高压辊磨预处理强化巴西镜铁矿球团

Improvement in pelletization of Brazilian specularite by high-pressure roller grinding

  • 摘要: 采用高压辊磨技术预处理镜铁矿,对强化其球团工艺及机理进行了研究.扫描电镜观测证实,通过优化高压辊磨闭路流程的循环负荷,巴西镜铁矿的表面形状及比表面积得到改善,成球性得到明显提高.以70%镜铁矿配加30%磁铁矿为原料,采用71%高压辊磨产品返回方式处理后,在添加2.4%的膨润土、造球时间15 min及造球水分8%的条件下,生球各指标与同配比未经高压辊磨处理的相比均有大幅度提高,其0.5 m落下强度达到4.5次,单球抗压强度10.25 N,爆裂温度455℃;生球在预热温度1 050℃、预热时间10 min,焙烧温度1 280℃、焙烧时间12 min的条件下焙烧,成品球单球抗压强度达到2 690.88 N,满足球团生产的要求.

     

    Abstract: The processing and mechanism of the improvement in pelletization of Brazilian specularite by high-pressure roller grinding (HPRG) were investigated. SEM observations show that after being pretreated by HPRG in a closed flow path at an optimized cyclic loading, the specific surface area of Brazilian specularite increases greatly and its ballability is dramatically improved. The pellet feed composed of 70% specularite and 30% magnetite was pretreated by HPRG at 71%-product cyclic loading in a closed flow path, mixed with 2.4% bentonite and balled for 15 min under the 8% moisture. Experimental results show that all indexes of green pellets are much higher than those of the pellets made of the same feed without the pretreating. The drop number is up to 4.5 times from the 0.5m height, the compression strength is 10.25 N per pellet, and the thermal shock temperature is 455℃. The compression strength of fired pellets was tested up to 2690.88 N per pellet by preheating at 1050℃ for 10 min and by roasting at 1280℃ for 12 min, which meets the demand of strength for commercial pellets.

     

/

返回文章
返回