Characterization of rice husk ash prepared by open air burning and furnace calcination

Abstract

Rice husk (RH) is an agricultural waste, and easily available in rice growing areas. The husk is mostly burnt as a way of getting rid of it. The ash obtained after burning or calcination may have economic application, mainly dependent on its properties. These properties in turn depend on the calcination method. However, for commercial viability, and for many applications, the calcination method should not only be as simple as possible but also cheap. This study characterized the elemental composition, crystallinity, functional bonds present and morphology of rice husk ash (RHA) obtained in two ways, that is, calcination of rice husks in a muffle furnace (FRHA) at a temperature of 700°C and open air burning (ORHA) at uncontrolled temperatures. The elemental composition done by Atomic Absorption Spectroscopy showed a high percentage of silicon that is 81.01 and 79.12% for ORHA and FRHA, respectively. X-ray fluorescence showed a high percentage of silica (SiO 2 ), 95.45 and 94.85% for ORHA and FRHA, respectively. X-ray diffractograms indicate that the FRHA was crystalline with the highest peak at 21.8°; while ORHA was amorphous in nature. Fourier Transform Infra-Red spectra confirmed the presence of -OH groups and O-Si-O bonds in the two types of ash. Scanning electron microscopy analysis showed agglomerated ORHA, which may be due to the presence of hydrogen bonding between silanol groups on the surface of rice husk ash for FRHA, and presence of -OH groups in ORHA. The study shows that ORHA is as good as FRHA in applications where crystallinity is optional.

Sustainable Thermochemical Extraction of Amorphous Silica from Biowaste

“…The surface of untreated rice hull reveals higher roughness than treated with acids because of hydrolysis with some of the organic components by the acid. SEM analysis showed agglomerated ORHA, which may be due to the presence of hydrogen bonding between Silanol groups on the surface of rice husk ash for FRHA [31].…”

Karakterisasi Abu Sekam Padi dengan Menggunakan XRD

“…Pemanfaatan sekam padi akan menambah nilai ekonomisnya dan mengurangi pencemaran lingkungan. Sekam padi memiliki potensi yang baik sebagai sumber silika terbarukan karena tiga alasan yaitu ketersediaan sekam padi melimpah, kadar silika dalam abu sekam padi yang besar yaitu sekitar 94-95 % [7] dan kemudahan perolehan silika dari sekam padi.…”

“…Silika amorf diperoleh antara suhu 500-700 °C dan kristalisasi terjadi pada suhu di atas 700 °C [10,11]. Pembakaran sekam padi di atas hot plate pada suhu yang tidak terkendali menghasilkan padatan amorf, sedangkan kalsinasi sekam padi dalam muffle furnace pada suhu 700°C selama 3 jam dan udara terbuka menghasilkan kristal dengan puncak tertinggi pada 21,8 °C [7]. Silika amorf memiliki luas permukaan spesifik yang besar dan formasi kacau dari struktur terbuka dengan lubang di jaringan di mana netralitas listrik tidak terpenuhi.…”

“…Kebanyakan RHA mengandung SiO2. Hal ini merujuk pada hasil penelitian Ikpong & Okpala dengan pembakaran sekam padi pada suhu 650 -700 0 C menghasilkan abu sekam padi (rice husk ash/RHA) yang mengandung 82,13% SiO2 dan sisanya oksida logam lainnya seperti Al2O3, Fe2O3, K2O, Na2O, MgO, dan CaO [8] dan hasil penelitian Kaleli pada pembahakaran RH pada 700 0 C menghasilkan RHA dengan 95,45 % SiO2 [7].…”

X-Ray And Microstructure Of Rice Husk Ash-Admixed Concrete

“…The characterization of the elemental composition, crystallinity, functional bonds and morphology of rice husk ash (RHA) by calcination of rice husks in a mu e furnace (FRHA) at a temperature of 700°C and open air burning (ORHA) at uncontrolled temperatures were undertaken by Khaleli et al [11]. Some of the results showed that the elemental composition by Atomic Absorption Spectroscopy had high percentage of Silicon, 81 % for calcination using FRHA, and 79 % for ORHA, respectively.…”