Thermal expansion coefficient tailoring of LAS glass-ceramic for anodic bondable low temperature co-fired ceramic application

The Li–Al–Si glass-ceramics were prepared by conventional glass-ceramic fabrication method. The influences of Na₂O content on the sintering property, microstructure, and coefficient of thermal expansion were investigated. The results show that the coefficient of thermal expansion of LAS glass-ceramics can be tailored to match that of silicon by the addition of Na₂O content. Na₂O has a remarkable influence on the crystallinity of Li–Al–Si glass-ceramic. The coefficient of thermal expansion of Li–Al–Si glass-ceramic is thus tunable between that of glass phase and crystal phase. The Si–O bond length change in stretch vibration modes introduced by Na₂O also contributes to the variation of coefficient of thermal expansion of the Li–Al–Si glass-ceramics. The coefficient of thermal expansion of the Li–Al–Si glass-ceramic with 1.5 wt% Na₂O addition is about +3.34 ppm/°C at 350 °C and shows a good compatibility to that of silicon in a wide temperature range, which makes it a promising candidate for anodic bondable low temperature co-fired ceramic substrate applications.     

First-principles calculations of electronic structures and optical,phononic, and thermodynamic properties of monoclinic α-spodumene

To further the applications of spodumene in ceramic materials, we performed first-principles density functional theory calculations using a quasi-harmonic approximation to investigate the electronic structures and optical, phononic, and thermodynamic properties of monoclinic types of α-spodumene with C2 and P2₁ structures. The electronic structures of C2- and P2₁-spodumene including band structure and density of states, were observed to be similar. These spodumene can be treated as wide-direct-band-gap insulators with band-gap widths of 5.537 eV for C2 -spodumene and 6.335 eV for P2₁-spodumene. The optical properties of C2- and P2₁-spodumene indicated that both C2- and P2₁-spodumene were found to be optically anisotropic and they can be used for UV shielding in optical devices. Additionally, we investigated the phononic properties of these spodumene to explore their thermodynamic characteristics, and found that both types are dynamically stable.     

First-principle investigation on mechanism of Ca ion activating flotation of spodumene

Different hypotheses of the activation mechanisms of metallic ions for silicate minerals flotation were stated in this work. Spodumene and Ca ion were taken to illustrate this issue. Flotation test results and diagram of Ca ion species distribution vs pH show that the dominant hydrolyzed species are Ca（OH）？and Ca（OH）2, which is in correspondence with the maximum flotation recovery of spodumene. Density functional theory（DFT） calculation results reveal further that the precipitation of calcium hydroxide on spodumene surface is the effective process to activate the flotation of spodumene.     

Mechanical enrichment of converted spodumene by selective sieving

Spodumene ore can be concentrated in large particle size of 1–6 mm by a dense media separation (DMS) process. The concentrate typically contains relatively large amounts of impurities due to the incomplete liberation of spodumene and the quite narrow density difference between spodumene and gangue minerals. The extraction of lithium from spodumene requires the phase transformation of spodumene from α- to β-form which takes place at 1100 °C. After heat treatment the Li₂O content of spodumene concentrate can be improved by particle size separation. In this work the technical and economical possibilities of producing first low grade concentrates by DMS method and increasing the grade afterwards by particle size separation were studied. Various DMS spodumene concentrates were mechanically enriched after heat treatment by selective sieving. Autogenous and ball mill grinding were used to increase the separation efficiency between the spodumene and the gangue minerals. The Li₂O contents of the concentrates were increased from 5.1%, 3.6%, 3.1% and 1.4% to 6.8%, 5.8%, 5.9% and 5.0%, respectively. The energy economy of the sieving method was evaluated from the perspective of increased energy consumption in the heat treatment process.     

江西某低品位难选锂辉石矿选矿工艺研究

江西某低品位锂辉石矿含Li₂O1.46%,主要赋存在锂辉石和腐锂辉石矿物中,矿石性质复杂,分选难度较大。本文采用锂辉石直接浮选工艺,即以NaOH作pH调整剂,Na₂CO₃作脉石矿物分散剂,CaCl₂作活化剂,(731 油酸)作混合捕收剂浮选该锂辉石矿物。实验室小型闭路试验在原矿含Li₂O1.46%的条件下,可以获得含Li₂O5.68%、回收率76.72%的锂辉石精矿。与现场“预先脱泥-尾矿浮锂辉石”工艺相比,新工艺不仅提高了锂辉石精矿品位,而且显著提高了锂回收率。     

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。     

Microscale insights into the influence of grinding media on spodumene micro-flotation using mixed anionic/cationic collectors

Here, the influence of grinding media with different shapes on the flotation performance of spodumene and its potential mechanism from microscale insights was investigated using a single mineral flotation experiment, X-ray diffraction (XRD) test, scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The flotation data indicated that under anionic/cationic (sodium oleate (NaOL)/DDA) collectors system, the rod milled spodumene has a higher floatability than ball milled ones. XRD results confirmed that rod medium makes spodumene exposed more {1 1 0} and {1 0 0} planes, while ball medium makes spodumene exposed more {0 1 0} planes. The typical anisotropic surface of spodumene makes the surface of rod milled spodumene possess more Al sites, further confirmed by SEM-EDS and XPS results. Additionally, it was found that the rod milled spodumene presents a larger value of elongation and flatness, which are parameters closely related to bubble adhesion. AFM analysis indicated that rod milled products have a rougher surface, while ball milled products have a smoother surface. Consequently, the rod medium enhanced the adsorption of NaOL/DDA on the spodumene surfaces. This work provides theoretical guidance for optimizing the separation of spodumene from the perspective of grinding.     

锂辉石对卫生瓷釉料性能的影响

论述了锂辉石对卫生瓷釉料性能的影响。实验表明：锂辉石的国入能显著降低釉料的熔融温度，拓宽其烧成范围，降低釉料的膨胀系数，改善坯釉结合性能，增加釉的流动性及光泽度，有助于乳浊力的提高。     

某复杂多金属矿低尾化综合利用技术研究

矿产资源在选矿过程中产生的大量尾矿,既是资源的浪费,又是环境污染源。因此,开展低尾化乃至无尾化综合利用研究,最大程度提高资源利用率是未来矿产资源开发、利用的必由之路。本文在研究国内某复杂多金属矿综合利用时,通过分析所含矿物的基因属性、赋存状态以及嵌布关系,先后进行了钽铌精矿、方解石精矿、锂精矿、云母精矿、长石精矿、石英精矿共计6个产品的选别回收,实现了除少量泥质、铁屑之外的全产品、无尾化综合利用技术路线,可为以后同类型复杂多金属矿的综合回收提供思路借鉴。     

Leaching Mechanism of the Spodumene Sulphuric Acid Process

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