ABSTRACT

Polymetallic nodules and nickel laterite ores are composed of various valuable metals and have similar nickel concentration, which makes them ideal alternatives for industries seeking to meet the increasing demand for nickel resources. The extraction process of polymetallic nodules can utilize the well-established nickel laterite treatment process without the need for developing new processes and thus, save capital costs. Herein, to efficiently extract nickel from these resources, high-temperature carbothermic reduction and sulfurization were investigated by optimizing the slag and matte systems. FactSage, a thermodynamic software was used to predict the slag system’s liquidus temperature and the formation of nickel matte. It was found that nickel matte formation was not dependent on CaSO₄ addition whereas the nickel concentration in matte decreased with an increasing amount of the sulfiding agent FeS. Furthermore, the addition of a reductant significantly affected the concentration of nickel in the matte. A nickel concentration of ≥30 wt% and iron concentration of ≤40 wt% in matte were achieved by adding 0.5 wt% and 3 wt% carbon to nickel laterite ores and polymetallic nodules, respectively. Furthermore, replacing the sulfiding agent FeS with CaSO₄ during the smelting of polymetallic nodules decreased the iron concentration in matte ≤15 wt% and increased the nickel concentration ≥50 wt%. Thus, this study confirmed the possibility of matte formation with high nickel concentration and low iron content by utilizing alternative nickel resources at 1350–1450°C.

摘要

多金属结核和镍红土矿石由各种有价值的金属组成，并且镍含量相似，这使其成为寻求满足对镍资源日益增长的需求的行业的理想替代品。多金属结核的提取工艺可以利用成熟的红土镍处理工艺，无需开发新工艺，从而节省资金成本。在此，为了有效地从这些资源中提取镍，通过优化炉渣和锍系统来研究高温碳热还原和硫化。FactSage 是一种热力学软件，用于预测炉渣系统的液相线温度和镍锍的形成。发现镍锍的形成不依赖于CaSO ₄而锍中的镍浓度随着硫化剂 FeS 量的增加而降低。此外，还原剂的添加显着影响锍中镍的浓度。通过分别向镍红土矿石和多金属结核中添加 0.5 wt% 和 3 wt% 的碳，可实现锍中 ≥ 30 wt% 的镍浓度和≤40 wt% 的铁浓度。此外，在多金属结核冶炼过程中，用 CaSO ₄代替硫化剂 FeS降低了锍中的铁浓度≤15 wt%，提高了镍浓度≥50 wt%。因此，本研究证实了通过在 1350–1450°C 下利用替代镍资源形成高镍浓度和低铁含量的锍的可能性。