To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of ...To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulovi？-Dabi？ model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth（NG）, interaction at phase boundaries（I）, and diffusion（D） in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.展开更多
The technology of coal-based direct reduction of high-ironcontent red mud is studied. The factors affecting this kind of direct reduction mainly are: coal sort, carbon amount, time, temperature and etc. has been inves...The technology of coal-based direct reduction of high-ironcontent red mud is studied. The factors affecting this kind of direct reduction mainly are: coal sort, carbon amount, time, temperature and etc. has been investigated. It has been shown that an ide展开更多
工业生产过程中产生大量粉煤灰、赤泥和煤气化渣,其堆积不仅侵占土地,还会严重破坏生态环境,危及人类健康。这3种固废均含有硅铝元素,且含量较高,硅铝比(氧化硅和氧化铝物质的量比)波动幅度较大。ZSM-5(Zeolite Socony Mobil 5)是一类...工业生产过程中产生大量粉煤灰、赤泥和煤气化渣,其堆积不仅侵占土地,还会严重破坏生态环境,危及人类健康。这3种固废均含有硅铝元素,且含量较高,硅铝比(氧化硅和氧化铝物质的量比)波动幅度较大。ZSM-5(Zeolite Socony Mobil 5)是一类硅铝比范围较宽的沸石分子筛,具有独特的孔道结构和良好的稳定性,在吸附和催化方面应用广泛。利用富含硅铝的固废制备ZSM-5是其高值化和资源化利用的重要途径之一。系统总结了富含硅铝的固废的活化除杂预处理通用方法,并且基于粉煤灰、赤泥和煤气化渣的理化性质特点,综述了固废基ZSM-5的合成及金属改性、磷改性、水热改性和酸碱改性4种方法的研究进展。分析固废作为硅铝源对ZSM-5合成、结构和性能的影响,指出固废在活化除杂过程中硅铝比的调控、杂质元素的去除转化、及主要元素的迁移转化规律是研究重点;讨论不同改性方法对ZSM-5结构和性能的影响机制,提出固废基ZSM-5中硅铝在骨架和非骨架中的分布、铁钙等杂元素的含量和存在形态、孔结构对改性效果起到非常重要的作用。通过对典型富含硅铝元素的固废基ZSM-5合成及其改性过程中存在问题和研究现状的分析和讨论,提出了粉煤灰、赤泥和煤气化渣多源固废复配,在无机模板剂或无模板剂条件下水热晶化制备ZSM-5,对固废基ZSM-5高效精准改性是未来发展方向。展开更多
以赤泥、粉煤灰、脱硫石膏及一种碱性固体废弃物外加剂为胶凝材料,煤矸石为骨料,制备得到环境友好型全工业固废路面基层混合料(RFDC).研究了4个龄期(7、28、56、90 d)下,不同粉煤灰掺量RFDC无侧限抗压强度(fUCS)和劈裂抗拉强度(fSTS)的...以赤泥、粉煤灰、脱硫石膏及一种碱性固体废弃物外加剂为胶凝材料,煤矸石为骨料,制备得到环境友好型全工业固废路面基层混合料(RFDC).研究了4个龄期(7、28、56、90 d)下,不同粉煤灰掺量RFDC无侧限抗压强度(fUCS)和劈裂抗拉强度(fSTS)的发展规律,分析了抗压试件和劈裂抗拉试件的破坏形态,探讨了固废胶凝材料中3种氧化物摩尔比与RFDC 7 d fUCS的相关性,揭示了RFDC的强度形成机理.结果表明:当粉煤灰掺量为15%时,RFDC的力学性能最佳,抗压试件为典型的中心抗压破坏,劈裂抗拉试件为煤矸石粗集料破坏;固废胶凝材料的n(CaO)/[n(SiO_(2))+n(Al_(2)O_(3))]值与RFDC 7 d fUCS的相关性最高;钙矾石(AFt)、水化硅(铝)酸钙(C-(A)-S-H)凝胶及沸石类物质等水化产物是RFDC强度的主要来源.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51302012 and 51234008)the China Postdoctoral Science Foundation(No.2016M590046)
文摘To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulovi？-Dabi？ model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth（NG）, interaction at phase boundaries（I）, and diffusion（D） in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.
文摘The technology of coal-based direct reduction of high-ironcontent red mud is studied. The factors affecting this kind of direct reduction mainly are: coal sort, carbon amount, time, temperature and etc. has been investigated. It has been shown that an ide
文摘工业生产过程中产生大量粉煤灰、赤泥和煤气化渣,其堆积不仅侵占土地,还会严重破坏生态环境,危及人类健康。这3种固废均含有硅铝元素,且含量较高,硅铝比(氧化硅和氧化铝物质的量比)波动幅度较大。ZSM-5(Zeolite Socony Mobil 5)是一类硅铝比范围较宽的沸石分子筛,具有独特的孔道结构和良好的稳定性,在吸附和催化方面应用广泛。利用富含硅铝的固废制备ZSM-5是其高值化和资源化利用的重要途径之一。系统总结了富含硅铝的固废的活化除杂预处理通用方法,并且基于粉煤灰、赤泥和煤气化渣的理化性质特点,综述了固废基ZSM-5的合成及金属改性、磷改性、水热改性和酸碱改性4种方法的研究进展。分析固废作为硅铝源对ZSM-5合成、结构和性能的影响,指出固废在活化除杂过程中硅铝比的调控、杂质元素的去除转化、及主要元素的迁移转化规律是研究重点;讨论不同改性方法对ZSM-5结构和性能的影响机制,提出固废基ZSM-5中硅铝在骨架和非骨架中的分布、铁钙等杂元素的含量和存在形态、孔结构对改性效果起到非常重要的作用。通过对典型富含硅铝元素的固废基ZSM-5合成及其改性过程中存在问题和研究现状的分析和讨论,提出了粉煤灰、赤泥和煤气化渣多源固废复配,在无机模板剂或无模板剂条件下水热晶化制备ZSM-5,对固废基ZSM-5高效精准改性是未来发展方向。
文摘以赤泥、粉煤灰、脱硫石膏及一种碱性固体废弃物外加剂为胶凝材料,煤矸石为骨料,制备得到环境友好型全工业固废路面基层混合料(RFDC).研究了4个龄期(7、28、56、90 d)下,不同粉煤灰掺量RFDC无侧限抗压强度(fUCS)和劈裂抗拉强度(fSTS)的发展规律,分析了抗压试件和劈裂抗拉试件的破坏形态,探讨了固废胶凝材料中3种氧化物摩尔比与RFDC 7 d fUCS的相关性,揭示了RFDC的强度形成机理.结果表明:当粉煤灰掺量为15%时,RFDC的力学性能最佳,抗压试件为典型的中心抗压破坏,劈裂抗拉试件为煤矸石粗集料破坏;固废胶凝材料的n(CaO)/[n(SiO_(2))+n(Al_(2)O_(3))]值与RFDC 7 d fUCS的相关性最高;钙矾石(AFt)、水化硅(铝)酸钙(C-(A)-S-H)凝胶及沸石类物质等水化产物是RFDC强度的主要来源.
