高压CO_(2)和机械搅拌下碳酸化钢渣粉的微结构形成机理  

Microstructure Formation Mechanism of Carbonated Steel Slag Powder under High Pressure CO_(2)and Mechanical Stirring

作　　者：胡晨光 付佳伟 刘刚 白瑞英 封孝信 HU Chenguang;FU Jiawei;LIU Gang;BAI Ruiying;FENG Xiaoxin(College of Materials Science and Engineering,North China University of Science and Technology,Tangshan 063210,China;Hebei Province Key Laboratory of Inorganic Nonmetallic Materials,Tangshan 063210,China)

机构地区：[1]华北理工大学材料科学与工程学院,河北唐山063210 [2]河北省无机非金属材料重点实验室,河北唐山063210

出　　处：《金属矿山》2025年第1期280-292,共13页Metal Mine

基　　金：河北省重点研发计划项目(编号:22373710D);河北省高端钢铁冶金联合基金项目(编号:E2020209010)。

摘　　要：钢渣含有碱性矿物可作为碳捕集和封存材料,而目前在高压CO_(2)和机械搅拌联合作用下碳酸化钢渣微结构的形成规律尚不清晰,研究模拟水泥砂浆搅拌方式,利用扇叶搅拌式高承压碳酸化反应釜,结合XRD、DSC-TG、FT-IR与SEM-EDS等测试手段,研究了碳酸化反应时间、CO_(2)压力、搅拌转速等参数对钢渣粉微结构的影响。结果表明:随着碳酸化时间的延长,硅酸盐矿物早期形成的“未反应矿物-凝胶层-碳酸钙层”核壳结构在碳酸钙体积膨胀和机械搅拌的双重作用下,向“内部多核壳颗粒堆积-凝胶嵌挤-外部大壳包裹”的“类石榴型”结构转变;增大CO_(2)压力将促进形成“未反应矿物-凝胶层-碳酸钙层”的核壳结构;提高搅拌速度将加速形成“类石榴型”结构。在碳酸化过程中,钢渣中RO相的MgO参与水化反应产生体积膨胀,与搅拌作用共同使RO相粉化,Mg2+从RO相溶出,并向外层富硅区迁移形成水化硅酸钙(镁)(C-(M)-S-H)凝胶。随着碳酸化时间的延长,RO相粉化程度提高,形成分散的颗粒状结构。铁酸钙参与碳酸化反应,会因生成的碳酸钙体积膨胀作用而粉化,增大CO_(2)压力会促进铁酸钙粉化而呈现“蜂窝状”结构。Steel slag containing alkaline minerals can be used as carbon capture and sequestration materials.At present,the formation of carbonated steel slag microstructure under the high pressure CO_(2)and mechanical stirring is not clear enough.The influence of carbonation reaction time,CO_(2)pressure,stirring speed on the microstructure of steel slag powder was investigated by utilizing the fan-blade stirred high-pressure carbonation reactor which simulated the mixing mode of cement mortar,and combined with XRD,DSC-TG,FT-IR and SEM-EDS.The results indicate that with the increase of carbonation time,the core-shell structure of"unreacted mineral,gels layer and calcium carbonate layer"was formed in the early stage of silicate minerals reaction,under the double effect of calcium carbonate volume expansion and mechanical stirring,the core-shell structure of the silicate minerals is transformed to the"pomegranate-like model"structure,which is characterized by the"accumulation of multiple core-shell particle in the inner part,embedded gels and encapsulated shell in the outer part".Increasing CO_(2)pressure will promote the core-shell structure of"unreacted mineral,gels layer and calcium carbonate layer",and the formation of"pomegranate-like model"structure will be accelerated by raising the rotational speed.In the carbonation process,the volume expansion of hydration produce for the MgO in the RO phases of steel slag participates,and together with the stirring effect cause the RO phases to be pulverized,and Mg2+ions leach out from the RO phases and migrate to the outer silica-rich zone,and then form the hydrated calcium(magnesium)silicate(C-(M)-S-H)gels.With the prolongation of time,the degree of pulverization of the RO phases continues to increase,and a dispersed granular structure is formed.Calcium ferrate is involved in the carbonation reaction,and will be pulverized due to the volume expansion of the generated calcium carbonate,and increasing the CO_(2)pressure promotes the pulverization of calcium ferrate and presents a"h

关 键 词：钢渣 高压 CO_(2) 机械搅拌 碳酸化 微结构 

分 类 号：TQ172[化学工程—水泥工业] TU528[化学工程—硅酸盐工业]