闪速炼铅非平衡多相反应体系中精矿迁移转化及反应强化机制

Lead flash smelting process is such a multi-phase reaction system far away from equilibrium that it cannot be precisely controlled to achieve energy conservation and emissions reduction targets, because the species distribution and transformation of the lead concentrate dropping down with the reaction shaft still cannot be understood. For this research, the dropping process of lead sulfide concentrate in reaction shaft of lead flash smelting furnace will be researched. At first, the reaction characteristic data (phase, composition, temperature, atmosphere, etc.) in different height of reaction shaft will be acquired, by analyzing the samples obtained on-sitely from industrial flash furnace with the method of high-temperature quenching and other technologies. Then, a concentrate transforming mathematical model will be proposed based on the assumption of local equilibrium, by treating the interior space of reaction shaft as a system where lead sulfide concentrate and oxygen achieve local equilibrium continuously while falling to the settler, and by establishing the relationship between system Gibbs free energy and the valence state, phase and composition of all elements in concentrate. Finally, based on the model, the principle of the phase transformation, element migration and chemical evolution of the lead sulfide concentrate in reaction shaft will be investigated under the integrated action of these technology parameters, such as concentrate composition, smelting temperature, oxygen consumption per ton concentrate, and concentrate feeding speed. After analyzing the concentrate reaction control link, the strengthening measures of lead sulfide concentrate reaction will be explored, and the relationship between these strengthening measures and efficiency parameters (sulfur content in blister, lead content in slag, and dust rate) will be studied as well. The expected objective of this research is to reveal the transforming mechanism of lead sulfide concentrate in reaction shaft and to establish the strengthening mechanism of smelting reactions, which can be applied to provide theoretical support for the control and optimization of lead flash smelting process.

闪速炼铅是远离平衡状态的多相反应体系，其生产过程难于精确调控是制约节能减排效能的主要因素，关键问题是精矿在反应塔中的形态分布和迁移转化行为还不清楚。项目以硫化铅精矿沿反应塔下降过程为对象，采用高温急冷取样等技术，获取工业炉反应塔特定高度的物相、组成、温度、气氛等特征数据；进而引入非平衡系统的局域平衡假设，将反应塔内部空间视为物料与反应气体不断达到局域平衡的多相反应体系，研究物料各元素价态、物相、组成与体系吉布斯自由能的关系，建立精矿迁移转化数学模型；在此基础上，重点研究物料组成、熔炼温度、吨矿氧量、进料速度等工艺参数耦合作用下精矿下降过程的物相转化、成分迁移和化学演变规律，剖析精矿反应控制性环节，探索反应强化措施及其与粗铅含硫、渣含铅、烟尘率等效能指标的关联，以期揭示反应塔中铅精矿迁移转化机理，建立高效能冶炼强化调控机制，为闪速炼铅过程控制及操作优化提供理论支持。

闪速炼铅生产过程难于精确调控是制约节能减排效能的主要因素，关键问题是精矿在反应塔中的形态分布和迁移转化行为还不清楚。为此，项目以硫化铅精矿沿反应塔下降过程为对象，通过研究建立基于两温两密度法的三元渣系成分软测量数学模型、炼铅渣系活度热力学模型、精矿物相组成线性规划计算模型、Rand-MQC耦合算法，进而引入非平衡系统的局域平衡假设，将反应塔内部空间视为物料与反应气体不断达到局域平衡的多相反应体系，自主研发了铅精矿迁移转化数学模型和仿真系统；在自制的高温闪速熔炼中试炉（Φ120 mm，H2700 mm）中开展了铅精矿闪速熔炼试验，获得了铅精矿闪速反应特征数据，并对数模进行了验证；基于建立的铅精矿迁移转化数学模型，开展了多因素耦合仿真试验，研究了物料组成、熔炼温度、吨矿氧量、进料速度等工艺参数耦合作用下精矿下降过程的物相转化、成分迁移和化学演变规律，剖析了精矿反应控制性环节，探索了反应强化措施及其与粗铅含硫、渣含铅、烟尘率等效能指标的关联，揭示了反应塔中铅精矿迁移转化机理，建立了高效能冶炼强化调控机制。研究成果为闪速炼铅过程控制及操作优化提供理论依据，其非平衡多相反应体系建模方法和思路，目前已推广应用于闪速炼铁这一国际前沿新技术的研发，已获科技部“十三五”重大专项和北京市科委“蓝天计划”项目等课题的支持。在本项目支持下，在国内外期刊上发表学术论文16篇，其中SCI、EI收录4篇；申请发明专利16项、授权6项，获软件著作权1项，获中国有色金属工业科学技术二等奖1项；培养了硕士研究生7名、毕业6名；组建了“闪速绿色开发与循环利用”创新团队，引进了博士教师5名，形成了特色科研方向，获批江西省闪速绿色开发与循环利用重点实验室。