鞍山式贫赤铁矿不同种类分选尾矿中铁的赋存规律

Study of the occurrence law of iron in different types of sorting tailings of Anshan-type low-grade hematite

以齐大山铁矿选矿分厂铁尾矿为例,对重选尾矿、磁选尾矿、浮选尾矿和综合尾矿4种不同种类尾矿的工艺矿物学性质进行对比分析,并对尾矿中铁的可回收性进行评价.研究结果表明,尾矿中铁矿物主要为赤铁矿,脉石矿物主要是石英,有害元素S、P的含量低;尾矿中铁的金属分布率随着粒级的变化,呈两端高、中间低的规律.重选尾矿中铁矿物主要包裹在粗颗粒脉石中,浮选尾矿中铁矿物主要赋存在细颗粒连生体中,磁选尾矿中的铁矿物粒度极细,综合尾矿粒度范围宽、粒度分布极不均匀.采用单一重选和磁选方法对不同种类尾矿进行再选,浮选尾矿指标最佳,重选尾矿次之,综合尾矿最差,磁选尾矿属于不可选.鞍山式贫赤铁矿分选尾矿中铁的赋存状态决定了铁的再回收潜力,可为此类分选尾矿的处理提供理论借鉴.

Anshan-type low-grade hematite ore is one of the most important types of iron ore in China.It is usually separated by a combined process of gravity concentration-magnetic separation-reverse flotation.However,the tailings produced by different separation operations have different properties,and a large amount of the residual iron in the minerals cannot be recovered effectively;therefore,mixing these tailings is unscientific for most concentrators.Given this situation,this paper takes the iron tailings of the Qidashan iron ore dressing plant as an example to make a comparative analysis of the technological mineralogy of four types of tailings(i.e.,gravity tailings,magnetic tailings,flotation tailings,and mixed tailings)and evaluate the recoverability of iron in these tailings.The results show that the main iron and gangue minerals are hematite and quartz,respectively.The content of harmful elements S and P is low in the tailings.In addition,the metal distribution rate of iron in the tailings varies with the size,showing a rule of high at both ends and low in the middle.It is also found that iron minerals are mainly wrapped in coarse gangue,and iron minerals in the flotation tailings are mainly contained in fine-grained conglomerates.Although the iron minerals in the magnetic separation tailings are extremely fine,mixed tailings have a wide range of particle sizes and extremely uneven distribution.Single gravity separation and magnetic separation methods are used to reconcentrate different types of tailings,and the best index is found to exist in flotation tailings,followed by gravity tailings,and that of mixed tailings is the worst.However,recovering iron from magnetic tailings is pointless.The mineralogical characteristics of Anshan-type hematite ore tailing underlies its recovery potential of iron and provides a reference for the retreatment of similar iron ore tailings.