The properties of aluminosilicate kalsilite have attracted the interest of researchers in chemical synthesis, ceramic industry, biofuels, etc. In this study, kalsilite was hydrothermally synthesized from microcline po...The properties of aluminosilicate kalsilite have attracted the interest of researchers in chemical synthesis, ceramic industry, biofuels, etc. In this study, kalsilite was hydrothermally synthesized from microcline powder in a KOH solution. The microcline powder, rich in potassium, aluminum, and silicon, was collected from Mountain Changling in Northwestem China. The effects of temperature, time, and KOH concentration on the decomposition of microcline were investigated. The kalsilite and intermediate products were characterized by means of wet chemistry analysis, X-ray Diffraction （XRD）, infi＇ared spectrometry （IR）, 29Si magic angle spinning nuclear magnetic resonance （29Si MAS NMR）, 27A1 MAS NMR, and scanning electron microscope （SEM）. With increasing temperature, the microcline powder transforms into a metastable KAlSiO4 polymorph before transforming further into pure kalsilite. A mixture of both kalsilite and metastable KAlSiO4 polymorph is obtained when the hydrothermal reaction is carried out within 2 h; but after 2 h, kalsilite is the predominant product. The concentration of KOH, which needs to be larger than 4.3 M, is an important parameter influencing the synthesis ofkalsilite.展开更多
The dripping zone in a blast furnace plays a crucial role in connecting the cohesive zone with the hearth,and its stability significantly impacts low-carbon smelting processes.Based on a detailed anatomical study of a...The dripping zone in a blast furnace plays a crucial role in connecting the cohesive zone with the hearth,and its stability significantly impacts low-carbon smelting processes.Based on a detailed anatomical study of a 2200-m3 blast furnace in China,it involves core sampling of the furnace dripping zone and uses scanning electron microscopy to investigate the micro-morphology of potassium(K)and sulfur(S)within this region.The formation process of kalsilite(KAlSiO4)and CaS inside the furnace is elucidated.The results show that when potassium vapor rises to the upper area of the dripping zone,some of it adsorbs onto the coke pore walls and reacts with the dripping slag and coke ash to form kalsilite.The formation pathways of CaS differ between upper and lower areas of the dripping zone.It forms mainly from the reaction of slag with SO2 in the gas flow and from the slag–coke interface reaction.The CaS generated from the slag–coke interface reaction is the major source of CaS in the dripping zone.Based on the formation mechanisms of kalsilite and CaS in the dripping zone,it is possible to regulate their formation by adjusting the temperature,slag phase composition,and the content of harmful elements in the raw materials.It provides theoretical insights into the behavior of harmful elements in the blast furnace,offering guidance for steel enterprises to ensure the stable operation of the dripping zone,reduce fuel consumption,and achieve greener production.展开更多
The transesterification reaction of soybean oil with methanol over kalsilite-based heterogeneous catalysts was investigated.The kalsilite was synthesized from potassium silicate,potassium hydroxide,and aluminum nitrat...The transesterification reaction of soybean oil with methanol over kalsilite-based heterogeneous catalysts was investigated.The kalsilite was synthesized from potassium silicate,potassium hydroxide,and aluminum nitrate aqueous solutions by controlling the pH value at 13.After calcination in air at 1200°C,a very porous kalsilite(KAlSiO4)was obtained with surface pores ranging from 0.2 to 1.0µm.However,this kalsilite had relatively low catalytic activity for the transesterification reaction.A biodiesel yield of 54.4%and a kinematic viscosity of 7.06 cSt were obtained at a high reaction temperature of 180°C in a batch reactor.The catalytic activity of kalsilite was significantly enhanced by introducing a small amount of lithium nitrate in the impregnation method.A biodiesel yield of 100%and a kinematic viscosity of 3.84 cSt were achieved at a temperature of only 120°C over this lithium modified catalyst(2.3 wt-%Li).The test of this lithium modified catalyst in pellet form in a laboratory-scalefixed-bed reactor showed that it maintained a stable catalytic performance with a biodiesel yield of 100%over thefirst 90 min.展开更多
Porcelain fused to metal(PFM)has received great attention over the last few years due to its importance in the dentistry.Kalsilite(K_(2)O·Al_(2)O_(3)·SiO_(2))is a high thermal expansion porcelain,suitable fo...Porcelain fused to metal(PFM)has received great attention over the last few years due to its importance in the dentistry.Kalsilite(K_(2)O·Al_(2)O_(3)·SiO_(2))is a high thermal expansion porcelain,suitable for bonding to metals.However,kalsilite is a metastable phase which gets converted into crystalline leucite upon heating.In the current work feasibility of developing stable kalsilite phase,dispersion of MgF2 in it as an additive and using mechanochemical synthesis are studied.Micro fine dental material has been formulated by mixing prepared kalsilite with low temperature frit(LTF)in different ratio.The crystalline phases evolved in fired powders are characterized by powder X-ray diffraction(XRD)technique.Kalsilite with different ratio of LTF has been cold pressed and heat treated to examine its coefficient of thermal expansion(CTE),flexural strength,apparent porosity(AP),bulk density(BD)and microstructure.Results indicate that MgF_(2) addition and high milling duration help in kalsilite stabilization.Temperature also plays an important role in this stabilization,and at 1100℃single phase kalsilite formation is observed.Present outcomes demonstrate that it is easily possible to synthesize a stable single phase kalsilite with desirable properties.展开更多
Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource wi...Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource with the main mineral of microcline is extremely abundant. The microcline powder used is collected from Mountain Changling, Luonan county of Shaanxi Province. The chemical analysis results showed that the main chemical components of the powder are SiO2, Al2O3 and K2O, the K2O content is up to 13.56% (shown in table 1).展开更多
基金financially supported by the Key Projects in the National Science & Technology Pillar Program during the Eleventh Five-year Plan Period (No. 2006BAD10B04)
文摘The properties of aluminosilicate kalsilite have attracted the interest of researchers in chemical synthesis, ceramic industry, biofuels, etc. In this study, kalsilite was hydrothermally synthesized from microcline powder in a KOH solution. The microcline powder, rich in potassium, aluminum, and silicon, was collected from Mountain Changling in Northwestem China. The effects of temperature, time, and KOH concentration on the decomposition of microcline were investigated. The kalsilite and intermediate products were characterized by means of wet chemistry analysis, X-ray Diffraction （XRD）, infi＇ared spectrometry （IR）, 29Si magic angle spinning nuclear magnetic resonance （29Si MAS NMR）, 27A1 MAS NMR, and scanning electron microscope （SEM）. With increasing temperature, the microcline powder transforms into a metastable KAlSiO4 polymorph before transforming further into pure kalsilite. A mixture of both kalsilite and metastable KAlSiO4 polymorph is obtained when the hydrothermal reaction is carried out within 2 h; but after 2 h, kalsilite is the predominant product. The concentration of KOH, which needs to be larger than 4.3 M, is an important parameter influencing the synthesis ofkalsilite.
基金financially supported by Key Laboratory of Metallurgical Industry Safety and Risk Prevention and Control,Ministry of Emergency Management,and the Fundamental Research Funds for the Central Universities(No.FRF-IDRY-22-021]).
文摘The dripping zone in a blast furnace plays a crucial role in connecting the cohesive zone with the hearth,and its stability significantly impacts low-carbon smelting processes.Based on a detailed anatomical study of a 2200-m3 blast furnace in China,it involves core sampling of the furnace dripping zone and uses scanning electron microscopy to investigate the micro-morphology of potassium(K)and sulfur(S)within this region.The formation process of kalsilite(KAlSiO4)and CaS inside the furnace is elucidated.The results show that when potassium vapor rises to the upper area of the dripping zone,some of it adsorbs onto the coke pore walls and reacts with the dripping slag and coke ash to form kalsilite.The formation pathways of CaS differ between upper and lower areas of the dripping zone.It forms mainly from the reaction of slag with SO2 in the gas flow and from the slag–coke interface reaction.The CaS generated from the slag–coke interface reaction is the major source of CaS in the dripping zone.Based on the formation mechanisms of kalsilite and CaS in the dripping zone,it is possible to regulate their formation by adjusting the temperature,slag phase composition,and the content of harmful elements in the raw materials.It provides theoretical insights into the behavior of harmful elements in the blast furnace,offering guidance for steel enterprises to ensure the stable operation of the dripping zone,reduce fuel consumption,and achieve greener production.
文摘The transesterification reaction of soybean oil with methanol over kalsilite-based heterogeneous catalysts was investigated.The kalsilite was synthesized from potassium silicate,potassium hydroxide,and aluminum nitrate aqueous solutions by controlling the pH value at 13.After calcination in air at 1200°C,a very porous kalsilite(KAlSiO4)was obtained with surface pores ranging from 0.2 to 1.0µm.However,this kalsilite had relatively low catalytic activity for the transesterification reaction.A biodiesel yield of 54.4%and a kinematic viscosity of 7.06 cSt were obtained at a high reaction temperature of 180°C in a batch reactor.The catalytic activity of kalsilite was significantly enhanced by introducing a small amount of lithium nitrate in the impregnation method.A biodiesel yield of 100%and a kinematic viscosity of 3.84 cSt were achieved at a temperature of only 120°C over this lithium modified catalyst(2.3 wt-%Li).The test of this lithium modified catalyst in pellet form in a laboratory-scalefixed-bed reactor showed that it maintained a stable catalytic performance with a biodiesel yield of 100%over thefirst 90 min.
基金The authors gratefully acknowledge the financial support of DST(TDT division,reference No.DST/SSTP/UP/197(G)2012),Ministry of Science&Technology,New Delhi,India.
文摘Porcelain fused to metal(PFM)has received great attention over the last few years due to its importance in the dentistry.Kalsilite(K_(2)O·Al_(2)O_(3)·SiO_(2))is a high thermal expansion porcelain,suitable for bonding to metals.However,kalsilite is a metastable phase which gets converted into crystalline leucite upon heating.In the current work feasibility of developing stable kalsilite phase,dispersion of MgF2 in it as an additive and using mechanochemical synthesis are studied.Micro fine dental material has been formulated by mixing prepared kalsilite with low temperature frit(LTF)in different ratio.The crystalline phases evolved in fired powders are characterized by powder X-ray diffraction(XRD)technique.Kalsilite with different ratio of LTF has been cold pressed and heat treated to examine its coefficient of thermal expansion(CTE),flexural strength,apparent porosity(AP),bulk density(BD)and microstructure.Results indicate that MgF_(2) addition and high milling duration help in kalsilite stabilization.Temperature also plays an important role in this stabilization,and at 1100℃single phase kalsilite formation is observed.Present outcomes demonstrate that it is easily possible to synthesize a stable single phase kalsilite with desirable properties.
基金Project supported by National Key Technologies Research and Development Program for 11th Five-year Plan (No. 2006 BAD10B04)China Geological Survey Project (No. 12120113087700)
文摘Agricultural potassium sulphate is one of the most important non-chloride potash, which is the main fertilizer of avoid chlorine crop. Soluble potassium resource is bare in China, while insoluble potassium resource with the main mineral of microcline is extremely abundant. The microcline powder used is collected from Mountain Changling, Luonan county of Shaanxi Province. The chemical analysis results showed that the main chemical components of the powder are SiO2, Al2O3 and K2O, the K2O content is up to 13.56% (shown in table 1).
