褐铁型红土镍矿矿相重构常压选择性提取镍钴新技术基础

Limonitic laterite ores are the dominant nickel-cobalt bearing mineral resources and also most commonly presented as important iron and chromium accompanying resources,nevertheless, their potential value has not been fully utilized until now. However, the traditional laterite treatments suffer from many predicaments,such as low resource utilization, high energy consumption, superabundant ancillary equipments, large initial costs and heavy environmental pollution. Considering the above situation, the applicant develops a novel technology system, namely mineralogical phase recombination - selective atmospheric pressure leaching nickel and cobalt - magnetizing roasting - magnetic separation for beneficiating and separating iron and chromium. This study concerns the critical scientific foudations for the key processes, mineralogical phase recombination and nickel-cobalt extraction, of this novel technology: 1) mineralogical interfacial property, lattice breaking and dynamical controlling mechanisims of mineralogical phase recombination, and 2) influences of recombined mineral characteristics on selective leaching of nickel and cobalt as well as controllable leaching of iron. The systematic study on transfer and transformation of the targeting elements druing the phase recombination and selective extraction will help to found the theoretical basis of effectively selective extracting nickel-cobalt and controllable extracting iron, and develop the foundations of nickel, cobalt, iron and chromium separation, beneficiation and utilization, gradually. In addition, it will also help to build an advanced and economical novel technical model for limonitic laterite ores with comprehensive utilizing of associated valuable elements including iron and chromium on the basis of effective extraction of nickel-cobalt.

褐铁型红土镍矿是主要的镍、钴矿产资源，同时也是重要的铁、铬伴生资源，但其潜在价值一直未被充分利用。鉴于处理红土镍矿的传统工艺存在资源利用率低、能耗高、配套设施多、投资大和环境污染重等问题，申请者提出了矿相重构－常压选择性浸出镍/钴－磁化焙烧－磁选富集分离铁/铬新技术体系。本项目就该新技术的核心工序--矿相重构和常压选择性浸出镍/钴的关键科学问题：①矿相重构过程的矿物界面性质、矿物结构破坏机制及动力学调控机理；②重构矿物特性对镍、钴选择性浸出的影响机理及铁的可控性浸出机制进行重点研究。通过揭示褐铁型红土镍矿中有价组元在矿相重构、选择性浸出过程的迁移/转化规律，建立镍、钴高效选择性浸出和铁的可控性浸出理论基础，逐步完善镍、钴、铁、铬分离、富集与利用的理论体系，构建出技术先进、经济合理的褐铁型红土镍矿综合利用新技术原型，实现镍、钴高效浸出和伴生有价元素铁、铬的综合利用。

褐铁型红土镍矿是主要的镍、钴矿产资源，同时也是重要的铁、铬伴生资源，但其潜在价值一直未被充分利用。鉴于处理红土镍矿的传统工艺存在资源利用率低、能耗高、配套设施多、投资大和环境污染重等问题，申请者提出了矿相重构－常压选择性浸出镍/钴－磁化焙烧－磁选富集分离铁/铬新技术体系。.本项目就该新技术的核心工序——褐铁型红土镍矿活化过程矿相转化常压选择性浸出镍/钴的关键科学问题展开系统研究。研究结果表明：（1）实验用褐铁型红土镍矿的主要组成矿物为铁的氧化物/氢氧化物,占比大于80%，且约91%的镍和56%的钴赋存于这些铁氧化物/氢氧化物中，其余镍和钴分布于脉石矿物和粘土矿物中；（2）活化处理可较易破坏镍、钴负载矿物的晶体结构，从而使其中的镍、钴解离，已解离的镍、钴可以由内向外迁移并暴露于反应相界面。在活化过程的优化条件下，目标元素镍、钴、铁生成新的矿相，分别为可溶性的NiSO4、CoSO4及难溶的Fe(OH)SO4和Fe2O3，有助于目标金属的选择性分离；（3）对比实验表明，与直接浸出相比活化预处理后镍、钴浸出率可分别从65.3%和79.3%增加到85.3%和93.9%，而铁的溶出率却从12.8%降低到2.4%。约15%的镍和6%的钴无法从原矿物中解离或重新进入新生矿相晶格导致这部分金属成惰性，阻碍了其进一步浸出；（4）褐铁型氧化镍矿较低温活化反应过程可用Avrami-Erofeev方程很好的拟合（R=0.993），受固膜内扩散控制。在本研究实验条件下，活化预处理过程反应宏观动力学方程为：.ln(－ln(1－α))＝0.34×ln t－7.33×103/RT + 0.46，.其表观活化能为7.33 kJ/mol。.通过揭示褐铁型红土镍矿中有价组元在矿相重构、选择性浸出过程的迁移/转化规律，建立了镍、钴高效选择性浸出和铁的可控性浸出理论基础，丰富了镍、钴、铁、铬分离、富集与利用的理论体系，构建出了技术先进、经济合理的褐铁型红土镍矿综合利用新技术原型，实现了镍、钴高效浸出和伴生有价元素铁、铬的综合利用。