Mechanoactivation Of Rice Husk Ash In Laboratory Conditions

2019 ◽  
pp. 20-26
Keyword(s):  
Mechanical Activation ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Silicon Oxide ◽  
Rice Husk Ash ◽  
Pozzolanic Activity ◽  
Maximum Solubility ◽  
Laboratory Conditions ◽  
Before And After ◽  
Mineral Additive

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.

Adaptation of Rice Husk Ash for Use as Pozzolanic Material

2014 ◽  
Vol 634 ◽  
pp. 182-192
Author(s):  
G. Amanda Kieling ◽  
A.M. Carlos Moraes ◽  
A. Feliciane Brehm ◽  
Daiane Calheiro ◽  
P. Marlova Kulakowski
Keyword(s):  
Chemical Composition ◽  
Construction Industry ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Specific Weight ◽  
Pozzolanic Activity ◽  
Dispersion Parameters ◽  
Pozzolanic Material ◽  
Mineral Additive ◽  
Interesting Approach

The use of waste in the construction industry is an interesting approach to minimize associated environmental impacts. A substantial body of research has proved the potential use of rice husk ash (RHA) as a mineral additive. A considerable portion of RHA presents pozzolanic characteristics, a result of its amorphous chemical structure and high silica contents. However, variations in particle size and chemical composition may affect applicability, limiting the use of RHA. In this scenario, this study presents a methodology to recycle RHA based on particle segregation and discusses how the process affects RHA performance in terms of its pozzolanic activity. Samples and respective segregated fractions were characterized using physical (loss on ignition, specific weight, surface area, grain size distribution), chemical (chemical composition and X-ray diffraction) and microstructural (scanning electron microscopy and energy dispersion) parameters. Pozzolanic activity was determined after milling of samples and segregation of fractions based on specific assays with cement and on electric conductivity. The results show that segregation opens new perspectives to increase the value of RHA in the construction industry.

scholarly journals CHARACTERISTIC OF XONOTLITE SYNTHESIZED BY HYDROTHERMAL REACTION USING RICE HUSK ASH AND ITS APPLICATION TO ABSORB CHROME (III) SOLUTION

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Trung Kien Pham ◽  
Tran Ngo Quan
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Hydrothermal Reaction ◽  
Mekong Delta ◽  
Molar Ratio ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Xrf Scanning ◽  
Before And After ◽  
Chrome Iii

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.

scholarly journals Optimization of nanostructured/nano sized rice husk ash preparation

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Particle Shape ◽  
Rice Husk Ash ◽  
Loss On Ignition ◽  
Shape Distribution ◽  
Disk Mill ◽  
Grinding Time

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

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.

The Ability of Crystalline and Amorphous Silica from Rice Husk Ash to Perform Quality Hardness for Ceramic Water Filtration Membrane

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nur Saadah Zainal ◽  
◽  
Zaleha Mohamad ◽  
Mohammad Sukri Mustapa ◽  
Nur Azam Badarulzaman ◽  
...  
Keyword(s):  
Rice Husk ◽  
Amorphous Silica ◽  
Rice Husk Ash ◽  
Water Filtration ◽  
Filtration Membrane

Characterization of Al1100-RHA composite developed by accumulative roll bonding

2018 ◽  
Vol 53 (15) ◽  
pp. 2047-2052 ◽  
Author(s):  
Mohamad Reza Nasresfahani ◽  
Morteza Shamanian
Keyword(s):  
Rice Husk ◽  
Amorphous Silica ◽  
Accumulative Roll Bonding ◽  
Structural Changes ◽  
Rice Husk Ash ◽  
Aluminum Matrix ◽  
Silica Particles ◽  
Ash Content ◽  
Scanning Electron Micrographs ◽  
Roll Bonding

A metal–matrix composite was developed by eco-friendly accumulative roll bonding process and agricultural wastes. Amorphous silica particles were obtained by heating rice husk at 600℃ and then ball milling. Amorphous silica particles as a reinforcement were embedded in a matrix of aluminum 1100. Composites with various amounts (1%, 2%, 3%, 4%, 5%, 6%, and 7%, mass fraction) of rice husk ash particles were developed. The produced aluminum–rice husk ash composites were evaluated for structural changes and mechanical properties. The scanning electron micrographs showed a uniform distribution of rice husk ash particles and were bonded well with the aluminum matrix after 10 cycles. By increasing the rice husk ash content, the composite strength increases first and then becomes constant because of the inappropriate connection of aluminum sheets. Increasing the rice husk ash content of the composite causes the change from the ductile to a relatively brittle type of fracture.

scholarly journals Strength and Microfabric of Expansive Soil Improved with Rice Husk Ash and Lime

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jinrong Ma ◽  
Yunhe Su ◽  
Yuyi Liu ◽  
Xiangling Tao
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Harmful Effect ◽  
Expansive Soil ◽  
Pozzolanic Activity ◽  
Strength Increase ◽  
Free Expansion ◽  
Improvement Effect ◽  
Cementing Material ◽  
Curing Age

Expansive soil has harmful effect on engineering. Rice husk ash (RHA) has high pozzolanic activity, so it can form new cementing material with lime or cement to solidify soil. In this paper, the tests of free expansion rate, water ratio limit, and optimum moisture content (OMC) are carried out; then, RHA and lime were added to artificial soil in different proportions of 5, 10, 15, and 20% by weight, in which the ratio of RHA to lime is 80 : 20. The unconfined compressive strength (UCS) in different curing age is measured, and the improvement effect of RHA and lime to expansive soil can be obtained. Finally, the reason of improvement effect is explained by using the scanning electron microscope (SEM). The results of the study show that (1) for the best utilization effect, the optimum percentage of RHA is 12% and lime is 3%; (2) the UCS is 2.6 times of the pure soil after curing of 14 d under the optimum percentage; (3) the curing age has a significant effect on strength; (4) the main reason for the strength increase of the modified soil is that the crystal produced by the pozzolanic activity fills the pores of the soil.

scholarly journals Measurement of Pozzolanic Activity Index of Scoria, Pumice, and Rice Husk Ash as Potential Supplementary Cementitious Materials for Portland Cement

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hieronimi A. Mboya ◽  
Cecil K. King’ondu ◽  
Karoli N. Njau ◽  
Alex L. Mrema
Keyword(s):  
Portland Cement ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Activity Index ◽  
Cementitious Materials ◽  
Pozzolanic Activity ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Setting Times

This work investigated the properties of scoria and pumice as supplementary cementitious materials (SCMs) for Portland cement and compared to those of rice husk ash (RHA). X-ray fluorescence, X-ray diffraction, and pozzolanic activity index (PAI) tests confirmed the suitability of these two materials as potential SCMs. Scoria and RHA samples achieved over 75% PAI at 7 days whereas pumice did this after 28 days. Initial and final mean setting times observed for the composite cement blended with these materials were 166 and 285 min, respectively. These setting times are longer than that of ordinary Portland cement but shorter compared to that of common Portland pozzolana cement. The ultimate mean compressive strengths achieved at 28 days of curing were 42.5, 44.8, and 43.0 MPa for scoria, pumice, and RHA, respectively, signifying that these materials are good SCMs. Higher fineness yielded higher ultimate mean strength. For instance, a scoria sample with a fineness of 575 m2/kg achieved the strength of 52.2 MPa after 28 days.

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