scholarly journals Investigation of silica from rice husk ash wastes as an alternative material for microwave absorbers

Author(s):  
I. Nyoman Sudiana ◽  
Seitaro Mitsudo ◽  
Muhammad Zamrun Firihu ◽  
La Aba ◽  
La Ode Ngkoimani ◽  
...  
2010 ◽  
Vol 69 ◽  
pp. 63-68 ◽  
Author(s):  
Chayanee Tippayasam ◽  
Sansanee Boonsalee ◽  
Suvimol Sajjavanich ◽  
Chiara Ponzoni ◽  
Elie Kamseu ◽  
...  

Geopolymer has been developed as an alternative material to Portland cement. Geopolymer is based on the polymerization of alkaline activation and oxide of silicon and aluminium. These oxides can be found in many pozzolanic materials such as metakaolin and the wastes from industries and agricultures in Thailand, e.g., fly ash, bagasse ash and rice husk ash. Pozzolanic materials were selected as source materials for making geopolymers into 4 different types. Sodium hydroxide concentration of 10 Molar (10MNaOH) and sodium silicate (Na2SiO3) solutions were used as alkaline activators by the mass ratio of Na2SiO3/NaOH at 1.5. The mixtures were cast in 25×25×25 mm. cubes. After casting, the geopolymers were cured at 80๐C for 24 hrs. in an oven and then at room temperature for 7 days. The pozzolanic materials effects, the Si/Al molar ratio and the Na/Al molar ratio were studied and characterized. An X-ray fluorescence (XRF) was chosen to determine the percentages of silica and alumina in order to verify the proper ratio of the fly ash, Rice husk ash, Bagasse ash and Metakaolin.The study also included the impact on mechanical and physical properties such as compressive strength, water absorption, density and porosity.


2020 ◽  
Vol 4 (1) ◽  
pp. 29-36
Author(s):  
Hurul 'Ain ◽  
Alan Putranto ◽  
Betti Ses Eka Polonia ◽  
Ahmad Ravi

The effect of the addition of rice husk ash (rice husk ash) to the K-175 formula quality concrete mixture, as an aggregate mixture to the concrete compressive strength test using a Compression Testing Machine to get the compressive strength value of concrete and can be used as an alternative material as an additional material in making concrete in improving the quality of building construction. The study uses K-175 concrete quality characteristics as a test material. Test object in the shape of a cube with a size of 15cm x 15cm. With 4 variations in levels of addition of rice husk ash by 0%, 1.5%, 3.5%, and 5% by weight of cement. The husk ash used is the husk ash that escaped the 2.36 mm filter size. From each type of mixture made 9 test specimens, every 3 specimens for the age of concrete 7 days, 14 days and 28 days. Concrete mortar design using ASTM method. With material sources using fine aggregate from the Pawan Ketapang River and coarse aggregate from Merak, Banten. Stages of implementation include examining the nature of aggregate materials, sample making, and testing of concrete compressive strength.


2018 ◽  
Vol 7 (2) ◽  
pp. 26-29
Author(s):  
Deepak Dhand

There is an increased awareness to preserve the environment in the present day society. Rice Husk (RH),is the widely available agricultural wastes and is a serious concern for the environment. It is a potential material for use as alternative material in the construction and insulation industry. The particle board made from rice husk (RH) or rice husk ash (RHA), bonded by resin under the application of pressure and temperature. Urea formaldehyde is the organic resin used in general for interior use whereas phenol formaldehyde for external disclosure. The said resins are preferred for their water-resistant properties and better binding strength. The present study investigates the potential of rice husk reinforced boards by experimenting the different compositions and thicknesses. The objective is to perform a thermal analysis of the processed Rice husk boards. Boards made from rice husk are biodegradable unlike glass wool & other synthetic insulations. After experimenting on different fabrication conditions, six samples were finalized and were tested for physical and thermal viability in their applications. This study found that by adding ash of rice husk, the density of board decreases with respect to the board of same weight and consisting of rice husk only. Moisture Content is higher in case of boards with RHA but is within permissible limits. RHA reinforced boards have improved thermal properties, which is desirable in case of insulation boards.


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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