云南禄劝细粒超贫赤铁—磁铁矿选矿工艺研究

【作者】 张敏；

【导师】 刘四清； 汤玉和；

【作者基本信息】 昆明理工大学 ， 矿业工程（专业学位）， 2013， 硕士

【摘要】 全球约50个国家拥有铁矿资源,铁矿分布较广,但绝大多数主要集中分布在其中的12个国家,每个国家都有自己的铁矿集中区,不同国家的铁矿资源从储量、矿床类型、铁矿类型、铁矿的贫富程度等都有较大差异,如巴西铁矿平均品位高于60%,澳大利亚铁矿平均品位在50%以上,而中国铁矿平均品位32%,一般认为品位25%以上才具有开采价值,品位低于20%的属于超贫铁矿,对贫铁矿和超贫铁矿的选矿工艺进行研究,结合我国贫矿多富矿少的铁矿资源形势,可以极大地提高我国铁矿的利用率,为铁矿的自给自足奠定基础。本课题以云南禄劝细粒超贫赤铁-磁铁矿为研究对象,原矿化学组成及基本工艺矿物学研究结果表明,矿石中主要有用矿物为赤铁矿和磁铁矿,赤铁矿含量略高于磁铁矿,主要脉石矿物为石英,有害杂质硫、磷、砷的含量极少,属于单一型铁矿；该矿石原矿含铁18.64%,属于超贫铁矿；且铁矿物呈细粒至微细粒嵌布于脉石矿物中。因此,针对该铁矿品位低和嵌布粒度细的特点和难点,展开一系列选矿试验研究,意义重大。首先对三个不同的矿样进行了“弱磁-分级-摇床重选”探索试验,并对综合矿样进行了干式磁选预先抛尾和全浮选的探索试验。干式磁选未能有效抛出尾矿；采用一粗一扫的浮选流程,寻求适宜捕收剂、抑制剂的种类和用量、磨矿细度等条件,在此基础上进一步进行浮选流程结构试验,未能获得合格铁精矿。因此,对低品位铁矿选矿的常见方法如预先抛废、浮选不适用于此铁矿石。为此,重点开展了大量的“阶段磨矿-磁选-重选”联合工艺条件试验研究,获得如下试验结果：将原矿磨矿至-200目占85%,在磁场强度13800e条件下进行弱磁粗选,弱磁选精矿再磨至-200目占95%,在磁场强度为8600e的条件下进行弱磁精选,获得弱磁选精矿铁品位50.72%,回收率38.62%；弱磁粗选尾矿经强磁抛尾后,其精矿品位与弱磁精选获得的尾矿品位均高于原矿品位,弱磁选精矿与摇床精矿混合后给入摇床重选,摇床精矿中铁得到富集,因此,最终弱磁精选精矿和摇床重选精矿精矿合并为最终精矿,其品位51.45%,回收率在62.12%。磁选和重选的联合工艺流程简单可行,为小型选矿厂建设提供了技术参考。更多还原

【Abstract】 The main iron ore resources are found in fifty countries of the world, and twelve countries account for the majority of the iron ore with large iron reserves. The characteristics of iron resources in different countries vary with different deposits, minerals, grade of raw ore and so on. For instance, the average grade of iron ores in Brail is higher than60%and iron ores assay more than50%Fe in Australia. However, the mean grade of iron ores in China is as low as32%Fe, which is regarded as lean iron ore. Moreover, iron minerals are finely disseminated in the lean ore. So it is necessary to study the beneficiation of the ores to meet the increasing demand of iron industries in China.In this research, three kinds of low grade and finely disseminated iron ore samples weighting800kg was obtained from Luquan county, Yunnan China. Through chemical analysis and mineralogical study on the samples, some conclusions about the raw ores were drawn. The valuable minerals in the ore are hematite and magnetite, and the main gangue mineral is quartz with small amount of impurity elements like S, P and As. The iron ore assays18.64%Fe, where hematite and magnetite are finely disseminated. According to above basic information, many tests on the composite iron ores were conducted.Dry magnetic separation was used for preconcentration to produce the tailings firstly, but it didn’t work. Flotation is one of the universal processes for iron ore processing, and flotation tests were employed in the preliminary study, including the investigation of the reagents and the grinding fineness by single-stage roughing and scavengering process. According to the results of the condition tests, optimized flowsheet was preliminarily determined but the marketable iron product could not be obtained. After that, tests to develop a combined flowsheet by "Stage Grinding-Magnetic Separation-Gravity Separation" were conducted. A low magnetic separator was used for roughing after primary grinding to-0.074mm85%and once cleaning after regrinding to-0.074mm95%. A high magnetic separator was used for tailings rejecting. A slime shaking table was used for reconcentration of the middings from low and high magnetic separators. The concentrates from the shaking table and the one from low magnetic separator can be merged into one as the final concentrate assaying above50% Fe with the recovery more than60%, and the other products were discarded as tailings. The whole process on the refractory iron ore is easy and economic, and provides technical basis for the further concentration of lean and finely disseminated iron ores.更多还原