Effect of amorphous silica by rice husk ash on physical properties and microstructures of recycled aluminium chip AA7075

2019 ◽  
Vol 50 (3) ◽  
pp. 283-288
Author(s):  
N.F. Mohd Joharudin ◽  
N. Abdul Latif ◽  
M.S. Mustapa ◽  
M.N. Mansor ◽  
W.A. Siswanto ◽  
...  

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.


2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata

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.


2021 ◽  
Vol 57 (3) ◽  
pp. 55-65
Author(s):  
RYOKO SEKIFUJI ◽  
LE VAN CHIEU ◽  
MASAFUMI TATEDA ◽  
HIROSHI TAKIMOTO

2018 ◽  
Vol 16 ◽  
Author(s):  
Siti Asmahani Saad ◽  
Nasir Shafiq ◽  
Maisarah Ali

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.


Author(s):  
Nur Saadah Zainal ◽  
◽  
Zaleha Mohamad ◽  
Mohammad Sukri Mustapa ◽  
Nur Azam Badarulzaman ◽  
...  

2018 ◽  
Vol 53 (15) ◽  
pp. 2047-2052 ◽  
Author(s):  
Mohamad Reza Nasresfahani ◽  
Morteza Shamanian

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.


2021 ◽  
pp. 103229
Author(s):  
Cyriaque Rodrigue Kaze ◽  
Adeyemi Adesina ◽  
Gisèle Laure Lecomte-Nana ◽  
Jordan Valdès Sontia Metekong ◽  
Liliane Van Essa Kamga Samen ◽  
...  

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