Synthesis and Properties of Al4SiC4 by Carbothermal Reduction

2010 ◽  
Vol 434-435 ◽  
pp. 99-102
Author(s):  
Jian Li Zhao ◽  
Chang An Wang ◽  
Akira Yamaguchi ◽  
Jia Lin Sun ◽  
Xin Sheng Zhang
Keyword(s):  
High Temperature ◽  
Metal Oxide ◽  
Carbothermal Reduction ◽  
Reduction Process ◽  
Sem Analysis ◽  
Raw Material ◽  
Molar Ratio ◽  
Oxidation Properties ◽  
The Stability ◽  
Platelet Shape

Al4SiC4 is probably used as non-oxide raw material for high-temperature ceramics. Al4SiC4 was synthesized by using starting materials of metal-carbon, metal-oxide- carbon or carbides. In this paper, Al4SiC4 has been synthesized by using oxides (Al2O3 and SiO2) and carbon as starting materials through carbothermal reduction process. The oxidation properties in air and O2 atmosphere by TG method and the stability of the synthesized Al4SiC4 heated in moisture were investigated. Pure Al4SiC4 phase was synthesized when heating the mixture powder of Al2O3, SiO2 and C (C : Al2O3 : SiO2 = 8 : 2 : 0.8, in molar ratio) at 1700°C for 8h in flowing Ar atmosphere. The synthesized Al4SiC4 powder consists of platelet shape grains with size of 68μm length, 35μm width and 1μm thickness. Al4SiC4 obviously oxidized from 800°C when heated in flowing air or O2 atmosphere. When keeping Al4SiC4 powder in moisture, it was not observed to be reacted with water by XRD and SEM analysis.

scholarly journals Recycling of Alkaline Batteries via a Carbothermal Reduction Process

Batteries ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 35 ◽  
Author(s):  
Selçuk Yeşiltepe ◽  
Mehmet Buğdaycı ◽  
Onuralp Yücel ◽  
Mustafa Şeşen
Keyword(s):  
Carbothermal Reduction ◽  
Reduction Process ◽  
Economic Benefits ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Alkaline Batteries ◽  
Primary Battery ◽  
Battery Recycling ◽  
Steel Container ◽  
Manganese Monoxide

Primary battery recycling has important environmental and economic benefits. According to battery sales worldwide, the most used battery type is alkaline batteries with 75% of market share due to having a higher performance than other primary batteries such as Zn–MnO2. In this study, carbothermal reduction for zinc oxide from battery waste was completed for both vacuum and Ar atmospheres. Thermodynamic data are evaluated for vacuum and Ar atmosphere reduction reactions and results for Zn reduction/evaporation are compared via the FactSage program. Zn vapor and manganese oxide were obtained as products. Zn vapor was re-oxidized in end products; manganese monoxide and steel container of batteries are evaluated as ferromanganese raw material. Effects of carbon source, vacuum, temperature and time were studied. The results show a recovery of 95.1% Zn by implementing a product at 1150 °C for 1 h without using the vacuum. The residues were characterized by Atomic Absorption Spectrometer (AAS) and X-ray Diffraction (XRD) methods.

New Method for Low-Cost Titanium Production

2010 ◽  
Vol 436 ◽  
pp. 41-53 ◽  
Author(s):  
Ana Maria Martinez ◽  
Karin Sende Osen ◽  
Egil Skybakmoen ◽  
Ole Sigmund Kjos ◽  
Geir Martin Haarberg ◽  
...  
Keyword(s):  
Anodic Oxidation ◽  
Carbothermal Reduction ◽  
Low Cost ◽  
Oxidation Mechanism ◽  
Raw Material ◽  
Electrochemical Studies ◽  
Complete Conversion ◽  
Molten Chloride ◽  
The Stability ◽  
Titania Slag

The present work deals with the investigation of an electrolytic method for titanium production that uses TiO2 enriched titania slag as raw material. The process involves two steps: i) carbothermal reduction of the slag to form titanium oxycarbide powder; and ii) electrolysis in a molten chloride-based electrolyte using a titanium oxycarbide consumable anode. Electrochemical studies show the stability of the different Ti species in the equimolar NaCl-KCl melt at 850oC. These results, together with previous work about the anodic oxidation mechanism of a consumable titanium oxycarbide anode in molten chlorides, allow us to optimize the anode and cathode voltages in the electrolysis experiments. The results show that best quality titanium deposits are obtained when the reduction occurs in a single electrochemical step, i.e. directly from di-valent titanium species to Ti metal. Then, the complete conversion of the Ti(III) ions released from the consumable oxycarbide anode to Ti(II) species by adding Ti sponge to the electrolyte, must be fulfilled.

scholarly journals Mechanism of CaF2 under Vacuum Carbothermal Conditions for Recovering Nickel, Iron, and Magnesium from Garnierite

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 129
Author(s):  
Wang ◽  
Gu ◽  
Qu ◽  
Shi ◽  
Luo ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Carbothermal Reduction ◽  
Inductively Coupled Plasma ◽  
Raw Materials ◽  
Reduction Process ◽  
Atomic Emission ◽  
Separation Process ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Nickel Iron

Nickel laterite ore is divided into three layers and the garnierite examined in this study belongs to the third layer. Garnierite is characterized by high magnesium and silicon contents. The main contents of garnierite are silicates, and nickel, iron, and magnesium exist in silicates in the form of lattice exchange. Silicate minerals are difficult to destroy so are suitable for smelting using high-temperature pyrometallurgy. To solve the problem of the large amounts of slag produced and the inability to recycle the magnesium in the traditional pyrometallurgical process, we propose a vacuum carbothermal reduction and magnetic separation process to recover nickel, iron, and magnesium from garnierite, and the behavior of the additive CaF2 in the reduction process was investigated. Experiments were conducted under pressures ranging from 10 to 50 Pa with different proportions of CaF2 at different temperatures. The experimental data were obtained by various methods, such as thermogravimetry, differential scanning calorimetry, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy. The analysis results indicate that CaF2 directly reacted with Mg2SiO4, MgSiO3, Ni2SiO4, and Fe2SiO4, which were isolated from the bearing minerals, to produce low-melting-point compounds (FeF2, MgF2, NiF2, etc.) at 1315 and 1400 K. This promoted the conversion of the raw materials from a solid–solid reaction to a liquid–liquid reaction, accelerating the mass transfer and the heat transfer of Fe–Ni particles, and formed Si–Ni–Fe alloy particles with diameters of approximately of 20 mm. The smelting materials appeared stratified, hindering the reduction of magnesium. The results of the experiments indicate that at 1723 K, the molar ratio of ore/C was 1:1.2, the addition of CaF2 was 3%, the recovery of Fe and Ni reached 82.97% and 98.21% in the vacuum carbothermal reduction–magnetic separation process, respectively, and the enrichment ratios of Fe and Ni were maximized, reaching 3.18 and 9.35, respectively.

Preparation of Phosphorus by Carbothermal Reduction Mechanism in Vacuum

2011 ◽  
Vol 361-363 ◽  
pp. 268-274 ◽  
Author(s):  
Yu Cheng Liu ◽  
Qiu Xia Li ◽  
Yong Cheng Liu
Keyword(s):  
Carbothermal Reduction ◽  
Carbothermic Reduction ◽  
Reduction Process ◽  
Molar Ratio ◽  
Main Reaction ◽  
Reduction Mechanism ◽  
Element Analysis ◽  
Reaction Phase ◽  
System Pressure ◽  
Increasing Temperature

The purpose of this work was to investigated the carbothermic reaction of fluorapatite process by the means of thermodynamics analyses, XRD and element analysis, respectively. Thermodynamic calculations indicated that phosphorus can be prepared by heating the mixture of Ca5(PO4)3F2 and C at 1173K under the system pressure of 100Pa. CO cannot react with Ca5(PO4)3F2 in the carbothermic reduction process at 973-1873K and 100Pa. Experimental results demonstrated that phosphorus can be produced by the reaction between Ca5(PO4)3F2 and C, the main reaction phase is P2(g), CO(g), CaO and CaF2, and with increasing temperature, the greater degree of response. The best technology conditions, the molar ratio of Ca5(PO4)3F2 to C is 1:7.5 at 1723K for 1h when the system pressure was about 100Pa. This study to provide experimental evidence for preparation of phosphorus by carbothermal reaction of fluorapatite in vacuum.

Synthesis of Ti(C,N) Powder via CRN Method from Rutile/Carbon Mixtures

2012 ◽  
Vol 512-515 ◽  
pp. 32-35
Author(s):  
Kai Chen ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Yan Gai Liu ◽  
Xin Ouyang
Keyword(s):  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Phase Evolution ◽  
Nitrogen Pressure ◽  
Synthesis Temperature ◽  
Granular Structure ◽  
Raw Material ◽  
Molar Ratio ◽  
Tin Content ◽  
N Powder

Ti(C,N) powder was prepared via carbothermal reduction nitridation (CRN) using rutile and carbon black as the raw material. The phase evolution and the reaction mechanism during the CRN synthesis of Ti(C,N) were investigated, and the effect of reaction temperature and C/TiO2molar ratio on the phase composition and x value in TiC1–xNxwas analyzed. The XRD and SEM results show that: Ti(C,N) powder was synthesized at 1500°C for 4h with the C/TiO2molar ratio of 2.2, under the nitrogen pressure of 0.2MPa. Irregular granular structure and the growth stripes were observed in the final products. The growth of Ti(C,N) grains in CRN process was followed by the gas-solid mechanism.The phase compositions of the products were quite dependent on the reaction temperature and the C/TiO2molar ratio. The TiN content in Ti(C,N) decreased with the increase of reaction temperature. TiC1–xNxpowder with different x values can be synthesized by optimizing the experiment conditions including the synthesis temperature and the C/TiO2molar ratio.

Phases Transformation of Boron Mud during Carbothermal Reduction Process

2011 ◽  
Vol 492 ◽  
pp. 415-418
Author(s):  
Xiao Chao Li ◽  
Zhao Hui Huang ◽  
Yang Gai Liu ◽  
Ming Hao Fang
Keyword(s):  
Phase Transformation ◽  
Firing Temperature ◽  
Carbothermal Reduction ◽  
Industrial Waste ◽  
Reduction Process ◽  
Raw Material ◽  
Partial Reduction ◽  
Graphite Content ◽  
Compound Powder ◽  
Boron Mud

By using the industrial waste boron mud as raw material, graphite as reductant, coke particles as burying materials. During carbothermal reduction process, the Mg-Fe forsterite phase in boron mud row materials can transformed into forsterite and Fe2O3 at 1550°C and 1600°C for 3 h, and the Fe3C can be generated from the partial reduction of Fe2O3 with graphite, The main phase in samples calcined under 1650°C for 3 h contained forsterite, Fe2O3, Fe3C and β-SiC. The compound powder of Mg2SiO4 and β-SiC was prepared through the carbothermal reduction process. The effects of different graphite proportion (theoretical proportion, exceeding 10%, 50% and 100%) and firing temperature (1550°C, 1600°C and 1650°C) on the phase transformation and microstructure of the products were investigated by XRD, SEM and EDS. The results show that β-SiC powders were obtained at 1650°C for 3 h when graphite content was theoretical.

Kinetics of Magnesium Removal from Garnierite by Carbothermal Reduction in Vacuum

2020 ◽  
Vol 996 ◽  
pp. 165-172
Author(s):  
Xu Peng Gu ◽  
Xiao Pan Zhang ◽  
Tao Qu ◽  
Ming Yang Luo ◽  
Lei Shi ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Carbothermal Reduction ◽  
Removal Rate ◽  
Reduction Process ◽  
Magnesium Silicate ◽  
Reduction Reaction ◽  
Sem Analysis ◽  
Exponential Factor ◽  
Chemical Reaction Kinetics ◽  
Kinetics Of

The removal of magnesium from garnierite in Yuanjiang area of Yunnan was performed by carbothermal reduction in vacuum. The effects of reduction temperature and reduction time on the removal rate of magnesium were investigated. The kinetics of the removal of magnesium by carbothermal reduction in vacuum was studied. The thermodynamic calculation results show that it is feasible to remove magnesium from garnierite by carbothermal reduction in vacuum. The experimental results show that the removal rate of magnesium in garnierite can reach 93.23% under the conditions of 1823K for 120min. The reduction process conforms to the chemical reaction kinetics model, which indicated that the reduction process is controlled by chemical reaction and whose expression is 1-(1-α)1/3=(-22850.1/T+2.6296) t, the apparent activation energy (Ea) and the pre-exponential factor (A) are 189.97 kJ/mol and 13.87 s-1, respectively. The results of XRD and SEM analysis show that the condensate obtained by carbothermal reduction in vacuum of the garnierite is magnesium, which is mainly obtained by the reduction reaction between magnesium silicate produced by the decomposition of serpentine in minerals and coal. At the same time, it is proved that it is feasible to directly extract magnesium metal from the garnierite.

Effect of B2O3 on the carbothermal reduction of vanadium titanium magnetite

2019 ◽  
Vol 116 (6) ◽  
pp. 630 ◽  
Author(s):  
Xing Xiangdong ◽  
Wang Sha ◽  
Pang Zhuogang ◽  
Zhang Qiuli
Keyword(s):  
Melting Point ◽  
Carbothermal Reduction ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Reduction Process ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Vanadium Titanium ◽  
First Order Chemical Reaction ◽  
Titanium Magnetite

The effect of B2O3 on the carbothermal reduction of vanadium titanium magnetite was investigated under different temperatures by isothermal experiments. XRD analysis, SEM analysis and kinetic analysis were used to reveal the mechanism of B2O3 in the reduction process. The results showed that B2O3 could accelerate the reduction rate of vanadium titanium magnetite, and the suitable addition amount was 3%. B2O3 was easy to melt during carbothermal reduction, B3+ diffused into the crystal lattice of ferrotitanium compound, resulting in a decrease in binding energy and an increase in lattice parameters. B2O3 had also an erosion effect on the surface of the iron ore, and the contact area between reducing agent CO and vanadium titanium magnetite increased, thereby promoting the reduction. Low melting point compound CaO ∙ B2O3 formed after adding B2O3, which could improve the fluidity of the system and change the melting point of non-ferrous phase to further promote the growth and aggregation of iron particles. The reduction process was firstly limited by the first-order chemical reaction, then it was controlled by three-dimensional diffusion of reactants. The activation energy calculated by the best model was smaller than that of without adding B2O3.

Effects of CaO Additives on the Phase Evolution of ZrO2-SiC Composites from Zircon by Carbothermal Reduction

2014 ◽  
Vol 602-603 ◽  
pp. 105-109
Author(s):  
Ze Lin Wu ◽  
Ming Hao Fang ◽  
Zhao Hui Huang ◽  
Yan Gai Liu ◽  
You Guo Xu ◽  
...  
Keyword(s):  
Phase Composition ◽  
Composite Materials ◽  
Carbothermal Reduction ◽  
Reduction Process ◽  
Phase Evolution ◽  
Synthesis Temperature ◽  
Raw Material ◽  
Natural Zircon ◽  
Synthetic Temperature ◽  
Sic Composites

In this study, Ca2+ stabilized ZrO2-SiC composite materials were prepared via carbothermal reduction, using natural zircon ore as raw material, CaO as additive, and black carbon as the reducing agent. The effects of synthesis temperature and CaO content on the phase composition of the products were investigated by XRD. The microstructure and micro-area chemical analysis of the products were characterized by SEM and EDS. The results indicate that: (1) Ca2+ stabilized ZrO2-SiC composite materials could be prepared from natural zircon ore with CaO addition between 1500°C and 1600°C for 4 hours by carbothermal reduction process. (2) The synthetic temperature has an important influence on the phase composition of the carbothermal reduction products of zircon. The production of m-ZrO2 and t-ZrO2 got obviously enhanced with increasing temperature from 1500°C to 1600°C. (3) At the same synthetic temperature, Ca2+ stabilized ZrO2 got enhanced with increasing adding amount of CaO. The optimized synthesis condition of Ca2+ stabilized cubic-ZrO2/SiC composite materials is sintering at 1600°C for 4 hours with adding 40 mol% CaO as additive.

Phase Behaviors of Talc Minerals in Carbothermal Reduction Process

2012 ◽  
Vol 512-515 ◽  
pp. 123-126
Author(s):  
Wen Juan Li ◽  
Zhao Hui Huang ◽  
Zi He Pan ◽  
Yan Gai Liu ◽  
Ming Hao Fang
Keyword(s):  
Silicon Carbide ◽  
Carbothermal Reduction ◽  
Acid Leaching ◽  
Reduction Process ◽  
Magnesium Silicate ◽  
Raw Material ◽  
Carbon Powder ◽  
Carbon Addition ◽  
Effects Of Temperature ◽  
Phase Behaviors

In this paper, we focus on the phase behaviors of talc minerals by carbothermal reduction (CR) method. The effects of temperature and carbon addition are both discussed in our work. In the experiment, acid-leaching talc was employed as raw material, carbon coke powders were adopted as reducing agent. The XRD results show that: When acid-leaching talc was used as raw material, quartz and few enstatite can be obtained at 1300 °C, with the temperature increasing, the diffraction intensities of enstatite increased. At 1550 °C, enstatite transformed to magnesium silicate and obvious β-SiC can be detected. At 1600 °C, the main phases in the final product are magnesium silicate and β-SiC. The SEM results reveal that the preferred, as-fabricated silicon carbide has morphology of irregular shape. Relatively pure β-SiC can be obtained by using acid-leaching talc mixed together with excess 50% of theoretical quantity of carbon powder sintered at 1550 °C for 4 h.

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