金属硅酸盐物料高压高温酸浸过程中抑制硅胶形成及沉硅调控机制

The metal silicate materials such as silicate minerals, smelter slag and smelting smoke belong to an important category of metal resources, and the production of silicone is a common problem in conventional acid leaching process. With the chemical behavior of silicon as the main research clue and based on pressure acid leaching metal silicate materials, this project carries out a series of interdisciplinary researches including pressure hydrometallurgy, colloid chemistry and coordination chemistry. To inhibit the formation of silica gel, this project will systematically study on the impact pathway and reaction mechanism of various factors and all kinds of conventional cation/anions which have an effect on the polymerization-gelation process under pressure acid leaching in Si-H2Osystem, identify the law of structural rearrangements and morphological transformation of amorphous silica, find out the common laws as well as the reasons for differences among the results of pressure acid leaching kinds of metal silicate materials in Me-Si-H2O system, and analyze the phase transformation and dissociation mechanism of colloidal pulp from a microscopic level. With a combination of thermodynamic analysis of silicon precipitation in hydrothermal process and dynamics analysis of silica gel condensation, make clear the evolution behavior of soluble silicon transforming into crystalline silica or silicate composite precipitation and try to attain an optimized control of this process，this project will also explore the influence of some factors such as high pressure, high temperature and components on the regulatory mechanism of silicon deposition, This project will lie a good foundation not only for improving the theory of silicate polymerization under the condition of high pressure-high temperature but also for the technology of direct metallurgy of metal silicate materials.

硅酸盐矿物、冶炼渣、冶炼烟尘等金属硅酸盐物料是一类重要的金属资源，常规酸浸过程中易产生硅胶。本项目基于加压酸浸法处理金属硅酸盐物料，以硅的化学行为作为研究主线，开展加压湿法冶金、胶体化学和配位化学等多学科交叉研究。为抑制硅胶形成，系统研究Si-H2O体系加压酸浸过程中各个工艺因素及各类常规阳离子/阴离子对硅酸聚合-胶凝的影响途径及作用机理，揭示无定形SiO2的结构重排和形态转化规律；基于Me-Si-H2O体系，查明加压酸浸法处理不同类别金属硅酸盐物料的共性规律及差异的形成原因，微观解析胶态矿浆的物相转化及解离机制。结合水热沉硅的热力学分析和硅酸胶凝的动力学分析，综合解析如何优化控制并实现可溶性硅转化成晶态二氧化硅或复合硅酸盐沉淀的演变行为，探索高压-高温-组分等多因素的沉硅调控机制。本项目的研究为完善高压高温条件下的“硅酸聚合作用”理论及金属硅酸盐物料的直接冶金技术研发奠定良好基础。

各类金属硅酸盐物料（金属硅酸盐矿物、冶炼渣、冶炼烟尘）资源量多面广，是一类重要的金属资源，该类资源常规酸浸技术的共性难题是容易形成硅胶及其带来的诸多危害。为抑制硅胶形成，项目探索研究了Si-H2O体系加压酸浸体系各个工艺因素及各类常规阳离子/阴离子对硅酸聚合-胶凝的影响规律及作用机理，探明Me-Si-H2O体系不同类别金属硅酸盐物料高压高温酸浸过程中的沉硅调控机制。项目研究的主要结果及意义如下：1）明晰了Si-H2O体系单硅酸转化为SiO2稳定相的热力学条件，查明了始酸浓度、反应温度、终点pH值、液固比等条件对硅的酸溶行为和矿浆过滤性能的显著影响规律。通过升高压力而维持更高的温度或适当调整终点pH值，均能降低硅的浸出率和改善矿浆的过滤性能。2）明确了常规阳离子Fe3+、Al3+、Ca2+、Mg2+及常规阴离子F-、Cl-对硅酸聚合-胶凝的影响规律，综合解析如何优化控制并实现可溶性硅转化成晶态二氧化硅或复合硅酸盐沉淀的演变行为。3）初步探明了高硅氧化锌矿、富锰渣、高硅富铟渣、黑铜渣、废镀锌板炼钢粉尘、黄磷电尘灰等金属硅酸盐物料加压酸浸工艺抑制硅胶形成的共性规律及作用机理；提出了酸浸体系避免硅胶形成的方法，优化控制工艺参数，均能实现Si的浸出率小于2%、矿浆过滤性能优越；高压高温、恰当pH值等强化条件对包裹金属组元的硅胶具有良好破坏和转化作用；酸浸体系中产生的正电性氢氧化物胶体，能与硅溶胶共聚成大颗粒的晶型复合硅酸盐沉淀。上述成果明晰了无定性二氧化硅的演变行为规律，阐明了多组分协同沉硅机理，实现了酸性液中沉硅的优化调控。本项目研究结果为金属硅酸盐物料资源的高效开发利用及湿法冶金过程中硅胶形成的抑制机制提供了理论和技术支撑，预期产业化应用前景广阔，社会和经济效益显著。

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