稻壳及其产品在环保等领域中的应用

本文综述了稻壳及其产品(如稻壳灰和稻壳活性炭)在环保、化工、食品、农业及建材方面的最新应用与研究进展,并简要的介绍了其综合利用的前景。     

稻壳及其产品在环保等领域中的应用

本文综述了稻壳及其产品(如稻壳灰和稻壳活性炭)在环保、化工、食品、农业及建材方面的最新应用与研究进展，并简要的介绍了其综合利用的前景。     

稻壳灰应用研究进展

稻壳灰作为重要的农业废弃物,其资源丰富。合理地利用稻壳灰可以促进农业经济效益的增长以及资源的持续发展。由于稻壳灰中含有大量的二氧化硅,使得稻壳灰的应用受到了极大的关注。介绍了近年来稻壳灰在多个行业和领域的应用和研究工作。     

稻壳生物质资源利用技术研究进展

稻壳是一种产量巨大的农业废弃物,直接丢弃或掩埋不但会造成资源浪费更会引起环境污染。稻壳中含有丰富的SiO₂、纤维素、半纤维素和木质素等。资源化利用是稻壳有效利用的发展方向和趋势。本文综述了近年来国内外稻壳资源化利用的研究进展。根据稻壳的特性,将资源化利用方式分为能源化利用、工业化利用及农业化利用,并对其研究现状进行了介绍。重点阐述了稻壳在气化制备可燃气、热裂解制备生物油、改性制备吸附剂、合成分子筛、制备催化剂载体、生产白炭黑与活性炭、水解制备糠醛、木聚糖、低聚木糖及发酵制备饲料等方面的研究进展,同时对其发展方向和趋势进行了展望,指出最大限度控制成本将成为稻壳资源化利用实现工业化的重要因素。     

粉煤灰建材资源化的研究进展

粉煤灰是火力发电厂的副产品,利用粉煤灰生产建材是粉煤灰资源化的有效途径;结合粉煤灰的性质,介绍了粉煤灰建材资源化的研究进展,尤其是在水泥、混凝土、烧结砖和微晶玻璃等方面的最新研究成果;指出粉煤灰建材资源化还存在一些不足,需要进一步研究来提高粉煤灰利用量.     

干法脱硫灰在建材领域资源化利用的研究进展

干法脱硫工艺因具有占地小、能耗低、脱硫效率高、无污水废酸排放等原因得到了空前发展.但脱硫副产物脱硫灰中因SO3含量较高,且主要矿相CaSO3·1/2 H2O的作用效果不明确,致使仍未广泛利用而大量堆积,又成为干法脱硫工艺推广的制约.本文系统介绍了干法脱硫灰在建材领域资源化利用的研究进展,并提出了一些建议,以期为进一步推动干法脱硫灰的资源化利用研究提供一定的借鉴.     

电石渣资源化应用研究进展

电石渣是电石水解制乙炔时的副产物.本文介绍了电石渣的化学成分和热分解特性,综述了电石渣在生产建筑材料、制备化学产品方面的资源化利用现状与研究进展,并阐述了目前电石渣资源化利用中存在的不足.对于利用电石渣生产建筑材料,应逐渐摆脱对水泥、建筑砌块等建材原料需求的长期依赖,着力研发高附加值建材产品;对于利用电石渣制备化学产品,应简化工艺流程、降低能耗,提高产品纯度;各项资源化利用过程中,不应忽视电石渣中所含污染物在迁移转化过程中形成的二次污染.     

钢渣在建材中资源化利用现状、问题及建议

介绍了钢渣的性能特点,阐述了钢渣在建材中的资源化利用途径。指出钢渣资源化利用存在的问题,并提出了高温重构改性、高效除铁工艺和设备、超细化粉磨技术、复合化技术等系列措施以改进钢渣性能,以便更好地推进钢渣的资源化利用。     

稻壳灰在橡胶工业中的应用

概述稻壳灰在橡胶和热塑性弹性体(TPE)中的应用,并对目前存在的问题进行分析,指出今后的研究方向.稻壳灰是稻壳燃烧后的产物,主要成分为二氧化硅.稻壳灰具有来源丰富、价廉和废物回收利用的特点,在橡胶和TPE中可以作为填料使用,其补强作用需在低填充量条件下或经过处理后才能显示出来.今后应加强其性质、表面改性方法和生产工艺对其性质的影响等方面的研究.     

稻壳的资源化利用

论述了稻壳的资源化利用的方法和途径.稻壳的主要成分为纤维素、木质素和二氧化硅,可用于制造木糖醇,糠醛,介孔二氧化硅,白炭黑,高纯二氧化硅、活性炭等产品,利用其燃烧热能可产生蒸汽发电.充分利用稻壳中的各种成分,回收能量,制成各种有价值产品,是稻壳的综合利用的方向.     

Environmentally sustainable rice husk ash reinforced cardanol based polybenzoxazine bio-composites for insulation applications

Polymer Bulletin - Tri-substituted cardanol based benzoxazine with functionalized rice husk ash (CBz/FRHA) bio-composites were developed using renewable resource materials, and...     

Study on the pozzolanic properties of rice husk ash by hydrochloric acid pretreatment

The pozzolanic properties of rice husk ash by hydrochloric acid pretreatment are reported in the paper. Three methods have been used to estimate the pozzolanic activity of rice husk ash. The heat evolution and the hydration heat of cement, the Ca(OH)₂ content in the mortar and the pore size distribution of mortar are determined. It is shown that compare with the rice husk ash heated untreated rice husk, the sensitivity of pozzolanic activity of the rice husk ash heated hydrochloric acid pretreatment rice husk to burning conditions is reduced. The pozzolanic activity of rice husk ash by pretreatment is not only stabilized but also enhanced obviously. The kinetics of reaction of rice husk ash with lime is consistent with diffusion control and can be represented by the Jander diffusion equation. A significant increase in the strength of the rice husk ash (pretreated) specimen is observed. The results of heat evolution indicate that the rice husk ash by pretreatment shows the behavior in the increase of hydration of cement. The cement mortar added with the rice husk ash by pretreatment has lower Ca(OH)₂ content after 7 days and the pore size distribution of the mortar with the rice husk ash with pretreatment shows a tendency to shift towards the smaller pore size.     

Reactive pozzolanas from rice husk ash: An alternative to cement for rural housing

This paper discusses the properties of rice husk ash samples produced from different types of field ovens to compare the performance of the ovens and to identify the most feasible method to produce a reactive pozzolana as an alternative to cement for building applications requiring lower strengths. Different types of ashes are produced and long-term strength of rice husk ash pozzolanas with lime or cement is investigated to suggest a sustainable affordable option in rural building applications, especially for rural housing in Kerala, a southern state of India.     

高活性稻壳灰的制备、提纯及应用的研究进展

稻壳灰是通过煅烧稻壳得到的一种高活性的火山灰材料,有着广泛而重要的用途。这里根据国内外研究现状及发展趋势,综述了高活性稻壳灰的制备、提纯及应用,特别就以稻壳硅为硅源的应用给予了重点阐述,并结合本课题组的研究,提出了稻壳灰的应用体会和展望。     

具有高比表面积的稻壳灰的制备及其化学活性的研究

Preparation of rice husk ash with high specific surface area and chemical reactivity of the product are reported in this paper. The amorphous rice husk ash with high specific surface area of 311 m^2.g^-1 was produced by heating acid treated rice husk at 700~C for 4 h. The isotherms of rice husk ash are similar in shape to type Ⅱ of Brunaner‘s classification with mesopores being predominant. The rice husk ash has a high chemical reactivity, especially that pretreated with acid. This chemical reactivity depends on ashing temperature and pretreatment conditions. There is an exponential relation between the specific surface area of rice husk ash and the change in the conductivity of saturated Ca(OH)2 solution with rice husk ash, from which the specific surface area can be known according to the conductivity change.     

Effect of rice husk ash addition on CO2 capture behavior of calcium-based sorbent during calcium looping cycle

Rice husk ash/CaO was proposed as a CO₂ sorbent which was prepared by rice husk ash and CaO hydration together. The CO₂ capture behavior of rice husk ash/CaO sorbent was investigated in a twin fixed bed reactor system, and its apparent morphology, pore structure characteristics and phase variation during cyclic carbonation/calcination reactions were examined by SEM-EDX, N₂ adsorption and XRD, respectively. The optimum preparation conditions for rice husk ash/CaO sorbent are hydration temperature of 75 °C, hydration time of 8 h, and mole ratio of SiO₂ in rice husk ash to CaO of 1.0. The cyclic carbonation performances of rice husk ash/CaO at these preparation conditions were compared with those of hydrated CaO and original CaO. The temperature at 660 °C–710 °C is beneficial to CO₂ absorption of rice husk ash/CaO, and it exhibits higher carbonation conversions than hydrated CaO and original CaO during multiple cycles at the same reaction conditions. Rice husk ash/CaO possesses better anti-sintering behavior than the other sorbents. Rice husk ash exhibits better effect on improving cyclic carbonation conversion of CaO than pure SiO₂ and diatomite. Rice husk ash/CaO maintains higher surface area and more abundant pores after calcination during the multiple cycles; however, the other sorbents show a sharp decay at the same reaction conditions. Ca₂SiO₄ found by XRD detection after calcination of rice husk ash/CaO is possibly a key factor in determining the cyclic CO₂ capture behavior of rice husk ash/CaO.     

RICE HUSK ASH AS FILLER IN UNSATURATED POLYESTER BASED SHEET MOULDING COMPOUNDS (SMC)

Sheet moulding compounds were made from unsaturated polyester resin as matrix material filled with calcium carbonate, white rice husk ash and black rice husk ash. The objective of this investigation was to utilize the white and black rice husk ash, which are available in large quantities and which pose environmental problems in rice-producing areas. The investigation showed that black ash has a profound effect to increase the modulus of rupture, modulus of elasticity, as well as to reduce the thickness swelling and water absorption. Scanning electron microscopic studies showed that the black ash retained the fibrous morphology and thus has a better reinforcing function than white ash, which is amorphous. Reduction in water absorption and thickness swelling should be attributed to the hydrophobic nature of carbonaceous residues present on the outer surface of black ash. Formation of organosilicon compounds during the processing of the black ash was at first suspected to be responsible for the water repellency; but the ²⁹Si MAS NMR studies did not provide evidence for the formation of such compounds.     

Synthesis and characterization of soybean‐oil‐based polyurethane composites containing industrial and agricultural residual wastes as fillers

Thermosetting composites were prepared from soybean‐oil‐based polyols (hydroxyl number = 190 mg of KOH/g, [OH]/[NCO] for 2,4‐toluene diisocyanate = 0.9) and fillers (10 wt %) from industrial and agricultural residual wastes. Different types of inexpensive residual wastes were used: black rice husk ash, coconut husk ash, calcined retorted oil shale, and retorted oil shale. The fillers were characterized by thermogravimetric analysis and measurements of particle size distribution, specific surface area, and pore size distribution. The fillers were microporous materials with different chemical compositions, with average particle diameters varying from 5.6 to 76.6 μm, specific surface areas varying between 6 and 165 m²/g, and thermal stability at the polyurethane cure temperature (65°C). All composites were characterized by dynamic mechanical analysis, flexural tests, Shore A hardness tests, thermogravimetric analysis, and scanning electron microscopy analysis. Coconut husk ash, rice husk ash, and retorted oil shale presented better mechanical properties; nevertheless, coconut husk ash and rice husk ash had higher particle sizes, which caused bad dispersion of the filler in the matrix and resulted in nonhomogeneous composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012