio of 1：9. The precipitation rate and granularity of the SiO_2 particles were 99.63% and 200 nm, respectively. We confirmed the quality of the obtained ultrafine silica by comparing the recorded indexes with those specified in Chinese National Standard GB 25576―2010.展开更多
A novel process was proposed for the utilization of potash feldspar by roasting in the presence of sodium carbonate.The effects of roasting temperature,granularity,molar ratio of sodium carbonate to potash feldspar an...A novel process was proposed for the utilization of potash feldspar by roasting in the presence of sodium carbonate.The effects of roasting temperature,granularity,molar ratio of sodium carbonate to potash feldspar and roasting time on the silica extraction rate were investigated.Under the optimal roasting conditions,the silica extraction rate was 98%.The optimal conditions,determined using an orthogonal experiment,were found to be roasting temperature of 875 °C,potash feldspar granularity of 74– 89 μm,molar ratio of sodium carbonate to potash feldspar of 1.2:1,and roasting time of 80 min.The kinetics of potash feldspar roasting in the presence of sodium carbonate was described by the shrinking core model and the reaction rate was found to be controlled by the chemical reaction at the particle surface.According to the Arrhenius expression,the activation energy was 164.99 k J/mol,and the process could be expressed as [1-(1-α)1/3]=2.66×105 exp[-164990/(RT)] t.展开更多
The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods h...The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods have positive effects on conversion of K in potash feldspar into water-soluble form, but the conversion is low; chemical method can change most of insoluble potassium into available form, and might be significant in industry to some extent.展开更多
The characterization of feldspar for electric porcelain and the behaviour of these materials after heating at 1230°C were studied. X-ray diffraction （XRD） and scanning electronic microscopy （SEM） were used to...The characterization of feldspar for electric porcelain and the behaviour of these materials after heating at 1230°C were studied. X-ray diffraction （XRD） and scanning electronic microscopy （SEM） were used to identify the present phases and the densification level. Feldspar sand was treated by flotation. The floated feldspar is constituted by microcline, quartz, and minor amounts of albite. The micro-structure of sintered feldspar at 1230°C is essentially vitreous with open microporosities. The dielectrical properties of composites were characterized by using the induced courant method （ICM）, which indicates that the charge trapping capacity depends on the mineralogical and chemical composition of feldspar.展开更多
The extraction of potassium from potash feldspar by NaCl, CaCl 2, SrCl 2 and BaCl 2 has been investigated as function of salt kind and calcination temperature. The phase compositions of potash feldspar and its calcina...The extraction of potassium from potash feldspar by NaCl, CaCl 2, SrCl 2 and BaCl 2 has been investigated as function of salt kind and calcination temperature. The phase compositions of potash feldspar and its calcinated, and water insoluble substances of NaCl, CaCl 2 co-calcinated potash feldspar were analyzed by XRD. The experiment results showed that the order of ion exchange extraction of potassium was Na +>Ca 2+>Sr 2+>Ba 2+, and at calcination temperature over the melting points of NaCl or CaCl 2, the two salts gave potassium ion-exchange degree >90% much greater than that calcinated with other salts.展开更多
基金the National High Technology Research and Development Program of China(No.2002AA302204)Science and Technology Program of Guangdong Province of China(No.2001A1070102)Science and Technology Program of Guangzhou City of China
文摘Leucite particles were synthesized from feldspar mixed with 0% to 52% potassium nitrate fired from 800 ℃ to 1 200 ℃ by solid state method. The X-ray Diffraction （XRD） patterns show that in the temperature range from 800 ℃ to 1 200 ℃, the leucite can be removed as the single crystalline phase. Kalsilite may be crystallized with leucite at 800 ℃, but can be eliminated after prolonged heating. The scanning electron Microscopy （SEM） images clearly display the that crystals of micrometer scale leucite, and the leucite crystals distribute evenly in the matrix. The Thermal expansion coefficient （TEC） of the samples fabricated is as high as 20.52×10^-6 ℃^-1 measured from 20 ℃ to 500 ℃. The mechanism of transformation from feldspar to leucite was proposed.
基金Funded by the National High-tech R&D Program of China(No.2007AA06Z123)the Hubei Provincial Key Laboratory of Pollutant Analysis and Recycling Project(KY2010G19)the Independent Innovation Research Fund of Wuhan University of Technology(2010-YB-16)
文摘A new permanent magnetic separator was introduced to treat the ores with the characteristics of weak magnetic iron minerals and in a fine size range. The new machine was applied to the iron removal from potash feldspar. The effects of the magnetic field intensity, pulp density and grinding fineness on the iron removal were investigated. The optimized operation parameters were achieved and listed as follows： the -0.074 mm content is 85%, the pulp density is 45% and the magnetic field strength is 2T. A close test of middles regrinding was also carried out to improve concentrate yield. The data show that the grade of TFe（total iron） in potash feldspar product decreased from 1.31% to 0.21% and the concentrate yield reached 85.32%. All the results indicated that the traditonal high-intensity electromagnetic separators can be betterly substituted by the new permanent magnetic separator. This study may provide the theoretical evidence for iron removal from potash feldspar.
基金financially supported by the National Nature Science Foundation of China (No. 51204054)the National Basic Research Program of China (No. 2007CB613603)the Basic Scientific Research Business Expenses Project of the Ministry of Education (No. 140204011)
文摘A novel process was developed for the preparation of ultrafine silica from potash feldspar. In the first step, potash feldspar was roasted with Na_2CO_3 and was followed by leaching using Na OH solution to increase the levels of potassium, sodium, and aluminum in the solid residue. The leaching solution was then carbonated to yield ultrafine silica. The optimized reaction conditions in the roasting process were as follows： an Na_2CO_3-to-potash feldspar molar ratio of 1.1, a reaction temperature of 875°C, and a reaction time of 1.5 h. Under these conditions, the extraction rate of SiO_2 was 98.13%. The optimized carbonation conditions included a final solution p H value of 9.0, a temperature of 40°C, a CO_2 flow rate of 6 m L/min, a stirring intensity of 600 r/min, and an ethanol-to-water volume ratio of 1：9. The precipitation rate and granularity of the SiO_2 particles were 99.63% and 200 nm, respectively. We confirmed the quality of the obtained ultrafine silica by comparing the recorded indexes with those specified in Chinese National Standard GB 25576―2010.
基金Project(51204054)supported by the National Natural Science Foundation of ChinaProject(2007CB613603)supported by the National Basic Research Program of ChinaProject(N140204011)supported by the Ministry of Education Basic Scientific Research Business Expenses,China
文摘A novel process was proposed for the utilization of potash feldspar by roasting in the presence of sodium carbonate.The effects of roasting temperature,granularity,molar ratio of sodium carbonate to potash feldspar and roasting time on the silica extraction rate were investigated.Under the optimal roasting conditions,the silica extraction rate was 98%.The optimal conditions,determined using an orthogonal experiment,were found to be roasting temperature of 875 °C,potash feldspar granularity of 74– 89 μm,molar ratio of sodium carbonate to potash feldspar of 1.2:1,and roasting time of 80 min.The kinetics of potash feldspar roasting in the presence of sodium carbonate was described by the shrinking core model and the reaction rate was found to be controlled by the chemical reaction at the particle surface.According to the Arrhenius expression,the activation energy was 164.99 k J/mol,and the process could be expressed as [1-(1-α)1/3]=2.66×105 exp[-164990/(RT)] t.
文摘The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods have positive effects on conversion of K in potash feldspar into water-soluble form, but the conversion is low; chemical method can change most of insoluble potassium into available form, and might be significant in industry to some extent.
文摘The characterization of feldspar for electric porcelain and the behaviour of these materials after heating at 1230°C were studied. X-ray diffraction （XRD） and scanning electronic microscopy （SEM） were used to identify the present phases and the densification level. Feldspar sand was treated by flotation. The floated feldspar is constituted by microcline, quartz, and minor amounts of albite. The micro-structure of sintered feldspar at 1230°C is essentially vitreous with open microporosities. The dielectrical properties of composites were characterized by using the induced courant method （ICM）, which indicates that the charge trapping capacity depends on the mineralogical and chemical composition of feldspar.
文摘The extraction of potassium from potash feldspar by NaCl, CaCl 2, SrCl 2 and BaCl 2 has been investigated as function of salt kind and calcination temperature. The phase compositions of potash feldspar and its calcinated, and water insoluble substances of NaCl, CaCl 2 co-calcinated potash feldspar were analyzed by XRD. The experiment results showed that the order of ion exchange extraction of potassium was Na +>Ca 2+>Sr 2+>Ba 2+, and at calcination temperature over the melting points of NaCl or CaCl 2, the two salts gave potassium ion-exchange degree >90% much greater than that calcinated with other salts.
