预还原褐铁矿型镍红土矿流态化选择性氯化及其过程强化

For efficient utilization of limonitic nickel laterite, this project presents a novel process to extract nickel and cobalt by pre-reduction – selective chlorination in fluidized bed –water leaching. To solve the existing key problems during selective chlorination of pre-reduced ore in fluidized bed, the reaction kinetics of iron, nickel and cobalt, and the chlorination mechanism are carefully studied. The regulation of the related reaction rates will be established, which can promote the chlorination of nickel and cobalt and the oxydrolysis of ferrous chloride but inhibit the oxidation of pre-reduced ore, to improve selective chlorination process. And the normal and hot state continuous experiments of selective chlorination in fluidized bed are also conducted. The effects of the structures of horizontal baffle and fluidizing bed on the inhibitory of backmixing and process intensification are investigated, and then the regulation for efficient selective chlorination in fluidized bed will be established combined with the regulation of the related reaction rates. The novel method for selective chlorination-water leaching of limonitic nickel laterite with new theory will be obtained. It is hope that the present application can provide scientific support for the efficient utilization of abundant nickel laterite in the world.

为了实现褐铁矿型镍红土矿的高效利用，项目提出了预还原-流态化选择性氯化-水浸提取镍钴的创新技术路线。针对预还原矿流态化选择性氯化过程存在的关键问题，项目拟通过研究铁、镍、钴组分的流态化反应动力学行为和氯化机理，建立相关反应速率的调控机制，提高镍、钴组分的氯化和氯化亚铁的氧化水解的反应速率，抑制预还原矿物的氧化反应，从而提高选择性氯化效果；并开展冷态/热态连续实验，研究水平挡板和床型结构对抑制颗粒返混及过程强化的作用规律，结合反应速率调控机制，建立高效选择性氯化的调控机制，形成选择性氯化焙烧-浸出处理褐铁矿型镍红土矿的新理论新方法，为镍红土矿高效利用提供重要的科学理论支撑。

褐铁矿型镍红土矿是一种重要的镍钴资源，其主要矿物组成为针铁矿和赤铁矿，含铁量高(TFe≥45%)，镍钴主要以浸染形式存在于铁矿物晶格中。工业上主要采用高压酸浸(HPAL)和还原焙烧–氨浸(Caron)工艺。为了实现褐铁矿型镍红土矿的高效利用，项目提出预还原-流态化选择性氯化-水浸提取镍钴的创新技术路线。针对预还原矿流态化选择性氯化过程存在的关键问题，项目研究了预还原褐铁矿型镍红土矿铁组分在低氧分压下氧化动力学规律和氯化亚铁的氧化水解行为规律，建立铁组分反应行为的优化调控机制；研究揭示了预还原褐铁矿型红土矿在HCl-H2O-O2气氛中的选择性氯化机理，通过有效抑制氧化副反应，获得了镍钴氯化率分别为90%和89%、铁氯化率仅为3%的良好效果；研究建立选择性氯化与冷轧废酸热解反应耦合强化的流态化新工艺。研究提出以氯气为氯化剂实现镍钴选择性氯化强化的新路线，分析确定了优化反应途径，揭示了矿物氯化和氯化亚铁氧化的反应行为规律和选择性氯化机理；并研究建立了优化调控机制，形成镍红土矿预还原矿在Cl2-O2气氛流态化选择性氯化的新方法。项目研究形成了选择性氯化焙烧-浸出处理褐铁矿型镍红土矿的新理论新方法，可为镍红土矿高效利用提供重要的科学理论支撑。