提钛废渣转化为固井新材料的制备工艺、组成、结构及水化机理研究

Chlorination titanium blast furnace slag is a industrial solid waste in Panxi region, the utilization rate of these residues is low, which has caused pollution to the environment and seriously violated the requirements of the development of circular economy. This research plans to achieve a cementing fluid and a novel self-solidified spacer fluid which based on the chlorination titanium blast furnace slag, MTC technology and drilling fluid technology. Slag composition and structure are the basis of hydration reaction. The structure of the slag composition is characterized by X-ray diffraction, nuclear magnetic resonance, high resolution transmission electron microscopy. The change of phase morphology, the composition in micro area and the change law of the phase composition for chlorination titanium blast furnace slag before and after treatment process are investigated with polarizing microscope, scanning electron microscope, mineral liberation analyzer and X-ray diffractometer. To improve the reactivity of chlorination titanium blast furnace slag, this project research chemical activation, mechanical activation and heat activation of slag and compares the activation methods. Based on the hydration mechanism of slag and the mechanism of retarder and fluid loss agent, the fluid loss additives and retarder of chlorination titanium blast furnace slag is designed and synthesized. This project research the application performance of chlorination titanium blast furnace slag cementing fluid. From the essence of hydration reaction, the research investigate physical and chemical characters and mechanism of chlorination titanium blast furnace slag cementing fluid. The research investigate the ions dissolution properties, pozzolanic property, the chemically combined water content, the reaction mechanism of slag, in order to provide theory foundation to solve the key problem of cementing fluid’s development. The results of this research could guide the design and application of chlorination titanium blast furnace slag cementing fluid, which help to ensure the environmental protection and economic development of Panxi region.

高钛型高炉渣在提钛处理后每年产生数十万吨提钛废渣，造成严重的固废污染和溃泄隐患。提钛废渣具有无机胶凝性质，利用此性质有可能配制可固化隔离液或代替油井水泥固井。本项目研究提钛废渣转化为固井新材料的制备工艺、组成、结构及水化机理，其内容包括：1）废渣处理工艺与其组成、结构、结晶学特点的关系；2）废渣的机械力激活、化学激活和热激活的效果及选择；3）优选或合成外加剂，制备以废渣为胶凝材料的固井液和可固化隔离液，掌握其应用性能；4）废渣在井下环境的水化过程、水化产物、水化热力学与水化动力学等水化特性。最终阐明提钛废渣的组成、结构、水化特性与应用性能间的关系和影响规律，创立有关理论体系和模型，指导提钛废渣在固井上的应用推广，产生材料科学与油气井工程的学科交叉效应；进一步推动提钛废渣的消解和资源化利用，对攀西战略资源创新开发试验区的国民经济和环境保护做出重要贡献。

为解决提钛废渣产量大、对环境危害大等问题，利用井下的高温高压环境研制以提钛废渣为胶凝材料的固井液体系。.在本研究中：1）探究了提钛废渣处理工艺与其物化结构之间的关系。研究发现，“高温碳化-低温氯化”工艺可以将钛含量从20～26%降至约10%；水洗可以除去废渣中80%以上的Cl-和酸性杂质从而提高废渣活性；水淬可以使废渣具备更多的玻璃相结构。2）探究了机械激活对提钛废渣活性的影响。通过改变废渣的球磨时间发现，球磨2 h后废渣的中值粒径下降68.37%，比表面积达到908 m2/Kg，球磨时间超过2 h后粒径和活性变化不再明显。3）对提钛尾渣固井液使用外加剂和激活剂进行了优选。最终确定了以CMC作为悬浮剂，以G33S为降失水剂，以NaOH为激活剂的基浆体系。HNJ-A和HNJ-B的复配缓凝剂加量为3%时可使稠化时间达到420 min。4）自行设计一种降失水剂，确定最佳合成条件为：单体摩尔比AMPS：DMC：DN-1：AA = 3.5:2.5：4.5：1.5；反应温度为65 ℃；引发剂加量为 0.7 wt.%；pH=8；反应时间为5h；单体浓度为25%。该物质具有良好的耐温性，与其余外加剂配伍性良好。在固井液中加量达到2%时即可满足施工需求。5）对固井液的工程性能进行了评价。固井液密度在1.4～1.7 g/cm3范围内可调，适用于30～90 ℃，与钻井液相容性良好，且混浆具有固化能力；6）通过对提钛废渣水化产物组成、结构的研究，探究提钛废渣的水化机理。提钛废渣中玻璃体的凝聚程度极高，因此需要高浓度OH-激活。在OH-和碳酸盐副产物的作用下，极大地提高了水化反应速率。此外，Mg、Al等元素使得水化产物呈多样化。7）对提钛废渣固井液固化体进行了增韧处理。4%的玄武岩纤维使得固化体的孔隙率降低了2%，提高了抗冲击能力，28 d抗压强度也提高了43.75%。玄武岩纤维主要是通过桥接作用达到增韧效果，不会对固化体的水化产物造成影响。.通过以上研究获得了一套具有工程应用前景的提钛废渣固井液体系。实现固废处理和油气井工程的交叉应用，进一步推动提钛废渣的消解和资源化利用，对国民经济发展和环境保护做出重要贡献。