【作者】 李伟峰；

【导师】 王京刚；

【作者基本信息】 北京化工大学 ， 环境工程， 2008， 硕士

【摘要】 随着钢铁工业的发展,钢渣的排放量逐年增加。钢渣的大量堆积不仅是不可再生资源的浪费,而且对环境造成巨大的污染。这就需要人们对钢渣进行综合利用,变废为宝。当前钢渣主要用来建筑行业等低附加值产品,为了拓展其应用途径,有必要对钢渣的本征特性进行深入研究。本实验以鞍山、宝山和南京钢铁公司的转炉钢渣为研究对象,观察了钢渣矿物在扫描电子显微镜背散射电子像下的特征形貌,进而识别了特征形貌的矿物类型,最终确立了代表性矿物的典型组成。对水杨酸-甲醇溶液（SAM）萃取钢渣中硅酸盐相进行了可行性研究,分析钢渣比表面积、溶解时间和水杨酸浓度对萃取硅酸盐相量的影响,对萃取机理也进行初步探讨。再者,研究了钢渣的粉磨性,并与矿渣的易磨性做出比较。最后,研究了钢渣作为火山灰质混合材在机械活化和碱激发作用下的胶凝性能。通过转炉钢渣的显微形貌及矿物相研究,探明了主要矿物的特征形貌、固熔形式和典型组成。结果表明:在高碱度钢渣中,硅酸二钙（C₂S）呈圆粒状和树叶状,硅酸三钙（C₃S）呈六方板状,铁铝钙相和镁铁相呈不规则形貌;主要矿物相为C₂S、铁铝钙及镁铁相固溶体,还含有少量的C₃S、f-CaO和MgO;铁铝钙相的典型组成是铁铝酸钙,其表达式为Ca₂（Al,Fe）₂O₅,还发现长期以来由于组成未知而被人们定名为RO相的物质成分是镁铁相,其代表性组成是MgO·2FeO。在水杨酸-甲醇（SAM）溶液萃取钢渣中硅酸盐相实验中发现,SAM溶液萃取硅酸盐相效果理想,通过对硅酸盐相萃取量的测定,为钢渣胶凝活性的快速评价提供了方法。实验结果表明:常温下,5g比表面积为600m²/kg的钢渣,经300mlSAM溶液（水杨酸浓度为0.2g/mL）萃取3h,钢渣中的硅酸盐相可完全溶解,其他矿物不溶或溶解甚微。对硅酸盐相溶解于SAM溶液的机理进行了初步探讨,可认为:硅酸盐相溶解是由于水杨酸电离出的配体（HO-C₆H₄-COO^-）与矿物表面阳离子(Ca²⁺)生成的络合物,通过键极化作用削弱Si-O键的稳定性,降低硅酸盐溶解活化能而致。钢渣粉磨性的研究结果表明,钢渣中70%的矿物具有良好的易磨性能,影响钢渣粉磨性能的并不是矿物本身,而是金属铁粒以及少量矿物的致密结构。钢渣主要矿物的难磨程度由高到低:首先是RO、C₂S,其次是Ca₂（Al,Fe）₂O₅,最后是氧化镁和Ca（OH）₂,这种粉磨性能的差异为其分离提供了有效的手段。同时发现,钢渣的易磨性优于矿渣。通过机械活化、碱激发和掺于矿渣等手段,转炉钢渣可制备出高活性火山灰质混合材。钢渣经过机械活化后,各龄期抗压强度都有显著增长,但活化效果差于矿渣。在碱激发作用下,1.2模数的水玻璃激发钢渣效果最好,但与矿渣相比激发效果不显著。由于水化过程的叠加效应,掺于一定量的矿渣可明显改善机械活化和碱激发效果。掺50%矿渣的钢渣,其2×2×2cm小试块的28d抗压强度可达48.6MPa。更多还原

【Abstract】 With the development of iron and steel industry,the output of steel increased year after year.It brought us a mass of steel slag,which is not reproducible and will bring lots of environmental pollutions.It is necessarily for people to reuse the steel slag comprehensively turning the waste into useful material.At current time,the steel slag is used as component of cement and construction aggregate material.Deep research on physicochemical properties should be carried out to find new recycle way.Micro-structures of slag samples from 3 steel plants were observed by the back scattered electron images of SEM.The element composition was determined by energy dispersive X-ray analysis,in order to ascertain mineral category the composition,data of the mineral phases with the same morphology characteristics was analyzed by statistics.And the possibility of extracting silicate phase from steel slag by Salicylic Acid Methanol（SAM） Solution was studied,and effect of specific surface area of steel slag, dissolving period of samples,concentration of salicylic acid on the extraction mass of silicate phase were analyzed.Furthermore,the basic extraction theory was also studied.With the grinding process,the ease of grinding of steel slag was investigated,and the comparison of grinding performance between steel slag and the slag was made.The cementitious behavior of the steel slag activated by mechanical and alkaline process was also studied.With the study of micro-structure and the mineral phases of Converter Slag,the characteristic conformation,the form of solid solution and representative composition were determined.The results show that morphology of C₂S in high alkalinity slag is round or leaf shape,C₃S is hexagonal,and the phase of Fe₂O₃-Al2O₃-CaO and MgO-FeO all are irregular. The main phases in the slag are C₂S,Fe₂O₃-Al₂O₃-CaO and MgO-FeO solid solution,the minor mineral is C₃S,f-CaO and MgO.It was found that the representative composition of the Fe₂O₃-Al₂O₃-CaO phase is calcium aluminoferrite,the chemical formula of which is Ca₂（Al,Fe）₂O₅,the RO phase, which has been unknown for a long time,is MgO-FeO solid solution,its representative composition is MgO·2FeO.The possibility of extracting silicate phase from steel slag by SAM was studied,and the SAM solution showed good ability for extraction of silicate phases.One way for the determination of the cementitious performance of the steel slag was offered by the measurement of extraction amount of the silicate phases.The results show that,with the extraction for 3h at ordinary temperature,the silicate phase in 5g steel slag（600m²/kg）can be totally extracted out,and only silicate phase was dissolved in SAM.It is in point that silicate phase extraction is due to forming the complex between legend of salicyclic acid and Ca²⁺on the surface of mineral,which weakens the stability of Si-O bond,then decreases the activation energy of silicate phase.The grinding results showed that:the grinding performance of steel slag was influenced by metal grains and compact configuration of some mineral, instead of the steel slag itself,the ease of grinding performance listed in descending order is RO,C₂S,Ca₂（Al,Fe）₂O5,MgO and Ca（OH）₂,the different grinding performance of which provide us a effective way for the separation of the steel slag.The grinding performance of steel slag was much better than that of slag.The cementitious ability of steel slag,from which preparation of high activation pozzolanic materials,was studied by several ways.And its cementitious performance improved a lot with the mechanical process. However,the mechanical activation effect of steel slag is inferior to the slag. For the lower amount of glass state contained in steel slag,it was difficult to activated than slag.Cementitious performance improved by mixing into the stag in evidence,as a result of compound function of hydrate process.And the compressive strength for 28d of 2×2×2cm specimen with 50%steel slag was 48.6Mpa.更多还原