Coal-based direct reduction of nickel slag and magnetic separation of iron are effective methods of secondary resource utilization. The growth characteristics of metallic iron particles in this process are of great significance for subsequent grinding and magnetic separation process. The nickel slag is mixed with coal powder and other additives in a certain proportion, and then subjected to a direct reduction experiment in a high-temperature furnace. Chemical analysis is made to obtain the components of the direct reduction product. The microstructure of the metallic iron particles in the reduction product was studied and the curves of average diameter change and the cumulative diameter percentage of the iron particles are obtained in the reduction process. The results show that the coal-based direct reduction technology can effectively reduce the iron oxides in the nickel slag, and the degree of metallization of the product can reach 91.89 pct. When the reduction time is increased from 10 to 60 minutes, the maximum size of metallic iron particles increases from 13 to 135 μ m. The control mechanism of iron particle growth is complicated, and the process is divided into two stages. The growth kinetic parameters (kinetics index, activation energy, and pre-exponential factor) in the two stages are 0.4697, 249.04 kJ mol −1 , 3.81 × 10 8 and 1.0774, 92.93 kJ mol −1 , 217.30, respectively. The growth model of metallic iron particles in the direct reduction of nickel slag is also constructed in the paper.

中文翻译：

---

镍渣直接还原中金属铁颗粒的生长特性

煤基直接还原镍渣和磁选铁是资源二次利用的有效方法。该过程中金属铁颗粒的生长特性对后续的磨矿和磁选过程具有重要意义。镍渣与煤粉和其他添加剂按一定比例混合，然后在高温炉中进行直接还原实验。进行化学分析以获得直接还原产物的组分。研究了还原产物中金属铁颗粒的微观结构，得到了还原过程中铁颗粒的平均直径变化曲线和累积直径百分比曲线。结果表明，煤基直接还原技术可有效还原镍渣中的氧化铁，产品金属化程度可达91.89%。当还原时间从 10 分钟增加到 60 分钟时，金属铁颗粒的最大尺寸从 13 微米增加到 135 微米。铁颗粒生长的控制机制复杂，过程分为两个阶段。两个阶段的生长动力学参数（动力学指数、活化能和指前因子）分别为0.4697、249.04 kJ mol -1 、3.81×10 8 和1.0774、92.93 kJ mol -1 、217.30。文中还建立了镍渣直接还原过程中金属铁颗粒的生长模型。当还原时间从 10 分钟增加到 60 分钟时，金属铁颗粒的最大尺寸从 13 微米增加到 135 微米。铁颗粒生长的控制机制复杂，过程分为两个阶段。两个阶段的生长动力学参数（动力学指数、活化能和指前因子）分别为0.4697、249.04 kJ mol -1 、3.81×10 8 和1.0774、92.93 kJ mol -1 、217.30。文中还建立了镍渣直接还原过程中金属铁颗粒的生长模型。当还原时间从 10 分钟增加到 60 分钟时，金属铁颗粒的最大尺寸从 13 微米增加到 135 微米。铁颗粒生长的控制机制复杂，过程分为两个阶段。两个阶段的生长动力学参数（动力学指数、活化能和指前因子）分别为0.4697、249.04 kJ mol -1 、3.81×10 8 和1.0774、92.93 kJ mol -1 、217.30。文中还建立了镍渣直接还原过程中金属铁颗粒的生长模型。两个阶段的活化能和指前因子）分别为 0.4697、249.04 kJ mol -1 、3.81 × 10 8 和 1.0774、92.93 kJ mol -1 、217.30。文中还建立了镍渣直接还原过程中金属铁颗粒的生长模型。两个阶段的活化能和指前因子）分别为 0.4697、249.04 kJ mol -1 、3.81 × 10 8 和 1.0774、92.93 kJ mol -1 、217.30。文中还建立了镍渣直接还原过程中金属铁颗粒的生长模型。