【作者】 张明；

【导师】 韩跃新； 印万忠；

【作者基本信息】 东北大学 ， 矿物加工工程， 2009， 博士

【摘要】 近年来,我国钢铁工业飞速发展,钢铁产量持续攀高,导致国内铁矿石市场呈现严重的供不应求局面,铁矿石进口量大幅度上升。“十五”期间,我国铁矿石进口量从2001年的9231万吨增加到2005年的2.75亿吨,增加了1.8亿吨；2007年、2008年我国进口铁矿石分别达到3.83亿吨和4.16亿吨,占我国铁矿石消耗量的50%以上。为保证我国钢铁工业的健康、可持续发展,国内迫切需要稳定、足量、优质的铁矿原料供给。对此,国家“十一五”规划明确提出“要积极利用低品位铁矿资源”,难选铁矿石的利用也迫在眉睫。因而,研究复杂难选铁矿的开发与利用意义重大。东鞍山铁矿石是我国典型的难选贫赤铁矿,具有品位低、嵌布粒度细、组成和结构构造复杂的特点,对其选矿技术研究从“六五”开始一直被列为国家和原冶金部的重点攻关项目。从两段连续磨矿、单一的正浮选到目前的两段连续磨矿、中矿再磨、重选—磁选—阴离子反浮选工艺流程演变看,高亚铁矿石得到利用,精矿品位也由60%提高到64.8%,但对含碳酸盐铁矿石入选适应性差的问题始终没有解决,特别是当碳酸铁矿石入选比例超过10%时浮选指标急剧恶化,直至不能分选。所以,从研究含碳酸盐铁矿石浮选行为入手,来解决东鞍山铁矿石浮选分离问题是十分必要的。本文对东鞍山含碳酸盐铁矿石工艺矿物学特性、主要矿物可浮性、浮选分离特性、浮选分离机理及浮选分离技术与工艺进行了系统研究。主要矿物可浮性研究表明,阴离子捕收剂浮选体系中淀粉和CaCl2组合,在pH为5-7的条件下,菱铁矿可浮性较好,磁铁矿、赤铁矿、石英可浮性较差；在pH>11的强碱性条件下,石英可浮性较好,磁铁矿和赤铁矿可浮性很差,矿物在不同的pH介质条件下出现较大的浮游差。主要矿物浮选分离特性及浮选分离机理研究表明,阴离子捕收剂浮选体系中,在强酸性或中性条件下,可实现含铁矿物与石英的正浮选分离；赤铁矿与石英采用反浮选工艺较易实现两者的浮选分离；菱铁矿的存在对铁矿物的浮选分离效果有很大的影响,随着菱铁矿的比例增大,精矿的富集比和选择性指数下降。由于菱铁矿在石英和赤铁矿表面吸附罩盖,使石英和赤铁矿表面性质与菱铁矿相近,导致这两种矿物呈现与菱铁矿类似的浮游性。所以,采取在pH为中性的条件下提前选出菱铁矿并消除其影响,然后在pH为强碱性的条件下浮选石英,即采用分步浮选工艺实现菱铁矿、赤铁矿、石英的分离。矿石的浮选分离工艺研究表明,东鞍山烧结厂现场混合磁选精矿的“分步浮选”实验室闭路浮选试验可获得铁品位为67.84%、回收率为69.47%的铁精矿,尾矿中铁的品位为19.15%,回收率19.14%；连续浮选试验获得了铁品位为66.37%、回收率为62.93%的铁精矿,尾矿中铁的品位为22.67%,回收率22.96%。通过第一步浮选,54.34%的菱铁矿进入菱铁矿精矿,含铁品位为38%左右的菱铁矿精矿,通过“焙烧—磁选”工艺处理,可以获得铁品位为57.80%、回收率为49.53%的铁精矿,菱铁矿精矿可以得到进一步的回收利用。本研究首次提出采用“分步浮选”工艺处理东鞍山含碳酸盐铁矿石,并取得了良好的分离效果,具有明显的创新性和实践性,本研究成果对东鞍山含碳酸盐铁矿石的高效开发与利用具有重要的指导意义。更多还原

【Abstract】 In recent year, the iron ore market of China shows a serious shortage situation and the imports of iron ore increase substantially because of the rapid development of iron and steel industry and the continuous rise of iron and steel production. In the period of Tenth Five-Year, the imports of iron ore of China were increased from 92.31Mt in 2001 to 275Mt in 2005, which increased 180Mt. The imports of iron ore of China were reached 383Mt in 2007 and 416Mt in 2008 respectively, which accounted for more than 50% of iron ore consumption of our country. In order to ensure the health and sustainable development of iron and steel industry of China, it is necessary to supply high quality iron ore with stability and enough. For this reason, it has been proposed clearly in the Eleventh Five-Year Planning that the low-grade iron ore resources should be used actively. It is also imminent to use the refractory iron ore. So, it is significant to explore and utilize the complex-refractory iron ore.The iron ore of Donganshan is classical refractory hematite in our country with the characteristics of low-grade, fine disseminated granularity and complex composition and structure. To study the technique of separating this type of iron ore is always regarded as the grand research project of our country and/or Metallurgical Department since Sixth Five-Year. Looking upon the flowsheet evolution which is changed from two-stage grinding, single direct floatation to two-stage grinding, middlings regrinding, gravity separation-magnetic separation-anionic reverse floatation which is running now, we can see that high ferrooxidans ore is utilized effectively and the concentrate grade is increased from 60% to 64.8%. But the problem of poor adaptability for separating the carbonate-containing iron ore has not been solved until now. Especially for separating the carbonate-containing iron ore which content is over 10%, the index of floatation is deteriorated rapidly, evenly, no separation is achieved. So, it is necessary to solve the separation problem of Donganshan iron ore floatation according to the floatation behaviour of carbonate-containing iron ore.The technical mineralogy characteristics, main minerals floatability, floatation separation characteristics, floatation separation mechanism and floatation technology and process of Donganshan carbonate-containing iron ore are studied systematically in this study.Studying of main minerals floatability shows that, using the combination of starch and CaCl2 as regulators in the floatation system of anionic collector, when pH is 5 to 7, the floatability of siderite is better and the floatability of magnetite, hematite or quartz is worse, but when pH is higher than 11, the floatability of quartz is better and the floatability of magnetite or hematite is worse. In different pH extent, an obvious floatation difference is appeared between different minerals.Studying of floatation separation characteristics and its mechanism shows that, in the floatation system of anionic collector, the iron minerals and quartz can be separated from each other by direct floatation in the strong acid or neutral condition, hematite and quartz can be separated from each other by reverse floatation. The existing of siderite creates a fatal impact on the floatation separation result of iron mineral. The enrichment ratio of concentrate and collective index are decreasing with the content of siderite increasing.Because siderite is adsorbed and covered on the surface of quartz and hematite, the surface properties of quartz and hematite is similar as the surface property of siderite, which leads to the similar floatability between these two minerals and siderite. So, a new flowsheet, step-floatation, is explored to separate siderite, hematite and quartz from each other, that is, siderite is separated firstly under neutral condition, so the influence of siderite can be eliminated, then, quartz is separated by floatation under strong alkaline condition.Studying on the floatation process shows that, using step-floatation to treat the mixed magnetic concentrate of Donganshan beneficiation plant, the result of the laboratory closed-circuit experiment can be obtained with concentrate grade 67.84%, recovery 69.47%, and tailings grade 19.15%, recovery 19.14%. The result of continuous floatation experiment can be obtained with concentrate grade 66.37%, recovery 62.93%, and tailings grade 22.67%, recovery 22.96%. By first step floatation, about 54.34% siderite in raw material is concentrated to the rougher concentrate which grade is about 38%. The rougher concentrate is treated by roasting-magnetic separation and the final concentrate with grade 57.80% and recovery 49.53% can be obtained. Thus, the final concentrate of siderite can be utilized further.In this study, a new flowsheet, step-floatation, to process Donganshan carbonate-containing iron ore is explored firstly, and a good separation result can be obtained using this new flowsheet, which has obvious innovation and practice. This research result has a great guiding significance for the exploitation and utilization of Donganshan carbonate-containing iron ore.更多还原