scholarly journals Effect of hydrothermal treatment temperature on morphology of obtained calcium silicate from rice husk ash

2016 ◽  
Vol 19 (3) ◽  
pp. 69-75
Author(s):  
Kien Trung Pham ◽  
Nguyen Pham Quang Tran ◽  
Thang Hoc Nguyen

This research report on the effect of hydrothermal treatment temperature on morphology of obtained calcium silicate from Vietnam Rice Husk Ash (VRHA). VRHA is collected at the Mekong Delta River, burn to obtain the active silica which can be used for further step. The obtained silica is hydrothermal treated in the present of Ca-source so that the Ca/Si molar ratio of 1.0 for different treatment temperature such as 110, 130, 150 and 180oC. XRD and SEM of samples before and after hydrothermal treatment confirm the present of nano-Calcium Silicate Hydrate (CSH) such as Tobermorite and Xonotlite. These CSH can be used as inorganic light weight thermal insulator application. The obtained calcium silicate after hydrothermal treatment at high temperature have leave-like crystal, and these crystal interlock together.

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Trung Kien Pham ◽  
Tran Ngo Quan

In this paper, we report on synthesizing xonotlite, calcium silicate hydrate (CSH), via a hydrothermal reaction using rice husk from the Mekong Delta, Vietnam. The rice husks were burnt at 1000 °C for 3 h. Grey rice husk ash was collected, then mixed with Ca(OH)2 at a Ca/Si molar ratio of 1 : 1. This was followed by a hydrothermal reaction at 180 °C for 24 h and 48 h to obtain the xonotlite mineral. Before and after adsorption, 3-mm xonotlite pellets were thoroughly characterized using X-ray diffractometry (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectroscopy. This material has potential application in chromium(III) removal during a chrome-plating process. The adsorption efficiency of the 3-mm pellet samples reached more than 76 % after 12 h.


2015 ◽  
Vol 1103 ◽  
pp. 1-7 ◽  
Author(s):  
Rimruthai Phuttawong ◽  
Napat Chantaramee ◽  
Pusit Pookmanee ◽  
Ratchadaporn Puntharod

Calcium silicate was successfully synthesized using agricultural byproduct such as rice husk ash and shell of snail namely Pomacea canaliculata by solid state reaction. Chemical composition of silica in rice husk ash and calcium oxide in shell were 91.50 and 98.25%, respectively by X-ray fluorescent determination. The rice husk ash and shell in molar ratio of 1:1 were milled for 5-8 hr and calcined at 800-1000 °C for 2 hr. The Fourier transforms infrared spectra and X-ray diffractometry pattern were confirmed the formation of calcium silicate as the milling time increased.


In many rice producing countries of the world, including in Vietnam, various research aimed at using rice husk ash (RHA) as a finely dispersed active mineral additive in cements, concrete and mortars are being conducted. The effect of the duration of the mechanoactivation of the RHA, produced under laboratory conditions in Vietnam, on its pozzolanic activity were investigated in this study. The composition of ash was investigated by laser granulometry and the values of indicators characterizing the dispersion of its particles before and after mechanical activation were established. The content of soluble amorphous silicon oxide in rice husk ash samples was determined by photocolorimetric analysis. The pizzolanic activity of the RHA, fly ash and the silica fume was also compared according to the method of absorption of the solution of the active mineral additive. It is established that the duration of the mechanical activation of rice husk ash by grinding in a vibratory mill is optimal for increasing its pozzolanic activity, since it simultaneously results in the production of the most dispersed ash particles with the highest specific surface area and maximum solubility of the amorphous silica contained in it. Longer grinding does not lead to further reduction in the size of ash particles, which can be explained by their aggregation, and also reduces the solubility of amorphous silica in an aqueous alkaline medium.


2021 ◽  
Vol 315 ◽  
pp. 16-24
Author(s):  
Somyote Kongkarat ◽  
Meekaruna Boonyaratchinda ◽  
Chirakit Chobtham

Ferrosilicon alloy has been commercially produced in an electric furnace at 1700 - 1750 °C, using quartz as a silica source. With an aim to reduce production cost, rice husk ash (RHA) had been introduced to the process as a silica source. The present study reports an in-depth investigation on the ferrosilicon alloy formation at 1550 °C via carbothermic reduction using RHA with coal and graphite. Blend A: RHA/Fe2O3/Coal and B: RHA/Fe2O3/Graphite were prepared according to the C/O molar ratio of 1/1. The well-mixed samples were compacted into a pellet and then heated at 1550 °C in the tube furnace for 30 and 60 minutes while the argon flowing at the rate of 1 L/min. XRD and SEM results show that the bulk metal mainly composes of FeSi phase, while SiC and other slag phases adhere at the surface of the droplet. Characteristics of the carbonaceous materials, especially ash oxides content affect the kinetic of ferrosilicon formation. Silicon concentration in the produced metal droplets was measured using an ICP technique. For blend A, Si content in the metal was 18.3 wt% and 81.9 wt% after 30 and 60 minutes, respectively. While, Si recovery in the metal for blend B reached 88.4 wt% since 30 minutes. The experimental results show that the production of ferrosilicon alloy from RHA can be produced at 1550 °C, which the temperature lower than that of the commercial method by 150-200 °C. The finding in this research is beneficial for ferrosilicon and agricultural industries and thus promotes the sustainable steelmaking industry.


2018 ◽  
Vol 197 ◽  
pp. 05002 ◽  
Author(s):  
Citra Deliana Dewi Sundari ◽  
Soni Setiadji ◽  
Yusuf Rohmatullah ◽  
Sanusi Sanusi ◽  
Denia Febby Nurbaeti ◽  
...  

Rice husk has a high silica content, so it can be utilized as silica source for zeolite synthesis. In this research, synthesis of zeolite L has been done using silica from rice husk ash without organic template. The synthesized zeolite L is then used as an adsorbent to adsorb methylene blue dye. The steps of zeolite L synthesis include: silica extraction from rice husk ash using NaOH and zeolite L synthesis using hydrothermal method with molar ratio 10 SiO2: Al2O3: 4 K2O: 100 H2O at 170°C for 24 hours. The resulting Zeolite L was then characterized by XRD and SEM. The absorption capacity of methylene blue solution by zeolite L was observed experimentally through the effect of pH of the solution, contact time, and initial concentration of the solution, then determining the isotherm and its absorption kinetics. From XRD and SEM results of zeolite L sample, it is shown that zeolite L has been formed and its particle morphology is a hollow cylinder with cylinder diameter of 0.049 - 0.123 μm. The adsorption process refers to the Freundlich isotherm model which provides the highest correlation coefficient. The methylene blue adsorption process by zeolite L follows pseudo second-order kinetics.


2017 ◽  
Vol 729 ◽  
pp. 24-29
Author(s):  
Thitipob Sirisoontornpanit ◽  
Atichat Wongkoblab ◽  
Supunnee Junpirom

SUZ-4 zeolite was synthesized by the sol-gel technique, followed by hydrothermal process. The effect of the molar ratio of rice husk ash based silicon dioxide to silica solution was investigated. The synthesized zeolite was characterized by XRD, SEM, N2 adsorption and temperature programmed desorption. The results show that the SUZ-4 zeolite was formed for all investigated conditions. However, the formation of MER zeolite occurred as an impurity for the content of rice husk ash higher than 75%. A needle shape crystal with mainly microporous structure is the feature of synthesized SUZ-4 zeolite. The result of temperature programmed desorption indicated that the chemical surface property of obtained SUZ-4 zeolite was weak acid sites.


2021 ◽  
Vol 263 ◽  
pp. 01001
Author(s):  
Elena Gotlib ◽  
Dilyara Sadykova ◽  
Ekaterina Yamaleeva ◽  
Alla Sokolova

As a modifying additive in PVC-compositions, silicates produced by means of rice husk processing are of practical interest. Rice husk ash obtained by burning at 350°C, along with synthetic and naturally occurring wollastonite, significantly reduce plasticizer’s migration from the PVC-composition due to their porosity. This is due to the fact that the part of hydroxyl components of the plasticizer EDOS has adsorbed on the surface or retained by the silicates pores. Along with that, Miwoll 10-97 ensures a greater decrease in plasticizer’s migration than synthetic calcium silicate on the base of rice husk ash. When all the researched silicates are modified by the rice husk and naturally occurring wollastonite, heat stability of PVC-compositions grows. This is preconditioned by the alkaline origin of the surface of filling compounds that allows their possible reaction with chlorine hydride released from PVC during thermal decomposition. Synthetic and naturally occurring wollastonite enhance strain-strength properties of PVC-compositions whereas silicates on the case of rice husk reduce these parameters.


Author(s):  
Tri Windarti ◽  
Widjijono Widjijono ◽  
Nuryono Nuryono

Hydroxyapatite (HA) has been deposited on silica (SiO2) particles to produce HA-SiO2 composite that will be used as the powder component of calcium phosphate cement. HA was expected to be on the composite surface to maintain its bioactivity. SiO2 was made by the sol-gel method, in which silicate solution was extracted from rice husk ash with NaOH solution. Deposition of HA on SiO2 was carried out by wet chemical deposition method at various Ca/Si molar ratio (in a range of 5–25) followed by calcination at 600 °C for 2 h. Results showed that HA was successfully deposited on SiO2 particles. The cell parameters of the HA crystals were slightly distorted by the presence of SiO2 and HA in the composite had a bigger cell volume than pure HA. The crystallite size of HA in the composites increased with the increase of the Ca/Si ratio but the values were smaller than pure HA. SiO2 acted as a morphology directing agent. At low Ca/Si ratio, the HA-SiO2 particles were in a form of short rod-like particles with sizes of < 50 nm, while at high Ca/Si ratio, a mixture of short and long rod-like particles with the size of < 100 nm was obtained. The zeta potential of composites was almost similar to pure HA. These properties indicated that HA-SiO2 composites support the bioactivity of injectable calcium phosphate cement.


2019 ◽  
Vol 11 (2) ◽  
pp. 45
Author(s):  
Sadang Husain ◽  
Ninis Hadi Haryanti ◽  
Suryajaya Suryajaya ◽  
Antung Permitaria

<p class="abstrak">Calcium silicate ceramics have been made using natural ingredients such as rice husk and snail shell with solid reaction techniques. The aim of this study to determine the characteristics of calcium silicate that have been sintered at a temperature of 900 <sup>°</sup>C, 1000 <sup>°</sup>C, and 1100 <sup>°</sup>C. Samples were characterized by X-Ray Diffraction (XRD), optical microscopy, and Fourier Transform Infra-Red (FTIR). The results of XRD characterization showed that CaSiO<sub>3</sub> (calcium silicate) along with the increase in calcination temperature and quantity was increased due to the increase of temperature of calcination. FTIR analysis showed that the Ca-Si-O bond was formed at wave number ranging from 848 cm<sup>-1</sup> and 999 – 1001 cm<sup>-1</sup>.</p>


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