Upgrading nickel grade in low-grade nickeliferous laterite ores before metallurgical extraction process is of utmost importance. However, most of nickel exists mainly in the form of isomorphism in serpentine or goethite, resulting in difficulty in upgrading of nickel by physical separation methods. In this paper, spinel ferrite transformation for enhanced upgrading nickel grade in laterite ore of various types was proposed. The mineral phase transformation and migration of valuable metals for various laterite ores during calcination process was investigated, as well the influences of mineral phases and chemical compositions on magnetic properties, separation efficiency, and nickel contents in separated laterite ore. The results show that spinel nickel ferrite mainly composed of nickel oxide and iron oxide could be completely formed after calcined at 800, 1000 and 900 °C for limonite, saprolite and transition laterite ore, respectively. With the increase of calcination temperature, the crystallinity and saturation magnetization Ms value of as-calcined samples become improved, leading to increased nickel recovery, while the nickel content in magnetic fraction is first increased and then slightly decreased. Under the optimum calcination conditions, the nickel recovery for limonite, saprolite and transition laterite ore could reach 68.5%, 68.9% and 67.3%, respectively, while the nickel contents in magnetic fraction are 3.01%, 3.23% and 3.15% with increasing by 1.82, 2.27 and 2.11 times, respectively. This paper could provide theoretical basis and technology support for enhanced upgrading of valuable metals from complex associated mineral resources.

在冶金提取过程之前，在低品位含镍红土矿石中升级镍品位至关重要。然而，大多数镍主要以同晶形式存在于蛇纹石或针铁矿中，导致通过物理分离方法难以提纯镍。本文提出了尖晶石铁素体相变以增强各种类型红土矿中镍品位的提高。研究了各种红土矿石在煅烧过程中矿物相的转化和有价值金属的迁移，以及矿物相和化学成分对分离的红土矿石中磁性，分离效率和镍含量的影响。结果表明，褐铁矿，腐泥土和过渡红土矿分别在800、1000和900℃煅烧后，可以完全形成主要由氧化镍和氧化铁组成的尖晶石镍铁素体。随着煅烧温度的升高，煅烧样品的结晶度和饱和磁化强度Ms值得到改善，从而导致镍回收率提高，而磁性部分中的镍含量先增加然后略有下降。在最佳煅烧条件下，褐铁矿，腐泥土和过渡性红土矿的镍回收率分别达到68.5％，68.9％和67.3％，而磁性部分中的镍含量分别为3.01％，3.23％和3.15％，增加了1.82％。 ，分别为2.27和2.11倍。