从二次资源中回收镓的现状及发展

重点介绍了目前国内外镓的资源现状及冶炼技术,并分析各种提取方法的优缺点,对从铝工业副产品、锌浸出渣、电子工业废料、粉煤灰及电尘灰中回收镓的方法进行了简述,并展望了利用生物及真空冶金提镓技术的发展前景。     

从电子废弃物中回收贵金属的方法概述

说明了从电子废弃物中回收贵金属的意义,概述了主要的贵金属回收技术,包括机械物理预处理、火法冶金、湿法冶金和生物湿法冶金处理,比较了各自优缺点,结合最新技术进展对电子废弃物中贵金属回收提出了几点建议。     

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。     

有色金属尾矿中镓的分析方法对比研究

尾矿中有价金属资源的回收利用不仅可实现资源的回收利用,同时缓解甚至消除尾矿带来的环境危害、安全隐患。镓是有色金属中最为常见的伴身元素之一,具有较高的回收利用价值,尾矿矿物组成复杂,且作为伴生元素的镓含量本身较低,目前对尾矿的镓含量测定缺乏系统理论研究,导致我国尾矿尾镓回收研究较为落后。随着镓的用途的不断扩展,如何测定复杂矿物中少量、微量甚至痕量的镓对尾矿镓的回收利用显得非常重要。文章综述了镓的常见测定方法,结合尾矿矿物性质,对比分析了不同方法的优缺点,并结合试验实际,分析了尾矿镓含量分析测定的方法。     

镍钴高温合金废料湿法冶金回收

由于高温合金废料中含有大量的镍、钴资源,如何使这些资源再生成为当今的热点话题。由于传统火法处理都存在金属回收率低、产品质量较差、生产成本高、环境污染大等缺点,因此用湿法冶金处理镍钴废料日益受到重视。本文简单介绍了高温合金废料的湿法冶金回收技术,包括合金废料的浸出处理技术和镍钴分离回收技术。     

电子废料中的贵金属回收技术进展

电子工业的迅猛发展产生了大量电子废料,既破坏环境又浪费金属资源。详细介绍了火法冶金、湿法冶金等传统处理电子废料的化学方法,以及近几年发展起来的物理法和生物法,并进一步介绍了各技术对环境的影响。同时简要介绍国外电子废料回收领域的新发展,并对我国电子废料回收业的发展提出了建议。     

电子废弃物资源化现状与展望

随着电子工业的高速发展,电子废弃物对环境的危害已经引起了人们的广泛关注。综述了电子废弃物的危害、回收利用的意义,详细介绍了目前国内外对电子废弃物回收利用的状况和具有代表性的处理技术,包括机械处理、湿法冶金、火法冶金或几种技术相结合等方法。探讨了中国电子废弃物资源化的发展方向。     

碘的回收方法及其在磷化工中的应用

我国是缺碘国家,从各类含碘废弃物中回收碘是缓解我国碘资源短缺的可行途径。不同碘回收方法有不同的碘富集和分离原理,据此对常用碘回收方法进行归纳及分类阐述;并针对磷矿伴生碘资源回收利用的重要性,介绍一些碘回收方法在磷化工中的应用。     

锡废料综合利用的研究进展

锡废料是锡金属及其化合物在生产和使用中产生的废弃物,是一种亟待利用的宝贵资源.作者叙述了锡废料来源以及从各种废弃的含锡资源中回收利用锡的方法.目前锡废料的综合利用采用火法挥化、湿法碱熔酸浸及尾矿再选方法进行处理.这些方法均可有效回收或富集锡废料中的锡.     

粉煤灰提取镓的预处理工艺研究

从粉煤灰中回收镓具有显著的经济价值和环境意义。实验研究了粉煤灰原料的前处理过程并确定了最佳条件和确定了从粉煤灰中实际回收镓的工艺参数。本文对粉煤灰提取镓前期预处理从碱熔炼法和酸浸法进行了试验对比,确定了强碱性熔剂和氧化碱性熔剂的用量,碱熔时间为10 min,温度700－750℃时,浸出率达98.7%。获得了一种新的有应用价值的从粉煤灰中吸附回收镓预处理的工艺方法。     

Recycling of GaN,a Refractory eWaste Material: Understanding the Chemical Thermodynamics

South Korea is a major producer of light‐emitting diode (LED) material, contributing 31% of total LED demand worldwide, and also a major consumer of electronic devices. During manufacturing and after end of life (EOL) of the consumer electronics, significant amount of GaN‐bearing waste is being generated. As the Republic of Korea depends upon the import of all mineral commodities, under the national policy of securing a stable supply, much attention has been paid to the notion of “urban mining.” The stringent international environmental directive for recycling of waste electrical and electronic equipment (WEEE), United Nations Environment Programme (UNEP) E‐Waste Management goal, restriction of the use of hazardous substances in EEE (RoHS), and extended producer responsibility (EPR) have made recycling an important responsibility. Recovery of the gallium from GaN‐bearing waste can be a promising feasible option; simultaneously from the waste, the wealth can be generated. As GaN is a refractory material, which is hard to leach in the recovery process, hence, needs a chemical pretreatment. In this study, thermodynamics of GaN oxidation and oxidative roasting using Na₂CO₃ has been studied. Thermodynamic feasibility for leaching of oxidized GaN either through acidic leaching or through alkali leaching has been explored.     

电子废弃物机械–物理协同强化资源化利用的研究进展

电子废弃物组成复杂，含有金属相、有机物、氧化物材料等；其结合方式复杂，有黏结、螺丝连接、焊锡固定和卡扣连接等。在这些复杂的成分之中不仅含有多种稀贵金属而且还包含像铅、镉等多种有毒的重金属和各种溴化阻燃剂等有毒的有机物。这些电子废弃物如果不能进行有效回收，将会对环境造成巨大的危害，同时电子废弃物中稀贵金属的含量远高于自然矿物，因此回收电子废弃物中稀贵金属将能有效地缓解自然资源日益紧张的局面。与传统的化学回收方法相比，机械物理的回收方法具有操作简单、经济效益好、环境污染小等优点，被广泛应用于电子废弃物的回收过程。本工作概述了近年来电子废弃物机械物理资源化利用的研究进展，对机械物理回收的各个过程进行了系统地总结，包括前期的拆解和破碎过程以及最重要的物理分选技术，通过对不同分选技术优缺点的比较，指出对破碎产物进行形态调控将极大地提高机械物理处理的回收效率。     

水热法合成羟基氧化镓与优化探索

羟基氧化镓（GaOOH）是合成氮化镓的重要原料,其微观形态特征对所制备氮化镓的物理性能有着重要影响。以氧化镓、浓盐酸、氨水为原料,用水热法合成出羟基氧化镓,并探讨了浓盐酸用量对羟基氧化镓纯度的影响。对合成产物进行XRD表征,结果表明合成产物为羟基氧化镓,且随着浓盐酸用量的增加,羟基氧化镓产品的纯度提高。     

Recent advances in the approaches to recover rare earths and precious metals from E-waste: A mini-review

In the present day, with the rapid rate of advancements in technology, gadgets become obsolete very fast. The chase to keep up with the latest technologies diminishes the gadget's lifespan considerably. Consequently, they are discarded within a short time after their production, resulting in electronic waste (E-waste) being the fastest growing waste stream globally, with an annual production rate of 2.44 million short tonnes. The metals present in such E-waste provide several attractive properties, rendering them crucial in several applications as components of electronic and electrical devices. The major roadblock faced by mankind today is an effective technology with high recovery, low cost, and minimal environmental impact to recycle such electronic waste. In this mini-review, we elucidate the various recycling routes for metal extraction from waste and recent advances in the same. We have attempted to highlight the recent trends adopted by various researchers to recycle and extract valuable metals and rare earths from E-waste. Finally, the challenges and prospects in the extraction of rare earths and precious metals for E-waste research have been clearly brought out and suggestions have been made for future work.     

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。     

Cross-linked polyvinyl amidoxime fiber: a highly selective and recyclable adsorbent of gallium from Bayer liquor

Gallium, a scarce metal produced mainly from Bayer liquor, is widely used in semiconductors. Ion-exchange method is currently considered as the most effective method to recover gallium from Bayer liquor. In this article, fibrous amidoxime adsorbents are introduced to recover gallium from Bayer liquor. In addition, hydrazine cross-linked polyvinyl amidoxime (HPAO) fibers have been prepared. The structure of the as-prepared fibers was ascertained by FTIR, elemental analysis and weight gain rate. The adsorption kinetics, adsorption isotherm and recycling performance were investigated by batch method. Cross-linking duration was studied and it turned out to be an important factor to optimize the adsorption capacity and recycling performance. After 1.5 h cross-linking time, the fiber showed the highest gallium adsorption capacity of 14.83 mg/g in Bayer liquor. After 3 h cross-linking time, the fiber showed the best recycling performance, which retained 82.9% of the initial adsorption ability after four cycles. Adsorption capacity of vanadium was lower than 1 mg/g for all samples. HPAO displayed very fast adsorption kinetics with an equilibrium at 60 min. The EDS results confirmed the low extraction of aluminum and vanadium provided by HPAO fibers. The gallium-loaded fiber could be effectively eluted by acidified thiourea. With proper control of the cross-linking duration by hydrazine, HPAO fiber with high selectivity towards gallium, high adsorption capacity and good recycle performance could be obtained, which is promising for recovering gallium needed for industrial applications.     

回收废旧电池制备功能材料研究进展

废旧电池中含有大量的金属物质，如果不妥善处理，会造成严重的环境污染和资源浪费。而将废旧电池回收之后用于制备功能材料，既能有效解决废旧电池难处置、危害大的问题，又可以减少功能材料的制备成本。文章首先概述了电池的组成及种类、废旧电池的回收意义与回收和处理现状；其次重点介绍了回收废旧电池制备功能材料的研究现状和最新进展，根据废旧电池制备功能材料所采用回收工艺的不同对废旧电池的回收利用进行了分类；最后探讨了目前回收废旧电池制备功能材料所存在的一些问题，并指出简单处理废旧电池制备功能材料将会是未来的主要发展趋势。     

生物强化技术处理化工碱渣废水

石油化工行业碱渣废水主要来自乙烯、柴油、汽油、液化气等产品碱洗精制、酸化提酚后的废水,该类废水水质复杂,含盐量和污染物浓度高,含硫化物、酚等有毒有害物质,其处理方法一直是困扰化工行业的一大难题,国内企业通常采用焚烧法、湿式氧化法、罐储滴排进常规污水处理设施等方法进行处理。但几种方法分别存在投资大、处理费用高、设备易腐蚀、易产生二次污染以及对常规污水处理设施造成较大冲击、影响正常处理效果等缺点。QBR生物强化技术不同于普通生物处理工艺,做为一种高效生物处理技术,不仅对碱渣进行高效的无害化处理,还节省了工程的投资及运行费用。     

Evolution of microstructure of IGZO ceramic target during magnetron sputtering

In this study, influence of magnetron sputtering on indium gallium zinc oxide (IGZO) ceramic target was studied to improve its performance and utilization. Results indicated that state of the target such as target grain uniformity, micro defects, C element pollution, and secondary phase showed significant influence on magnetron sputtering process. Atoms located in small grains were easily bombarded out of IGZO target, and grains with slow sputtering rate protruded from target surface. Porous microstructure of IGZO ceramic created abnormal electric field of the target during sputtering, resulting in the poisoning of target. Moreover, more indium atoms were sputtered from the target, and the proportion of In after sputtering decreased by 0.62–0.97%. The difference in sputtering rates between secondary phase and main phase led to the formation of IGZO cladding layer with poor conductivity under the combined action of sputtering and re-sputtering. In sum, these findings may provide strong guidance for further improvement and performance enhancement of IGZO sputtering target.     

Current approaches to waste polymer utilization and minimization: a review

The mass production of polymer products, in particular plastics, and their widespread use depending on the inherent advantages they have, make these materials ironically a threat to life on Earth. Polymer recycling is being considered as one of the most widely accepted remedies to the threat of growing amounts of plastic waste by both the public and scientists. In practice, recycling is associated with many difficulties, such as problems related to separation, sorting and cleaning operations, lack of fiscal subsidies, instability of selective garbage separation programs, high transport and electricity costs, etc. Still, a large section of society and the authorities agree on the necessity and importance of recycling to protect the environment, and natural habitats and resources for future generations in a balanced manner to conserve raw materials, and to reduce energy consumption, municipal solid waste production and greenhouse gas emission. The recycling effort is almost endless in itself and includes a variety of approaches such as refurbishing, mechanically reshaping, chemically treating, thermally utilizing, etc. Some novel approaches such as application in carbon capture or synthesis of carbon nanostructures from the plastic waste are among the new process technologies of recycling. From traditional and promising polymer waste utilization approaches, this review will highlight sustainable methods to reduce impacts of plastic waste on the environment. © 2018 Society of Chemical Industry