镜铁矿磁化焙烧前后矿物组成与嵌布结构变化分析
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摘要
镜铁矿因为矿物组成复杂、嵌布粒度细微,是一种难选矿,因此对其细粒粉矿,采用回转窑进行磁化焙烧—磁选试验研究。试验结果表明,原矿焙烧效果良好,在细磨至-0.074 mm占85%,磁选强度为144 k A/m的工艺条件下,磁选精矿的铁品位仅为55.22%,显微镜分析结果表明,磁铁矿未充分单体解离,影响精矿铁品位。通过分析焙烧过程中含铁矿物的物相及其微观结构,表明原矿经过磁化焙烧,菱铁矿、褐铁矿及其大多镜铁矿已经转变成磁铁矿,部分磁铁矿解离发育完全,颗粒疏松多孔。但大多数磁铁矿的矿石结构沿袭原矿中的镜铁矿,嵌布特征与嵌布粒度未发生明显变化,磁铁矿的矿石构造仍旧以粗粒条带状,稠密集与稀疏侵染状为主,并呈"不等粒"形式嵌布于脉石矿物之中,部分磁铁矿嵌布粒度较细,影响后续磨矿解离。
Thanks to its complex composition and subtle disseminated extent,the specularite is a refractory iron ore. In this paper,a magnetic roasting experiment was implemented on specularite ore fines by a rotary kiln. The good roasting results had been achieved,and under the condition of grinding fineness(-0. 074 mm) of about 85% and magnetic field intensity of 144 k A/m,a concentrate with Fe grade at55. 22% was obtained. The microscope analysis results indicated insufficient magnetite discrete which affecting the Fe grade of resulting concentrate. The phase analysis and microstructure of iron-bearing minerals during the roasting process suggested that that after magnetic roasting the siderite,limonite and most of specularite had been converted to magnetite,and some magnetite was dissociative,however,the resulting magnetite mainly remained the texture of the original specularite,and the embedded characteristics and disseminated extent was not changed significantly. The most magnetite had coarse band,dense and sparse infected structure,and unevenly embedded in gangue,while the disseminated extent of some magnetite was fine,all these had a significant effect on subsequent dissociation of magnetite.
Thanks to its complex composition and subtle disseminated extent,the specularite is a refractory iron ore. In this paper,a magnetic roasting experiment was implemented on specularite ore fines by a rotary kiln. The good roasting results had been achieved,and under the condition of grinding fineness(-0. 074 mm) of about 85% and magnetic field intensity of 144 k A/m,a concentrate with Fe grade at55. 22% was obtained. The microscope analysis results indicated insufficient magnetite discrete which affecting the Fe grade of resulting concentrate. The phase analysis and microstructure of iron-bearing minerals during the roasting process suggested that that after magnetic roasting the siderite,limonite and most of specularite had been converted to magnetite,and some magnetite was dissociative,however,the resulting magnetite mainly remained the texture of the original specularite,and the embedded characteristics and disseminated extent was not changed significantly. The most magnetite had coarse band,dense and sparse infected structure,and unevenly embedded in gangue,while the disseminated extent of some magnetite was fine,all these had a significant effect on subsequent dissociation of magnetite.
引文
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[2]Zhang Zhirong,Chen Zhou,Zhou Huahui,et al.The practice of improving the quality and production of magnetization roasting of shaft furnace of the concentrating and sinter plant of JISCO[J].Ming and Metallurgical Engineering,2012,32:121-123.(张志荣,陈洲,周华辉,等.酒钢选烧厂提高磁化焙烧竖炉产质量实践[J].矿冶工程,2012,32:121-123.)
[3]Luo Liqun,Yu Yongfu,Zhang Jingshen.Flash magnetic roasting and microstructure characteristics and phase transformation of iron minerals[J].Joumal of Central South University(Science and Technology),2009,40(5):1173-1175.(罗立群,余永富,张泾生.闪速磁化焙烧及铁矿物的微观相变特征[J].中南大学学报,2009,40(5):1173-1175.)
[4]Ren Yafeng,Yu Yongfu.Present status and development orientation of magnetization roasting technology for refractory red iron ores[J].Metal Mine,2005(11):20-21.(任亚峰,余永富.难选红铁矿磁化焙烧技术现状及发展方向[J].金属矿山,2005(11):20-21.)
[5]Zhang Yimin.The separation theory and technology of solid material[M].Beijng:Metallurgical Industry Press,2007:166-167.(张一敏.固体物料分选理论与工艺[M].北京:冶金工业出版社,2007:166-167.)