几种典型煤气化炉渣的碳热还原氮化过程

煤气化炉渣是煤炭气化过程产生的固体废弃物。选取5种煤气化炉渣作为研究对象,在分析其化学和显微结构后,将炉渣分别在1 350~1 500℃进行碳热还原氮化,并对氮化产物的物相组成和显微结构进行表征。结果表明:1 5种无定性炉渣的化学结构均可描述为Si O4四面体与Al O4四面体相互连接的架状结构;2炉渣中的玻璃相呈规则球体状,无定性碳呈多孔海绵、长带或长片状;3 5种炉渣经碳热还原氮化反应均可合成出Ca-α-Si Al ON粉体,且Ca-α-Si Al ON的形成过程一致;4炉渣氮化产物中杂质相的产生与炉渣的化学组成中Ca O,Si O2,Al2O3和C的相对含量密切相关;5在氮化过程中,炉渣中玻璃球体发生表面粗糙、多孔、空心等形态的变化,这些变化在一定程度上反映出炉渣的氮化进程。

Carbothermal reduction nitridation process of several typical coal gasification slag

Coal gasification slag is a kind of solid waste produced from coal gasification process.In this paper,five kinds of gasification slag were selected.The chemical structure and microstructure of the slags were studied firstly.Then,the phase composition and microstructure of nitridation products obtained by carbothermal reduction nitridation (CRN) of slags at 1 350-1 500 ℃ were comprehensively investigated.The results show that:① The chemical structure of five kinds of amorphous slag can be generally described as the frame structure of SiO4 tetrahedra branched with AlO4 tetrahedra;② The glass phase in slag tends to exist in spherical shape,whereas the amorphous carbon tends to stay in porous sponge,long strip or sheet-like shape;③ Ca-α-SiAlON can be synthesized from CRN of each slag.Moreover,the formation steps of Ca-α-SiAlON in each CRN process are the same;④ The formation of impurity in nitridation products is closely related to the relative content of CaO,SiO2,Al2O3 and C in raw slag;⑤ During the CRN process,the morphological evolution of glass balls in raw slag can be used as the indicator showing the process of CRN,such as rough surface,porous or hollow structure.