Synthesis Parameters of Ultrafine YAG Powder Materials via Hydrothermal Precipitation Method

2018 ◽  
Vol 279 ◽  
pp. 99-103
Author(s):  
Ming Han Xu ◽  
Ai Xia Chen ◽  
Rui Hua Wang ◽  
Long Tao Liu ◽  
Zhi Hui Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Synthesis Parameters ◽  
Hydrothermal Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that when the molar ratio of salt to alkali that Y3+: OH- is 1:8, the more uniform morphology of the particles can be prepared, when the molar ratio of salt to alkali is increased, the morphology of the particles will not change. The reaction time is longer, the particle size will be thicker. The smaller the concentration of Y3+ ions is, the larger the particle size will be small. The experimental results show that the rod-like particles have a poly-crystal structure at the reaction temperature of 200°C, reaction time of 2 days and the molar ratio of salt to alkali of 1:8. The diameter of the rod-like particles is most of the powders have a particle size of 1000 nm and a small amount of powder has a particle size of about 5000 nm. The purity of powder is higher through the test of XRD.

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

scholarly journals Optimization of medium–low-grade phosphorus rock carbothermal reduction process by response surface methodology

2020 ◽  
Vol 9 (1) ◽  
pp. 349-358
Author(s):  
Biwei Luo ◽  
Pengfei Li ◽  
Yan Li ◽  
Pengpeng He ◽  
Jun Ji ◽  
...  
Keyword(s):  
Particle Size ◽  
Response Surface Methodology ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Reduction Rate ◽  
Molar Ratio ◽  
Temperature Reaction ◽  
Rock Particle ◽  
Phosphorus Reduction

AbstractPhosphorus extraction from phosphorus rock was conducted by carbothermal reduction with silica and coke. The effects of reaction temperature, reaction time, coke excess coefficient, molar ratio of silicon–calcium, and phosphorus rock particle size on the phosphorus reduction rate were investigated by the response surface methodology (RSM). The central composite design (CCD) with five factors and five levels was used to explore the effects of variables’ interactions on the phosphorus reduction rate. The results showed that there are significant interactions between reaction time and temperature; reaction temperature and molar ratio of silicon–calcium; reaction temperature and phosphorus rock particle size; coke excess coefficient and molar ratio of silicon–calcium; and coke excess coefficient and phosphorus rock particle size. The optimum conditions in the experimental range are reaction time 92 min, reaction temperature 1340°C, coke excess coefficient 1.27, molar ratio of silicon–calcium 1.28, and phosphorus rock particle size 75–106 µm, which were derived from the quadratic statistic model. Under these conditions, the phosphorus reduction rate can reach 96.88%, which is close to the model prediction value 99.40%. The optimized carbothermal reduction conditions of phosphorus rock by the RSM are helpful to reduce the energy cost of thermal phosphoric acid process.

scholarly journals A Method of Synthesizing Lithium Hydroxide Nanoparticles Using Lithium Sulfate from Spent Batteries by 2-Step Precipitation Method

2020 ◽  
Vol 58 (4) ◽  
pp. 286-291
Author(s):  
Soyeong Joo ◽  
Hyun-Woo Shim ◽  
Jin-Ju Choi ◽  
Chan-Gi Lee ◽  
Dae-Guen Kim
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Lithium Hydroxide ◽  
Precipitation Method ◽  
Solution Temperature ◽  
Lithium Sulfate ◽  
Experimental Conditions ◽  
Mean Size ◽  
Enhance Efficiency

In this work, LiOH was synthesized using highly soluble Li2SO4. To enhance efficiency, this synthesis was performed using the precipitation method, and the correlation between each experimental condition and the synthesis of LiOH was investigated. The particle size and crystalline properties were tailored by controlling various experimental conditions, including the mole ratio of [Li]/[OH](Li: lithium sulfate, OH: barium hydroxide), reaction temperature, and reaction time. First, precursors with a ratio of 1:0.5 were reacted for 60 min at a solution temperature of 40 oC and filtered to remove precipitates. For the double reaction, half the hydroxyl precursor was added to the filtered solution and reacted under the same conditions. Using two-step precipitation, we were able to synthesize powder with a pure LiOH phase, a particle mean size of 100 nm, and purity over 99%.

Role of Synthesis Parameters on Structural and Electrical Properties of M-Type Hexa-Ferrites

2012 ◽  
Vol 510-511 ◽  
pp. 201-205
Author(s):  
G. Asghar ◽  
S. Nasir ◽  
M.S. Awan ◽  
G.H. Tariq ◽  
M. Akram ◽  
...  
Keyword(s):  
Particle Size ◽  
Diffraction Analysis ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Narrow Particle Size Distribution ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Volume Rate ◽  
Synthesis Parameters

Phase purity, particle size and its distribution contributes a lot to the physical properties of M-type hexa-ferrites. These parameters are strongly influenced by the variation in synthesis parameters. In the present work, effect of synthesis parameters such as molar ratio (Fe/Sr) and volume rate of addition of precipitating agent on M-type hexa-ferrite (SrFe12O19) prepared by co-precipitation method have been investigated systematically. The molar ratio (Fe/Sr) in SrFe12O19was varied as 12, 11, 10, 09, and 08. X-ray diffraction analysis revealed that molar ratio does not affect the phase purity. X-ray diffraction analysis of the samples prepared with different volume rate of addition of precipitating agent indicated that phase purity and micro-structural properties of SrFe12O19are greatly influenced by the above synthesis parameter. High volume rate of addition of precipitating agent resulted in high phase purity, smaller particle size, and narrow particle size distribution.

Optimization of the Process Parameters for the Synthesis Process of Battery-Grade Ferrous Oxalate by Response Surface Method

NANO ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. 1650123 ◽  
Author(s):  
Keyu Zhang ◽  
Xiaoyan Yang ◽  
Jian Wu ◽  
Xiaopeng Huang ◽  
Yaochun Yao
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Reaction Temperature ◽  
Ferrous Sulfate ◽  
Raw Material ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Preparation Conditions ◽  
Ferrous Oxalate ◽  
Crystallographic Planes

This study investigates the optimal conditions for the synthesis of battery-grade ferrous oxalate as a raw material for preparing cathode material. Ferrous oxalate was prepared by liquid-phase precipitation method using ferrous sulfate and oxalic acid. Central composite design (CCD) was used to determine the effects of three preparation variables on purity and particle size: reaction temperature, aging time and concentration of ferrous sulfate. Based on CCD, the significant factors on each experimental design response identified the analysis of variance (ANOVA). The optimum ferrous oxalate preparation conditions were obtained reaction temperature of 31.32[Formula: see text]C, aging time of 56.52[Formula: see text]min, and ferrous sulfate concentration of 5%. Under these optimum conditions, ferrous oxalate with purity of 99.69% and particle size of 4.92[Formula: see text][Formula: see text]m was obtained as best product which met and exceed the requirements of battery-grade ferrous oxalate. In addition, the special morphologies of ferrous oxalate prepared under different dispersant proportion was characterized by scanning electron microscope (SEM) to analyze the mechanism of synthesis. Morphology control study revealed that the dispersant could effectively change the surface energy between crystallographic planes, then result in anisotropic growth of the crystal structure and change the morphology of synthetic products.

scholarly journals Pawpaw (Carica papaya) Peel Waste as a Novel Green Heterogeneous Catalyst for Moringa Oil Methyl Esters Synthesis: Process Optimization and Kinetic Study

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5834
Author(s):  
Babatunde Oladipo ◽  
Tunde V Ojumu ◽  
Lekan M Latinwo ◽  
Eriola Betiku
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Carica Papaya ◽  
Methyl Esters ◽  
Molar Ratio ◽  
Coefficient Of Determination ◽  
Synthesis Process ◽  
Solid Base ◽  
X Ray ◽  
The Impact

This study evaluated pawpaw (Carica papaya) peel ash as a green solid base catalyst for Moringa oleifera oil methyl esters (MOOME) production. Taguchi orthogonal array approach was used to examine the impact of vital process input variables (calcined pawpaw peel (CPP) loading, reaction temperature, methanol-to-M. oleifera oil (MeOH:MOO) molar ratio and reaction time) on the MOOME yield. Catalytic potency potential of the CPP was evaluated by Fourier transform infrared (FTIR), Barrett-Joyner-Halenda (BJH), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) methods. The results obtained indicate that the CPP consists of nanoparticles and alkaline elements K (23.89 wt.%), Ca (2.86 wt.%) and Mg (1.00 wt.%). The high values of coefficient of determination, R2 (0.9992) and adjusted R2 (0.9968) as well as the low value of the coefficient of variation (0.31%) for the model developed indicate it can be used to sufficiently describe the transesterification process. MOOME yield of 96.43 ± 0.10 wt.% was achieved at the optimum values of 3.5 wt.% CPP loading, 9:1 MeOH:MOO molar ratio, 35 °C reaction temperature and 40 min reaction time. The kinetic modeling of the transesterification process determined the reaction rate constant and overall reaction order as 0.20465 L·mol−1·s−1 and 2, respectively. The results of this study demonstrate both CPP and MOO are feasible renewable resources for MOOME production. The kinetic data generated may be useful in reactor design for the transesterification process.

scholarly journals Effects of Process Variables on Properties of CoFe2O4 Nanoparticles Prepared by Solvothermal Process

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3056
Author(s):  
Hong Diu Thi Duong ◽  
Dung The Nguyen ◽  
Kyo-Seon Kim
Keyword(s):  
Particle Size ◽  
Oleic Acid ◽  
Reaction Time ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Synthesis Process ◽  
Process Conditions ◽  
Solvothermal Process ◽  
Cofe2o4 Nanoparticles ◽  
Oleic Acid Concentration

Controlling the morphology and magnetic properties of CoFe2O4 nanoparticles is crucial for the synthesis of compatible materials for different applications. CoFe2O4 nanoparticles were synthesized by a solvothermal method using cobalt nitrate, iron nitrate as precursors, and oleic acid as a surfactant. The formation of CoFe2O4 nanoparticles was systematically observed by adjusting synthesis process conditions including reaction temperature, reaction time, and oleic acid concentration. Nearly spherical, monodispersed CoFe2O4 nanoparticles were formed by changing the reaction time and reaction temperature. The oleic acid-coated CoFe2O4 nanoparticles inhibited the growth of particle size after 1 h and, therefore, the particle size of CoFe2O4 nanoparticles did not change significantly as the reaction time increased. Both without and with low oleic acid concentration, the large-sized cubic CoFe2O4 nanoparticles showing ferromagnetic behavior were synthesized, while the small-sized CoFe2O4 nanoparticles with superparamagnetic properties were obtained for the oleic acid concentration higher than 0.1 M. This study will become a basis for further research in the future to prepare the high-functional CoFe2O4 magnetic nanoparticles by a solvothermal process, which can be applied to bio-separation, biosensors, drug delivery, magnetic hyperthermia, etc.

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.

Controlled Synthesis of Different Morphologies of SrWO4 Crystals via a Surfactant-Assisted Hydrothermal Precipitation Method

2013 ◽  
Vol 785-786 ◽  
pp. 449-454
Author(s):  
Yan Zhao ◽  
Chun Yan Wu ◽  
Dan Qin ◽  
Xin Lai ◽  
Si Wu ◽  
...  
Keyword(s):  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Parameters ◽  
Infrared Spectrometer ◽  
Luminescent Spectra ◽  
Hydrothermal Precipitation ◽  
Surfactant Assisted

SrWO4 octahedrons, flowers, bundles, ellipsoids and dendrites had been successfully synthesized via surfactant-assisted method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photo-luminescent spectra techniques (PL) and fourier transrform infrared spectrometer (FTIR). By through various comparison experiments, it can be found that some related experimental parameters including the reagent concentration, [Sr2+]/[WO42-] molar ratio (R), aging temperature and the pH value had great influences on morphology of the products.

scholarly journals Optimization of Enzymatic Synthesis of Betulinic Acid Amide in Organic Solvent by Response Surface Methodology (RSM)

2019 ◽  
Vol 19 (4) ◽  
pp. 849
Author(s):  
Nurul Atikah Amin Yusof ◽  
Nursyamsyila Mat Hadzir ◽  
Siti Efliza Ashari ◽  
Nor Suhaila Mohamad Hanapi ◽  
Rossuriati Dol Hamid
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
Reaction Temperature ◽  
Betulinic Acid ◽  
Enzymatic Synthesis ◽  
Acid Amide ◽  
Molar Ratio ◽  
Percentage Yield ◽  
Substrate Molar Ratio

Optimization of the lipase catalyzed enzymatic synthesis of betulinic acid amide in the presence of immobilized lipase, Novozym 435 from Candida antartica as a biocatalyst was studied. Response surface methodology (RSM) and 5-level-4-factor central-composite rotatable design (CCRD) were employed to evaluate the effects of the synthesis parameters, such as reaction time (20–36 h), reaction temperature (37–45 °C), substrate molar ratio of betulinic acid to butylamine (1:1–1:3), and enzyme amounts (80–120 mg) on the percentage yield of betulinic acid amide by direct amidation reaction. The optimum conditions for synthesis were: reaction time of 28 h 33 min, reaction temperature of 42.92 °C, substrate molar ratio of 1:2.21, and enzyme amount of 97.77 mg. The percentage yield of actual experimental values obtained 65.09% which compared well with the maximum predicted value of 67.23%. The obtained amide was characterized by GC, GCMS and 13C NMR. Betulinic acid amide (BAA) showed a better cytotoxicity compared to betulinic acid as the concentration inhibited 50% of the cell growth (IC50) against MDA-MB-231 cell line (IC50 < 30 µg/mL).

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