Study on a New Process and its Kinetics of Iron Recovery and Glass-ceramics Preparation from Desulfurization Slag

2021 ◽  
Author(s):  
Zhibo Tong ◽  
jingting sun ◽  
ShiChang Liu ◽  
Wei Zhang ◽  
MeiLing Kuang
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Glass Ceramics ◽  
Growth Index ◽  
Slag System ◽  
Thermal Reaction ◽  
Raw Material ◽  
Crystallization Activation Energy ◽  
Differential Heat ◽  
New Process

Abstract The melting point and phase of slag was calculated with Factsage thermodynamics software, and base on this, taking desulfurization slag as the main raw material, which is leached by ammonium chloride as pretreatment. The composition of target slag system was adjusted with high aluminum powder coal ash and glass cullet, and then the reducing slag and metallic iron were separated by high temperature carbon thermal reaction. The prepared glass-ceramics with main crystal phases of diopside and nepheline were obtained by heat treatment, which shows that the new process is feasible. The crystallization activation energy was calculated by using Kissinger, Ozawa and Augis-Bennett method base on the differential heat curve. The results show that the crystallization activation energy is relatively high, and the crystal growth index n are all less than 3, which means that the crystallization capacity of the glass-ceramics is low. At the heating rate of 5 K/min, the n value of sample No. 3 is the largest, which is 2.7, and the mode of volumetric crystallization changes from two-dimensional to one-dimensional with the increase of heating rate, therefore, nucleating agent is needed in the preparation of glass-ceramics.

Crystallization Behavior and Microstructure of B2O3-Al2O3-SiO2 Glass-Ceramics

2008 ◽  
Vol 51 ◽  
pp. 149-154
Author(s):  
Han Ning Xiao ◽  
Tao Sun ◽  
Hua Bin Liu ◽  
Yin Cheng
Keyword(s):  
Activation Energy ◽  
Metal Oxides ◽  
Crystalline Phase ◽  
Crystallization Behavior ◽  
Glass Ceramics ◽  
Earth Metal ◽  
Crystallization Activation Energy ◽  
Alkali Earth Metal ◽  
Alkali Earth ◽  
Bulk Crystallization

The influences of B2O3/SiO2 ratio and different alkali earth metal oxides MO (M= Ba, Mg, Ca) on the crystallization behavior of B2O3-Al2O3-SiO2 (BAS) glass were investigated by means of DSC, XRD and SEM. With the reduction of B2O3/SiO2 ratio, the crystallization activation energy increases at first and then decreases, reaching the minimum value of 375.4 kJ·mol-1 when the B2O3/SiO2 ratio is 2.2. The crystalline indices (n) are all more than 4, which indicates that the glass is in bulk crystallization. When the glass was heated to 800°C, the primary precipitated crystalline phase was Al4B2O9. With the increase of temperature up to 1100°C, Al18B4O33 and Al5BO9 appeared and became the major crystalline phases in BAS glass-ceramics.

scholarly journals Thermal Decomposition Study of Ferrocene [(C5H5)2Fe]

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ashis Bhattacharjee ◽  
Amlan Rooj ◽  
Debasis Roy ◽  
Madhusudan Roy
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Heating Rate ◽  
Isoconversional Methods ◽  
Thermal Reaction ◽  
Single Step ◽  
Model Free ◽  
Probable Reaction ◽  
Single Heating ◽  
Made In

A single-step thermal decomposition of ferrocene [(C5H5)2Fe] using nonisothermal thermogravimetry (TG) has been studied using single- as well as multiple-heating rate programs. Both mechanistic and nonmechanistic methods have been used to analyze the TG data to estimate the kinetic parameters for the solid state reaction. Two different isoconversional methods (improved iterative method and model-free method) have been employed to analyze the TG results to find out whether the activation energy of the reaction depends on the extent of decomposition and to predict the most probable reaction mechanism of thermal decomposition as well. A comparison of the activation energy values for the single-step thermal reaction of ferrocene estimated by different methods has been made in this work. An appraisal on the applicability of single-heating rate data for the analysis of single-step thermal decompositions over the recommendations by the International Confederation for Thermal Analysis and Calorimetry (ICTAC) is made to look beyond the choice.

Field-Assisted Isothermal Oriented Crystallization of SrO-TiO2-SiO2 Polar Glass-Ceramics

2009 ◽  
Vol 66 ◽  
pp. 49-52 ◽  
Author(s):  
Hong Cheng Wang ◽  
Qi Ming Liu ◽  
Jin Shu Cheng
Keyword(s):  
Activation Energy ◽  
Electric Field ◽  
Glass Surface ◽  
Crystallization Process ◽  
Glass Ceramics ◽  
Experimental Results ◽  
Piezoelectric Constant ◽  
Crystallization Activation Energy ◽  
Oriented Growth ◽  
Oriented Crystallization

The polar glass-ceramics of 2.0SrO-1.0TiO2-2.9SiO2 system were prepared by the process of recrystallization with additional applied isothermal and electric field. The results showed that the glass-ceramics piezoelectric constant d33 was 12×10-12 C/N. The study of its oriented crystallization by SEM and XRD indicated that Sr2TiSi2O8 crystal performed oriented growth, which was perpendicular to the glass surface and made it be orientally crystallized with the assisted the isothermal and electric field. The further experimental results showed that the additional electric field reduced the crystallization activation energy, which provided a force for the isothermal orientating crystallization process.

scholarly journals Characterization of Glass Insulating Thick Films with Ag Conductors for Multilayer Packages

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 494
Author(s):  
Jun Fang ◽  
Renli Fu ◽  
Xiguang Gu ◽  
Xinyao Zhang ◽  
Guojun Li
Keyword(s):  
Activation Energy ◽  
Multilayer Structure ◽  
Silver Content ◽  
Glass Ceramics ◽  
Dielectric Strength ◽  
Crystallization Activation Energy ◽  
Sio2 Glass ◽  
Packaging Structure ◽  
Main Component

In this paper, an insulating film was successfully prepared by sintering 35 wt % CaO-15 wt % Al2O3-10 wt % B2O3-40 wt % SiO2 glass at 875 °C. After sintering, the main component of the insulating film was glass-ceramics. The main crystal phase was CaAl2Si2O8, and the crystallization activation energy was 189.76 kJ/mol. After preparing the insulating film, its color turned yellow, and the diffusion of Ag was found by XPS and XRD data. When the temperature increased to 875 °C, the color of the insulating film became lighter, and the silver content decreased. The adhesion of the multilayer structure could reach 875 N. The dielectric constant of the insulating film in the multilayer structure was approximately 5, and the dielectric loss was 0.0011. After sintering, the dielectric strength of the insulating film could reach 13.11 kV/mm, which fully meets the requirements of a complex packaging structure.

scholarly journals Determination of Thermodynamic Parameters of Polylactic Acid by Thermogravimetry under Pyrolysis Conditions

2021 ◽  
Vol 11 (21) ◽  
pp. 10192
Author(s):  
Paul Palmay ◽  
Melissa Mora ◽  
Diego Barzallo ◽  
Joan Carles Bruno
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Thermodynamic Parameters ◽  
Polylactic Acid ◽  
Reaction Model ◽  
Raw Material ◽  
Heating Rates ◽  
Statistical Validation ◽  
Exponential Factor ◽  
Degradation Temperature

In the present study, the thermodynamic parameters of Polylactic Acid (PLA) under conditions of thermal degradation were determined. The PLA material, previously sampled and characterized, was analyzed by dynamic thermogravimetry (TG) at heating rates of 5, 10 and 15 °C min−1 with a nitrogen flow of 20 mL min−1 from a temperature of 25 to 900 °C. The data were treated using isoconversional kinetic models to obtain the activation energy and the pre-exponential factor of each model. To fit the DTG curves, the Arrhenius equation was used applying the Contraction Sphere reaction model: two-dimensional phase limit reaction (R2). The thermodynamic parameters such as enthalpy, Gibbs free energy and entropy were determined from the kinetic parameters of suitable models for each heating rate after statistical validation and comparison with other studies. The results showed that as the heating rate increases, the degradation temperature also increases, while the activation energy, enthalpy and pre-exponential factor decrease. According to the value of ∆G (171.65 kJ mol−1), PLA has a significant potential to be used as a raw material to produce bioenergy/biofuels by pyrolysis.

The Study of Fe-Based Broad Amorphous Ribbon’s Variable-Temperature Kinetics

2012 ◽  
Vol 560-561 ◽  
pp. 134-139
Author(s):  
Qiang Gui ◽  
Li Jun Wang
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Differential Scanning Calorimeter ◽  
Crystallization Temperature ◽  
Variable Temperature ◽  
Cube Root ◽  
Crystallization Activation Energy ◽  
Heating Rates ◽  
Amorphous Ribbons ◽  
Initial Crystallization Temperature

Variable temperature kinetics under different heating rates for the Fe-based amorphous ribbons are studied by differential scanning calorimeter (DSC) technology. The results show that imported and domestic amorphous ribbons have the same overheating degree under the same heating rate, and the initial crystallization temperature is proportional to the cube root of the heating rate. The calculation indicate that the crystallization activation energy of imported and domestic amorphous ribbons are about 297~300 kJ/mol and 335~340 kJ/mol, respectively.

scholarly journals Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acid Hydrolysis ◽  
Energy Production ◽  
Combustion Process ◽  
Operating Conditions ◽  
Raw Material ◽  
Energy Of Combustion ◽  
Increasing Temperature ◽  
Hydrolysis Of ◽  
Chamaecytisus Proliferus

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.

Preparation of Glass-Ceramics Using Molybdenum Tailings

2011 ◽  
Vol 284-286 ◽  
pp. 1431-1434 ◽  
Author(s):  
Jin Rui Zhang ◽  
Ru Wang
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Crystalline Phase ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
The Other ◽  
Raw Material ◽  
Physical Chemical ◽  
Nucleation Agents

In order to utilization the molybdenum tailings which be deposited in large quantities. Test used it to prepare glass-ceramics as main raw material, TiO2 as nucleation agents and CaO-Al2O3-SiO2 system and wollastonite as the principal crystalline phase. Heat treatment system of glass-ceramics was based on the differential thermal analysis. The crystalline phase, microstructure and characteristics of glass-ceramics were analysis by XRD, SEM and physical, chemical properties test. The result shows that the performance of glass-ceramics was superior to the other types of building decoration stone.

Microstructure, Mechanical Properties, and Electrical Resistivities of Mica Glass-Ceramics with Flake Phlogopite and Waste Glass

2014 ◽  
Vol 602-603 ◽  
pp. 640-643
Author(s):  
Yu Fei Chen ◽  
Yan Gai Liu ◽  
Xiao Wen Wu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
High Speed ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Waste Glass ◽  
Raw Material ◽  
Bending Test ◽  
Electric Locomotive ◽  
Molding Process ◽  
Electrical Resistivities

Mica glass-ceramics can be applied in all kinds of electrical equipment, locomotive internal circuits in high-speed rail, ordinary electric locomotive and subway locomotive. In this study, mica glass-ceramics were prepared by sintering process using flake mica and waste glass as the main raw material with low cost. Different mica glass-ceramic samples were fabricated by changing the formula of raw materials, molding process and sintering temperature. X-ray diffraction, scanning electron microscopy, three-point bending test, and balanced-bridge technique were applied to investigate the phase, microstructure, mechanical and electrical resistivities of the samples, respectively. The results show that the optimum sintering temperature is 900 to 1000 °C holding for two hours, the desirable ratio is 70 wt% of mica powder while 30 wt% of glass powder. In that condition the sample could be less porosity, high flexural strength (63.3 MPa) and eligible electrical resistivity (0.4×1013 Ω·cm).

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