Experimental Study on Catalytic Reduction of SO2 by Rare Earth Compound

2014 ◽  
Vol 955-959 ◽  
pp. 2173-2176
Author(s):  
Zhe Hua Du
Keyword(s):  
Experimental Study ◽  
Rare Earth ◽  
Flue Gas ◽  
Elemental Sulfur ◽  
Catalytic Reduction ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Activation Process ◽  
Oxide Mixture ◽  
Rare Earth Compound

Compared with a great deal of traditional desulphurization crafts, the catalytic reduction of SO2 with CO to elemental sulfur is considered to be the best technology for the removal of SO2 from flue gas. Adding rare earth oxide CeO2 with variable valences to La2O3 formed a mixture of rare earth oxides. By means of dipping CeO2, La2O3 and their mixture, whose carriers are allγ-Al2O3, are used as the catalyst for the reduction of SO2 by CO. The activation process of this catalyst without O2 was investigated. The result shows that the rare earth oxide mixture composing of CeO2 and La2O3, as the catalyst for the reduction of SO2 by CO, can remove SO2 mostly without O2.

Nano Crystallite ZrO2, La2O3 and CeO2: Synthesis, Characterization and their Properties

2013 ◽  
Vol 209 ◽  
pp. 212-215
Author(s):  
A.K. Patel ◽  
A.R. Umatt ◽  
B.S. Chakrabarty
Keyword(s):  
Rare Earth ◽  
Surface Area ◽  
Gas Adsorption ◽  
Chemical Properties ◽  
Rare Earth Oxide ◽  
Combustion Method ◽  
Rare Earth Oxides ◽  
Precipitation Method ◽  
Reaction Conditions ◽  
The Rare Earth

It is well known that a minor addition of rare earth oxides can provide a beneficial effect towards various catalytic reactions. Use of rare earth oxide in different applications could improve commercial productivity in an affordable way. Among the rare earth oxides, ZrO2, La2O3 and CeO2 are very interesting due to their various characteristics showing a large range of applications in organic reactions. The changes in the molecular properties of materials at the nano scale level greatly enhance their physical properties as well as chemical properties and activity. Due to the extremely small size of the particles, an increased surface area is provided to the reactant enabling more molecules to react at the same time, thereby speeding up the process. In this work, the enhancement in the catalytic activity of these nano structured rare earth oxides has been studied under different reaction conditions. Nano crystalline ZrO2, La2O3 and CeO2 samples were synthesized using precipitation method and optimum reaction conditions have been established; whereas the corresponding bulk samples were synthesized by combustion method. The identification of phase and crystalline size of synthesized oxides have been done by X-ray diffraction, the band gape of these three oxides in both the forms has been analyzed by UV absorbance and surface area has been determined by gas adsorption analysis (BET). Moreover their different properties and the activity of nano crystallite oxides have also been compared with their bulk counterparts. Even the activity of ZrO2 is also compared with the rare earth oxides La2O3 and CeO2.

Surface Aluminizing and Internal Oxidation of Cu-Al-Y Alloy

2007 ◽  
Vol 336-338 ◽  
pp. 2661-2663
Author(s):  
Xiao Hong Chen ◽  
Yan Li ◽  
Bao Hong Tian ◽  
Yi Zhang ◽  
Juan Hua Su ◽  
...  
Keyword(s):  
Rare Earth ◽  
Internal Oxidation ◽  
Rare Earth Oxide ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Layer Depth ◽  
Nitrogen Gas ◽  
Rare Earth Compound ◽  
Gas Medium ◽  
Commercial Nitrogen

A method of the aluminizing treatment on the surface of Cu-Al-Y alloy with addition of rare earth compound CeCl3 in 1173K was carried out. The followed internal oxidation of the aluminized Cu-Al-Y alloy was also carried out in the commercial nitrogen gas medium to generate Al2O3 dispersed hardening copper matrix composites. The hardness distribution in aluminized layer and microstructure were studied. Results show that the addition of rare earth oxide CeCl3 has great accelerating effect on the aluminizing, the aluminized layer deeper and uniform than that not add CeCl3 at the same condition. It is possible to generate Al2O3 particles dispersed hardening layer depth reached about 200μm in the surface of specimens with aluminizing and internal oxidation technique.

Creep Behavior of Multi-Cation α-SiAlON Partially Stabilized Produced with an Yttrium-Rare Earth Oxide Mixture(CRE2O3)

2005 ◽  
Vol 498-499 ◽  
pp. 575-580
Author(s):  
Claudinei dos Santos ◽  
Kurt Strecker ◽  
M.J.R. Barboza ◽  
Sandro Aparecido Baldacim ◽  
Francisco Piorino Neto ◽  
...  
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
High Temperature ◽  
Liquid Phase ◽  
Creep Behavior ◽  
Rare Earth Oxide ◽  
Si3n4 Ceramic ◽  
Creep Tests ◽  
Oxide Mixture ◽  
Metallic Cations

a−SiAlON (a’) is a solid solution of a−Si3N4, where Si and N are substituted by Al and O, respectively. The principal stabilizers of the a’-phase are Mg, Ca, Y and rare earth cations. In this way, the possible use of the yttrium-rare earth oxide mixture, CRE2O3, produced at FAENQUIL, in obtaining these SiAlONs was investigated. Samples were sintered by hotpressing at 17500C, for 30 minutes, using a sintering pressure of 20 MPa. Creep behavior of the hot-pressed CRE-a-SiAlON/b-Si3N4 ceramic was investigated, using compressive creep tests, in air, at 1280 to 1340 0C, under stresses of 200 to 350 MPa, for 70 hours. This type of ceramic exhibited high creep and oxidation resistance. Its improved high-temperature properties are mainly due to the absence or reduced amount of intergranular phases, because of the incorporation of the metallic cations from the liquid phase formed during sintering into the Si3N4 structure, forming a a’/b composite.

scholarly journals High pressure sintered ZrO2-6%wt REO

2007 ◽  
Vol 39 (1) ◽  
pp. 17-24
Author(s):  
C. Kuranaga ◽  
G.S. Bobrovnitchii
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Rare Earth ◽  
High Temperature ◽  
Room Temperature ◽  
Rare Earth Oxide ◽  
Micro Hardness ◽  
Oxide Mixture ◽  
Sintering Conditions ◽  
High Temperature High Pressure

The sintering conditions employed in this work are innovative, due to the use of an alternative technology to process ZrO2-REO (rare earth oxide mixture), so called high temperature - high pressure (HPHT). A pressure of 5GPa was used, temperatures of 1100, 1200, and 1300 o C, for times of 2 and 5 minutes. The best results were obtained for samples sintered at 5GPa/1300 o C/5min., where a micro-hardness of 4.8GPa, fracture toughness of 5.3MPa.m ?, density of 97.9%, and 88% in volume of a tetragonal phase retained at room temperature were achieved.

Creep Behavior of Multi-Cation α-SiAlON Partially Stabilized Produced with an Yttrium-Rare Earth Oxide Mixture(CRE2O3)

2005 ◽  
pp. 575-580
Author(s):  
Claudinei dos Santos ◽  
Kurt Strecker ◽  
M.J.R. Barboza ◽  
Sandro Aparecido Baldacim ◽  
F. Piorino Neto ◽  
...  
Keyword(s):  
Rare Earth ◽  
Creep Behavior ◽  
Rare Earth Oxide ◽  
Oxide Mixture

Internal Oxidation of Rare Earth Additive Accelerating Aluminized Layer on Copper Matrix

2010 ◽  
Vol 139-141 ◽  
pp. 685-688
Author(s):  
Bao Hong Tian ◽  
Yi Zhang ◽  
Yong Liu ◽  
Feng Zhang Ren
Keyword(s):  
Rare Earth ◽  
Internal Oxidation ◽  
Gas Flow ◽  
Pure Copper ◽  
Composite Layer ◽  
Oxidation Mechanism ◽  
Rare Earth Oxide ◽  
Copper Matrix ◽  
Hardness Profile ◽  
Rare Earth Compound

The aluminizing treatment on the surface of commercial pure copper with addition of rare earth compound CeCl3 was carried out. The followed internal oxidation of the aluminized copper was also carried out in the industrial nitrogen gas flow. The influences of the aluminizing and internal oxidization processing time on the thickness, hardness profile and microstructure were investigated. Results show that the addition of rare earth oxide CeCl3 has great accelerating effect on the aluminizing and internal oxidation processing. The hardness of the surface Al2O3 dispersion hardened copper composite layer by means of internal oxidation with addition of rare earth compound is higher than that of the without addition. The internal oxidation mechanism of the aluminized layer on copper matrix is comprehensive processes of the oxygen inner-toward diffusion and localized internal oxidation of the inner-toward diffusion of aluminum.

Substitution of Y2O3 by a rare earth oxide mixture as sintering additive of Si3N4 ceramics

2000 ◽  
Vol 45 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Kurt Strecker ◽  
Reinaldo Gonzaga ◽  
Sebastião Ribeiro ◽  
Michael J. Hoffmann
Keyword(s):  
Rare Earth ◽  
Rare Earth Oxide ◽  
Oxide Mixture ◽  
Sintering Additive ◽  
Si3n4 Ceramics
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