The method of producing ferronickel at low temperature (1250–1400°C) has been applied since the 1950s at Nippon Yakin Kogyo, Oheyama Works, Japan. Limestone was used as an additive to adjust the slag composition for lowering the slag melting point. The ferronickel product was recovered by means of a magnetic separator from semi-molten slag and metal after water quenching. To increase the efficiency of magnetic separation, a large particle size of ferronickel is desired. Therefore, in this study, the influences of CaO, CaF₂, and H₃BO₃ additives on the evolution of ferronickel particle at ≤1250°C were investigated. The experiments were conducted at 900–1250°C with the addition of CaO, CaF₂, and H₃BO₃. The reduction processes were carried out in a horizontal tube furnace for 2 h under argon atmosphere. At 1250°C, with the CaO addition of 10wt% of the ore weight, ferronickel particles with size of 20 µm were obtained. The ferronickel particle size increased to 165 µm by adding 10wt% CaO and 10wt% CaF₂. The addition of boric acid further increased the ferronickel particle size to 376 µm, as shown by the experiments with the addition of 10wt% CaO, 10wt% CaF₂, and 10wt% H₃BO₃.

自1950年代以来，在日本Oheyama Works的Nippon Yakin Kogyo一直采用低温（1250-1400°C）生产镍铁的方法。石灰石用作添加剂以调节炉渣成分以降低炉渣熔点。水淬后，通过磁选机从半熔融的炉渣和金属中回收镍铁产品。为了提高磁性分离的效率，需要大粒径的镍铁。因此，在本研究中，研究了CaO，CaF ₂和H ₃ BO ₃添加剂对≤1250°C的镍铁颗粒演变的影响。实验是在900–1250°C的温度下进行的，添加了CaO，CaF ₂和H ₃ BO₃。还原过程在氩气气氛下在水平管式炉中进行2 h。在1250℃下，通过添加占矿石重量的10wt％的CaO，获得尺寸为20μm的镍铁颗粒。通过添加10wt％的CaO和10wt％的CaF ₂，镍铁颗粒尺寸增加到165μm 。如通过添加10wt％的CaO，10wt％的CaF ₂和10wt％的H ₃ BO ₃的实验所示，添加硼酸进一步将镍铁的粒径增加到376μm 。