Comparative Study of Different Pretreatment and Combustion Methods on the Grindability of Rice-Husk-Based SiO2

Abstract

The rice husk (RH) combustion pretreatment method plays a crucial role in the extraction of nanoscale SiO2 from RH as a silicon source. This study examined the effects of diverse pretreatment methods and combustion temperatures on the particle size distribution of nanoscale high-purity amorphous SiO2 extracted from rice husk ash (RHA) post RH combustion. The experiment was structured using the Taguchi method, employing an L9 (21 × 33) orthogonal mixing table. The median diameter (D50) served as the output response parameter, with the drying method (A), combustion temperature (B), torrefaction temperature (C), and pretreatment method (D) as the input parameters. The results showed the torrefaction temperature (C) as being the predominant factor affecting the D50, which decreased with an increasing torrefaction temperature (C). The optimal parameter combination was identified as A2B2C3D2. The verification test revealed that roasting could improve the abrasiveness of Rh-based silica and reduce the average particle size. Torrefaction at medium temperatures might narrow the size distribution range of RHA-SiO2. We discovered that the purity of silica increased with an increasing roasting temperature by evaluating the concentration of silica in the sample. The production of RHA with silica concentrations up to 92.3% was investigated. X-ray diffraction analysis affirmed that SiO2’s crystal structure remained unaltered across different treatment methods, consistently presenting as amorphous. These results provide a reference for extracting high-value products through RH combustion.

A Comparative Study on Rice Husk, as Agricultural Waste, in the Production of Silica Nanoparticles via Different Methods

“…In our earlier research, we concentrated on developing a method for creating silica from RH using a top-down approach, specifically calcination. The process was refined to a specific protocol, identified as 270/700 ZW [ 29 , 30 ]. Initially, RH was boiled in deionized water continuously for 2.5 h. After boiling, it underwent a triple rinse with deionized water and was drained to eliminate contaminants.…”

“…Additionally, the calcination method has been explored for SiNP extraction from RH. This process involved optimizing the preparation of RH-based silica through calcination, using statistical approaches to refine the procedure [ 29 , 30 ]. The significant factors and optimal processes affecting the particle size distribution of silica extracted from RH by aerobic pyrolysis have been explored.…”