scholarly journals Extraction of alumina from alumina rich coal gangue by a hydro-chemical process

2020 ◽  
Vol 7 (4) ◽  
pp. 192132 ◽  
Author(s):  
Quancheng Yang ◽  
Fan Zhang ◽  
Xingjian Deng ◽  
Hongchen Guo ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Chemical Process ◽  
Energy Dispersive Spectrometer ◽  
Coal Gangue ◽  
Added Value ◽  
High Alumina ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
X Ray

Vast quantities of gangue from coal mining and processing have accumulated over the years and caused significant economic and environmental problems in China. For high added-value utilization of alumina rich coal gangue (ARCG), a mild hydro-chemical process was investigated to extract alumina. The influences of NaOH concentration, mass ratio of alkali to gangue, reaction temperature and reaction time were systematically studied. An alumina extraction rate of 94.68% was achieved at the condition of NaOH concentration 47.5%, alkali to gangue ratio of 6, reaction temperature of 260°C and reaction time of 120 min. The obtained leaching residues were characterized through X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometer. Research confirmed that kaolinite the main alumina-bearing phase of ARCG can be decomposed and transformed to Na 8 Al 6 Si 6 O 24 (OH) 2 (H 2 O) 2 and Ca 2 Al 2 SiO 6 (OH) 2 at relatively low temperature and short reaction time. Additionally, Na 8 Al 6 Si 6 O 24 (OH) 2 (H 2 O) 2 and Ca 2 Al 2 SiO 6 (OH) 2 are unstable and will transform to alumina-free phase NaCaHSiO 4 under the optimal conditions, which is the major reason for high alumina extraction rates.

Experimental Study on Combustion Reaction between Silicon and Nitrogen in Transport Bed

2013 ◽  
Vol 860-863 ◽  
pp. 1374-1377
Author(s):  
Shao Wu Yin ◽  
Li Wang ◽  
Li Ge Tong ◽  
Chuan Ping Liu ◽  
Xing Long Zheng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Experimental Study ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Combustion Reaction ◽  
X Ray Diffraction ◽  
Amorphous Silicon Nitride ◽  
X Ray ◽  
Scanning Electron

Combustion reaction between silicon powders and nitrogen in transport bed was studied. The reaction temperature ranged from 1523 to 1653 K, and the reaction time ranged from 0 to 2.7 min. The phase compositions, morphologies and chemical composition of the products were analyzed by X-ray diffraction, scanning electron microscopy and O/N determinater, respectively. The experimental results showed, in the case of silicon powders with particle size of 2.2 μm, the conversion rate of silicon was 61.9% at reaction temperature of 1653 K and reaction time of 2.7min, and the products mainly comprised amorphous silicon nitride powders.

The Influence of the Hydrothermal Conditions on the Morphologies of β-Ni(OH)2

2012 ◽  
Vol 562-564 ◽  
pp. 494-497
Author(s):  
Xiao Ming Fu
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Reaction Time ◽  
Scanning Electron Microscope ◽  
Reaction Temperature ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Low Reaction Temperature ◽  
Scanning Electron

Flower-like β-Ni(OH)2 and nanoflakes have been successfully synthesized with nickel nitrate as nickel source and stronger ammonia water as precipitant via the hydrothermal method. The phase and the morphologies of the samples have been characterized and analyzed by XRD (X-ray diffraction) and SEM (Scanning electron microscope), respectively. XRD shows that the phase of the samples is β-Ni(OH)2. SEM confirms that The low reaction temperature is propitious to the synthesis of flower-like β-Ni(OH)2, and with the increase of the reaction time the nanoflakes of flower-like β-Ni(OH)2 become much thinner. However, The high temperature is in favor of the synthesis of β-Ni(OH)2 nanosflakes, and with the further increase of the reaction temperature.

Synthesis of CuO Flower-Nanostructure via the Hydrothermal Method

2013 ◽  
Vol 873 ◽  
pp. 131-134
Author(s):  
Xiao Ming Fu ◽  
Jie Ren
Keyword(s):  
Electron Microscope ◽  
Reaction Time ◽  
Scanning Electron Microscope ◽  
Hydrothermal Method ◽  
Reaction Temperature ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

CuO flower-nanostructures are successfully synthesized with CuCl2 as copper source and Na2CO3 as auxiliary salt at 180 °C for 24 h via the simple hydrothermal method. The phase and the morphologies of the samples have been characterized and analyzed by XRD (X-ray diffraction) and SEM (Scanning electron microscope), respectively. XRD analysis shows that the phase of as obtained samples is CuO. SEM analysis confirms that the increase of the reaction temperature is propitious to synthesize CuO flower-nanostructures while the increase of the reaction time is not in favor of their synthesis. The influence of the increase of the auxiliary salt on the morphology of CuO flower-nanostructures is not remarkable. The mechanism of the formation of CuO flower-nanostructure is discussed.

Controlled Synthesis and Upconversion Luminescence Properties of Yb3+-Tm3+ Codoped NaYF4 Hexagonal Submicroplates

2012 ◽  
Vol 528 ◽  
pp. 117-120
Author(s):  
Wen Juan Huang ◽  
Chun Hua Lu ◽  
Yan Song ◽  
Heng Ming Huang ◽  
Ya Qin Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Upconversion Luminescence ◽  
Controlled Synthesis ◽  
Synthetic Route ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Highly Uniform ◽  
Co Doped

We reported the preparation of cubic (α-) and hexagonal (β-) NaYF4 particles in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), through a thermal decomposition synthetic route. The as-prepared products were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence (PL) spectra. By tuning the reaction temperature and time, we could manipulate the morphology, size, and crystal phase of the products. It was found that the α→β phase transition was favored by high reaction temperature and long reaction time. Highly uniform β-NaYF4 hexagonal submicroplates were obtained from α-NaYF4 nanoparticles by prolonging the reaction time. The Yb3+-Tm3+ co-doped β-NaYF4 hexagonal submicroplates showed sSubscript texttrong blue Subscript textand weak red upconversion luminescence under 980nm laser diode excitation. In addition, the dependence of the UC emission intensities upon pump power was investigated.

Synthesis and Characterization of Nano Melamine Phosphate

2014 ◽  
Vol 989-994 ◽  
pp. 301-304
Author(s):  
Zheng Zhou Wang ◽  
Shao Hong Xu
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Solvothermal Method ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Melamine Phosphate ◽  
Infra Red ◽  
Time Changes

nanomelamine phosphate (NMP) flame retardant was synthesized by means of a solvothermal method, and was characterized by Fourier transform infra-red spectroscopy, X-ray diffraction, and scanning electron microscopy. Effects of reaction temperature and reaction time on the morphology of reaction products were investigated. It was observed that the morphology of the products changes greatly as reaction temperature or reaction time changes.

Chemically-Induced Graft Copolymerization of Diethylenetriamine onto Bagasse Celluloses

2011 ◽  
Vol 295-297 ◽  
pp. 1494-1498
Author(s):  
Nan Nan Xia ◽  
Hong Xiang Zhu ◽  
Shuang Fei Wang ◽  
Ying Xiao Mu ◽  
Chao Bing Deng ◽  
...  
Keyword(s):  
Reaction Time ◽  
Aqueous Medium ◽  
Reaction Temperature ◽  
Graft Copolymerization ◽  
Optimum Process ◽  
Process Conditions ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Chemically Induced ◽  
Ft Ir

Graft copolymerization of diethylenetriamine onto bagasse celluloses was investigated with ammonium ceric nitrate as initiator in an aqueous medium. The condition of the graft copolymerization initiator concentration, the mass ratio of monomer/cellulose, reaction temperature, reaction time based on the experiment is optimized according to the zeta potential. The results showed the relative optimum process conditions were: the concentration of initiator at 36.98mmol/L, the mass ratio of the monomer and cellulose at 1:1, the reaction temperature at 70°C, and the reaction time by 3h. In addition, the graft copolymers were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction analysis (XRD). The results showed that bagasse celluloses could be grafted with diethylenetriamine in aqueous medium.

scholarly journals Synthesis and characterization of thiourea

2019 ◽  
Vol 21 (3) ◽  
pp. 35-39
Author(s):  
Chuanbo Dai ◽  
Hongyu Zhang ◽  
Ruiduan Li ◽  
Haifeng Zou
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Raw Materials ◽  
High Yield ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Step Method ◽  
Lawesson’S Reagent ◽  
One Step ◽  
Lawesson's Reagent

Abstract Herein, a simple and effective method for the preparation of thiourea using a nucleophilic substitution reaction is reported. Urea and Lawesson’s reagent were used as the raw materials to prepare thiourea via a one-step method involving the sulfuration reaction, and the reaction mechanism was analyzed. The effect of the reaction time, reaction temperature, and mass ratio of the raw materials on the yield of thiourea were investigated.The most beneficial conditions used for the reaction were determined to be: Reaction time = 3.5 h, reaction temperature = 75°C, and mass ratio of urea to Lawesson’s reagent = 2:1. Under these optimal conditions, the average yield of thiourea over five replicate experiments was 62.37%. Characterization using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) showed that the as-synthesized substance was thiourea. Our synthetic method has the advantages of high yield, mild reaction conditions and simplicity.

scholarly journals Extraction of Boron from Ludwigite Ore: Mechanism of Soda-Ash Roasting of Lizardite and Szaibelyite

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Energy Dispersive Spectrometer ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selective Activation ◽  
X Ray ◽  
Shed Light ◽  
Soda Ash ◽  
Scanning Electron

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.

Full-field X-ray diffraction microscopy using polymeric compound refractive lenses

2014 ◽  
Vol 47 (6) ◽  
pp. 1882-1888 ◽  
Author(s):  
J. Hilhorst ◽  
F. Marschall ◽  
T. N. Tran Thi ◽  
A. Last ◽  
T. U. Schülli
Keyword(s):  
Imaging Techniques ◽  
Light And Electron Microscopy ◽  
Added Value ◽  
Acquisition Time ◽  
Imaging Method ◽  
X Ray Diffraction ◽  
Polymeric Compound ◽  
Full Field ◽  
X Ray ◽  
Diffraction Imaging

Diffraction imaging is the science of imaging samples under diffraction conditions. Diffraction imaging techniques are well established in visible light and electron microscopy, and have also been widely employed in X-ray science in the form of X-ray topography. Over the past two decades, interest in X-ray diffraction imaging has taken flight and resulted in a wide variety of methods. This article discusses a new full-field imaging method, which uses polymer compound refractive lenses as a microscope objective to capture a diffracted X-ray beam coming from a large illuminated area on a sample. This produces an image of the diffracting parts of the sample on a camera. It is shown that this technique has added value in the field, owing to its high imaging speed, while being competitive in resolution and level of detail of obtained information. Using a model sample, it is shown that lattice tilts and strain in single crystals can be resolved simultaneously down to 10−3° and Δa/a= 10−5, respectively, with submicrometre resolution over an area of 100 × 100 µm and a total image acquisition time of less than 60 s.

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