破碎方式对贫磁铁矿预选效率和磨矿特性的影响

对贫磁铁矿进行高压辊磨破碎和传统颚式破碎, 对比研究了不同破碎工艺对破碎产物预选分离指标和磨矿特性的影响。结果表明, 与传统颚式破碎相比, 高压辊磨的破碎比(F₈₀/P₈₀)高31.52%, 产物中-0.074 mm粒级含量高8.46个百分点；干式抛尾精矿全铁品位高2.66个百分点, 全铁回收率和磁性铁回收率分别高4.54和4.47个百分点。在-0.074 mm粒级占85%的磨矿细度下, 高压辊磨产物与传统破碎产物的相对可磨度为1.24, 高压辊磨产物在磨矿过程中细粒级的生成速率比传统破碎快；高压辊磨破碎产物表面产生的微裂纹比传统破碎多, 这是高压辊磨能提高破碎产物预选分离指标和可磨性的主要因素。

Effect of Crushing Methods on Preconcentration Efficiency and Grinding Characteristics of Lean Magnetite Ore

High pressure grinding roller (HPGR) and conventional jaw crusher (JC) were introduced to crush a low-grade magnetite ore and the influence of crushing processes on preconcentration index and grinding characteristics of crushed products were comparatively studied. Results show that, compared to JC, the reduction ratio (F₈₀/P₈₀) of HPGR increased by 31.52%, and the -0.074 mm size fraction in HPGR product increased by 8.46 percentage points. After dry magnetic separation was used to discard tailings of HPGR and JC products, the TFe grade of concentrate was improved by 2.66 percentage points, while the TFe recovery and the recovery of magnetic iron were respectively improved by 4.54 and 4.47 percentage points. With a grinding fineness of -0.074 mm 85%, the relative grindability of HPGR and JC products is 1.24. Fine fraction of product with more micro-cracks can be more quickly generated in the crushing process with HPGR, compared to JC, which could contribute to an improvement in the preconcentration index and grindability of crushed product by HPGR.