Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

Ziegler, Daniele; Formia, Alessandra; Tulliani, Jean‐Marc; Palmero, Paola

doi:10.3390/ma9060466

Cited by 41 publications

(15 citation statements)

References 49 publications

(78 reference statements)

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“…There exist only a relatively small number of studies on the utilisation of RHA as a precursor for the production of AAB. RHA was blended with other precursors such as fly ash (Detphan and Chindaprasirt, 2009;Hwang and Huynh, 2015;Ziegler et al, 2016), calcined water treatment sludge (Nimwinya et al, 2016), slag and palm oil fuel ash (Karim et al, 2013), slag and fly ash (Karim et al, 2015), slag (Suksiripattanapong et al, 2017), or red mud (He et al, 2013). Research results confirmed the reactivity of RHA in an alkaline environment as a Si donor.…”

Section: Introductionmentioning

confidence: 70%

Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

Tong

Vinai

Soutsos

2018

Journal of Cleaner Production

193

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Geopolymer and Alkali-Activated Binders (AAB) has recently emerged as a new, green material with the potential to replace Portland cement in several applications. They can reduce the CO2 footprint of concrete by up to 80% and this is in addition to being more durable in certain aggressive environments. However, commercial alkaline activators contribute significantly to the cost and CO2 footprint of AAB concrete mixes. This research investigated the production of a low cost, low environmental impact sodium silicate solution (waterglass) from Rice Husk Ash (RHA) and more specifically RHA from Vietnam. A hydrothermal process for the dissolution of RHA in sodium hydroxide solution was developed. Sodium hydroxide solution concentration, process temperature and duration were studied. Optimised procedure parameters were found to be: NaOH concentration 3M, heating temperature 80 ℃ and heating duration 3h. The obtained solution was used for the production of AAB mortar made with a blend of fly ash and ground granulated blast furnace slag. Obtained compressive strength of mortar was in the range of 60 MPa at 28 days, matching the strength obtained from control samples produced with commercially available activators. Microstructural investigation (isothermal calorimetry, infrared spectroscopy, X-ray diffraction and thermogravimetric analysis) on pastes confirmed the equivalence between the solution produced with the optimised method and commercially available options. Cost analysis indicated that the proposed method could allow a reduction of almost 55% of the cost for the activation of AAB. Results from a simplified preliminary environmental analysis suggested increased sustainability of the RHA-derived solution when compared with commercially available waterglass.

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Section: Introductionmentioning

confidence: 70%

Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

Tong

Vinai

Soutsos

2018

Journal of Cleaner Production

193

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“…Compared with other industrial fields, the use of amorphous RHA silica in the production of concrete can realize large-scale consumption and reuse of waste, and hence eventually reduces the environmental impact due to improper disposal and land occupation. RHA is economical, widely available and highly reactive as a supplementary cementing material, due to its excellent physically filling and chemically pozzolanic effects [ 18 , 19 , 20 , 21 , 22 ]. It is also a promising substitute for replacing silica fume (SF) in high-performance concrete production.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Water-Leaching and Acid-Leaching Pretreatment on the Thermal Stability and Reactivity of Biomass Silica for Viability as a Pozzolanic Additive in Cement

Wei

Chen

et al. 2018

Materials

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The present work aims to introduce a novel and eco-friendly method, i.e., a water-leaching pretreatment for extracting highly reactive biomass silica from rice husk (RH), for viability as a pozzolanic additive in cement. For comparison, the traditional acid pretreatment method was also employed throughout the experimental study. The silica from RH was extracted using boiled deionized water and acid solution as leaching agents to remove the alkali metal impurities, and then dried and submitted to pyrolysis treatment. The results indicated that potassium was found to be the major contaminant metal inducing the formation of undesirable black carbon particles and the decrease in crystallization temperature of amorphous RHA silica. The boiling-water-leaching pretreatment and acid-leaching pretreatment on RHs significantly removed the metallic impurities and reduced the crystallization sensitivity of RHA silica to calcination temperature. A highly reactive amorphous silica with purity of 96% was obtained from RH via 1 N hydrochloric acid leaching followed by controlled calcination at 600 °C for 2 h. The acid treatments increased the crystallization temperature of silica to 1200 °C and retained the amorphous state of silica for 2.5 h. In the case of water-leaching pretreatment, leaching duration for 2.5 h could yield an amorphous silica with purity of 94% and render the silica amorphous at 900 °C for 7 h. The RHA silica yielded by water-leaching pretreatment presented a comparable enhancing effect to that of acid leaching on hydration and improved the strength of cement. Furthermore, compared with the acid-leaching method, the water-leaching pretreatment method is more environmentally friendly and easier to operate, and hence more widely available.

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“…The porous geopolimer-type compositions were produced using the rice hulls ash with aluminum powder as a foaming agent [20]. Addition of aluminum powder to the composition increases the porosity and decreases the density of the material.…”

Section: Discussionmentioning

confidence: 99%

Rice Hulls as a Renewable Complex Material Resource

et al. 2018

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As a result of rice grain processing, a big amount of waste (up to 20%) is produced. It is mainly rice hulls. The main components of rice hulls are cellulose, lignin and mineral ash. The mineral ash quantity in rice hulls varies from 15 up to 20%, by weight of the rice hulls. The mineral ash consists of amorphous silica (opal-type). Due to the high content of silica in rice hulls, the material burns with difficulty under natural conditions, and it is biodegradably destroyed only with difficulty, when composted. Utilization of rice hulls then becomes an ecological problem due to huge rice production and its continuous growth. At the same time, the annual quantity of silica content in rice hulls is comparable with the quantity of amorphous silica produced as a mineral resource. The issue of manufacturing cellular glass silica construction materials from rice hulls as a renewable resource is discussed in this paper. The utilization technology is based on an amorphous silicon oxide with the use of energy from the combustion of the organic component of rice hulls.

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Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

Cited by 41 publications

References 49 publications

Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

Use of Vietnamese rice husk ash for the production of sodium silicate as the activator for alkali-activated binders

Comparative Study of Water-Leaching and Acid-Leaching Pretreatment on the Thermal Stability and Reactivity of Biomass Silica for Viability as a Pozzolanic Additive in Cement

Rice Hulls as a Renewable Complex Material Resource

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