白云鄂博西矿含铁岩选矿工艺试验研究

为实现白云鄂博西矿TFe品位13%~16%铁素资源(含铁岩)的回收利用,本文以含铁岩为研究对象,通过采用化学分析、X射线衍射仪、光学显微镜等检测手段研究其矿石性质,并在此基础上进行系统的选矿试验。研究结果表明:该含铁岩中TFe品位13.14%,可回收的主要金属矿物为磁铁矿,占全铁比例为52.28%。含铁岩需破碎至−3 mm时才能获得TFe品位20%以上的预选粗精矿,且通过阶段破碎-分级预选流程试验可获得尾矿抛除产率56.01%、粗精矿TFe品位20.62%、磁性铁品位14.80%、TFe回收率69.19%、磁性铁回收率94.27%的技术指标,推荐采用三段破碎-两级预选-高压辊磨超细碎抛尾的原则流程作为预选技术改造方案。将预选粗精矿细磨至−0.045 mm含量85.80%时,经过两次弱磁选后最终获得TFe品位65.10%、TFe回收率50.25%、磁性铁回收率93.03%的合格铁精矿。该研究结果可为含铁岩的高效回收利用提供科学依据。

Reaction characteristics of carbon-bearing pellets of Bayan Obo lean iron ores in a static magnetic field

The use of low-grade,refractory and composite paragenetic mineral resources is necessary for overcoming the shortage of iron ore resources in China.As a solution to the treatment of such iron ores,the direct reduction of carbon-bearing pellets can ensure complete iron removal and the effective enrichment of other high-value elements.Thus,this technology enjoys a broad application prospect.However,there are several problems with low-temperature reduction,such as low iron ore reaction efficiency,long reaction time,and high energy consumption.To improve the low-temperature carbothermic reduction efficiency of iron ores,a static magnetic field with magnetic induction intensity of 1.0 T was introduced.An isothermal reduction experiment was conducted at 1223 K to study the low-temperature self-reduction characteristics of carbon-bearing pellets of Bayan Obo lean iron ores in the static magnetic field.Also,the acting mechanism of the magnetic field was explored from the perspective of the reduction process,reaction efficiency,phase composition,microstructure changes,and dynamic behavior of iron ores.The results showed that the magnetic field can increase the low-temperature reduction rate of carbon-bearing pellets of Bayan Obo lean iron ores.Under the conditions of reduction temperature of 1223 K,magnetic induction intensity of 1.0 T,and reduction time of 60 min,the reduction degree was 92.42%,1.65 times that without a magnetic field.The magnetic field promoted the replacement of Ca^(2+)and Fe^(2+),so that the hard-to-reduce iron-bearing silicates were reduced in the order of Fe2SiO_(4)→(Ca,Na)FeSiO_(4)→FeO→Fe.The magnetic field enabled loose minerals,more pores and cracks,and changes in the growth morphology and distribution position of metallic iron.Compared with the case under the non-magnetic condition,the metallic iron precipitated from the slag phase in a foliated shape,separated from the matrix iron oxides,and grew up at the junction of the slag phase and coke.The magnetic field significantly increased the interfacial chemical reaction rate of the carbothermic reduction of iron ores and reduced the internal diffusion resistance of gas in the product layer.Specifically,the interfacial chemical reaction rate increased by 138%and the internal diffusion coefficient increased by 309%.Therefore,the effect of the magnetic field on the internal diffusion resistance was the main cause for strengthening the low-temperature reduction of iron ores.

安益贫铁矿矿区钻孔波速试验研究

结合野外地质调查和钻孔岩心资料,在安益贫铁矿矿区选取5个钻孔,采用单孔波速法对各钻孔不同层位岩石进行波速试验;通过采集的纵波和横波试验数据计算各种类型岩石的动泊松比以及动弹性模量。得出如下结论 :粉砂质、钙质泥岩波速值小,底砾岩波速值较小,绢云绿泥千枚岩波速值中等,钛磁铁二长闪辉岩、含二长钛磁铁单辉岩、闪辉二长岩、显微闪长岩波速值较大,绢云板岩及石英岩波速值大。

Digital Mine Research and Practice Based on Mining and Metallurgy System Engineering

Iron ore is necessarily basic raw material for industrialization and urbanization and related to the industrial distribution and development programming.The lean iron ore resource in our country is high-cost and low-efficiency,which cannot meet the demand of iron and steel industry,and even endanger the safety of industrial economy.Ansteel mining has created "grade decisionbased multi-system integration" mode of mining and metallurgy system engineering and realized scale and efficient development of lean iron ore on basis of the construction of digital mines.Moreover,the "wisdom mines" was proposed and had led to the transformation and upgrading of iron developments.