常温常压下含钒钢渣不焙烧选择性酸浸提钒的机制研究

Acid leaching technique without roasting, which has the advantages in high leaching rate and environmental friendliness, is an important research direction in vanadium extraction field. However, as for as the acid leaching without roasting of vanadium-bearing steel slag for vanadium extraction, there still exist some unsolved problems such as unconscionable acid consumption and the difficult separation of vanadium and iron caused by high Ca and Fe content in vanadium-bearing steel slag. Most seriously, mechanism research is few and there is no clear understanding about mechanism of the acid leaching vanadium without roasting from vanadium-bearing steel slag. Aiming to solve the above problems, based on preliminary research, a new no-roasting acid leaching method which named "beneficiation pretreatment - selective stage acid leaching vanadium without roasting under normal temperature and pressure" is proposed creatively, and its mechanism problems will be systematically researched. . In this project, properties characteristics will be studied first in terms of process mineralogy to structure the fine distinguishable pattern of properties characteristics of vanadium-bearing steel slag; And then, the rule of refining beneficiation pretreatment and its effects on acid leaching vanadium without roasting will be deeply studied and revealed; Meanwhile, by adopting various basic principles combined with modern microscopic measuring and testing technologies, the thermodynamics action of selective acid leaching vanadium under normal temperature and pressure, the relationships of elements leaching behavior, external conditions and change of properties characteristics to selective stage acid leaching will be systematically studied to achieve a better separation between vanadium and impurities just in leaching procedure and to elucidate the mechanism of selective leaching vanadium from multi-angle and multi-level. Finally, through scientific integration of above single research results, a new mechanism for selective acid leaching vanadium without roasting under normal temperature and pressure can be established, and a solid theoretical support for vanadium extraction work can be provided.

不焙烧酸浸技术具有浸出率高、环境友好的优势，是提钒的研究方向。但是，含钒钢渣不焙烧酸浸提钒，因钙、铁含量高而引起的酸耗过高、钒与铁杂质难以分离的问题尚未解决，此外，更重要的问题是其机制研究不清。针对上述问题并基于前期工作，本项目创新性地提出一种含钒钢渣不焙烧酸浸提钒的新方法，即"选矿预处理-常温常压下选择性分段酸浸提钒"，并拟对该法的机制问题进行研究。. 项目拟首先从矿物学角度出发，研究物性特征，构建含钒钢渣物性精细辨识新模式；依据物性研究成果，深化研究并揭示精细化选矿预处理的规律及其对不焙烧酸浸提钒的效应；运用各基本原理、结合现代测试手段，系统研究常温常压下选择性浸钒的热力学及元素溶出行为、外界因素、物性变化与选择性分段酸浸的关系等，浸出阶段即实现钒、杂分离，多层次多角度阐明选择性浸钒机理。最终通过上述单一成果的集成，构建常温常压下不焙烧选择性酸浸提钒的机制，为提钒工作提供有力的理论支撑。

本项目创新性地提出了一种含钒钢渣不焙烧酸浸提钒的新方法，即“选矿预处理-常温常压下选择性分段酸浸提钒”，并对其机制进行了深入、系统的研究。. (1)从矿物学角度出发，研究了含钒钢渣的物性特征，分析了物性特征与提钒的关系，获得了含钒钢渣多元复杂体系的结构、特点、组元行为等，构建了多维多系统相互补充的含钒钢渣物性精细辨识新模式。(2)依据含钒钢渣的物性特征，通过思路创新，将传统的“选矿技术”应用于钢渣提钒，提出了“精细化选矿预处理”的观点，分析了预处理后含钒钢渣的成分组成，揭示了精细化选矿预处理的规律：可脱钙除杂、回收铁、富集钒，确定了预处理对不焙烧酸浸提钒的效应：提高浸出指标和浸出效率、降低酸浸液中铁钒浓度比、减少浸出酸耗。(3)对预处理后的含钒钢渣的硫酸浸出体系进行了热力学的计算与分析，可从理论上指导酸浸的方法和工艺条件，并为选择性浸钒提供了科学的热力学数据；基于元素浸出行为的独立性和相关性，依据热力学研究结果：“FeO的浸出比钒具有更大的热力学趋势，当终酸浓度为1×10-4mol•L-1时，FeO理论上能全部被硫酸浸出，而钒基本不被浸出”，开发出“选择性分段酸浸”新方法，Ⅰ段预浸除杂、Ⅱ段浸出提钒，在浸出阶段即可在很大程度上实现钒与铁等杂质的分离；对选择性浸钒热力学以及元素溶出行为、外界因素、物性变化与选择性酸浸的关系等进行了探析，多层次多角度阐明了常温常压下选择性酸浸提钒的机理。. 最终，将精细化选矿预处理、选择性分段酸浸有机结合，实现了“选矿”与“冶金”联合除杂、提钒理论与工艺的有机结合，优势互补，为钒资源的利用提供了新思路；选择性分段酸浸新方法的开发及其机理的阐明，丰富和发展了净化除杂的方法与理论；含钒钢渣精细辨识模式、选矿预处理规律与效应、选择性分段浸钒机理科学集成，初步建立了常温常压下不焙烧选择性酸浸提钒的机制，可为提钒工作提供有力的理论支撑。