烧结气氛对煤矸石陶粒烧结过程的影响

Effect of sintering atmosphere on sintering process of coal gangue ceramsite

以全煤矸石陶粒为研究对象,采用氮气气氛分段保护焙烧等实验方法,分析了气氛对煤矸石陶粒烧结过程的影响机理。研究表明,在空气下烧制的陶粒形成红棕色外壳和黑色内核的分层结构,外层中多存在赤铁矿相,而内层多存在含碳相。空气下烧结的陶粒孔结构均匀致密,氮气气氛下烧结的样品未出现明显的脱碳后的孔洞。不同阶段采用氮气保护的焙烧实验证明,陶粒在升温过程主要以碳的氧化为主,在高温及降温过程以含铁矿相的氧化为主。煤矸石陶粒烧制主要分为四个阶段:300~600℃的挥发分和有机碳燃烧阶段、600~900℃的固定碳脱除阶段、900~1125℃的陶粒致密化阶段,以及陶粒烧结后的塑形氧化阶段。

The effect of atmosphere on sintering process of all coal gangue ceramsite was analyzed by using nitrogen atmosphere protection.The results showed that the ceramsite fired in the air formed a layered structure of red-brown shell and black core,with hematite in the shell and carbon residue in the core.The pores of the air-fired ceramsite were uniform and dense,while the pores of the nitrogen fired ceramsite did not appear after decarburization.The experiments of roasting with nitrogen protection at different stages showed that the sintering of coal gangue ceramsite was mainly dominated by the oxidation of carbon in the heating process and iron phase in the high temperature and cooling process.The firing of coal gangue ceramics can be divided into four stages:the combustion stage of volatile and organic carbon at 300~600℃,the removal stage of fixed carbon at 600~900℃,the densification stage of ceramic particles at 900~1125℃,and the molding and oxidation stage of ceramic particles after sintering.