开江—梁平海槽西侧飞仙关组不同类型鲕滩储层特征及其控制因素研究

针对开江—梁平海槽西侧飞仙关组鲕滩储层特征及主控因素存在较大差异的问题,基于鲕滩沉积演化规律，结合物性与地球化学分析，对开江—梁平海槽西侧飞仙关组鲕滩储层进行了研究。结果表明:伴随区内飞仙关期高能坡折带不断迁移，对应形成三期鲕滩，发育鲕粒云岩和鲕粒灰岩2类储层，物性及孔隙结构以鲕粒云岩型储层最优，次为鲕粒灰岩型储层。在鲕滩沉积的物质基础上，轻度蒸发海水诱发的回流渗透叠加深部热液白云石化作用共同控制鲕粒云岩型储层的形成，而有机酸主导的埋藏期保孔-扩孔作用既进一步改善先期形成的鲕粒云岩型储层，又影响了鲕粒灰岩型储层的形成。该研究对鲕滩储层的差异性成储机理相关研究有很好的借鉴意义。     

河南某鲕状赤铁矿石工艺矿物学研究

河南某鲕状赤铁矿石铁品位为52.50%,铁主要以赤铁矿形式存在,分布率为75.37%。矿石中主要矿物为赤铁矿、伊利石及菱磷铝锶矾。为给矿石合理开发利用提供参考,对其进行了工艺矿物学研究。结果表明:赤铁矿常呈椭圆形鲕粒,细粒或隐晶状赤铁矿集合体与脉石矿物呈椭圆状的包复颗粒由核心和同心状外壳聚集而成,鲕粒中各成分相互混杂,局部赤铁矿聚集;部分赤铁矿呈他形粒状单体或集合体不均匀分布;偶见赤铁矿呈隐晶状胶结物分布于砂屑粒间;赤铁矿嵌布粒度微细,0.037~0.003 mm粒级占87.17%。采用传统选矿方法处理该矿石难以取得理想的指标。推荐采用深度(直接)还原工艺将微细粒弱磁性铁矿物转变为可通过弱磁选分离的磁铁矿或金属铁,再通过磁选分离。     

东鞍山某鲕状赤铁矿石悬浮焙烧试验

东鞍山某鲕状赤铁矿石铁品位为44.53%、P2O5含量为2.25%。矿石中赤铁矿主要以鲕状集合体形式存在,嵌布粒度微细,属难选矿石,采用传统选矿工艺难以获得理想的选别指标。为给该矿石合理开发利用提供依据,进行了悬浮焙烧—磁选试验。结果表明:在给矿细度为-0.074 mm占75%、总气流量为8 m~3/h、H2浓度为40%、焙烧温度为650℃、焙烧时间为75 s条件下进行悬浮焙烧,焙烧产品磨细至-0.074 mm占95%,在磁场强度为85.1k A/m条件下磁选,获得了铁品位为56.73%、回收率为83.96%、磷含量为0.78%的铁精矿,该精矿磷含量较高,还需进一步进行降磷研究。试验结果为我国鲕状赤铁矿石的开发利用提供了参考。     

高硅鲕状赤铁矿阶段磨矿阶段磁选提铁降硅试验

中东某鲕状赤铁矿石铁品位为47.44%，铁主要以磁性铁的形式存在，铁在磁性铁中分布率为60.26%。为给该矿石开发利用提供依据，采用阶段磨矿阶段磁选的方法进行了试验研究。结果表明：一段磨矿细度-0.074 mm含量80.8%，一段磁选磁场强度0.12 T，二段磨矿细度-0.074 mm含量93.3%，二段磁选磁场强度0.8 T，三段磨矿细度-0.074 mm含量95.2%，三段磁选磁场强度0.4 T，可以得到铁品位61.02%、回收率53.25%的精矿。有效实现了铁与杂质矿物的分离与富集。     

湖北某难选鲕状赤铁矿还原焙烧-磁选试验

简介了湖北某难选鲕状赤铁矿的工艺矿物学特征,对该矿石还原焙烧的合适温度、还原剂用量、焙烧时间以及磁选的合适场强进行了试验研究。研究表明,铁品位为47.57%的鲕状赤铁矿在焙烧温度为850 ℃、碳粉用量为25%、焙烧时间为60 min、冷淬后磨矿细度为-0.074 mm占85%、磁选场强为127.39 kA/m情况下,能获得铁品位为56.75%、回收率为79.96%的铁精矿产品。     

A composite sphere assemblage model for porous oolitic rocks: Application to thermal conductivity

The present work is devoted to the determination of linear effective thermal conductivity of porous rocks characterized by an assemblage of grains (oolites) coated by a matrix. Two distinct classes of pores, i.e. micropores or intra oolitic pores (oolite porosity) and mesopores or inter oolitic pores (inter oolite porosity), are taken into account. The overall porosity is supposed to be connected and decomposed into oolite porosity and matrix porosity. Within the framework of Hashin composite sphere assemblage (CSA) models, a two-step homogenization method is developed. At the first homogenization step, pores are assembled into two layers by using self-consistent scheme (SCS). At the second step, the two porous layers constituting the oolites and the matrix are assembled by using generalized self-consistent scheme (GSCS) and referred to as three-phase model. Numerical results are presented for data representative of a porous oolitic limestone. It is shown that the influence of porosity on the overall thermal conductivity of such materials may be significant.     

某鲕状赤铁矿循环流化床焙烧-磁选试验研究

采用实验室循环流化床装置，以CO与N2的混合气体和电加热方式模拟燃煤还原焙烧气氛，对铁品位为47.20%的鄂西某鲕状赤铁矿进行磁化焙烧-弱磁选试验，结果表明，在合适的焙烧温度、焙烧时间、焙烧气氛、气体流量、磁场强度及-325目占80%的最终磨矿细度下，经过循环流化床焙烧-阶段磨矿-一粗一精两段弱磁选，可获得精矿铁品位为56.60%，对焙烧矿铁回收率为77.79 %的较好选别指标。     

辽宁野猪沟铁矿石工艺矿物学研究

系统地研究了辽宁野猪沟铁矿石的化学组成、矿物组成及嵌布特征。结果表明：矿石以鲕状构造为主，具有典型的同心环带结构。矿石中铁、锰矿物主要以粉末状和致密块状两种状态存在。粉末状赤铁矿、褐铁矿、氧化锰多形成松散的土状集合体，致密块状的赤铁矿则分布于石英砂粒周围；磁铁矿多包裹石英砂粒。矿石的上述特性造成有用矿物难以单体解离并易于泥化，因而使矿石难选。     

难选鲕状赤铁矿复合药剂制度脱泥试验研究

分析了鲕状赤铁矿大多由于嵌布粒度细、不均匀,且有用矿物和脉石矿物间的物理化学性质差异不十分明显,常规的重选、磁选、浮选等工艺或重磁浮联合工艺已无法有效地分选出超细粒嵌布矿物的有价成分。研究通过复合药剂联合使用,采用选择性絮凝-反浮选工艺,矿石铁品位从47.85%提高到54.63%,回收率达到82.49%。红外光谱和扫描电镜检测显示,复合药剂制度选择性絮凝-反浮选对于鲕状赤铁矿是一种有效的脱泥方式。     

Reduction behaviour of apatite in oolitic haematite ore using coal as a reductant

An oolitic haematite ore containing 1.31% P was reduced in the presence of coal at temperatures ranging from 1473 to 1548?K. The reduction behaviour of apatite, which is the only P-containing mineral in the ore, was studied at different reduction conditions based on the thermodynamic analysis. Thermodynamic calculation showed that the SiO₂, Al₂O₃ or SiO₂–Al₂O₃ could decrease the standard Gibbs free energy and initial temperature of the apatite reduction significantly. The initial temperature of the apatite reduction decreased from above 1650?K to 1497, 1541 and 1419?K in the presence of SiO₂, Al₂O₃ and SiO₂–Al₂O₃, respectively. Experimental results indicated that the reduction conditions obviously affected the reduction behaviour of apatite. A higher reduction temperature, C/O molar ratio and a longer reduction time were favourable for the apatite reduction. The reduction degree of apatite reached 83.62% at 1548?K with a C/O molar ratio of 2.5 and after 60?min reduction. In addition, the reduction kinetics of apatite was investigated by common order reactions, and the corresponding kinetic parameters were computed according to the Arrhenius function. The results demonstrated that the most suitable mechanism for the apatite reduction was first-order reaction, and the apparent reaction rate of apatite reduction increased with increasing reduction temperature and C/O molar ratio. Furthermore, both the apparent activation energy and pre-exponential factor of apatite reduction decreased slightly with increasing C/O molar ratio.