scholarly journals SYNTHESIS OF PURE SILICA FROM RICE HUSK ASH AS AN ANTI–CAKING AGENT FOR FERTILIZER INDUSTRY IN VIETNAM

2018 ◽  
Vol 55 (1B) ◽  
pp. 193
Author(s):  
Nguyen Huu Hieu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Silica Particles ◽  
Average Particle ◽  
X Ray ◽  
Pure Silica ◽  
Npk Fertilizer

Pure silica particles have been successfully synthesized from rice husk ash (RHA) by precipitation method. The characterization of silica was performed by X–ray diffraction, X–ray fluorescence, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller specific surface area, and transmission electron microscopy. The characterization results show that the obtained amorphous silica was 99.8 % purity with average particle size of 5–10 nm, and high specific surface area of 224 m2/g. Additionally, for the first time that RHA–silica was successfully applied as an anti–caking agent for a NPK–fertilizer. A suitable content of silica was evaluated through the level of anti–caking. The testing results show that with only 1.5 wt% of RHA–silica particles could replace kaolin as an anti–caking agent for the NPK–fertilizer. 

Preparation of Zeolite Nanocrystals via Hydrothermal and Solvothermal Synthesis Using of Rice Husk Ash and Metakaolin

2016 ◽  
Vol 872 ◽  
pp. 242-247 ◽  
Author(s):  
Naruemon Setthaya ◽  
Prinya Chindaprasirt ◽  
Kedsarin Pimraksa
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Molar Ratio ◽  
X Ray ◽  
Stirring Time ◽  
Electron Dispersion ◽  
Solvothermal Methods

Synthesis of zeolite nanocrystals from rice husk ash and metakaolin was studied. Hydrothermal and solvothermal methods at 120 °C for 6 h were used as comparative study. Starting mixes were prepared with SiO2/Al2O3 molar ratio of 4. Two factors; stirring time before hydrothermal and solvothermal treatments and solvent types were studied. The synthesized products were characterized in terms of mineralogy using X-ray diffraction, specific surface area using N2 adsorption and desorption isotherm, morphology and composition using scanning electron microscopy and electron dispersion X-ray analysis. The results showed that faujasite and zeolite P1 were obtained from both of hydrothermal and solvothermal methods. However, crystals sizes of the synthesized zeolites from solvothermal method were smaller than that of hydrothermal method in that 100-300 nm and 100-1500 nm for solvothermal and hydrothermal methods, respectively. Specific surface area of the zeolites obtained from hydrothermal and solvothermal methods were 418 and 487 m2/g, respectively.

scholarly journals PHYSICOCHEMICAL PROPERTIES AND POZZOLANIC PERFORMANCE OF ULTRAFINE TREATED RICE HUSK ASH (UFTRHA) AS ADDITIVE IN CONCRETE

2018 ◽  
Vol 16 ◽  
Author(s):  
Siti Asmahani Saad ◽  
Nasir Shafiq ◽  
Maisarah Ali
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Rice Husk Ash ◽  
High Energy ◽  
Size Analysis ◽  
Pre Treatment

Rice husk ash (RHA) contains high amount of amorphous silica that is ubiquitous in the pozzolanic reaction of SCM in concrete. However, usage of conventional RHA is currently unfavourable in concrete industry due to its properties inconsistency. In this regard, improvement on the RHA properties by introduction of thermochemical pre-treatment prior to burning procedure is seen as an excellent way to reach the goal. In this paper, raw rice husk was pre-treated using 0.1N hydrochloric acid (HCl) and heated at 80oC. It was then mechanically activated by high energy planetary ball mill for 15 minutes at speed of 300rpmand ball-to-powder ratio (BPR) of 15:1. The chemical composition, mineralogical properties, particle size analysis, specific surface area as well as microstructure properties of ultrafine treated rice husk ash (UFTRHA) were determined accordingly. As for amorphous silica content of the optimum sample was recorded as 98.60% incinerated at 600oC with four hours of pre-treatment soaking duration. In terms of particle size and specific surface, it was also observed that, burning temperature of 600oC, pre-treated at four hours were recorded to produce finest size of UFTRHA where d(0.1), d(0.5) and d(0.9) were obtained as 1.416?m, 4.364 ?m and 14.043 ?m respectively. Largest specific surface area value was obtained at 219.58 m2/g with the similar pre-treatment conditions. Meanwhile, the strength activity of UFTRHA from the optimum pre-treatment process was measured by testing the compressive strength of mortars. The highest compression value obtained was 50.17MPa with 3% UFTRHA replacement at 28 days.

New Insight Technique for Synthesis of Silica Gel from Rice Husk Ash by Using Microwave Radiation

2014 ◽  
Vol 1025-1026 ◽  
pp. 574-579 ◽  
Author(s):  
Nuchanaporn Pijarn ◽  
Pichit Galajak
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Silica Gel ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Pore Volume ◽  
Rice Husk Ash ◽  
Sol Gel ◽  
Microwave Technique

Silica gel is the chemical substance that has many good advantages such as absorbed moisture, porosity, small diameter, high surface area, and lightweight. It was synthesized by using rice husk ash via sol – gel heating in the microwave technique. The objectives in this work compose of synthesis silica gel by using the microwave technique before characterizatization. This raw material was archived from rice husk ash, obtained from agricultural waste. The silica gel, synthesized by conventional method (CVM) and commercial silica gel (COM), was also studied for comparison purposes. The results showed that successfully synthesized the silica gel by sol - gel technique using microwave. The XRD pattern of silica gel enhanced from this method was not sinificantly different as compared with CVM and COM methods. And the physical properties of this technique could be debated. The particle size of silca gel was determined by zetasizer and it was approxmately 50-70 nm. The pore size diameter, pore volume, and specific surface area of silica gel were calculated by Flowsorb II and a Quantachrome Autosorp-1. The pore size diameter, pore volume, and specific surface area of silica gel are 10-30 nm, 0.7-1.0 cm3/g, and 400-700 m2/g, respectively. Consequently, this work is considered to be the waste to make useful, and a great way to save energy and time in the silica gel synthesis.

scholarly journals PHYSICOCHEMICAL PROPERTIES AND POZZOLANIC PERFORMANCE OF ULTRAFINE TREATED RICE HUSK ASH (UFTRHA) AS ADDITIVE IN CONCRETE

2018 ◽  
Vol 16 (6) ◽  
Author(s):  
Siti Asmahani Saad ◽  
Nasir Shafiq ◽  
Maisarah Ali
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Rice Husk Ash ◽  
High Energy ◽  
Size Analysis ◽  
Pre Treatment

Rice husk ash (RHA) contains high amount of amorphous silica that is ubiquitous in the pozzolanic reaction of SCM in concrete. However, usage of conventional RHA is currently unfavourable in concrete industry due to its properties inconsistency. In this regard, improvement on the RHA properties by introduction of thermochemical pre-treatment prior to burning procedure is seen as an excellent way to reach the goal. In this paper, raw rice husk was pre-treated using 0.1N hydrochloric acid (HCl) and heated at 80oC. It was then mechanically activated by high energy planetary ball mill for 15 minutes at speed of 300rpmand ball-to-powder ratio (BPR) of 15:1. The chemical composition, mineralogical properties, particle size analysis, specific surface area as well as microstructure properties of ultrafine treated rice husk ash (UFTRHA) were determined accordingly. As for amorphous silica content of the optimum sample was recorded as 98.60% incinerated at 600oC with four hours of pre-treatment soaking duration. In terms of particle size and specific surface, it was also observed that, burning temperature of 600oC, pre-treated at four hours were recorded to produce finest size of UFTRHA where d(0.1), d(0.5) and d(0.9) were obtained as 1.416?m, 4.364 ?m and 14.043 ?m respectively. Largest specific surface area value was obtained at 219.58 m2/g with the similar pre-treatment conditions. Meanwhile, the strength activity of UFTRHA from the optimum pre-treatment process was measured by testing the compressive strength of mortars. The highest compression value obtained was 50.17MPa with 3% UFTRHA replacement at 28 days.

scholarly journals PREPARATION OF ACTIVATED CARBON-ZEOLITE COMPOSITES FROM RICE HUSK ASH

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Miyuki Miyazaki ◽  
Takeshi Shiono
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Thermal Power ◽  
Value Added ◽  
Raw Material ◽  
Zeolite A

Rice husk (RH) is a biomass resource that contains about 20 mass% silica. In Southeast Asia countries, RH is used as fuel for thermal power plants, and it produces a large amount of ash (Rice Husk Ash: RHA), as industrial waste. Furthermore, our research group has reported that consolidated zeolite A could be prepared from RHA as a raw material. Zeolite A has hydrophilic micropore in the structure and is used for adsorption and a builder for detergent. From processing point of view, the remaining carbon must be removed before synthesizing of zeolite A. However, the utility of carbon in RHA has not been studied sufficiently. In the present study, therefore, the possibility of usage of both silica and carbon in RHA as a raw material was investigated for the high value-added application of RHA. Before the synthesis of zeolite, activation treatment of carbon was carried out for RHA under specific conditions to make the carbon become porous. The specific surface area was measured by BET for activated RHA. Additionally, hydrothermal treatments were attempted after adjusting the composition of raw materials for the preparation of composites of carbon and zeolite. For the obtained specimens, XRD analysis and SEM were conducted as characterizations to confirm crystalline phases and microstructures respectively. Activation treatment made the specific surface area of RHA larger. As the activation time and temperature increased, silica was crystallized to cristobalite and the reactivity was decreased. The crystalline phase of zeolite A was recognized in the specimens with an appropriate composition. Furthermore, the homogenous zeolite A particles with a size smaller than 1 μm were also observed. Therefore, activated carbon-zeolite composites could be synthesized from RHA.

Influence of particle size and specific surface area on the pozzolanic activity of residual rice husk ash

2011 ◽  
Vol 33 (5) ◽  
pp. 529-534 ◽  
Author(s):  
Guilherme Chagas Cordeiro ◽  
Romildo Dias Toledo Filho ◽  
Luis Marcelo Tavares ◽  
Eduardo de Moraes Rego Fairbairn ◽  
Simone Hempel
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Pozzolanic Activity

Synthesis of Faujasite and Analcime Using of Rice Husk Ash and Metakaolin

2013 ◽  
Vol 770 ◽  
pp. 209-212 ◽  
Author(s):  
Naruemon Setthaya ◽  
Chitsophin Pindi ◽  
Prinya Chindaprasirt ◽  
Kedsarin Pimraksa
Keyword(s):  
Specific Surface ◽  
Cation Exchange ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Cation Exchange Capacity ◽  
Rice Husk Ash ◽  
Raw Materials ◽  
Exchange Capacity ◽  
Molar Ratio

Faujasite and analcime were synthesized by two-step process via hydrothermal method using the rice husk ash and metakaolin as starting materials. In the first step, the raw materials were prepared using the SiO2/Al2O3molar ratio of 4 and pretreatment with NaOH solution under various stirring conditions. The suspension was subjected to hydrothermal treatment at various reacting time and temperature in second step. The mineralogy, morphology, specific surface area and cation exchange capacity of the synthesized products were investigated using X-ray diffraction, Scanning electron microscopy, N2adsorption and desorption isotherm and ammonium acetate method, respectively. Faujasite was obtained using low temperature and short-time synthesis, while the analcime was obtained at high temperature and long-time synthesis. The stirring time did not affect zeolite types but the specific surface area. The cation exchange capacity of the synthetic faujasite and analcime were 263-280 and 280-302 meq/100 g, respectively.

Study on the kinetics of process for obtaining cobalt nanopowder by hydrogen reduction under isothermal conditions

2021 ◽  
Vol 1 (1) ◽  
pp. 49-56
Author(s):  
Hieр Nguyen Tien
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hydrogen Reduction ◽  
Average Particle Size ◽  
Chemical Deposition ◽  
Average Particle ◽  
Isothermal Conditions ◽  
Electron Microscopes ◽  
Kinetics Of

The kinetics of metallic cobalt nanopowder synthesizing by hydrogen reduction from Co(OH)2 nanopowder under isothermal conditions were studied. Co(OH)2 nanopowder was prepared in advance by chemical deposition from aqueous solutions of Co(NO3)2 cobalt nitrate (10 wt.%) and NaOH alkali (10 wt.%) at room temperature, pH = 9 under continuous stirring. The hydrogen reduction of Co(OH)2 nanopowder under isothermal conditions was carried out in a tube furnace in the temperature range from 270 to 310 °C. The crystal structure and composition of powders was studied by X-ray phase analysis. The specific surface area of samples was measured using the BET method by low-temperature nitrogen adsorption. The average particle size of powders was determined by the measured specific surface area. Particles size characteristics and morphology were investigated by transmission and scanning electron microscopes. Kinetic parameters of Co(OH)2 hydrogen reduction under isothermal conditions were calculated using the Gray–Weddington model and Arrhenius equation. It was found that the rate constant of reduction at t = 310 °C is approximately 1.93 times higher than at 270 °C, so the process accelerates by 1.58 times for 40 min of reduction. The activation energy of cobalt nanopowder synthesizing from Co(OH)2 by hydrogen reduction is ~40 kJ/mol, which indicates a mixed reaction mode. It was shown that cobalt nanoparticles obtained by the hydrogen reduction of its hydroxide at 280 °C are aggregates of equiaxed particles up to 100 nm in size where individual particles are connected to several neighboring particles by contact isthmuses.

Physical Properties Variability of Zinc Powders Obtained by Electrochemical Method

2021 ◽  
Vol 316 ◽  
pp. 689-693
Author(s):  
K.D. Naumov ◽  
V.G. Lobanov
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Bulk Density ◽  
Surface Area ◽  
Specific Surface Area ◽  
Current Density ◽  
Zinc Concentration ◽  
Regulatory Change ◽  
Average Particle ◽  
Zinc Powders

The aim of this paper is to establish a regulatory change of zinc powders key physicochemical properties with varying electroextraction conditions. It was studied influence zinc concentration, alkali concentration and current density. Quantitative dependencies of zinc powders particle size and specific surface area from mentioned electroextraction parameters are shown. At increasing of zinc concentration, decreasing of NaOH concentration and decreasing of current density of powders particle size growth, correspondingly specific surface area is declined. It is indicated, that electrolytic zinc powders bulk density varies from 0.61 g/cm3 to 0.75 g/cm3 with a decrease of average particle size from 121 μm to 68 μm. In comparison, spherical powders bulk density used in various industries is currently 2.45-2.6 g/cm3. In all experiments, metal zinc content varied in the range of 91.1-92.5%, the rest - ZnO. To a greater extent, this indicator depends on powder washing quality from alkali and storage conditions.

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