加压酸浸锰烟尘回收锰过程选择性强化浸出机理研究

In the situation of manganese resources depleted increasingly, it is necessary to processing manganese dust from manganese smelting system and the valuable metal manganese was recycled comprehensively. Pressure hydrometallurgy technology was suited for processing the complex and hard smelting non-ferrous metal resources especially, the comprehensive utilization of resources were realized. On the basis of previous work, the laboratory pressure acid leaching test was in combination with computational fluid dynamics (CFD) numerical simulation, the leaching behavior of manganese dust was researched to explore the law of dissolution and precipitation in pressure acid leaching process under high temperature, the selective extraction and separation mechanism of manganese and impurity elements in pressure acid leaching process were revealed; The kinetics behaviors of manganese dust pressure acid leaching and the regularity of three-phase synergy were studied systematically and comprehensively, and the nonlinear dynamic model of manganese dust pressure acid leaching process was set up, the polynomial relationship between manganese leaching rate and various influencing factors was established, and then the physics and mathematics model of solid-liquid, gas-liquid two phase flow which is submit to the practical situation of manganese dust pressure acid leaching process was constructed. The selective reinforcement leaching mechanism of pressure acid leaching manganese manganese dust recycling process was revealed eventually. The theory basis of this project was provided for recycling manganese dust efficiently by pressure acid leaching technology, and it has great significance for improving China's manganese resources situation and increasing the degree of manganese resources.

在锰资源日益贫化的形势下，将锰烟尘从锰冶炼系统中开路处理，综合回收有价金属锰尤为必要。加压湿法冶金技术特别适于处理复杂、共伴生和难选冶有色金属资源，实现资源的综合利用。本项目在前期工作的基础上，采用实验室加压酸浸试验和计算流体动力学（CFD）数值模拟相结合的方式，研究锰烟尘加压酸浸过程浸出行为，探究加压高温作用下各组分的溶出及沉淀规律，揭示锰烟尘加压酸浸过程中锰与杂质元素选择性提取分离机制；系统全面的研究锰烟尘加压酸浸动力学行为及三相协同作用规律，建立锰烟尘加压酸浸过程非线性动力学模型，建立锰浸出率与各个影响因素之间的多项式关系，构建适合锰烟尘加压酸浸过程实际情况的固-液、气-液两相流物理数学模型。最终揭示加压酸浸锰烟尘回收锰过程的选择性强化浸出机理。本项目为加压酸浸技术在锰烟尘高效回收利用上的推广提供理论依据，对改善我国锰资源形势及提高锰资源保障程度具有重要意义。

在锰资源日益贫化的形势下，将锰烟尘从锰冶炼系统中开路处理，综合回收有价金属锰尤为必要。本项目采用实验室加压酸浸试验和计算流体动力学（CFD）数值模拟相结合的方式开展加压酸浸锰烟尘回收锰过程选择性强化浸出机理研究。计算并绘制了在298K和373K时Mn-H2O系、Fe-S-H2O系与Mn-H2O系、S-H2O系、Si-Al-H2O系电位-pH图。锰烟尘加压浸出较优的工艺条件为：锰烟尘100g，初始硫酸浓度120g/L，液固比5:1，浸出温度120℃，压力0.8MPa，浸出时间2h，搅拌转速350r/min。锰浸出率可达96.1%以上，铁浸出率仅7%，终酸残余率34.9%，渣率为55.3%。浸出液中锰和铁的浓度分别为44.74g/L和2.52g/L。低温低压条件下浸出高硅锰烟尘过程锰的浸出率低、过滤性能差的主要原因是由于浸出过程中大量硅溶胶的生成，随着温度和压力的提高，硅溶胶逐渐转化为易于过滤分离的二氧化硅沉淀。浸出过程由界面化学反应控制，并遵循界面化学反应控制的“核收缩模型”，浸出活化能为43.4 kJ/mol，反应级数0.864。运用UG对左右不对称搅拌釜进行三维结构的建模，运用欧拉-欧拉模型、PBM模型、标准k-ε模型的耦合对搅拌釜进行数值模拟，搅拌速度与温度、通气速率、压力相比，搅拌速度对釜内流体状态的影响较大，随着搅拌速度的增加，气含率逐渐增大。增大液体粘度，使得搅拌轴右侧出现明显气体聚集上升，但搅拌桨叶端切向、轴向、径向速度有不同程度的降低。采用颗粒动力学理论（KTGF）、k-ε湍流模型和Gidaspow曳力模型作为封闭模型的双流体模型对液固两相模拟，以搅拌转速、液体介质粘度、固体体积分数为变量模拟得出液相速度随着搅拌转速的增加而增加，随着粘度、固体体积分数的增加而降低，湍流动能随着搅拌转速、粘度的增加而增加，随着固体体积分数的增加而降低，原因为固体的加入与液体发生作用，能量损失导致液相速度减小。三种不同结构的搅拌釜中，双层椭圆型搅拌釜分散效果最好，单层椭圆型次之，单层平底型最差。本项目为加压酸浸技术在锰烟尘高效回收利用上的推广提供理论依据，对改善我国锰资源形势及提高锰资源保障程度具有重要意义。