Thermal insulators made with rice husk ashes: Production and correlation between properties and microstructure

Gonçalves, Maraísa; Bergmann, C.P.

doi:10.1016/j.conbuildmat.2006.05.057

Cited by 100 publications

(44 citation statements)

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“…This shows that the NV of RHA varies widely according to its origin. This variability may be a consequence of the burning temperature, which varies from 500 to 1200 °C in industries where rice husk is used as energy source, according to Gonçalves & Bergmann (2007), and of the addition of other residues to the RHA, before being released by the industry.…”

Section: Effect Of Liming On Soil Phmentioning

confidence: 99%

“…The proportions of these components can vary according to the combustion efficiency, but the residue has been designated by the generic term rice husk ash (RHA). On average, RHA corresponds to 15 % of the mass of the rice husk used in the process (Gonçalves & Bergmann, 2007) and does, in itself, not represent a high damaging potential for the environment. According to the norms of ABNT (NBR 10004, 2004), RHA can be classified as a nonhazardous and non-inert residue (class II).…”

Section: Introductionmentioning

confidence: 99%

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Rice husk ash as corrective of soil acidity

Islabão

Vahl²,

Timm³

et al. 2014

Rev. Bras. Ciênc. Solo

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SUMMARYRice husk ash (RHA) is a by-product from the burning of rice husk that can have favorable effects on the soil in terms of acidity correction. The objectives of this study were to determine the effective calcium carbonate equivalent (ECC) of RHA under field conditions, and establish technical criteria as a basis for estimating the overall ECC of RHA. The 12 treatments of the experiment consisted of 10 RHA dosages (0, 10, 20, 30, 40, 60, 80, 100, 120, and 140 Mg ha -1 ) and two references, one of which was an absolute control (AC) and the other a plot limed and fertilized according to official recommendations (recommended fertilization -RF). The soil was sampled twice (15 and 210 days after incorporating RHA), in the layers 0.00-0.10 and 0.10-0.20 m, to determine the pH(H 2 O) and base saturation (V%). The ECC and neutralizing value (NV) of RHA were also determined. The results showed that RHA neutralizes soil acidity, in a faster reaction than conventional limestone, despite a low ECC (around 3 %).Index terms: acidity correction, neutralizing value, effective calcium carbonate equivalent. RESUMO: CINZA DE CASCA DE ARROZ COMO CORRETIVO DE ACIDEZ DO SOLOA cinza de casca de arroz (CCA) é produzida a partir da queima da casca de arroz proveniente dos processos de beneficiamento, podendo apresentar efeitos favoráveis sobre a correção da acidez no solo. Os objetivos deste trabalho foram quantificar o poder relativo de neutralização total (PRNT) da CCA em condições de campo e elaborar critérios técnicos que sirvam de base para a estimativa do PRNT das CCAs em geral. O experimento foi constituído por 12 tratamentos compostos por 10 dosagens de CCA equivalentes a 0, 10, 20, 30, 40, 60, 80, 100, 120 e 140 Mg ha -1 e duas referências, sendo uma testemunha absoluta (TA) e outra com calagem e adubação recomendada (AR). Foram realizadas duas amostragens de solo aos 15 e 210 dias, após a incorporação da CCA, nas camadas de 0,00-0,10 e 0,10-0,20 m para a determinação do pH(H 2 O), e da saturação por bases (V%). Também foram determinados o PRNT e o poder de neutralização (PN) da CCA. Os resultados evidenciaram que a cinza de casca de arroz atua como corretivo de acidez de solo, reagindo mais rápido que o calcário convencional, mas apresentando PRNT baixo, da ordem de 3 %.Termos de indexação: correção de acidez, poder de neutralização, poder relativo de neutralização total.

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Section: Effect Of Liming On Soil Phmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rice husk ash as corrective of soil acidity

Islabão

Vahl²,

Timm³

et al. 2014

Rev. Bras. Ciênc. Solo

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“…This will be the case if biosourced or recycled aggregates can be used [7][8][9]. Moreover, the accelerated carbonation blocks should lead to improved mechanical performances, lower porosity and a reduced risk of efflorescence: the denser microstructure of concrete, which improves the durability of the product and, therefore, the duration of life.…”

Section: Principles and Advantages Of Carbonationmentioning

confidence: 99%

Carbonated miscanthus mineralized aggregates for reducing environmental impact of lightweight concrete blocks

Courard¹,

Parmentier²

2017

Sust. Build.

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Abstract. At a time when the cement industry is largely responsible for the production of CO 2 in the construction sector, it is useful to make this production a reverse phenomenon: that is CO 2 capture. The CO 2 absorption process called carbonation, improves specific properties of the concrete during the conversion of carbon dioxide CO 2 into calcium carbonate CaCO 3 . Current environmental concerns motivate the study of carbonation in order to maximize the absorption of carbon dioxide. Moreover, lightweight concrete with biobased products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Before identifying and quantifying the basic physical characteristics of concrete made from miscanthus, it is necessary to optimize the composition of the product. The long-term stability as well as the reinforcement may be obtained by means of a mineralization process of the natural product: a preparation with a lime and/or cement-based material is necessary to reinforce the cohesion of the bio-based product. Mineralization process is described as well as the way of producing blocks for CO 2 capture by means of accelerated carbonation. Finally, concrete blocks produced with miscanthus mineralized aggregates offer interesting mechanical properties and minimal environmental impact.

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“…Cordierite salah satu material dengan struktur silika yang bervariasi, diantaranya entatite, magnesium silicate, dengan cordierite memiliki kandungan silika paling tinggi dan stabil [1], yang secara luas telah diaplikasikan di berbagai industri seperti, industri gelas, industri keramik dan industri elektronik sebagai isolator panas dan listrik, karena memiliki kestabilan termal dan daya tahan terhadap zat kimia yang tinggi serta koefisien termal rendah [2]. Keramik cordierite dapat disintesis dari berbagai bahan baku silika mineral seperti fumed silika, kaolinite, TMOS (tetramethylortosilicate), maupun TEOS (tetraethylorthosilicate), melalui berbagai metode diantaranya, teknik reaksi padatan (solid-state reaction) [3,4], teknik sol-gel [5,6], teknik melting [7,8].…”

Section: Pendahuluanunclassified

Pengaruh Suhu Tinggi terhadap Karakteristik Keramik Cordierite Berbasis Silika Sekam Padi

Sembiring

Manurung

Karo-Karo

2009

JFA

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IntisariThis study was carried out to investigate the effect of high temperature on the functional groups, microstructure and physical characteristics of cordierite ceramics obtained from an aqueous solution of magnesium nitrate hydrate ((Mg(NO3)2.6.12H2O)), aluminium nitrate hydrate (Al(NO3)2.9.15H2O) and silica sols extracted from rice husk. The samples were sintered at temperature of 1000• C, 1200• C and 1400• C. Functional groups and microstructural characteristics of cordierite ceramics were examined by FTIR and SEM, respectivelly. FTIR study shows that the absence of the vibration bands of Na-OH, Si-OH, C-O, Si-O-Si on the samples. However, the formation of cordierite structure was dominated on this high temperature. Microstructure results confirmed the presence of irregular morphology of the solid and compact phases. In addition, the densities, shrinkage and hardness of cordierite increase significantly with increasing temperature, but porosity decreases with increasing temperature.KATA KUNCI: rice husk, cordierite, mikrostructure, sintering I. PENDAHULUANCordierite salah satu material dengan struktur silika yang bervariasi, diantaranya entatite, magnesium silicate, dengan cordierite memiliki kandungan silika paling tinggi dan stabil [1], yang secara luas telah diaplikasikan di berbagai industri seperti, industri gelas, industri keramik dan industri elektronik sebagai isolator panas dan listrik, karena memiliki kestabilan termal dan daya tahan terhadap zat kimia yang tinggi serta koefisien termal rendah [2]. Keramik cordierite dapat disintesis dari berbagai bahan baku silika mineral seperti fumed silika, kaolinite, TMOS (tetramethylortosilicate), maupun TEOS (tetraethylorthosilicate), melalui berbagai metode diantaranya, teknik reaksi padatan (solid-state reaction) [3,4], teknik sol-gel [5,6], teknik melting [7,8].Pada penelitian yang telah dilakukan terhadap karakteristik cordierite pada suhu rendah yakni 300-700• C dengan menggunakan silika sekam padi [9] menunjukkan bahwa karakteristik fungsionalitas cordierite terdiri dari Si-OH, Si-O-Al, Mg-O-Al, Na-OH, N-O, C-O dan C-H pada suhu 300• C dan 500• C, dan proses kristalisasi pembentukan cordierite melalui spinel MgAlO 2 pada suhu sintering 700• C. Sebagai tambahan, hasil analisis SEM/EDS menunjukkan bahwa mikrostruktur dengan pori dan kekerasan meningkat dengan meningkatnya suhu sintering dengan kehadiran komposisi elemen Si, Al, Mg dan O. Perubahan sifat fisis (shrinkage, porositas, densitas dan kekerasan mengalami perubahan yang signifikan pada suhu sintering 700• C. Dari penelitian awal yang dilakukan, dapat disimpulkan bahwa proses kristalisasi diantaranya pemadatan (densification), pemben- * E-MAIL: Simbiring@yahoo.com.au tukan cordierite tergantung suhu sintering dan membutuhkan energi termal yang lebih tinggi untuk mengubah struktur. Berdasarkan latar belakang yang dipaparkan di atas, untuk melengkapi informasi pembentukan cordierite maka penelitian ini dilakukan dengan tujuan untuk mempelajari pengaruh temperatur tinggi terhadap karakteristik fu...

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Thermal insulators made with rice husk ashes: Production and correlation between properties and microstructure

Cited by 100 publications

References 1 publication

Rice husk ash as corrective of soil acidity

Rice husk ash as corrective of soil acidity

Carbonated miscanthus mineralized aggregates for reducing environmental impact of lightweight concrete blocks

Pengaruh Suhu Tinggi terhadap Karakteristik Keramik Cordierite Berbasis Silika Sekam Padi

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