电感耦合等离子体发射光谱法测定锂辉石中氧化锂

采用盐酸-硝酸-氢氟酸-高氯酸混合酸消解锂辉石样品,建立了电感耦合等离子体发射光谱法测定锂辉石中氧化锂含量的方法。试验确定的锂元素分析谱线为Li 610.362 nm,观测方式为径向观测,锂元素检测的高频功率为1.1 kW,雾化气流量为1.0 L/min,蠕动泵泵速为1.5 mL/min,样品溶液介质为浓度3%的盐酸。氧化锂浓度为0~50 mg/L时,氧化锂浓度-谱线强度曲线的线性相关系数为0.999 7;氧化锂含量的检出限为0.007 mg/L,相对标准偏差（RSD）为0.81%。该方法具有检出限低、灵敏度高、干扰少、准确度高、线性范围宽、操作简单等优点,可对大批量锂辉石样品氧化锂含量进行精确测定。     

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。     

国内外锂矿物资源概况及其选矿工艺综述

介绍了锂的性质和用途,以及国内外锂矿资源的特点;归纳总结了国内外常见的锂提取工艺;分析了目前锂辉石、锂云母浮选工业实践中存在的问题。指出我国作为锂资源大国,在锂资源开发利用方面与发达国家之间的差距,建议从锂矿石理化性质、浮选药剂及浮选工艺等方面深入展开研究工作。     

Spodumene-bearing rock as flux for triaxial ceramic bodies

Abstract

Abstract

In this work, spodumene-bearing rock, a waste from mineral processing, was used as a flux in ceramic bodies, and its reactivity to other raw materials such as quartz and kaolin was analysed. The petrology properties of the pegmatite (parent rock) from which the flux is extracted were characterised. The grindability, fluxing strength and pyroplastic deformation of the spodumene-bearing rock were investigated. In addition, the influence of spodumene-bearing rock on technological properties of the final pieces, mainly in relation to the firing temperature, phases formation and microstructure was also analysed. Then, the firing behaviour to other commercial fluxes such as albite and feldspar was compared. The spodumene-bearing rock was considered an effective flux, capable of reducing the firing temperatures of the tested bodies by viscous flow.     

First-principles theory on electronic structure and floatability of spodumene

The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory(DFT) and further analyzed in detail. The calculation results reveal that the O in spodumene is the most active and easily links with H+in the water, but the active Li is very low, so it is better to add activator to increase the concentrate grade and recovery rate of spodumene in the flotation process. Si–O bonds in spodumene crystal are mainly covalent, since the covalency of Al–O bonds is stronger than that of Li–O bonds,and minerals dissociate along the weakest Li–O bonds. In addition, the study of the frontier orbital indicates that both O and Si atoms have large contribution to the frontier orbital in the spodumene crystal. Oleate and dodecylamine are used as the collectors of spodumene. The results contribute to the understanding of crystal structures of spodumene, and can be used in guiding related practical applications.     

Solid-state field-assisted ion exchange of Ag in lithium aluminum silicate glass-ceramics: A superfast processing route toward stronger materials with antimicrobial properties

Lithium-aluminum-silicate glass-ceramics (LAS) are of pivotal relevance in various applications as they combine excellent mechanical and functional properties. Due to their use in medical devices and cooking articles, antimicrobial properties are obviously of interest.Herein, we report the solid-state field-assisted (Ag→Li,Na) ion exchange in LAS glass-ceramics containing β-quartz and β-spodumene solid solutions. The ion-exchange is extremely rapid and deep silver penetration (>100 μm) can be achieved within a few minutes (<5 min), this being proportional to the treating time and applied current. The elemental profiles are characterized by a relatively complex shape which reflects the different alkali mobility in the different phases. The ion exchange initiates structural modifications involving: (i) β→α transition in spodumene; (ii) formation of lattice microstrain and quartz cell expansion; (iii) substantial changes in the IR absorption spectra. The obtained materials possess improved resistance to crack formation and antimicrobial activity against Staphylococcus aureus.     

超声波辅助NaCl-MnO2改性沸石及其吸附性能

本文的研究对象为四川某锂辉石矿,矿石属伟晶岩型低品位锂辉石矿,矿石中Li2O含量为1.36%。主要矿物组成简单,为锂辉石、石英、长石等,粒度粗大。主回收元素锂主要分布于锂辉石中,锂辉石中锂的分布率为96.6％,锂辉石本身含铁0.15％。加之部分锂辉石发育的解理缝、裂缝中被铁锰质充填污染,易对锂辉石品级造成影响。共伴生的锡、铌、钽主要以锡石、铌铁矿、重钽铁矿存在,嵌布于锂辉石、石英、长石粒间,粒度细小,与主要矿物粒度差异巨大,是否综合回收应从经济效益角度考虑。     

锂辉石浮选捕收剂及调整剂研究综述

从捕收剂和调整剂2大方面对国内外锂辉石浮选药剂进行了介绍和总结。锂辉石浮选捕收剂主要包括传统单一捕收剂、组合捕收剂和新型捕收剂3类。调整剂主要包括应用最广泛的NaOH-Na2CO3-CaCl2“三碱”组合调整剂,同时难免金属阳离子、无机阴离子、有机酸等调整剂对浮选过程的影响、对锂辉石活化作用及其选择性抑制作用的影响及对浮选机理的影响研究都是研究的热点。研发新型高效、高选择性、环保、耐低温、经济的捕收剂和调整剂将成为锂辉石浮选药剂未来发展的主要趋势。综合述评可以为锂辉石浮选药剂的研究提供参考。     

贵州某锂辉石矿石选矿试验

贵州某锂辉石矿石Li2O含量为1.21%。主要脉石矿物有石英、长石、磷灰石、磁铁矿、高岭石等。为确定锂辉石的回收工艺,进行了选矿试验。矿石采用浮选工艺富集锂辉石、磁选工艺剔除混入锂辉石精矿中的磁铁矿。结果表明,在磨矿细度为-0.074 mm占83.2%的情况下,以油酸钠+水杨羟肟酸(质量配合比为1∶1)为捕收剂,总用量为1 200 g/t,以氯化铁为活化剂,用量为100 g/t,采用1粗1扫3精、中矿顺序返回浮选流程富集锂辉石,1次弱磁选(磁场强度为198.94 k A/m)流程脱铁,最终获得Li_2O品位为6.16%、含铁0.45%、Li_2O回收率为85.43%的锂辉石精矿。     

Properties of selective laser melted spodumene glass-ceramic

In this article, we established the process conditions and characterised the resulting properties of additively manufactured spodumene important for selective laser melting of LAS–Al₂O₃. X‐ray diffraction analyses revealed the as‐printed samples printed with layer thickness of 50 μm were fully crystalline. Energy dispersive X-ray spectroscopy showed that the major elements before and after the printing process were present and in similar quantity. Micro‐computerised tomography inspection also revealed layer thickness‐dependent pore formation in all printed samples. In terms of mechanical properties, the highest flexural strength measured using the three‐point bend test method was 4.33 MPa. More importantly, these results demonstrated that there is still potential in the direct laser melting of ceramics.