由于煤种及气化工艺不同,使煤气化渣玻璃体含量和组成存在一定差异。以壳牌煤气化渣为主要原料,通过升温诱导结晶方法,研究了煤气化渣玻璃体组成和含量对碱激发胶凝材料力学性能和微观形貌的影响机理。结果表明,煤气化渣基胶凝材料在最佳碱激发条件下抗压强度可达30MPa。高温诱导结晶导致煤气化渣中析出钙长石晶体,钙长石晶体的析出不仅降低了煤气化渣玻璃体含量,且提高了玻璃体中活性硅铝组分比例。碱性环境下,钙长石未参与溶解-聚合反应,玻璃体含量减少,降低了Si和Al溶出率,从而减少凝胶相生成,导致胶凝材料力学强度降低,玻璃体含量与胶凝材料力学性能呈线性相关关系;玻璃体中硅铝组分比例增加,影响Si和Al溶出比例,活性硅铝的溶出比例对碱激发剂的选择及凝胶相的生成具有一定影响。微观形貌分析表明:玻璃体含量较高的煤气化渣表面光滑,且碱性环境下生成的凝胶相较多,养护过程中,胶凝材料微观结构变得致密,力学强度增加。

The composition and content of glassy phase in coal gasification slag ( CGS) change due to the difference in coal speciesand gasification process. I order to study the effect of glassy phase in CGS on mechanical properties and micromorphology of alkali-excit⁃ed cementitious material, a CGS of shell gasifier was used as raw material, and the content and composition of glassy phase in CGSwas changed by crystallization process at high temperature. The results show that the compressive strength of CGS based cementitious mate⁃rial can reach 30 MPa under the optimal alkali excitation condition. High temperature induced crystallization causes the formation of anor⁃thite in CGS, which not only decreases the content of glassy phase, but also increase the Si/ Al of glassy phase. In alkaline environment,anorthite does not take part in dissolution-polymerizationreaction, and less glassy phase in slag leads to decreasing dissolution of Si andAl, which is detrimental to mechanical properties. Besides, the mechanical property of cementitious material is linearly related to contentof glassy phase in CGS. Si/ Al of glassy phase decides the dissolution ratio of Si and Al under alkaline condition, which is useful for choiceof alkali activator to increasethe formation of gel in cementitious material. The micromorphology analysis shows that the surface of coal gasi⁃fication slag with high glassy phase is smooth, and more gel is generated in alkaline condition. During curing process, the microstructureof cementitious material becomes dense, which lead to increase of mechanical strength.

0 引言

1 试验

   1.1 试验原料

   1.2 升温诱导结晶试验

   1.3 碱激发胶凝材料试块的制备

   1.4 煤气化渣硅铝在NaOH溶液的溶出试验

   1.5 样品检测与表征

   1.6 分析方法

2 结果与讨论

   2.1 试验参数对试块力学强度的影响

   2.2 晶体析出对煤气化渣玻璃体含量和组成的影响

   2.3 前驱体玻璃体含量对碱激发材料力学强度的影响

   2.4 煤气化渣在碱性环境下硅铝组分的溶出规律

   2.5 胶凝试块物相及微观形貌分析

3 结论