Preparation of Al2O3 from the Nepheline Ore of Nanjiang County, Sichuan Province of China

2015 ◽  
Vol 814 ◽  
pp. 230-234
Author(s):  
Yu Chong Qiu ◽  
Ke Hui Qiu ◽  
Jun Han Li ◽  
Pei Cong Zhang
Keyword(s):  
Crystal Structure ◽  
Calcination Temperature ◽  
Sichuan Province ◽  
Dissolution Process ◽  
Mother Solution ◽  
Calcination Process ◽  
Major Phase ◽  
Naoh Solution ◽  
Crystal Phases ◽  
Crystalline Alumina

Crystalline alumina samples with Al2O3 content of 95.23 wt.% were prepared directly from the nepheline ore in Nanjiang county, Sichuan province of China. Four steps were involved in the experiment of alumina preparation, including calcination, dissolution, carbonation and re-calcination. Lime was used in the calcination process with the nepheline concentrates powders to generate soluble aluminates and insoluble silicates. NaOH solution was used as the mother solution in the dissolution process. CO2 was introduced into the solution to precipitate the Al (OH)3 precursor, which was then fired to obtain crystalline alumina. Among the crystalline alumina obtained three phases of crystals existed which were detected by XRD and SEM, including δ-Al2O3 as the major phase, while θ-Al2O3 and κ-Al2O3 as the minor phases. Various crystal phases of alumina could be ascribed to the purity and crystal structure of precursor, as well as the re-calcination temperature and time.

Lead-Free Ferroelectric Material: Dysprosium Doped Bi4Ti3O12

2008 ◽  
Vol 55-57 ◽  
pp. 837-840 ◽  
Author(s):  
N. Thongmee ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon
Keyword(s):  
Crystal Structure ◽  
Calcination Temperature ◽  
Bismuth Titanate ◽  
Thermal Analyses ◽  
Thermal Characteristics ◽  
Ferroelectric Material ◽  
Calcination Process ◽  
X Ray ◽  
Dysprosium Titanate ◽  
Simple Solid State Reaction

This study investigated fundamental of phase formation, crystal structure and calcination process for bismuth dysprosium titanate (Bi4-xDyxTi3O12; BDT) powders when x = 0, 0.25, 0.5, 0.75 and 1.0. BDT powders were prepared using a simple solid-state reaction on mixtures of reagent grade Bi2O3, Dy2O3 and TiO2 powders. The mixtures were calcined at temperature in the range of 500-800°C for 4 h at a heating/cooling rate of 5°C/min. Thermal characteristics of powders were studied using thermogravimetric/differential thermal analyses which indicated that the formation of Bi4Ti3O12 and Bi3Dy1Ti3O12 powders occurred at ~500oC. Effect of Dy3+ concentration on phase and crystal structure was investigated using X-ray diffractometry. The results revealed that at small concentration of Dy dopant (x £ 0.25), optimum calcination temperature for providing bismuth titanate-based phase was 650oC. Increasing content of Dy dopant seemed to reduce calcination temperature to 600oC. This study suggested the alternative environmental friendly BDT materials which may be used as starting powders for production of high quality BDT ceramics.

Effects of Calcination Temperature on Crystal Structure of Pr-Nd Oxides

2011 ◽  
Vol 233-235 ◽  
pp. 2918-2921 ◽  
Author(s):  
Hui Qing Li ◽  
Rui Xiang Zhang ◽  
Hai Wang Liu ◽  
Shi Zhi Wang ◽  
Xian Ku Hao
Keyword(s):  
Crystal Structure ◽  
Calcination Temperature ◽  
Chloride Solution ◽  
Neodymium Oxide ◽  
Raw Material ◽  
Praseodymium Oxide ◽  
Hexagonal System ◽  
Binary Oxides ◽  
Hydrogen Carbonate ◽  
Ammonium Hydrogen

Ammonium hydrogen carbonate is taken as the precipitating agent to prepare Pr-Nd carbonates from the raw material of Pr-Nd chloride solution. Pr-Nd oxides have been prepared at different calcination temperature in the range of 800°C-1500°C. The oxides were characterized by XRD and XPS.Calcination temperature effects on the structure of Pr-Nd oxides and the valence state of Pr in Pr-Nd oxides have been studied; Results showed that praseodymium oxide full entered into the lattices of neodymium oxide. The crystal structure changed from cubic into hexagonal system with increasing calcination temperature.The valence of Pr in Pr-Nd binary oxides are Pr3+ and Pr4+.

Effects of Calcination Temperature on the Microstructure and Adsorption Properties of Attapulgite Microspheres

2018 ◽  
Vol 913 ◽  
pp. 907-916 ◽  
Author(s):  
Shu Yan ◽  
Yi Ming Pan ◽  
Lu Wang ◽  
Xiao Yan Zhang ◽  
Jing Jing Liu ◽  
...  
Keyword(s):  
Calcination Temperature ◽  
Adsorption Properties ◽  
Order Kinetic ◽  
Dyeing Wastewater ◽  
Drying Method ◽  
Calcination Process ◽  
Potential Applications ◽  
Median Diameter ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The attapulgite microspheres were produced by spray drying method and calcination process subsequently. The effects of calcination temperature on the microstructure and adsorption properties of methylene blue(MB) were investigated systematically. Results show that the median diameter of the microspheres increases after calcination. The adsorption capacity and removal efficiency of MB reaches the maximum values(96.62mg/g and 96.6%) after calcined at 600°C and decreases with the temperature increasing. The adsorption process can be described better by the pseudo-second-order kinetic model and fit the the Langmuir equation. The attapulgite microsphere shows good adsorption properties, which may be used as potential applications in various dyeing wastewater fields.

Combining CDIF and PDF information in problem solving: Crystal structure of a corrosion deposit, hexaaquairon(II) trifluoromethanesulfonate

1999 ◽  
Vol 14 (3) ◽  
pp. 166-170
Author(s):  
J. A. Kaduk
Keyword(s):  
Crystal Structure ◽  
Problem Solving ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Powder Diffraction ◽  
Title Compound ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
Major Phase ◽  
Corrosion Deposit

The title compound was identified as the major phase in a corrosion deposit by indexing its powder pattern, and locating an isostructural vanadium(II) compound in the NIST Crystal Data Identification File. The identity of the compound was confirmed by a Rietveld refinement. Hexaaquairon(II) trifluoromethanesulfonate crystallizes in the monoclinic space group C2/m, with a=18.6415(14), b=6.9291(5), c=6.5938(5) Å, β=104.742(6)°, V=823.68(10) Å3, and Z=2. The structure consists of alternating layers of octahedral hexaaquairon(II) cations and triflate anions. The cations and anions are linked into layers parallel to the bc plane by hydrogen bonds. Each water molecule donates two protons to sulfonate oxygens, and each sulfonate oxygen acts as an acceptor of two protons. A reference powder diffraction pattern is reported.

Synthesis, Crystal Structure and Thermal Properties of Silver(I) Bromide Ethylenediamine Coordination Polymers

2004 ◽  
Vol 59 (9) ◽  
pp. 992-998 ◽  
Author(s):  
Christian Näther ◽  
Andreas Beck
Keyword(s):  
Crystal Structure ◽  
Thermal Properties ◽  
Coordination Polymer ◽  
Three Dimensional ◽  
Compound I ◽  
Major Phase ◽  
Dimensional Network ◽  
Pure Phase ◽  
Compound Ii ◽  
Silver Atoms

Reaction of silver(I) bromide with ethylenediamine (en) leads to the formation of the 1:1 compound poly[AgBr(μ2-en-N,N’)] (I). In the crystal structure the silver atoms of AgBr dimers are connected to two bridging bromine atoms and two nitrogen atoms of different en ligands. The dimers are thus connected by the ligands into layers via μ-N,N’ coordination. In the 2:1 coordination polymer poly[(AgBr)2(μ2-en-N,N’)] (II) a three-dimensional AgBr substructure occur which consists of helical AgBr chains that are connected via peripheral Ag-Br contacts into a three-dimensional network that contains large channels. The en ligands are situated in these channels bridging the Ag atoms. From solution this compound cannot be obtained as a pure phase, since compound I is always formed as the major phase. On heating the 1:1 compound I in a thermobalance the sample mass decreases slowly and several mass steps are observed, which are not fully resolved. If the reaction is stopped at 230°C, pure AgBr has formed. At 115°C only traces of compound II are found. The major phase consists of an as yet unidentified ligand poor compound.

Synthesis of Ce0.8Nd0.2O1.9 Nanocrystalline Powders by Low Temperature Combustion Process

2011 ◽  
Vol 399-401 ◽  
pp. 860-863
Author(s):  
Yang Feng Huang ◽  
Ye Bin Cai ◽  
Hao Liu
Keyword(s):  
Calcination Temperature ◽  
Combustion Process ◽  
Nanocrystalline Powders ◽  
Low Temperature Combustion ◽  
Calcination Process ◽  
Structure Morphology ◽  
Gel Combustion ◽  
Temperature Combustion ◽  
Metal Ratio ◽  
Dsc Curves

In this work, synthesis of the nanocrystalline Ce0.8Nd0.2O1.9Solid solution Powders by a nitrate-glycine gel-combustion process was investigated. The effects of glycine/metal ratio and calcination temperature on the powders phase structure, morphology and particle were investigated. TG-DSC curves and XRD peak of different glycine/metal ratio show that smaller particle size can be obtained with a slightly fuel-deficient ratio. XRD results indicate that the as-prepared powders are crystallinzed in a single fluorrite structure. The crystalline size ranges from 9 nm to 24 nm, which increases with the increase of calcination temperature. The SEM results imply some organic agent may be eliminated by high temperature calcination process.

Effect of Calcination Temperature on Phase Transformation and Microstructure of Al2O3/GdAlO3 Compound Powder Prepared by Co-Precipitation Method

2012 ◽  
Vol 512-515 ◽  
pp. 535-538 ◽  
Author(s):  
Shuai Sun ◽  
Qiang Xu
Keyword(s):  
Calcination Temperature ◽  
Raw Materials ◽  
Metastable Phase ◽  
Precipitation Method ◽  
Calcination Process ◽  
Compound Powder ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Diffraction Peaks ◽  
Co Precipitation

A Coprecipitation Method Was Applied to Synthesize Al2O3/GdAlO3 Compound Powder, Using Ammonia as the Precipitator. Gadolinium Oxide and Aluminium Nitrate Were Used as the Raw Materials with the Eutectic Ratio( 77 mol% Al 3+ – 23 mol% Gd 3+ ). the Precursor Was Calcined at Different Temperatures from 1200 to 1600 °C. the Phase Identifications at Different Temperatures Were Characterized by X-ray Diffractometry (XRD). the Growth Morphology of Particles Were Investigated Using Field Emission Electro Microscopy (FE-SEM). the Results Reveal that GdAlO3 Crystallized Earlier than α-Al2O3. the Diffraction Peaks of α-Al2O3 Phase Were Observed after Calcination at 1300°C for 1 H. Metastable Phase Gd3Al5O12 Underwent Complete Decomposition at 1600°C for 1 H. Gadolinium Aluminate and α-Al2O3 Showed Different Growth Mechanism during the Calcination Process. the Average Grain Size of the Calcined Powder Increased from ~40 to ~900 Nm as the Calcination Temperature Increased from 1200 to 1600 °C.

Effect of calcination temperature and atmosphere on crystal structure of BaTiO3 nanofibers

2010 ◽  
Vol 16 (3) ◽  
pp. 453-457 ◽  
Author(s):  
Deuk Yong Lee ◽  
Myung-Hyun Lee ◽  
Nam-Ihn Cho ◽  
Bae-Yeon Kim ◽  
Young-Jei Oh
Keyword(s):  
Crystal Structure ◽  
Calcination Temperature

Utilization of Chicken Eggshells as Catalyst in Biodiesel Synthesis from Waste Cooking Oil

2021 ◽  
Vol 58 (S) ◽  
pp. 85-95
Author(s):  
Lizda Johar Mawarani ◽  
Thomas Andherson Sihombing ◽  
Doty Dewi Risanti ◽  
Muhannad Illayan Massadeh ◽  
Dwi Prananto
Keyword(s):  
Reaction Time ◽  
Calcination Temperature ◽  
Calcium Oxide ◽  
Waste Cooking Oil ◽  
Solid Oxides ◽  
Calcination Process ◽  
Cooking Oil ◽  
Biodiesel Synthesis

Solid oxides are the most used catalyst for the synthesis of biodiesel, one of which is calcium oxide (CaO). This research reports the synthesis of CaO catalysts sourced from chicken eggshells through the calcination process. Chicken eggshells were cleaned and dried for 24 h at 120 oC. The eggshells were then calcined at temperatures varying from 600 oC to 900 oC for 6 h and the resulted sample were characterized by FTIR and XRD. The biodiesel synthesis was conducted at 65 ºC with a reaction time of 2 h and the concentration of catalyst was varied at 3 wt%, 6 wt%, and 9 wt%. The optimal biodiesel synthesis was obtained at a concentration of CaO catalyst formed at a calcination temperature of 900 ºC at 9 wt%. The yield of biodiesel conversion was obtained at 81.43 % and glycerol was produced as a by-product.

Preparation of Activated Alumina Admixture

2011 ◽  
Vol 84-85 ◽  
pp. 489-493
Author(s):  
Xiao Yan Wang ◽  
Hong Jian Wang ◽  
Gui Qin Hou ◽  
Zhao Xia Lv
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Crystalline State ◽  
Activated Alumina ◽  
Calcination Process ◽  
X Ray ◽  
Active Alumina ◽  
Alkali Aggregate Reaction

Through calcining bauxite, the preparation of active alumina (Al2O3) admixture was investigated. The effect of calcination temperature and time on the activity of alumina was studied. Calcination production species and crystalline state were determined by X-ray diffractometer, and the specific surface area referred as an important parameter was also determined. The results showed that the best calcination process of acquiring activated alumina admixture was 500°C1.0h. Alkali-aggregate reaction was inhibited effectively by the active alumina admixture.

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