THE MANUFACTURING OF NIOBIUM POWDER BY HUNTER PROCESS

2010 ◽  
Vol 17 (02) ◽  
pp. 223-228
Author(s):  
JAE-SIK YOON
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Average Particle Size ◽  
Reduction Process ◽  
Reducing Agent ◽  
Raw Material ◽  
Average Particle ◽  
Metallothermic Reduction ◽  
Niobium Powder ◽  
Yield Rate

Niobium powder was fabricated by metallothermic reduction process using K2NbF7 as the raw material, KCl and KF as the diluents and Na as the reducing agent. The apparatus for the experiment was designed and built specifically for the present study. Varying properties of niobium powder depending on reaction temperature and excess of reducing agent were analyzed. The niobium particle size increased significantly as the reduction temperature increased from 993 to 1093 K. The particle size was fairly uniform at a given reaction temperature, varying from 0.2 μ m to 50 nm depending on the reaction temperature. The yield of niobium powder increased from 58 to 83% with an increase in reaction temperature. The average particle size of niobium powder was improved from 70 nm to 0.2 μ m with the increase in the amount of Na excess. In addition, the yield rate of Nb powder was 82% in the 5% excess sodium.

Fabrication of Nano-Sized Tin Oxide Powder by Spray Pyrolysis Process

2009 ◽  
Vol 1174 ◽  
Author(s):  
Jaekeun Yu ◽  
Jwayeon Kim ◽  
Jeoungsu Han
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Reaction Temperature ◽  
Tin Oxide ◽  
Average Particle Size ◽  
Raw Material ◽  
Nano Particles ◽  
Average Particle ◽  
Average Size ◽  
20 Nm

AbstractBy using tin chloride solution as the raw material, a nano-sized tin oxide powder with average particle size below 50 nm is generated by spray pyrolysis reaction. This study also examines the influences of the reaction parameters such as reaction temperature and the concentration of raw material solution on the powder properties. As the reaction temperature increases from 800 to 850 ℃, the average particle size of the generated powder increases from 20 nm to 30 nm. As the reaction temperature reaches 900 ℃, the droplets are composed of nano-particles with average size of 30 nm, while the average size of individual particles increases remarkably up to 80˜100 nm. When the tin concentration reaches 75 g/L, the average particle size of the powder is below 20 nm. When the tin concentration reaches 150 g/L, the droplets are composed of nano particles with average size around 30 nm, whereas the average size of independent particles increases up to 80˜100 nm. When the concentration reaches 400 g/L, the droplets are composed of nano-particles with average size of 30 nm.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Metallothermic Reduction at Low Temperature Synthesis of Ti4O7 Powder with Lithium Ion Insertion/Extraction Property

2019 ◽  
Vol 956 ◽  
pp. 55-66
Author(s):  
Bei Lei Yan ◽  
Wei Wei Meng ◽  
San Chao Zhao
Keyword(s):  
Reduction Method ◽  
Average Particle Size ◽  
Active Material ◽  
Reduction Process ◽  
Lithium Ion ◽  
Thermal Reduction ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Metallothermic Reduction ◽  
Extraction Property

In this work, a thermal reduction process via ultrafine titanium powder as the reducing agent under argon atmosphere is firstly used to prepare Ti4O7. Compared with the conventional method, this experiment process reduces the sintering temperature to 850°C. The phase transformation and the morphology of the as-prepared powders are examined by X-Ray diffraction (XRD) and scanning electron microscopy (SEM). Besides, it is found that the Ti4O7 powders obtained by titanium thermal reduction method exhibited the crystal structure, distinctly possessing an average particle size around 750 nm. The as-prepared Ti4O7 nanoparticles are used as anode active material in lithium battery. The results demonstrate that the anode with Ti4O7 calcined at 850°C by titanium thermal reduction method exhibited insertion/extraction lithium ion property.

Synthesis of nanoscale particles of Ta and Nb3Al by homogeneous reduction in liquid ammonia

2001 ◽  
Vol 16 (9) ◽  
pp. 2544-2549 ◽  
Author(s):  
Hongmin Zhu ◽  
Donald R. Sadoway
Keyword(s):  
Particle Size ◽  
Liquid Ammonia ◽  
Average Particle Size ◽  
Multicomponent System ◽  
Mixed Conductor ◽  
Average Particle ◽  
Metallothermic Reduction ◽  
Solid Product ◽  
Order Of Magnitude ◽  
Co Reduction

The analysis of metallothermic reduction as an electronically mediated reaction predicted that the particle size of solid product could be reduced if the reaction were conducted in a medium that is a mixed conductor (ionic and electronic). This prediction was confirmed by reacting TaCl5 with sodium, each dissolved in liquid ammonia, to produce tantalum powder having an average particle size over an order of magnitude finer than the micron-sized powders produced commercially today. Metallothermic reduction in a mixed conducting medium has been extended to a multicomponent system in order to synthesize nanosized powder of Nb3Al by co-reduction of NbCl5 and AlCl3 both dissolved in liquid ammonia.

Preparation of Nanosized Barium Titanate Powder by a Direct Reactive Precipitation Method

2013 ◽  
Vol 690-693 ◽  
pp. 454-457
Author(s):  
Hong Bo Li ◽  
Shu Yan Wu ◽  
Jing Wang ◽  
Chun Jie Li
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Surface Active Agent ◽  
Average Particle Size ◽  
Active Agent ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Particle ◽  
Powder Particle Size ◽  
Powder Morphology

Columnar crystaldendriteequiaxial dendritescolumnar crystalNanosized powder was synthesized by direct-reactive precipitation process using a stoichiometrical mixture of TiCl4, BaCl2 as the reactants while NaOH as precipitant. Under the ratio of Ba to Ti is 1.02, PH=13, three reaction temperature of 70°C, 80°C and 90°C were conducted respectively. Morphology and phase structure of powder were investigated, and the influence of reaction temperature on powder morphology was discussed. The result indicates that synthesized powder is single cubic BaTiO3 and contains no impurities. BaTiO3 powders generally show spherical, and average particle size decreases with increasing reaction temperature. When reaction temperature is 80°C, BaTiO3 powder has best uniformity and dispersivity with the diameter of 80-100nm. The influence of reaction temperature on powder particle size can be attributed to the corporate contribution of nucleation and growth rate. Polyglycol as surface active agent has a significant effect in restraining agglomeration.

Preparation and Characterization of Macromeritic Tungsten Powder Reduced by Ammonium Paratungstate at Medium Temperature

2012 ◽  
Vol 468-471 ◽  
pp. 2584-2587
Author(s):  
Rui Xin Wang ◽  
Zhi Meng Guo ◽  
Jun Jie Hao ◽  
Ji Luo ◽  
Yan Jun Xin
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Tungsten Powder ◽  
Average Particle Size ◽  
Raw Material ◽  
Metal Salts ◽  
Average Particle ◽  
Medium Temperature ◽  
Ammonium Paratungstate ◽  
Ammonium Tungstate

The macromeritic tungsten powder was prepared by wet hydrogen reduction at medium temperature; the coarse powder of Ammonium paratungstate powder (APT) was used as raw material. It is obtained by evaporating and crystallizating adding alkalia metal salts in the solution of ammonium tungstate. The microstructure, phase composition and particle size of the macromeritic tungsten powder were investigated by SEM, XRD and test analysis sieves. The effects of kinds, contents of alkali metal salts and the temperature in the reduction were studied. The results revealed that ideal tungsten powder, with the good fluditity, spherical, integrate and well-distributed, could be obtained. The raw material is the solution of ammonium tungstate adding NaCl, Li2CO3 and KCl , the concentration of them are all 3g/L, and it is under the condition of 1000°C,180min in wet hydrogen atmosphere. The average particle size is 67μm, the maximum is 150μm, the biggest loose density is 13.41g/cm3, and the best powder flowability is 9s/50g.

Properties of Nanosize Aluminum Nitride Powders Synthesized by Chemical Vapor Synthesis

2010 ◽  
Vol 434-435 ◽  
pp. 830-833
Author(s):  
Jae Hwan Pee ◽  
Jong Chul Park ◽  
Kwang Taek Hwang ◽  
Soo Ryong Kim ◽  
Woo Seok Cho
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Average Particle Size ◽  
Chemical Vapor ◽  
Heating System ◽  
Tube Furnace ◽  
Average Particle ◽  
Low Oxygen ◽  
Chemical Vapor Synthesis ◽  
Nano Size

AlN powders by the chemical vapor synthesis (CVS) process in the AlCl3-NH3-N2-H2 system were successfully synthesized. Gasified AlCl3 as a starting material was generated by pre-heating system and transported to the tube furnace in NH3-N2-H2 atmosphere. High crystalline AlN was synthesized at over 900°C. The average particle size of spherical AlN powders decreased from 250 to 40nm with increasing the reaction temperature of the tube furnace. Porous nano-size particles synthesized at high reaction temperature have low oxygen contents.

Synthesis of Several Micrometer-Size Cu Particles by a Green Wet Reduction Method

2014 ◽  
Vol 711 ◽  
pp. 210-213
Author(s):  
Jun Ho Hwang ◽  
Jong Hyun Lee
Keyword(s):  
Particle Size ◽  
Chemical Process ◽  
Reduction Method ◽  
Average Particle Size ◽  
Reducing Agent ◽  
Average Particle ◽  
Effective Agent ◽  
Powder Samples ◽  
Wet Chemical ◽  
Micrometer Size

Several micrmeter-size Cu powders were synthesized by a simple and green wet-chemical process. Moreover, changes in particle size are examined with different synthesis temperatures and amounts of gelatin reducing agent. All powder samples synthesized in this study were indexed as a Cu phase despite the synthesis was performed in air. The particle size decreased with increasing the gelatin content in principle, indicating that gelatin is an effective agent in suppressing aggregation between synthesized particles. The smallest average particle size was 1.53 μm.

scholarly journals Effects of Flotation Deinking on Environmentally Friendly Offset Paper Printing Ink

2022 ◽  
Author(s):  
Shujie Yang ◽  
Jianbin Shen ◽  
Tiefei He ◽  
Chao Chen ◽  
Junming Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Vegetable Oil ◽  
Paper Industry ◽  
Average Particle Size ◽  
Environmentally Friendly ◽  
Raw Material ◽  
Waste Paper ◽  
Average Particle ◽  
Distribution Analysis ◽  
Uv Led

Abstract Waste paper has become a promising raw material for the pulp and paper industry due to its low cost and because it is conducive to sustainable development. Unfortunately, waste paper contains a high volume of printed paper that is difficult to deink, which restricts its applications. Flotation deinking plays an essential role in the product quality and process cost of wastepaper recycling. This study was performed to evaluate the deinkability of environmentally friendly offset inks by flotation deinking. For this purpose, three series of four-color inks, namely, hybrid light emitting diode ultraviolet (LED‒UV), LED‒UV, and vegetable oil‒based inks, were printed on white lightweight coated papers under laboratory conditions. The deinking methodology involves repulping, deinking agent treatment, flotation, hand sheet making, and evaluation of the produced hand sheets. The obtained results indicated that the hybrid LED‒UV prints had the best deinkability. After flotation deinking, the deinking efficiency and the whiteness of the hybrid LED‒UV ink increased by 58.1% and 47.6%, respectively. LED‒UV ink had a 46.9% increase in the deinking efficiency and a 37.0% increase in the whiteness of the hand sheet. The deinking efficiency of the vegetable oil‒based ink was the lowest, at 42.1%, and the whiteness of the hand sheet increased only by 23.8%. The particle size distribution analysis demonstrated that the hybrid LED‒UV four-color ink exhibited a larger value of the average particle size than the two other. Scanning electron microscopy revealed that the hybrid LED‒UV ink particles on the surface of the fibers were the least abundant after deinking. The physical strength properties of the hand sheets, including tensile index, folding resistance, and cohesion of the hybrid LED‒UV, LED‒UV inks, and vegetable oil‒based inks, increased.

Influence of Reaction Parameters on Size and Shape of Silica Nanoparticles

2006 ◽  
Vol 6 (11) ◽  
pp. 3343-3346 ◽  
Author(s):  
Jung Whan Yoo ◽  
Dong Shin Yun ◽  
Hyun Jung Kim
Keyword(s):  
Particle Size ◽  
Chain Length ◽  
Reaction Temperature ◽  
Sol Gel ◽  
Average Particle Size ◽  
Ammonia Concentration ◽  
Carbon Chain Length ◽  
Average Particle ◽  
Size And Shape ◽  
Silicon Alkoxides

It was investigated that the effect of various synthesis parameters such as, types of silicon alkoxides and alcohols, ammonia (catalyst) concentration, and reaction temperature on the particle size and shape of silica nanosphere by Sol–Gel method. When different silicon alkoxides were used, the silica particles except tetramethylorthosilicate (TMOS), all were spherical, and after reaching a maximum, the sizes were decreased with carbon chain length due to its steric effect. As the alcohol chain length increased from methanol (MeOH) to n-butanol (BuOH), the average particle size was increased from 30 nm to 800 nm. In general, all are having narrow particle size except BuOH sample were distributed bimodally (150 and 800 nm). When ammonia concentration increases, the particles also increased, however on increasing the reaction temperature, the particle sizes were reduced.

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