【作者】 杨华美；

【导师】 杨华全；

【作者基本信息】 长江科学院 ， 水工结构， 2010， 硕士

【摘要】 我国西南地区钒钛矿产资源丰富。随着冶金工业的发展,作为工业副产品的高钛矿渣排放量急剧增加,不仅占用大量土地资源,而且一旦其中含有的有害物质渗入地下,会对土壤、地下水、地表水及地表生物造成严重的危害。随着人们环保意识的增强,废物资源化利用已被国际公认为保护环境、节能减排的新途径。因此,寻找利用高钛矿渣的途径意义重大。论文对高钛矿渣的化学成分、矿物组成以及物理性能进行了系统的分析。结果表明,高钛矿渣中CaO、SiO₂含量较少,仅为50%左右,而TiO₂含量高,大于20%,属低钙高钛矿渣。主要矿物组成为钛辉石、钙钛矿、巴依石、尖晶石,这类矿物在水介质条件下溶解能力和解体能力低,在高钛矿渣中呈现明显的结晶特性,有大量的晶体析出、长大。随着高钛矿渣掺量的增加,掺高钛矿渣的水泥净浆用水量减少,凝结时间稍延长;高钛矿渣需水量比随比表面积的增加略有提高。高钛矿渣中无死烧相,经压蒸检验安定性合格。探讨了高钛矿渣比表面积以及掺量对复合胶凝体系胶砂强度的影响规律。结果表明,水泥—高钛矿渣复合胶凝体系的胶砂强度不高,始终低于不掺高钛矿渣的胶砂强度,且随着高钛矿渣掺量的增加,胶砂强度逐渐降低;高钛矿渣比表面积存在一个最佳值（约为400m²/kg）,小于这个值,水泥—高钛矿渣复合胶凝体系的胶砂强度随比表面积的增加而增大;超过此值,比表面积继续增加,强度反而有降低的趋势。高钛矿渣比表面积不是影响复合胶凝体系胶砂强度的主要因素。随着掺量的增大,比表面积对掺高钛矿渣复合胶凝体系的胶砂强度的影响逐渐减小。高钛矿渣的潜在水硬活性很低,作为水泥混凝土掺和料时,掺量不宜大于30%。掺入高钛矿渣,水泥基复合胶凝体系的胶砂强度发展趋势类似于掺II级粉煤灰,最终强度略低于掺II级粉煤灰;当掺和料掺量控制为30%时,II级粉煤灰与高钛矿渣复掺能产生一定的复合胶凝增强效应,有利于水泥基复合胶凝体系强度的提高,但II级粉煤灰的掺量不宜过大。借助扫描电镜分析（SEM）、X射线衍射分析（XRD）、热分析（TG-DSC）等微观测试方法,以及吸水动力学等方法,分析了不同细度、不同掺量下水泥—高钛矿渣复合胶凝体系的水化过程、水化产物及孔结构的发展趋势。试验结果表明,高钛矿渣的水化产物主要有C-S-H凝胶、Ca（OH）₂晶体,还有少量AFt晶体;高钛矿渣具有填充效应和微集料效应,适量掺入高钛矿渣可以增加水化体系的致密程度,但掺量过高时,会降低整个体系的水化程度。随着水化反应的进行,水化凝胶产物明显增多,逐渐将高钛矿渣晶体颗粒包裹,使硬化水泥石的强度能够正常发展。但由于高钛矿渣中活性成分较少,导致生成的C-S-H凝胶含量较少,致使不能形成致密的网状结构,使得最终强度仍很低。随着高钛矿渣掺量的增加,掺高钛矿渣的水泥净浆试件平均孔径参数逐渐增大,均匀性参数逐渐减小。通过机械粉磨和掺入NaOH、Ca（OH）₂、Na₂CO₃、Na₂SiO₃、CaSO₄、Na₂SO₄以及掺石膏等方式来激发高钛矿渣的活性。试验结果表明,高钛矿渣粉磨细度在400m²/kg左右时,水化活性最高;继续增加粉磨细度,对强度贡献不大。掺入化学激发剂,对于提高高钛矿渣的水化活性整体效果不明显,水泥—高钛矿渣复合胶凝体系的早期强度略有改善,到90d龄期时,外掺激发剂体系的胶砂强度反而低于不掺激发剂体系的胶砂强度,这有可能与高钛矿渣的稳定性晶体结构有关,具体原因尚有待进一步研究确认。高钛矿渣作为骨料的混凝土性能试验结果表明,与灰岩骨料混凝土相比,高钛矿渣作为骨料的强度差别不大,但干缩值明显增加,自生体积变形呈膨胀状态,且膨胀量较大。更多还原

【Abstract】 Resources of vanadium titano-magnetite are abundant in Southwest of China.With the development of metallurgical industry，the intensive increment in the amountof high titanium slag discharged as industrial byproduct, not only occupies a large ofland resources, but also endangers living beings in the soil, underground water,surface water and earth’s surface seriously in case that the harmful substancescontained in the high titanium slag might permeate into the ground. With theincreased awareness of environmental protection, taking full advantage of wastematerials has been recognized as a new approach to protect environment and conserveenergy. Therefore, it is significant to find new ways to exploit high titanium slag.It has comprehensively analyzed chemical components, mineral compositions andphysical properties of high titanium slag. Results indicate that, in terms of chemicalcomponents, high titanium slag contains relatively few content of CaO and SiO2, onlyapproximately 50%, and high content of TiO2, more than 20%. In terms of mineralcomposition, it mainly contains titanaugite, perovskite, spinel and basnite, which arenot only difficult to dissolve and disaggregate in the condition of aqueous medium,but also are of obvious crystal characteristics which are typical of a large number ofcrystal precipitations and growth. With increment in content of high titanium slagincorporated into cement paste increases, normal consistency of cement pastedecreases and setting time extends a little. Water demand ratio of high titanium slagincreases slightly with its specific surface area increases. It fails to find dead burningphase in the high titanium slag and its soundness is qualified by autoclave inspection.It investigates influence of specific surface area and content of high titanium slagon mortar strength of composite cementitious system. Results show, mortar strengthof composite cementitious system made with cement and high titanium slag is slowerthan that without high titanium slag. What’s more, mortar strength decreases with increment in content of high titanium slag. The optimum specific surface area of hightitanium slag is about 400m²/kg, less than which mortar strength of compositecementitious system increases with fineness while beyond which mortar strength yettends to decrease. Influence degree of fineness on mortar strength is diminishedgradually with high titanium slag content increases, which indicates that specificsurface area is not the major influencing factor on mortar strength of compositecementitious system. Potential activity of high titanium slag is so slow that it is notadvisable that its content by mass of cement should not exceed 30% when it is used ascement or concrete additive. The development trendency of mortar strength ofcement-based cementitious materials with high titanium slag is similar to that withgrade II fly ash, yet its final strength is slightly lower than the latter. When givenadditive content is 30%, mixing with grade II fly ash and high titanium slag canproduce a certain enhancement effect so that it is favorable to improve mortar strengthof composite cementitious system.In virtue of various measurements including scanning electron microscope, x-raydiffraction, thermal analysis and water-absorpting dynamics, it reveals the fulldevelopment of hydration process，hydration products and pore structure ofcement-high titanium slag cementitious with age in terms of fineness and content ofhigh titanium slag. Test results can be concluded as follows: Hydration products ofcement-based cementitious doped with high titanium slag mainly include C-S-H gel,Ca（OH）2 crystal and few AFt crystal. High titanium slag particles possess fillingeffects and micro-aggregate effects so that incorporating appropriate content of hightitanium slag into cement paste could enhance compact degree of hydration systemyet excessive high titanium slag may reduce hydration degree as a whole. Amount ofhydration products increases obviously with age, which enwrap high titanium slagparticles gradually and favor the development of mortar strength. However, as a resultof few active ingredients in the high titanium slag, C-S-H gel contents produced arequite few, correspondingly it fails to form compacted network structure, which resultin low final strength. High titanium slag will enhance pore average diameterparameter and aggravate pores distribution irregularity. By mechanical grinding and adding chemical reagents such as NaOH, Ca（OH）₂,Na₂CO₃, Na₂SiO₃, CaSO₄, Na₂SO₄ and gypsum, it investigates activation of hightitanium slag. Results show that, among the given ground fineness, when specificsurface area is around 400 m²/kg, hydration activity of high titanium slag ranks thehighest. It contributes little to mortar strength if continuing to increase groundfineness. Adding chemical reagents only improves early strength of cement-hightitanium slag cementitious slightly. At 90 days, mortar strength of compositecementitious system is lower than that without adding chemical reagents instead,which may be connected with stable crystal structure of high titanium slag. Furtherefforts are needed to confirm this point.It examines concrete performances made with high titanium slag as aggregate.Results indicate that, in terms of concrete strength, there is little difference betweenconcrete made with limestone aggregate and high titanium slag individually yetdrying shrinksge of the latter is obviously bigger, while its autogenous volumedeformation is relatively mocro expansive.更多还原