湿法炼锌浸出渣与高铁锌精矿协同浸出及相互作用机理研究

High-iron sphalerite is a refractory mineral resource, and zinc neutral leach residue is an intermediate slag in the hydrometallurgy of zinc which has a low zinc but high iron content, as well as values of enriched indium, silver, copper and germanium. There is a deficiency in the traditional zinc-making technique, which alone is inadequate to deal with the high-iron sphalerite. Therefore, the key of research and development focus shuold be on a technique for an efficient separation of zinc and iron.A new synergic leaching method capable of simultaneous treatment of high-iron sphalerite and zinc leach residue might result in an efficient and clean extraction of values and comprehensive utilization of the resources. By making use of the mineralogical characteristics of the mineral, the difference in the physic-chemical properties of its components, properties such as chemical composition, phases and the microstructure of insoluble components, the dissolution behavior and chemical reactions between complex zinc-iron compounds, and the associated elements and refractory sulfides, the project will study and determine the mechanism for the interactions between the mineral and residue in synergic leaching and optimize technical parameters. Meanwhile, the mechanisms for the heterogeneous conversion dissolution reaction, the mutual conversion and transmission of Fe3+/Fe2+ and S0/S2- couples, the formation of elementary sulfur and its coating, and the dissociation on the surface of mineral particles, will be investigated. The pattern of influence of the different solution potential on the existence form of sulfur will be explored. Through these studies, a kinetic model, an interfacial action and an coupling mechanism for the multiphase heterogeneous reactions in the new leaching system will be constructed. In order to provide a theoretical guide and technical support for efficient utilization of the high-iron sphalerite and zinc leach residue, the scientific issues such as the essence and fundamentals of synergic leaching will be elucidated.

高铁闪锌矿是一种难处理矿产资源，中性浸出渣是湿法炼锌中间渣，其具有含锌低含铁高，富含有价金属铟铜银等特点。针对现有炼锌方法不宜单独处理高铁锌精矿的不足，抓住锌铁分离关键技术这个核心，研发了能同时高效处理高铁锌精矿和浸出渣的协同浸出新方法。围绕该新技术，采用现代检测手段和冶金热力学及动力学研究方法，开展其难溶矿物组成、物相、结构等特性研究，复杂锌铁化合物、伴生元素和复杂硫化矿之间的溶出行为和化学反应机理研究，绘制热力学状态图，确立协同浸出渣矿相互作用机制及技术参数的优化耦合；研究非均相转化溶解反应机理，研究铁硫离子对氧化还原、相互转化与传递机制，研究元素硫生成及其对固体矿物表面包裹机理及解离机制，探索溶液不同电位对元素硫存在形态的影响规律，建立新型浸出体系多元多相反应动力学模型及其界面作用规律，阐明渣矿协同浸出的本质和基本规律等科学问题，为高铁闪锌矿及锌浸出渣的高效利用提供理论指导与技术支撑

针对高铁锌精矿和浸出渣的协同浸出新技术，开展了矿物组成、物相、结构等研究，绘制了热力学状态图，研究了复杂锌铁化合物、伴生元素和复杂硫化矿之间的溶出行为和化学反应机理，矿物的转化溶解反应机理，铁硫离子对氧化还原、相互转化与传递机制，元素硫生成及其对固体矿物表面包裹机理及解离机制，协同浸出过程锌浸渣与锌精矿相互作用机制及技术参数的优化耦合，建立了协同浸出体系反应动力学模型，阐明了渣矿协同浸出的本质。.（1）高铁锌精矿中锌主要以闪锌矿和铁闪锌矿形态存在，锌浸出渣中杂质铁和金属铟含量较高，渣中锌元素主要以铁酸锌和硅酸锌形态存在。.（2）在“锌浸出渣-高铁锌精矿协同浸出”体系中，锌浸出渣溶解释放的Fe3+离子为高铁锌精矿的溶解提供了氧化剂，高铁锌精矿对溶液中Fe3+离子的还原，促进锌浸出渣溶解。.（3）铁酸锌的溶解速率随反应温度、浸出剂浓度和混合物料中闪锌矿比例的升高及固体颗粒粒度的降低而加快；闪锌矿的溶解速率随反应温度、浸出剂浓度和混合物料中铁酸锌比例的升高及固体颗粒粒度的降低而加快。.（4）铁闪锌矿中硫被氧化成单质硫，并进入渣中。新生物相单质硫的生成，不仅来源于闪锌矿与Fe3+发生氧化还原反应，且闪锌矿与硫酸发生酸溶反应生成H2S，再与Fe3+发生氧化还原反应生成单质硫。.（5）锌、铁的浸出动力学过程遵循“收缩核模型”，在浸出反应前期，锌、铁浸出速率受界面化学反应控制，其表观活化能分别为55.11kJ/mol和43.42kJ/mol，硫酸的反应级数分别为1.14和1.12；反应后期，浸出渣中单质硫在矿物颗粒表面形成致密包裹，锌、铁浸出速率受产物层扩散控制。.（6）在协同浸出过程中，锌浸出渣基本完全溶解，高铁锌精矿中仍然有少量硫化物未溶解而残留在浸出渣中，高铁锌精矿的溶解是制约协同浸出体系中有价金属浸出率高低的主要因素。.（7）通过两级逆流协同浸出，锌、铟、铁、铜的浸出率分别达96%、96%、95%、97%以上，同时实现了浸出液中Fe3+离子的还原，浸出液中Fe3+离子、残余硫酸浓度低，分别为3g/L左右、30g/L左右。.本项目发表论文16篇，授权专利6项，毕业博士1名、硕士3名，在读博士生2名、硕士生4名。