The effect of various reaction parameters on carbothermal reduction of kaolinite

1999 ◽  
Vol 25 (5) ◽  
pp. 467-473 ◽  
Author(s):  
P.K. Panda ◽  
L. Mariappan ◽  
T.S. Kannan
Keyword(s):  
Carbothermal Reduction ◽  
Reaction Parameters

Phase Behavior Analysis of Low-Grade Bauxite and Rutile by Carbothermal Reduction-Nitridation

2012 ◽  
Vol 624 ◽  
pp. 239-243
Author(s):  
Tao Yang ◽  
Yan Gai Liu ◽  
Ding Yun Ye ◽  
Qi Wang ◽  
Zhao Hui Huang ◽  
...  
Keyword(s):  
Phase Composition ◽  
Phase Transitions ◽  
Phase Behavior ◽  
Carbothermal Reduction ◽  
Raw Materials ◽  
Nitrogen Atmosphere ◽  
Low Grade ◽  
Reaction Parameters ◽  
Nitridation Process ◽  
Nitridation Reaction

In this study, β-Sialon/Al2O3/TiN diphase powder was synthesized using low-grade bauxite and rutile via carbothermal reduction-nitridation. The phase transitions of low-grade bauxite and rutile in the carbothermal reduction and nitridation process were analyzed by XRD, SEM and EDS. The effects of different reaction parameters such as reaction temperature, rutile addition on the phase composition and microstructure of products were analyzed. The results showed that β-Sialon/Al2O3/TiN powder was prepared using low-grade bauxite and rutile as raw materials and coke as reducing agent by carbothermal reduction-nitridation reaction in flowing nitrogen atmosphere of 0.03 MPa at 1350-1375 °C, for 4 h.

scholarly journals β-Si3N4 Microcrystals Prepared by Carbothermal Reduction-Nitridation of Quartz

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3622 ◽  
Author(s):  
Meng Zhang ◽  
Zhi Chen ◽  
Juntong Huang ◽  
Saifang Huang ◽  
Zhihui Hu ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Formation Mechanism ◽  
Carbothermal Reduction ◽  
Single Phase ◽  
Heating Temperature ◽  
Holding Time ◽  
Spectral Emission ◽  
Reaction Parameters ◽  
Future Potential ◽  
Coke Powder

Single phase β-Si3N4 with microcrystals was synthesized via carbothermal reduction-nitridation (CRN) of quartz and carbon coke powder as starting materials. The effects of reaction parameters, i.e., heating temperature, holding time, C/SiO2 ratio, Fe2O3 additive and β-Si3N4 seeds on the phase transformation and morphology of products were investigated and discussed. Rather than receiving a mixture of both α- and β- phases of Si3N4 in the products, we synthesized powders of β-Si3N4 single polymorph in this work. The mechanism for the CRN synthesis of β-Si3N4 from quartz and the formation mechanism of Fe3Si droplets were discussed. We also firstly reported the formation of Fe3Si Archimedean solids from a CRN process where Fe2O3 was introduced as additive. Comparing to the gear-like short columnar morphology observed in samples without β-Si3N4 seeding, the addition of β-Si3N4 seeds led to an elongated morphology of final products and much finer widths. In addition, the β-Si3N4 microcrystals exhibited a violet‒blue spectral emission range, which could be highly valuable for their future potential optoelectronic applications.

Surfactant involved in Copper Sulfide Nanocrystallites Synthesis

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina
Keyword(s):  
Copper Sulfide ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Shape Of Nanoparticles ◽  
Tem Transmission Electron Microscopy ◽  
Shape And Size

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.

Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

2020 ◽  
Vol 71 (8) ◽  
pp. 21-26
Author(s):  
Elena-Emilia Oprescu ◽  
Cristina-Emanuela Enascuta ◽  
Elena Radu ◽  
Vasile Lavric
Keyword(s):  
Maximum Yield ◽  
Strength Distribution ◽  
Point Of View ◽  
Reaction Parameters ◽  
X Ray ◽  
Ethyl Levulinate ◽  
Ft Ir ◽  
Ir Analysis ◽  
Biodiesel Blend ◽  
Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

Investigation of the products of carbothermal reduction of yttrium oxide by the hydrolysis method

1984 ◽  
Vol 49 (4) ◽  
pp. 936-943 ◽  
Author(s):  
Bohumil Hájek ◽  
Pavel Karen ◽  
Vlastimil Brožek
Keyword(s):  
Yttrium Oxide ◽  
Carbothermal Reduction ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Method ◽  
Sample Decomposition ◽  
Products Of Reaction ◽  
Hydrolysis Of ◽  
Lower Carbon

For the investigation of the products of reaction of yttrium oxide with carbon mixed in various proportions, the chemical and X-ray diffraction methods of analysis were combined with the gas chromatographic analysis of the mixture of hydrocarbons and hydrogen formed on the sample decomposition with water. The carboreduction of Y2O3 was examined at relatively low temperatures, convenient for obtaining the reaction intermediates in higher yields. At 1 600 °C and pressures of 10-3 Pa the reduction of a mixture of Y2O3 with carbon in a stoichiometric ratio of 1 : 7 yields YC2 in equilibrium with 20% of Y2OC phase. At lower carbon contents (down to the Y2O3 : C ratio of 1 : 2) tha fraction of the Y2OC phase increases up to approximately 30%. In addition to Y2O3, the reaction mixture contains also Y2C, Y2OC and a phase giving propyne on hydrolysis. The presence of traces of C3 hydrocarbons and small amounts of methane in the product of hydrolysis of the carbide sample prepared by the carbothermal reduction of the oxide can be explained in terms of the occurrence of the Y15C19 phase, probably substituted in part by oxygen, and of the Y2OC phase. The results are compared with those obtained previously for the Sc2O3 + C system.

Radiation Induced Graft Copolymerization of Vinyl Acetate and Isopropenyl Acetate Onto Isotactic Polypropylene

1996 ◽  
Vol 61 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Bhupendra N. Misra ◽  
G. S. Chauhan ◽  
Inderjeet Kaur
Keyword(s):  
Vinyl Acetate ◽  
Isotactic Polypropylene ◽  
Graft Copolymerization ◽  
Optimum Conditions ◽  
Reaction Parameters ◽  
Maximum Percentage ◽  
Radiation Induced ◽  
Isopropenyl Acetate

Radiation-induced graft copolymerization of vinyl acetate (VAC) and isopropenyl acetate (PAC) onto isotactic polypropylene (IPP) has been studied. The percentage of grafting was calculated for various reaction parameters, and the optimum conditions for attaining the maximum percentage of grafting were determined. Maximal achieved extents of grafting are 39% and 29% for VAC and PAC, respectively. The reactivity of the two monomers with respect to grafting is discussed.

scholarly journals Screening a Strain of Klebsiella sp. O852 and the Optimization of Fermentation Conditions for Trans-Dihydrocarvone Production

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2432
Author(s):  
Li Chen ◽  
Lu-Lu Zhang ◽  
Jing-Nan Ren ◽  
Xiao Li ◽  
Gang Fan ◽  
...  
Keyword(s):  
Ethanol Concentration ◽  
Flavor Compounds ◽  
Accession Number ◽  
Reaction Parameters ◽  
Isolation And Characterization ◽  
Biotransformation Process ◽  
Pharmaceutical Industries ◽  
Final Ethanol Concentration ◽  
Optimization Of Fermentation

Flavors and fragrances have high commercial value in the food, cosmetic, chemical and pharmaceutical industries. It is interesting to investigate the isolation and characterization of new microorganisms with the ability to produce flavor compounds. In this study, a new strain of Klebsiella sp. O852 (accession number CCTCC M2020509) was isolated from decayed navel orange (Citrus sinensis (L.) Osbeck), which was proved to be capable of converting limonene to trans-dihydrocarvone. Besides, the optimization of various reaction parameters to enhance the trans-dihydrocarvone production in shake flask was performed for Klebsiella sp. O852. The results showed that the yield of trans-dihydrocarvone reached up to 1 058 mg/L when Klebsiella sp. O852 was incubated using LB-M medium for 4 h at 36 °C and 150 rpm, and the biotransformation process was monitored for 36 h after adding 1680 mg/L limonene/ethanol (final ethanol concentration of 0.8% (v/v)). The content of trans-dihydrocarvone increased 16 times after optimization. This study provided a basis and reference for producing trans-dihydrocarvone by biotransformation.

scholarly journals Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics

2021 ◽  
Vol 10 (1) ◽  
pp. 157-168
Author(s):  
Biwei Luo ◽  
Pengfei Li ◽  
Yan Li ◽  
Jun Ji ◽  
Dongsheng He ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Reaction Time ◽  
Carbothermal Reduction ◽  
Industrial Waste ◽  
Phosphate Rock ◽  
Molar Ratio ◽  
Low Grade ◽  
Carbon Excess ◽  
Fluxing Agent

Abstract The feasibility of industrial waste fly ash as an alternative fluxing agent for silica in carbothermal reduction of medium-low-grade phosphate ore was studied in this paper. With a series of single-factor experiments, the reduction rate of phosphate rock under different reaction temperature, reaction time, particle size, carbon excess coefficient, and silicon–calcium molar ratio was investigated with silica and fly ash as fluxing agents. Higher reduction rates were obtained with fly ash fluxing instead of silica. The optimal conditions were derived as: reaction temperature 1,300°C, reaction time 75 min, particle size 48–75 µm, carbon excess coefficient 1.2, and silicon–calcium molar ratio 1.2. The optimized process condition was verified with other two different phosphate rocks and it was proved universally. The apparent kinetics analyses demonstrated that the activation energy of fly ash fluxing is reduced by 31.57 kJ/mol as compared with that of silica. The mechanism of better fluxing effect by fly ash may be ascribed to the fact that the products formed within fly ash increase the amount of liquid phase in the reaction system and promote reduction reaction. Preliminary feasibility about the recycling of industrial waste fly ash in thermal phosphoric acid industry was elucidated in the paper.

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