Production of silica gel from residual rice husk ash

Abstract

Recebido em 11/2/10; aceito em 24/7/10; publicado na web em 26/11/10 PRODUCTION OF SILICA GEL USING RESIDUAL RICE HUSK ASH. This paper presents a study on the production of silica gel in hydrothermal process using residual rice husk ash. Measurements of the chemical composition, X-ray diffraction, infrared spectroscopy, particle size distribution, and pozzolanic activity were carried out in order to characterize the obtained material, and the optimal silica gel was selected for use as a mineral additive in cement pastes. The compressive strengths were determined for cement pastes containing silica gel (0.0, 2.5 or 5% by mass) in different times. The results indicate that the mixtures containing silica gel showed improved mechanical behavior over all time periods evaluated.

Improving soil silicon and selected fertility status for rice production through rice-mill waste application in lowland sawah rice field of southeastern Nigeria

“…As anticipated, soil available Si recorded for RHA and RHD in 2014 and 2015 cropping seasons was higher than the initial soil available Si (31.0 mg kg −1 ). The present results corroborate the findings of Magale et al (2011) and Lima et al (2011) who reported that application of increasing amounts of Si-rich sources enhanced greater availability of Si in the soil. Across both cropping seasons, increase in treatment application rates significantly increased soil available Si (Table 4).…”

Pozzolanic Reaction of a Biomass Waste as Mineral Addition to Cement Based Materials: Studies by Nuclear Magnetic Resonance (NMR)

“…According to John et al (2003), this kind of ash can present high K 2 O contents in its composition (above 20%). This fact precludes its direct use in cement, where the potassium would induce the alkali-aggregate reaction and concomitant degradation of the cement matrices (Lima et al 2011). For this reason, the ash previously was treated with a 3.3% (v/v) hydrochloric acid (HCl) solution and heated at 90 °C for 1 h, which reduced the K content by about 70%.…”

Transesterification of Coconut Oil Using Dimethyl Carbonate and TiO2/SiO2 Heterogeneous Catalyst

“…Preparation of catalyst was carried out adopting the method previously applied [21][22]. An aliquot of 100 mL silica sol, which contains 20 g of silica, was transferred into Erlenmeyer flask placed in ultrasound cleaner.…”