关键词: 铬铁矿, 分级, 脱泥, 摇床重选, 高梯度强磁选, 磁重联合工艺

Abstract: There is 8.51% Cr₂O₃ in a low-grade chromite ore in Yunnan Province.Chromium mainly distributed in 0.020~0.12 mm size fraction，with distribution rate of 83.79%，while for +0.12 mm is 6.55%，and 9.67% distributed in -0.02 mm.Aiming at chromium distribution rate both in coarse and fine fraction is low，preseparation process using classification-desliming by hydrocyclones was conducted，grit with Cr₂O₃ grade of 18.52% and recovery rate of 84.61% was obtained.To provide reasonably basis for beneficiation of grit，contrast test was done by single gravity separation，single high gradient high intensity magnetic separation and magnetic-gravity combined separation process.The results show that via single high intensity gravity separation process，chromium concentrate with Cr₂O₃ grade of 40.56% and recovery rate of 72.71% was obtained；via single high gradient high intensity magnetic separation process，chromium concentrate with Cr₂O₃ grade of 38.93%(unable to reach standards of 40%) and recovery rate of 55.83% was obtained；via magnetic-gravity combined separation process，chromium concentrate with Cr₂O₃ grade of 45.29% and recovery rate of 73.38% was obtained.Finally，the combined process of classification-desliming-high gradient high intensity magnetic separation-shaking table gravity separation process was conducted，effective recovery of chromium resources was realized.

Key words: Chromite, Classification, Desliming, Gravity separation by shaking-table, High gradient high intensity magnetic separation, Magnetic-gravity combined process