Optimization of nanostructured/nano sized rice husk ash preparation

Medhat Mostafa,Hamdy Salah,Nabila Shehata,Amro B Saddek

doi:10.21123/bsj.2020.17.3(suppl.).0953

Medhat Mostafa, Hamdy Salah + Show 2 more

Open Access

https://doi.org/10.21123/bsj.2020.17.3(suppl.).0953

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Abstract

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.

Highlights

According to food and agriculture organization of the United Nations (FAO), more than 769 Mt of rice paddy are annually produced in the world in 2018 (1)
The preparation of rice husk ash (RHA) should be optimized to be used as a partial replacement of Portland cement (6)
The partial replacements of Portland cement depend on pozzolanic activity which depends on parameters such as content of amorphous silica, specific surface area of particles and particle size distribution (7)

Summary

Introduction

According to food and agriculture organization of the United Nations (FAO), more than 769 Mt of rice paddy are annually produced in the world (around 510 Mt, milled basis) in 2018 (1). Grinding is recommended to increasing the pozzolanic reactivity by increasing the specific surface area and decreasing the particle size. Selection of the best method to determine RHA particle size depends on using of Zetasizer Nano ZS (Malvern Instruments, Worcestershire, UK) particle size distribution D50 and D99 at different grinding time was measured by using Laser diffraction apparatus combined with laser diffraction-SSA, laser particle size analyzer (Model BT-9300S by Bettersize) according to the International Standard ISO 13320 (17).

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Results

Conclusion