Synthesis of β-sialon/Ti(C, N) powders from mineral waste residue via carbothermal reduction nitridation

RSC Advances ◽  
2014 ◽  
Vol 4 (59) ◽  
pp. 31493-31502 ◽  
Author(s):  
Dexin Yang ◽  
Yan-gai Liu ◽  
Hao Ding ◽  
Jian Chen ◽  
Zhaohui Huang ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Reducing Agent ◽  
Low Grade ◽  
Composite Powders ◽  
Mineral Waste

β-Sialon/Ti(C, N) composite powders were synthesized via carbothermal reduction nitridation method with low-grade bauxite and ilmenite as starting materials and coke as the reducing agent.

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.

In Situ Synthesis of ZrB2–SiC Composite Powders by Carbothermal Reduction Method

2018 ◽  
pp. 101-107
Author(s):  
Bingying Xie ◽  
Jincheng Yu ◽  
Yujun Zhang ◽  
Hongyu Gong ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Reduction Method ◽  
In Situ Synthesis ◽  
Composite Powders ◽  
Carbothermal Reduction Method

Reduction-Roast Leaching of Low-Grade Pyrolusite Using Bagasse as a Reducing Agent

2013 ◽  
Vol 699 ◽  
pp. 28-33 ◽  
Author(s):  
Yun Fei Long ◽  
Jing Su ◽  
Xian Jia Ye ◽  
Hai Feng Su ◽  
Yan Xuan Wen
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Weight Ratio ◽  
Reducing Agent ◽  
Manganese Sulfate ◽  
Low Grade ◽  
Manganese Ore ◽  
Optimal Conditions ◽  
Roasting Temperature

Bagasse, a fibrous residue from sugarcane juice extraction, was used as a reducing agent to roast low-grade pyrolusite in N2. The roasted ore was further leached using sulfuric acid, to convert manganese oxide in the ore to manganese sulfate. The effects of weight ratio of bagasse to manganese ore, roasting temperature, roasting time, leaching temperature, leaching time, stirring speed and sulfuric acid concentration on the leaching recovery of manganese were investigated. Optimal conditions were determined to be a bagasse to manganese ore weight ratio of 0.8:10, roasting temperature of 500°C for 40 min, leaching stirring speed of 100 rpm, sulfuric acid concentration of 3 mol•L-1 and leaching temperature of 50°C for 40 min. The leaching recovery rate of manganese was up to 97.8% at the optimal conditions.

Effect of temperature on the vacuum carbothermal reduction of low-grade phosphate ore

2019 ◽  
Vol 6 (7) ◽  
pp. 075513 ◽  
Author(s):  
Qinghui Wu ◽  
Run Huang ◽  
Xiaodong Lv ◽  
Xing Qian ◽  
Li Liu ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Effect Of Temperature ◽  
Low Grade ◽  
Phosphate Ore

Synthesis of TiC–TiB2 composite powders via carbothermal reduction and its reaction mechanism

2017 ◽  
Vol 116 (7) ◽  
pp. 409-417 ◽  
Author(s):  
J. L. Hu ◽  
H. X. Peng ◽  
S. M. Wang ◽  
W. M. Guo ◽  
C. Y. Hu ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Carbothermal Reduction ◽  
Composite Powders

Synthesis of β-Sialon/Ti(C,N) Composites Using Low and Middle Grade Bauxite and Ilmenite by Carbothermal Reduction-Nitridation

2012 ◽  
Vol 624 ◽  
pp. 112-116 ◽  
Author(s):  
De Xin Yang ◽  
Yan Gai Liu ◽  
Ding Yun Ye ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
High Purity ◽  
Carbothermal Reduction ◽  
Nitrogen Atmosphere ◽  
Reducing Agent ◽  
Raw Material ◽  
Reaction Products ◽  
Middle Grade ◽  
Rutile Tio2

β-Sialon/Ti(C,N) composites were prepared using low and middle grade bauxite and ilmenite as raw material,while coke as reducing agent in high purity nitrogen atmosphere through carbothermal reducrion-nitridation(CRN).The main phases of low and middle grade bauxite are kaolinire(Al2O3•2SiO2•2H2O) and (Al2O3•H2O)2 and ilmenite mainly contain ilmenite(FeTiO3) and rutile(TiO2).The reaction products of bauxite are the β-Sialon(Z=3,Si3Al3O3N5) while those of ilmenite are TiC and Fe.The results showed that the main phases are β-Sialon,Ti(C,N),Al2O3 and Fe when the reaction temperature is at 1400°C holding for 4 hours(10wt% ilmenite and 90wt% bauxite as raw material).However,β-Sialon decomposes into 21R at 1450°C and into 15R and AlN at 1500°C.So 1400°C is selected as the proper temperature to synthesize β-Sialon/Ti(C,N) composites.At 1400°C,the β-Sialon crystals with the largest quantity grow well and show long column in shape.With the increase of the reacrion temperature β-Sialon begin to decompose,the β-Sialon crystals change to short columnar,with the number decreasing quickly.

Features of Formation of Composite Nanopowders Based on Al2O3 and AlN

2012 ◽  
Vol 1371 ◽  
Author(s):  
M. Vlasova ◽  
P. A. Márquez Aguilar ◽  
M. Kakazey ◽  
V. Stetsenko ◽  
A. Bykov ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Carbothermal Reduction ◽  
Complex Surface ◽  
Composite Powders ◽  
Defective Structure ◽  
Technological Processes

ABSTRACTTwo technological processes of synthesis of nanopowders containing Al2O3, AlN, and AlON have been investigated. It has been established that AlN nanoparticles formed on the base of ablation products (Al and N2) during laser irradiation of AlN targets are coated with AlON films of different composition and have a complex surface defective structure. In composite powders obtained by carbothermal reduction of Al2O3, along with AlN and AlON, initial oxide Al2O3 is present, which indicates the incompleteness of the process.

scholarly journals Investigation on microwave carbothermal reduction behavior of low-grade pyrolusite

2020 ◽  
Vol 9 (4) ◽  
pp. 7862-7869
Author(s):  
Guo Chen ◽  
Yeqing Ling ◽  
Qiannan Li ◽  
Hewen Zheng ◽  
Jiang Qi ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Low Grade ◽  
Reduction Behavior
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