高铝粉煤灰提取氧化铝过程中镓的转化规律研究

研究了镓在高铝粉煤灰提取氧化铝工艺中的迁移转化规律。在主要生产流程中设置取样点,对镓的富集分布情况进行检测分析。结果表明:高铝粉煤灰中的镓有75%进入成品氢氧化铝,碳循环母液中镓的富集浓度最高,达到46.0 mg/L。     

高铝粉煤灰碱法提铝过程镓的吸附研究

我国内蒙古中西部以及山西北部地区的高铝粉煤灰中氧化铝含量高达50%以上,伴生的镓含量可达60 mg/kg,是重要的含铝、镓二次资源。为进一步提升高铝粉煤灰资源化利用附加值,实现粉煤灰提铝过程低浓度含镓溶液的高效提取,本文基于高铝粉煤灰预脱硅拜耳-亚熔盐联合法提铝工艺中的含镓碱液体系,研究了含镓模型溶液中镓离子的静态吸附规律,系统考察了不同吸附时间、吸附温度、镓初始浓度以及碱浓度对螯合树脂吸附镓离子的影响,完成了吸附动力学与吸附等温线的考察,并采用吸附柱进行了低浓度含镓碱液动态吸附及淋洗试验验证。静态吸附试验结果表明:采用LSC-600型螯合吸附树脂可实现低浓度含镓碱液中镓离子的高效吸附,树脂的平衡吸附容量随静态吸附时间增大而增大,吸附24 h后树脂吸附容量达到平衡;镓离子初始浓度低于400 mg/L,树脂的平衡吸附容量受吸附温度影响较小,在镓离子浓度高于400 mg/L体系中,树脂的平衡吸附容量随吸附温度升高而降低,其中吸附温度为50℃时树脂对镓离子的平衡吸附容量最大;随含镓碱液碱浓度增加,螯合树脂对镓离子的吸附容量先增大后减小,螯合树脂对镓离子的平衡吸附容量随镓离子初始浓度增大而增大,镓离子初始浓度高于1 200 mg/L时树脂吸附容量达到饱和,吸附温度为50℃,镓离子初始浓度为1 200 mg/L,碱浓度为5 mol/L时树脂的最大吸附容量为36 mg/g。动力学拟合结果表明:碱体系树脂对镓离子的吸附动力学过程符合准二级动力学方程,属于化学吸附过程;吸附等温线拟合结果表明,LSC-600型螯合树脂对镓离子的吸附满足Langmuir等温方程,说明镓离子的螯合吸附过程为单层吸附。树脂的动态吸附和淋洗结果表明,液体流速越大,树脂达到吸附平衡时的穿透床层数越小,树脂对镓离子的吸附容量和吸附率均较低,镓离子初始浓度50 mg/L,吸附温度为50℃,吸附流速为2. 5 BV/h时,树脂对低浓度含镓碱液吸附效果最优,最大吸附容量为3. 13 mg/g,淋洗过程淋洗液镓离子浓度随着床层数增加先增大后降低,淋洗流出液达到0. 7 BV时镓浓度最高为1 936mg/L,高浓度段(0. 3～1. 5 BV)溶液中镓离子浓度为1 248 mg/L,富集倍数达25倍。     

LX-92树脂对硫酸体系低浓度镓离子的动态吸附

研究了粉煤灰模拟硫酸浸出液中的镓在聚苯乙烯树脂(LX-92)上吸附分离的可能性,采用固定床吸附装置考察了树脂动态吸附?脱附镓的行为,利用Thomas, Yoon-Nelson和Adam-Bohart经验模型对动态吸附过程进行了分析和预测。结果表明,降低流速(F)、增加床层高度(Z)、减小镓(Ш)初始浓度(C0)有助于提高固定床吸附效率和平衡吸附容量;在C0为260 mg/L, Fad为5.0 mL/min、吸附温度为55℃的条件下,树脂的最大动态平衡吸附容量为56.65 mg/g;用3.0 mol/L H2SO4在1.0 mL/min流速的最佳洗脱条件下,洗脱率达到94.40%;树脂在硫酸体系中对低浓度镓离子的吸附?脱附具有良好的循环使用性,经过吸附?脱附镓离子可富集10倍以上;树脂吸附镓的动态行为满足Yoon-Nelson动态吸附模型,建立了动态吸附速率常数KYN和半穿透时间τ值常数与初始离子浓度、流速、床层高度的对应方程,为低浓度镓离子的吸附法提取工程化提供了理论基础。     

粉煤灰酸法提镓探索研究

针对晋北粉煤灰酸法提铝工艺,探索从粉煤灰中酸法预提镓的方法,研究了焙烧温度、盐酸浓度对镓提取率的影响。结果表明,粉煤灰提镓的适宜条件为:灰样不经焙烧,盐酸浓度为6 mol/L,60℃浸泡8 h,镓浸出率最大,可达44%以上。该实验为从粉煤灰中获得纯金属镓作了初步溶出富集研究。     

离子交换水质量对栲胶分析结果的影响

自1970年以来,我厂化验室使用732~#阳离子交换树脂与717~#阴离子交换树脂,制备分析用水,用于落叶松栲胶分析。由于控制不严(如:阴、阳离子交换树脂比例不当,再生条件控制不佳,不作阴离子浓度检验等),结果有时出现不合格水。电导率最高曾达360微伏/厘米,氯离子含量55毫克/     

高纯水制备工艺和设备改革

我厂用水属于中等规模,因此选择动态交换、固定式离子交换装置。根据郑州水质无机盐及重碳酸盐含量较高的情况,选用复床加混合床系统流程,即:一支离子交换柱,国产732~#强酸性阳离子交换树脂;一支阴离子交换柱,国产717~#强碱性阴离子交换树脂;一支混合离子交换柱。为了去掉水中的     

镓试剂催化的有机反应

镓位于元素周期表中第四周期第三主族,化学性质与铝相似,易被制成各种镓盐和有机镓试剂并参与化学反应。重点综述了近5年来金属镓、镓盐及其他镓试剂参与的形成碳碳键和碳杂键的各类化学反应,介绍了镓试剂促进的一些新型反应的特点和优势及其在有机合成中的应用,提出了镓试剂今后研究和发展的重点与方向。     

离子交换法脱除己内酰胺产品中的无机盐

采用不同的阴阳离子交换树脂,对己内酰胺产品进行了精制研究,脱除了产品中微量的硫酸铵等无机杂质。通过静态和动态实验对比考察了不同树脂对硫酸铵的吸附性能。结果表明,离子交换反应是吸热的过程,树脂的吸附量随温度、初始浓度和接触时间的增加而增加。动态穿透曲线能很好地符合Adams-Bohart和Thomas模型,并得到树脂的最大交换容量,阳离子交换树脂D001对NH_4⁺的最大交换容量为61.51 mg/g,阴离子交换树脂717对SO_4+的最大交换容量为61.51 mg/g,阴离子交换树脂717对SO_4^(2-)的最大交换容量为7 640.4 mg/g。在吸附过程中,己内酰胺的含量稳定不变,且电导率的测定可用于检测实际己内酰胺溶液中硫酸铵的浓度变化。     

BER对羰基精细合成中间体的还原

以 KBH_4与717~#阴离子交换树脂反应制备了聚合物支载硼氢化试剂(BER),并用 BER 对多种含羰基的化合物进行了还原。讨论了 BER 的浓度及羰基化合物的结构对反应速度、产率的影响,以及支载试剂的再生复用。     

分离富集—MPT-AES法测定食用菌中的磷

采用717型阴离子交换树脂分离富集-MPT-AES法测定食用菌中的磷元素,排除了高含量的Zn、Fe、Ca、Mg等金属元素的基体干扰,并对分析谱线的选择、样品消解方法、仪器工作条件和分离富集条件进行了详细的研究,在最佳条件下测得P的检出限为0.49mg/l,相对标准偏差0.23%~1.45%。     

MOCVD生产废料中镓、铟提取工艺及其动力学研究

近年来，LED以其节能及环境友好等特性被广泛运用于各类照明领域。作为LED产品关键部件，采用金属有机气相沉积(MOCVD)生产外延片过程产生大量的生产废料。随着LED行业的快速发展，绿色、清洁回收MOCVD生产废料备受关注。本研究以硫酸为浸出剂，重点研究了MOCVD生产废料中Ga和In元素的浸出行为和浸出动力学。通过对浸出试剂种类、H2SO4浓度、固液比、浸出温度和浸出时间等参数的过程优化，在H2SO4浓度3 mol/L、固液比50 g/L、温度80℃、反应2 h的最佳工艺条件下，Ga和In的浸出率仅为67.50%和91.46%。动力学研究表明，在293.15~333.15 K温度范围内，Ga和In的浸出动力学符合收缩核模型，浸出过程受表面化学反应和外扩散混合控制。同时，XRD和SEM-EDS结果也印证了符合收缩核模型。在293.15~333.15 K温度范围内，Ga和In的浸出活化能分别为25.7和21.7 kJ/mol。基于对Ga和In浸出行为的动力学分析，提出并验证了MOCVD生产废料强化焙烧-浸出工艺的可行性。研究结果表明，强化焙烧-酸浸工艺可以使Ga和In的浸出率分别由67.50%和91.46%提升至88.27%和98.32%，并得到了氧化镓副产品。本研究结果有望为MOCVD生产废料的工业化资源循环提供基础数据支撑和新路径选择。     

The interaction between molten gallium and the hydrocarbon medium induced by ultrasonic energy—can gallium carbide be formed?

Ultrasonic irradiation of molten gallium in organic liquids (decane, dodecane, etc.) results in dispersion of the gallium into nanometric spheres. These were examined by several analytical methods XRD, DSC, Raman and IR spectroscopy) as well as electron microscopy (SEM, TEM) and found to be composed of Ga and C. The DSC analysis indicates that the Ga has possibly reacted with carbon, while the Raman spectrum of the product demonstrates a strong additional peak that could not be identified. This work explores the possibility that the product is gallium carbide or another gallium‐carbon complex. To investigate the nature of the product, we performed detailed extended X‐ray absorption fine structure (EXAFS) and X‐ray absorption near‐edge structure (XANES) analyses. On the basis of DSC, IR, and Raman it appear to be formation of GaC, whereas the analysis by EXAFS and XANES demonstrated that the gallium is found to be in a higher reduced state (almost metallic), supported by carbon. The question that remains open in addition to the one related to the formation of galium carbide is whether a complex structure, including oxygen contamination is involved in the layers surrounding the Ga as indicated by the EXAFS results.     

粉煤灰中战略金属镓的提取与回收研究进展

镓被广泛应用于半导体、催化、医疗等多个领域。随着半导体行业的蓬勃发展,对镓需求量的日益增长促使人们寻找新的来源。从粉煤灰中回收镓不仅可以减少环境污染和资源浪费,还可以一定程度上缓解对镓资源日益增长的需求。综述了粉煤灰中镓的赋存形式、浸出工艺和镓提取分离方法的最新研究进展,重点介绍了溶剂萃取法和吸附法用于粉煤灰中镓资源回收的现状,总结了现有技术存在的问题,并对粉煤灰中镓资源的回收进行了展望,提出了粉煤灰中镓和其他伴生元素协同提取的资源化利用方向。     

Proton‐poor, gallium‐ and indium‐loaded zeolite dehydrogenation catalysts

The catalytic (propane dehydrocyclization) and reduction behaviors of near 1:1 cation (Ga, In)/framework‐Al MFI zeolites were examined under conditions where the materials were initially either in fully protonated or zero−protonated states. Reductions at appropriate temperatures proceeded up to ∼100% exchange of protons for reduced univalent cations. Further aqueous exchange of alkali (K⁺>) or alkaline earth (Ba²⁺) cations increased the selectivity for dehydrogenation reactions at little or no sacrifice in overall activity. This revised version was published online in July 2006 with corrections to the Cover Date.     

镓的分离提取技术研究

镓(Ga)具有优异的物理与化学性质,是当代半导体、光电子、新材料、化工军工等高技术领域的重要支撑材料。主要介绍了镓(Ga)及其化合物的用途和分离提取技术。     

Effective synthesis of propylene carbonate from propylene glycol and carbon dioxide by alkali carbonates

Quantum-chemical calculations give insight in the experimentally observed higher rate of hydrogen–deuterium exchange for oxidized Ga/HZSM-5 over reduced Ga/HZSM-5. The reaction is computed to be more facile over reduced (Ga⁺) than over oxidized (GaO⁺) cations. The difference lies in the difficult formation of active GaH₂⁺ cations from Ga⁺ compared to facile hydrogen dissociation over GaO⁺ to give active GaHOH⁺ cations. Neutral gallium oxide clusters are shown to have a lower intrinsic activity than GaO⁺ cations.     

Change in the decomposition mode of 1-propanamine due to the presence of cations in MFI zeolite

The adsorption and thermal analysis of 1-propanamine has been compared over MFI zeolites which contain H, Ga, and In cations. In the case of H⁺-containing materials, NH₃ and propene are simultaneously desorbed above 600 K. This behavior, is well known and characteristic of the Hofmann elimination reaction. However, a distinctly different mode of reaction is observed in the case of Ga and In containing materials. NH₃ is released below 600 K, propene and other products are released above 600 K, and a stable residue remains above 800 K. It is suggested that such behavior results from Lewis acid interactions of Ga or In cations with propanamine.On leave from the Bulgarian Academy of Sciences, Institute of Organic Chemistry.     

Thermodynamic Assessment of the Gallium-Oxygen System

The experimental information relevant to the Ga-O binary system has been critically assessed. A self-consistent set of Gibbs energy functions describing the phases in this system and a phase diagram are presented for the first time. The adjustable parameters of the models are obtained by a least-squares fit to the experimental data. The liquid phase is described by Hillert's partially ionic liquid model. The gallium oxides (α-, β-, γ-, and δ-Ga₂O₃) are modeled as stoichiometric phases. The gas phase is treated as an ideal solution of the species Ga, Ga₂, Ga₂O, GaO, O, O₂, and O₃. The calculated phase diagram and thermodynamic properties agree very well with most of the experimental measurements.     

The effect of gallium and phosphorus on the corrosion behaviour of aluminium in sodium chloride solution

In order to cause shifting of the potential in the negative direction and to simultaneously control dissolution in sodium chloride solutions, aluminium alloys utilized as anodes in electrochemical power sources contain small additions of alloying elements. This can be achieved with highly pure aluminium alloys. The binary Al-0.2% Ga alloy made of high purity aluminium has a high negative potential (–1570 mV at 10 mA cm^–2), but also a high corrosion rate. The addition of 0.2% P to the above alloy decreases corrosion. Impurities present in technically pure aluminium considerably affect the anodic and corrosion behaviour of the investigated alloys. It was found that corrosion of the Al-0.2% Ga and Al-0.2% Ga-0.2% P is controlled not only by the alloying elements, but also by intermetallic compounds (insoluble in the matrix) which contain alloying elements and impurities (Fe) present in technically pure aluminium.     

Approaching ‘Kit‐Type’ Labelling with 68Ga: The DATA Chelators

The DATA chelators are a novel class of tri‐anionic ligands based on 6‐amino‐1,4‐ d i a zepine‐ t riacetic a cid, which have been introduced recently for the chelation of ⁶⁸Ga. Compared with macrocyclic chelators based on the cyclen scaffold (i.e., DOTA, DO3A, and DO2A derivatives), DATA chelators undergo quantitative radiolabelling more rapidly and under milder conditions. In this study, a systematic evaluation of the labelling of four DATA chelators—DATA^M, DATA^P, DATA^Ph, and DATA^PPh—with ⁶⁸Ga is presented. The results highlight the extraordinary potential of this new class of chelators for application in molecular imaging using ⁶⁸Ga positron emission tomography (PET).