An Improved Process for the Preparation of High-Quality Bio-silica Microparticles from Rice Husk Ash

2018 ◽  
Vol 11 (5) ◽  
pp. 2227-2233
Author(s):  
Guanqiao Liang ◽  
Long Zhang
2014 ◽  
Vol 979 ◽  
pp. 216-219 ◽  
Author(s):  
Weerachon Phoohinkong ◽  
Udomsak Kitthawee

Silica with nanostructure are the high quality silica that are used in many industry areas. The applications of silica nanostructure frequently depend on physical properties such as morphology and size of structure. Rice husk ash is the waste from biomass power plants and is a high quality, raw material as a silica source. The conventional methods for synthesis of nanosilica from rice husk ash are energy consumption or time consumption. The objective of this work was to investigate the synthesized of nanosilica from rice husk ash via sodium silicate solution. nanosilica particles were obtained via alkaline extraction and a fast acid precipitation method at room temperature by adding inorganic salts and without surfactant or template. The flow synthesis was investigated at ambient temperature, varying the concentration of hydrochloric acid, sodium chloride, and flow-rate while fixing the concentration of sodium silicate. The samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results revealed that the sodium chloride is significantly inorganic salt for generated nanosilica, with uniform spherical morphology (80-150 nm), without curing or aging time. In the flow synthesis method, the silica nanoparticles, of diameter around 10 nm and aggregate particles of around 50 to 200 nm, were obtained. This method may be applicable to control different grade of silica and can easily scaling up of silica production for different industries.


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.


2014 ◽  
Vol 27 (2) ◽  
pp. 148-160
Author(s):  
Hassan K. Hassan ◽  
Najla J. Al-Amiri ◽  
Mohammed M. Yassen

2018 ◽  
Vol 60 (4) ◽  
pp. 3-7
Author(s):  
Thi To Yen Nguyen ◽  
Phung Anh Nguyen ◽  
Thi Thuy Van Nguyen ◽  
Tri Nguyen ◽  
Ky Phuong Ha Huynh ◽  
...  
Keyword(s):  
Red Mud ◽  

2015 ◽  
Vol 57 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Ahmad Adlie Shamsuri ◽  
Ahmad Khuzairi Sudari ◽  
Edi Syams Zainudin ◽  
Mazlina Ghazali

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3440
Author(s):  
Mohd Na’im Abdullah ◽  
Mazli Mustapha ◽  
Nabihah Sallih ◽  
Azlan Ahmad ◽  
Faizal Mustapha ◽  
...  

The utilisation of rice husk ash (RHA) as an aluminosilicate source in fire-resistant coating could reduce environmental pollution and can turn agricultural waste into industrial wealth. The overall objective of this research is to develop a rice-husk-ash-based geopolymer binder (GB) fire-retardant additive (FR) for alkyd paint. Response surface methodology (RSM) was used to design the experiments work, on the ratio of RHA-based GB to alkyd paint. The microstructure behaviour and material characterisation of the coating samples were studied through SEM analysis. The optimal RHA-based GB FR additive was formulated at 50% wt. FR and 82.628% wt. paint. This formulation showed the result of 270 s to reach 200 °C and 276 °C temperature at equilibrium for thermal properties. Furthermore, it was observed that the increased contents of RHA showed an increment in terms of the total and open porosities and rough surfaces, in which the number of pores on the coating surface plays an important role in the formation of the intumescent char layer. By developing the optimum RHA-based GB to paint formulation, the coating may potentially improve building fire safety through passive fire protection.


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