Effect of Silica Sources on Synthesis of Alumina-Mullite-Silicon Carbide Composite

2012 ◽  
Vol 488-489 ◽  
pp. 607-611 ◽  
Author(s):  
Sutham Niyomwas
Keyword(s):  
Silicon Carbide ◽  
Carbothermal Reduction ◽  
Rice Husk Ash ◽  
Horizontal Tube ◽  
Argon Gas ◽  
Carbide Composite ◽  
Whisker Morphology ◽  
Horizontal Tube Furnace ◽  
Sem Analyses

Synthesis of alumina-mullite-silicon carbide composite (Al2O3-Al6Si2O13-SiCw) was obtained in situ by carbothermal reduction of a mixture of kaolin and two different silica sources. The carbothermal reduction was carried out in a horizontal tube furnace under flow of argon gas. The synthesized products were mixtures of alumina, mullite and silicon carbide in the form of whiskers. The effects of adding two different silica sources of rice husk ash and silica powder to the mixture of kaolin and activated carbon were investigated. XRD and SEM analyses indicate complete reaction of precursors to yield Al2O3-Al6Si2O13-SiC as product powders, with the SiC having whisker morphology.

In situ synthesis and mechanism of mullite-silicon carbide composite ceramics for solar thermal storage

2018 ◽  
Vol 44 (15) ◽  
pp. 18541-18550 ◽  
Author(s):  
Hao Cheng ◽  
Fen Ye ◽  
Jianfeng Wu ◽  
Wei Shi ◽  
Senglin Leng ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Thermal Storage ◽  
In Situ Synthesis ◽  
Solar Thermal ◽  
Composite Ceramics ◽  
Carbide Composite

Fabrication of Silicon Carbide from Rice Husk by Carbothermal-Reduction and In Situ Reaction Bonding Technique

2014 ◽  
Vol 608 ◽  
pp. 235-240 ◽  
Author(s):  
Chalermkwan Makornpan ◽  
Charusporn Mongkolkachit ◽  
Suda Wanakitti ◽  
Thanakorn Wasanapiarnpong
Keyword(s):  
Silicon Carbide ◽  
Rice Husk ◽  
Carbothermal Reduction ◽  
Nitrogen Atmosphere ◽  
Silicon Oxynitride ◽  
Reaction Bonding ◽  
Silicon Carbide Particle ◽  
Silicon Carbide Whisker ◽  
Sic Ceramics

Silicon carbide (SiC) ceramics were prepared by carbothermal reduction together with in-situ reaction bonding. Raw rice husk was carbonized in an incineration furnace. The carbonized rice husk was ground and was then treated with hydrochloric acid by varying concentrations. The sample powders were mixed with silicon metal powder and pyrolyzed at various temperatures in either argon or nitrogen atmosphere. Silicon carbide phase was found in all pyrolyzed samples. Cristobalite was found in argon atmosphere pyrolyzed samples while silicon oxynitride was found in the samples pyrolyzed in nitrogen atmosphere at lower than 1500 °C. Silicon carbide whisker is the main phase on the surface of pyrolyzed sample. Increasing pyrolysis temperatures decreased the amount and size of silicon carbide whisker but increased the silicon carbide particle. Porosity and weight loss of samples after pyrolysis were increased with increasing temperatures due to the reaction in the system.

Synthesis of TiO2-B2O3-Al Based Porous Composites

2012 ◽  
Vol 626 ◽  
pp. 1-5
Author(s):  
Sutham Niyomwas
Keyword(s):  
Energy Minimization ◽  
Standard Gibbs Energy ◽  
Equilibrium Composition ◽  
Temperature Synthesis ◽  
Minimization Method ◽  
Argon Gas ◽  
High Temperature Synthesis ◽  
Porous Composites ◽  
Sem Analyses

The TiB2-Al2O3 porous composites were obtained in situ by self-propagating high temperature synthesis (SHS) of TiO2-B2O3-Al System. The reaction was carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of increasing aluminum mole ratio to the precursor mixture of TiO2, B2O3 and Al were investigated. XRD and SEM analyses indicate complete reaction of precursors to yield TiB2-Al2O3 as product composite

Production of Metallic Iron from Iron Oxide (Fe2O3) Using End-of-Life Rubber Tyre and its Blends with Metallurgical Coke as Reductants

2013 ◽  
Vol 10 ◽  
pp. 1-12
Author(s):  
James Ransford Dankwah ◽  
Pramod Koshy
Keyword(s):  
Iron Oxide ◽  
End Of Life ◽  
High Purity ◽  
Metallic Iron ◽  
Horizontal Tube ◽  
Metallurgical Coke ◽  
Argon Gas ◽  
Composite Pellets ◽  
Infrared Gas Analyser ◽  
Horizontal Tube Furnace

The production of metallic iron from iron oxide using end-of-life tyres (RT) and its blends with metallurgical coke as reductants has been investigated through experiments conducted in a laboratory scale horizontal tube furnace. Composite pellets of iron oxide (96.89 % Fe2O3) with RT, coke and coke/RT blends (in four different proportions) were rapidly heated at 1500 °C under high purity argon gas and the off gas was continuously analysed for CO and CO2 using an online infrared gas analyser (IR). The extent of reduction after ten minutes, level of carburisation of the reduced metal and the total amount of CO2 emissions were determined for each carbonaceous reductant. The results indicate that metallic iron can be effectively produced from Fe2O3 using RT and its blends with coke as reductant. The extent of reduction and level of carburisation are significantly improved when coke is blended with RT. Blending of coke with RT resulted in significant decrease in CO2 emissions.

Effect of HDPE addition on the Pre-reduction of Mn3O4 to MnO by Metallurgical Coke

2014 ◽  
Vol 33 (4) ◽  
pp. 345-353 ◽  
Author(s):  
J.R. Dankwah ◽  
P. Koshy
Keyword(s):  
Mass Balance ◽  
High Density Polyethylene ◽  
Horizontal Tube ◽  
Gas Analysis ◽  
High Density ◽  
Metallurgical Coke ◽  
Argon Gas ◽  
Pure Argon ◽  
Composite Pellets ◽  
Horizontal Tube Furnace

AbstractThe effect of high density polyethylene (HDPE) addition on the pre-reduction of Mn3O4 to MnO by metallurgical coke (Coke) has been investigated through experiments conducted in a laboratory horizontal tube furnace coupled with off-gas analysis through an infrared (IR) gas analyser. Composite pellets of Mn3O4 with Coke, HDPE and blends of Coke with HDPE (in three different proportions) were rapidly heated at 1150 °C under pure argon gas and the off gas was analysed continuously for CO, CO2 and CH4. The extent of pre-reduction of Mn3O4 to MnO was then calculated by mass balance for removable oxygen. The results showed improvements in the extent of pre-reduction of Mn3O4 to MnO when coke is blended with HDPE. The time for complete pre-reduction was found to decrease with an increase in the amount of HDPE that was blended with coke. A decrease in CO2 emissions was observed with HDPE addition.

Reduction of FeO in EAF Steelmaking Slag by Blends of Metallurgical Coke and Waste Polypropylene

2014 ◽  
Vol 33 (2) ◽  
pp. 107-114 ◽  
Author(s):  
James R. Dankwah ◽  
Pramod Koshy
Keyword(s):  
High Purity ◽  
Horizontal Tube ◽  
Metallurgical Coke ◽  
Steelmaking Slag ◽  
Argon Gas ◽  
Composite Pellets ◽  
Infrared Gas Analyser ◽  
Eaf Slag ◽  
Waste Polypropylene ◽  
Horizontal Tube Furnace

AbstractThe reduction of FeO-containing slag by blends of metallurgical coke and waste polypropylene (PP) has been investigated through experiments conducted in a laboratory scale horizontal tube furnace. Composite pellets of EAF slag (47.1% FeO) with coke, PP and blends of coke/PP (in three different proportions) were rapidly heated at 1500 °C under high purity argon gas and the off gas was continuously analysed for CO and CO2 using an online infrared gas analyser (IR). The extent of reduction after fifteen minutes, level of carburisation and desulphurization were determined for each carbonaceous reductant. The results show that FeO can be effectively reduced from EAF slag to produce metallic iron using waste PP and its blends with coke as reductants; improvements in the extent of reduction and levels of carburisation and desulphurisation of the reduced metal were observed when coke was blended with PP.

Reordering and Crystallization of Silicon Carbide Amorphized by Neutron Irradiation

2000 ◽  
Vol 650 ◽  
Author(s):  
Lance L. Snead ◽  
Martin Balden
Keyword(s):  
Thin Film ◽  
Silicon Carbide ◽  
Crystallization Kinetics ◽  
Neutron Irradiation ◽  
Onset Temperature ◽  
Kinetics Of Crystallization ◽  
Crystallization Onset Temperature ◽  
Crystallization Onset ◽  
Kinetics Of

ABSTRACTDensification and crystallization kinetics of bulk SiC amorphized by neutron irradiation is studied. The temperature of crystallization onset of this highly pure, fully amorphous bulk SiC was found to be between 875-885°C and crystallization is nearly complete by 950°C. In-situ TEM imaging confirms the onset of crystallization, though thin-film effects apparently alter the kinetics of crystallization above this temperature. It requires >1125°C for complete crystallization of the TEM foil. Annealing at temperatures between the irradiation and crystallization onset temperature is seen to cause significant densification attributed to a relaxation, or reordering, of the as-amorphized structure.

Sign in / Sign up

Export Citation Format

Share Document