四川省壤塘县斯约武锂、铌钽矿床地质特征及成因研究

本矿床位于斯约武与纳合花岗岩体外接触带。矿化伟晶岩墙大多受NE向纵向节理控制,并位于幕阜山岩体的边缘。矿区内已发现4条主要矿体,它们通常呈脉状,延深约数百米。矿石为花岗伟晶结构和条带状构造。含铌、钽的矿物主要包括铌铁矿、钽铁矿、黑钨矿、锂辉石、石英和绿柱石等,它们主要分布于分异晚期的块体带中。经研究表明,该矿床为一岩浆-交代伟晶岩型矿床,成因上与斯约武和纳合花岗岩体有关。     

Fully-coupled simulations of thermally-induced cracking in pegmatite due to microwave irradiation

Fully-coupled thermo-mechanical simulations are implemented in COMSOL Multiphysics to investigate micro-scale stress-strain variability in pegmatite specimens subjected to thermal loading using microwaves. Thermally-induced compressive and tensile stresses increase as the microwave irradiation duration increases. The dielectric constant, coefficient of expansion, and type and size of mineralogical boundary have significant impacts on the responses of the rock to microwave irradiation. The maximum principal stress of the chlorite is the smallest, indicating that the chlorite experiences the most damage under microwave irradiation, followed by the quartz. The maximum principal stress values of plagioclase and orthoclase are larger, indicating that they are likely to incur the least damage. Where quartz or chlorite is dominant, the resulting von Mises stresses are consistently higher after 120 s of microwave irradiation. The rate of generation of von Mises stresses increases most rapidly along the interface between quartz and plagioclase, and the interface between quartz and orthoclase, followed by the interface between quartz and chlorite, and finally the interface between plagioclase and orthoclase. The presented modeling approach provides a practical method to investigate stress-strain relationships within mineralogical boundaries inside a rock thin section.     

川西伟晶岩型锂辉石矿选择性磨矿—强化浮选试验研究

川西伟晶岩型锂辉石矿中锂辉石普遍结晶较大、易于解离且在碎磨过程中容易细化,而入选锂辉石矿样的粒度对浮选结果具有很大的影响,采用选择性磨矿—强化浮选的工艺来加强对锂辉石的回收。试验确立了最佳的磨矿条件:钢球球径配比制度为35 mm∶30 mm∶25 mm∶15 mm=2∶5∶3∶7,钢球充填率为30%,磨矿时间为8 min,磨矿浓度为65%。在这一最佳的磨矿条件下可以生产最大量的有利于锂辉石浮选分离的中粒级-74+38μm产品。磨浮选工艺闭路试验可获得Li2O品位5.81%、回收率79.52%的锂精矿。     

利用本地伟晶岩生产细炻器

经调研分析及工艺试验，将本地伟晶岩引入炻器坯料中，开发了资源，降低了生产成本。     

四川马尔康党坝花岗伟晶岩型稀有金属矿床成矿时代的限定: 来自LA-MC-ICP-MS锡石U-Pb定年的证据

热达门稀有金属矿床位于川西可尔因伟晶岩型矿田的南西部,文章在详细的矿床地质特征研究基础上,系统采集同一矿脉同一矿体不同标高（3540～3830 m）的矿石,分析测试了锂辉石单矿物中的C-H-O同位素组成以及不同矿物中的包裹体特征。矿物中包裹体主要以富液相包裹体为主,锂辉石中包裹体盐度集中于8%~20%,均一温度180~330℃,属于中-低盐度、中-高温成矿流体;石英中包裹体盐度集中于0%~8%,均一温度150~240℃,属于低盐度、低温流体。C-H-O同位素测试结果显示热达门稀有金属矿床中的锂辉石δD值为-97.5‰～-104.7‰（平均-102.8‰）,相对于可尔因地区其他锂矿床,δD值明显偏小,δ¹⁸O_H2O值为-0.34‰～2.88‰（平均1.032‰）,表明成矿流体可能有大气降水的混入,并受到了围岩黑云母而长花岗岩体的影响。矿床中锂辉石的δ¹³C_V-PDB值为-10‰～-16.6‰,平均-12.7‰,反映主成矿期碳的来源具有岩浆系统和大气降水系统的混合性质,与岩浆-地幔源（花岗岩、地幔多相体系）的低温蚀变有关,并可能混入部分由沉积有机物质经脱羧基作用（decarboxylation）生成CO₂。通过对矿物C-H-O同位素及流体包裹体进行研究,进一步明确了成矿流体来源及演化过程。     

某伟晶岩型锂辉石矿石浮选试验

某锂辉石矿石Li₂O品位为1.46%，矿物组成复杂，主要有用矿物为锂辉石，主要脉石矿物为石英、长石、云母等，锂辉石与石英、长石的嵌布关系密切，多呈聚粒状分布，局部分散，有的呈针状被云母、石英包裹，或呈片状、粒状等形态分布于云母裂隙中，属于复杂难选伟晶岩型锂辉石矿石。为确定该矿石的开发利用工艺，进行了选矿试验研究。结果表明，矿石在磨矿细度-0.074 mm占72.2%的情况下，采用磁选（636.94 kA/m）脱铁、浮选锂辉石工艺回收锂辉石，其中浮选以Na2CO₃+NaOH作pH调整剂和脉石矿物分散剂，CaCl₂作锂辉石的活化剂，TSY-15作捕收剂，经1粗2精3扫、中矿顺序返回流程处理，最终获得Li₂O品位为6.02%、Li₂O回收率为80.65%、Fe₂O₃含量为0.67%的锂辉石精矿，达到陶瓷级锂辉石精矿质量标准。     

伟晶岩型铝硅酸盐矿物的晶体化学特征计算与分析

探讨了伟晶岩型铝硅酸盐矿物(锂辉石、长石和云母)的晶体结构,三者晶体结构最大不同之处在于Al—O配位方式不同。其中,锂辉石晶体结构中Al在硅氧四面体骨干之外,以六配位的形式组成[AlO_6]八面体;钠长石晶体结构中Al取代了Si呈[AlO_4]四面体;而白云母晶体结构中[AlO_4]四面体和[AlO_6]八面体同时存在。同时,以键价的观点对这三种矿物晶体结构中化学键的特征进行理论计算。结果发现,M~(n+)静电价强度、M~(n+)—O~(2-)键平均键长、库仑力、平均键价之间具有极好的一致性。在伟晶岩型铝硅酸盐矿物结构中,[SiO_4]四面体Si—O键是最强的,当Al取代Si时,[AlO_4]四面体中Al—O键的键强次之,[AlO_6]八面体Al—O键的键强较弱,其它金属M—O键的键强最弱。     

Porcelain stoneware with pegmatite and nepheline syenite solid solutions: Pore size distribution and descriptive microstructure

Investigations correlating the pore size distribution-cumulative pore volume to the microstructure are used to compare the efficiency of two solid solutions of pegmatite and nepheline syenite as fluxing agents for the design of porcelainized stoneware. Particularly the fusibility of the two solid solutions was modified by adjusting the CaO content of the bodies. As results, the pegmatite based flux produced an extended viscous phase capable on embedding the crystalline phases and close open porosity as from 1175 °C. Conversely, the bodies with nepheline syenite remained relatively porous up to 1225 °C although the similar results of the mechanical strength at this temperature. The investigations on microstructure, pores size distribution and cumulative pore volume indicated almost complete reduction of the open pores in the pegmatite based bodies and the development of a band of closed pores ranged between 0.080 and 0.9 μm showing P series as a more compact structure. For the nepheline syenite based bodies, the incomplete reduction of the open pores and the relative absence of the band of pores between 0.080 and 0.9 μm were ascribed to the difference in fusibility and the viscosity of the glassy phases. These differences were interpreted in term of the differential action of CaO in Na₂O–Al₂O₃–SiO₂ and K₂O–Al₂O₃–SiO₂ on the amount and viscosity of the liquid phase formed already described in the literature.     

东秦岭宽坪花岗岩体及其附近含铷伟晶岩的成矿机理

东秦岭宽坪岩体是华北板块与杨子板块碰撞后形成的钙碱性花岗岩体,岩体内部及附近地层中发育有花岗伟晶岩脉。通过地球化学分析,利用A/CNK-A/NK图解及微量元素R₁-R₂构造环境判别方法,分析认为伟晶岩脉的形成与岩体具有一定的继承性,是宽坪岩体晚期热液岩浆结晶的产物。通过岩体及伟晶岩脉稀有元素含量对比分析、矿石多元素及光谱半定量分析,认为伟晶岩中铷的富集与钾含量关系密切,为东秦岭商丹地区寻找伟晶岩型铷矿提供了方向。     

某低品位伟晶岩型锂辉石选矿试验

为降低某低品位伟晶岩型锂辉石选矿生产成本,采用重介质分选工艺,预测可抛弃近70%的粗粒尾矿,可获得Li₂O品位为5.25%,Li₂O回收率为63.70%的锂辉石精矿。为提高其选矿回收率,采用研发的捕收剂EL进行了浮选试验研究,试验可获得Li₂O品位为4.12%,Li₂O回收率为80.76%的锂辉石精矿。精选抛尾工艺流程可在一定程度上消除矿泥对精选的影响,同时减少金属量在矿泥中的损失,该研究成果对选矿厂技术改造具有一定的指导意义。