废蓄电池清洁再生铅膏预脱硫反应机制研究与过程强化

There are about 110 million lead-acid batteries scraped every year in our country, which contains more than 3 million tons of lead. The regeneration of lead-acid battery is necessary for environmental protection and resources circulation. As the inapplicable imported technology and equipment to the situation in China and the insufficient of domestic independent technology equipment, the clean regeneration of the lead-acid battery in our country had always been blocked. The desulphurization of lead paste is the key to the whole regeneration process, so carrying out basic and applied research on it has great significance to the regeneration of lead-acid battery and the upgrade of lead circulation industry. On the basis of acquaint different kinds of lead paste properties, the project is mainly to study the problem of lead paste covered by desulfurization reaction product on the surface layer which can hinder the desulfurization reaction. The study mainly includes revealing the characteristics of pre-desulfurization conversion process, especially the characteristics of micro interfacial mass transfer and reaction and the properties of product layer; Researching the effect and strength of three kinds of Surface Update mechanism namely hydraulic shear, physical milling and the collision of reaction particles; Building the system of surface forced update reaction containing “particles double circular broken by grinding” and “reaction particles self collision based on the multiphase flow”; Exploring the functional mechanism and structure-property relationship of the “surface force updating” paste desulphurization system; Analyzing the characteristics of fluid mechanics and reaction kinetics in the desulphurization process. The result has universal guiding significance to the reaction mechanism research and process intensification for the reaction containing liquid-solid heterogeneous and solid product.

我国每年有1.1亿只蓄电池报废，含铅300多万吨，清洁再生蓄电池是环境保护和铅资源循环的必然需求。进口技术装备不适应中国国情，自主技术装备储备又不足，国家推行清洁再生工艺曾一度受阻，目前基本可行的自主全套技术装备已开发成功，铅膏脱硫是全过程的核心，对其开展基础与应用研究，对蓄电池清洁再生与铅资源循环行业进步和产业升级意义重大。项目在充分认识铅膏特性基础上，针对铅膏脱硫反应产物层包裹反应物、阻碍反应进行的问题开展研究，揭示脱硫转化过程特征、尤其微界面传质与反应特征及产物层特性，研究水力剪切、物理研磨和反应颗粒自碰撞三种反应物表面更新机制的作用及强度，构建“粒子双循环研磨破壳”与“基于多相流的反应颗粒自碰撞”表面强制更新反应系统，探究表面强制更新铅膏脱硫系统的作用机制、构性关系，探明系统的流体、力学、反应动力学特征。项目成果对液-固非均相、产物为固体的一类反应的机制研究与过程强化有普遍指导意义

我国每年报废近700万吨铅蓄电池，废铅蓄电池资源清洁再生与高效利用是生态文明建设的必然要求。《再生铅行业准入条件》明确要求“铅膏必须进行脱硫预处理或送硫化铅精矿冶炼厂合并处理，脱硫母液必须进行处理并回收副产品”。截止目前，全国100余家再生铅企业中仅极少数具备废铅膏与硫化铅精矿合并处理的条件，其余都须对废铅膏进行预脱硫处理并回收副产物。我国的废铅膏晶型复杂、粒度差异大，之前行业普遍采用的脱硫技术无法有效打破脱硫过程产物壳层对反应物传递的阻碍，脱硫耗时长、脱硫铅膏含硫率波动很大，无法满足生产要求，产业政策推行受阻。项目在系统研究了我国废铅膏的特性，针对铅膏脱硫反应产物层包裹反应物、阻碍反应进行的问题开展研究，揭示脱硫转化过程特征、尤其微界面传质与反应特征及产物层特性，研究水力剪切、物理研磨和反应颗粒自碰撞三种反应物表面更新机制的作用及强度，提出了脱硫物料储存与反应分离的新工艺、开发了脱硫产物壳层破坏与副产物高效结晶新技术、创制了新设备，构成了完整、系统的废铅蓄电池铅膏预脱硫与产物高效回收工艺技术装备体系，适应各种工况要求。项目授权发明专利7项，实用新型专利1项，发表论文4篇。项目成果至今在国内推广5套、出口2套，处理废铅蓄电池37万吨/年，源头减排二氧化硫2.664万吨/年。项目成果攻克了铅膏预脱硫过程反应物传质的瓶颈性障碍，为国家再生铅产业政策的推行奠定了必要基础，对再生铅行业铅膏预脱硫产业技术进步形成了有力的支撑。