Reaction behavior of associated rare earth minerals during coal-based reduction

In order to ascertain the reaction behavior of rare earth minerals in coal-based reduction, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy dispersive spectroscopy（EDS） analyses were applied to investigate the rare earth minerals in Bayan Obo.The occurrence state and regularity of rare earth elements were analyzed under different reduction time. The results reveal that rare earth elements in rare earth minerals exist in RE（CO3）F（bastnaesite） and REPO4（monazite）. In this research, at 1,498 K with a C/O molar ratio（i.e., molar ratio of fixed carbon in the coal to reducible oxygen in the ore） of2.5, rare earth minerals primarily decompose into RE2O3at5 min. When the time is extended to 10 min, solid-phase reactions occur among RE2O3, CaO, and SiO2, and the resultant is cerium wollastonite（CaO·2RE2O3·3SiO2）. At reaction time 〉20 min, rare earth elements mainly exist in cerium wollastonite（CaO·2RE2O3·3SiO2）, and the grain size varies in the range of 10–30 μm. The results show that coal-based reduction is efficient to recover rare earth minerals in reduced materials.     

也门共和国矿产资源与矿业开发前景

也门共和国地处阿拉伯-努比亚(Arabian-Nubian)地盾,地质结构复杂多样,在火山岩和沉积岩区蕴藏着丰富的黄金、铅、银、铜、锌和其他金属矿产。也门的金矿主要位于Sanaa省,与火山和岩浆活动有关;铅锌矿成因类型较复杂,最大的铅锌矿产出于JabalSalab地区侏罗纪的白云岩中;铜镍矿存在于基性、超基性的侵入岩中,主要位于Taiz和Amran省。也门矿产资源丰富但大量矿床尚未被开发,有巨大的找矿潜力。本文结合也门矿产的资源情况及矿业开发现状圈定了优势矿产的找矿远景区,如Al Jawf省西部的金-银矿远景区,Saada省北部的铜-镍矿远景区,以及Shabwah省东南部的锌-铅矿远景区等。也门共和国矿产资源丰富,矿业及税收政策宽松,定会成为未来矿业投资的热点区域。     

青海省小干沟金矿区蚀变矿物光谱特征研究及应用

使用地面光谱仪对小干沟金矿区进行了地表及深部各典型岩(矿)石主要蚀变矿物光谱数据获取,分析各光谱曲线特征。研究总结了矿区地表蚀变分带特征和深部蚀变强度变化,同时分析研究了深部蚀变延伸趋势;结合矿区地质特征、围岩蚀变特征、矿产特征,建立了构造蚀变岩型金矿床地面蚀变矿物分布模型;进而预测小干沟金矿区西侧及矿区深部蚀变矿物分布规模较大、强度较高,找矿前景较好。     

湖南奥陶纪天马山组中沉积型氧化锰矿的发现

在湖南常宁市茶潦村的天马山组下段地层中,首次发现有沉积氧化锰矿存在.矿区位于湘桂盆地南东边界,矿区含锰岩系由泥质岩及粉砂岩组成,矿体与围岩整合接触,该矿床沉积相属外陆棚、次深海陆缘斜坡相浊流沉积.断陷槽区域的离散拉张环境对锰成矿作用至关重要,茶潦凹陷带就发育于这种区域离散环境,且营造了相对缺氧的、滞流的安静环境.据此在湖南寻找同类型氧化锰矿的思路应顺层位找矿,顺含锰岩系找矿,并顺断陷槽找矿.     

745矿生物浸矿过程中铀矿物的变化

采用电子探针分析了浸出前后745铀矿物赋存形式及其变化情况。结果表明,该矿床矿石中铀矿物种类比较单一,主要以沥青铀矿为主,其次为铀石、铀钍石和钛铀矿;铀矿物主要以不规则树枝状或细脉状、颗粒状、星点状产出于矿物裂隙中,少部分被其它矿物包裹;粒度多在10μm以上、大者可达100μm以上。生物浸矿后,尾渣中剩余的铀矿物明显减少,残存的铀矿物种类仍然是沥青铀矿、铀石和钛铀矿,但粒度多在1~2μm以内,主要存在于石英颗粒内。说明裂隙中的沥青铀矿与铀钍石容易被浸出,被石英包裹的铀则难以被浸出。     

某高碱贫铀矿石的微生物酸法池浸探索

先采用盐酸去除某高碱性铀矿石中的大部分碱性物质,然后采用微生物酸法池浸技术对铀进行浸出。结果表明,大粒径(5mm)矿石中的铀很难被提取,去除部分大粒径矿石后,当碱性物质去除率达65%时,铀的浸出率可以达到91.2%。     

西北某难选混合铅锌矿浮选试验

针对西北某难选混合铅锌矿氧化率高,品位较低、共生关系复杂的特点,采用抑锌浮铅的优先浮选工艺方案进行了矿石选矿试验研究。试验研究结果表明,在适宜的磨矿细度和药剂制度下,采用试验确定的闭路试验流程处理该矿石,可获得铅品位为67.85%、铅回收率为82.28%的铅精矿;锌品位为60.13%、锌回收率为82.76%的锌精矿。     

煅烧气氛对水泥浆体流变性的影响

用旋转黏度计和微型坍落度仪测定水泥浆体的流变性,又利用岩相分析、XRD、水化热等测试方法分析相关的作用机理,研究探讨煅烧气氛对水泥浆体流变性的影响。结果表明,在还原气氛下煅烧的熟料,其中的Fe2O3部分被还原为FeO、FeS,因而减少了C4AF含量,增大了C3A含量,使得水泥的水化速度加快,浆体的流变性降低。     

碱法提高铝硅矿物的铝硅比

采用NaOH溶液时铝硅矿物进行预脱硅处理,测出溶渣中SiO2和Al1O3的含量,计算得出渣中的铝硅比.考察液固比、溶出温度、溶出时间、碱浓度等因素对铝硅矿物溶出后渣中铝硅比的影响.实验表明,在液固比为40∶1、温度95℃、溶出时间3 h、40%碱浓度条件下,矿物的脱硅率可达55%以上.预脱硅后渣中铝硅比由0.89提高到...     

The impact of hardpans and cemented layers on oxygen diffusivity in mining waste heaps: diffusion experiments and modelling studies

This study reports column tests and modelling results to assess the impact of hardpans and cemented layers on oxygen supply in mine waste sediments. The analysed sediment samples were obtained from a low-sulphide and low-carbonate polymetallic mine waste tailings impoundment located in the Freiberg mining district in Germany. The three samples were characterised by different degrees and types of cementation. After physical and mineralogical properties of the samples had been determined, breakthrough curves of oxygen were measured in column studies at different degrees of water saturation, and the diffusivities were assessed using a numerical modelling approach. Results demonstrate that cemented layers and hardpans in undisturbed sediments associated with fine-grained material operate as preferential pathways for diffusive gas transport during rewetting, leading to higher oxygen diffusivities compared to disturbed sediments. Under air-dry conditions, the disturbed samples show higher diffusivities than the undisturbed sample, indicating clogging of the porosity by precipitation of secondary minerals such as trivalent Fe oxyhydroxides acting as a barrier and thereby decreasing the diffusivity of the undisturbed sample. In contrast to sediments without cementation, diffusion experiments of sediments with cemented layers used in this study yield similar tortuosities in spite of their different grain size distributions, pointing to the important role of these heterogeneities for gas diffusion.