低m(Cr)/m(Fe)铬铁矿除铁工艺的实验研究

以南非铬铁矿为对象,在热力学分析的基础上,采用碳热还原法开展了低m(Cr)/m(Fe)铬铁矿除铁工艺的实验研究.结果表明:实验中铬铁矿选择性除铁的适宜温度为1 100℃左右,符合热力学计算结果.低于此温度时还原出的富铁相与基体分离不彻底,难以结瘤析出;高于此温度时尖晶石相中的铬元素还原严重,影响铬的回收率.在1 100℃还原0.5 h并经酸浸处理后,铬铁矿可由化工级提升至冶金级,在相同温度下还原2 h后,m(Cr)/m(Fe)可由1.7提高至5.8,为实现低m(Cr)/m(Fe)铬铁矿的高效利用提供了新思路.

Experimental Study on Separation of Iron from Low m (Cr)/m (Fe) Chromite

Based on thermodynamic analysis， some experiments on separation of iron from low m(Cr)/m(Fe) South Africa chromite by carbothermic reduction were conducted. It was found that the separation result of iron from chromite was notably influenced by reduction temperature， and the experimental optimum reduction temperature was 1100℃. Below 1100℃， the reduction precipitation and matrix interacted by embedding.Above 1100℃， the reduction degree of chromium rose sharply， leading the recovery yield of chromium get worse. Metallurgical-grade chromite was obtained from chemical-grade chromite by 0.5h reduction at 1100℃ and an acid leaching treatment. Furthermore， the m(Cr)/ m(Fe) was elevated from 1.7 to 5.8 with only a minor loss of chromium after 2h reduction at 1100℃. The study on the separation of iron from low m(Cr)/m(Fe) chromite may provide a new idea for comprehensive utilization of chromite.