从废电线电缆中回收金属铜的新方法

<正> 一般废旧电缆的表皮和一部分较粗的电线均可以用轧辊轧开,回收铜和部分塑料,但电缆中的细线及大部分软导线、仪表软带等几乎无法处理。美国曾提出将废电线电缆切碎,再用溶剂浸泡后分选,还有人提出以有机溶剂将电线塑料溶解实现铜塑分离,而后再从溶剂中回收塑料,但由于技术     

废印刷线路板中稀贵金属的回收现状

由于稀贵金属特殊的物理和化学性能，已成为电子元器件中不可缺少的成分。然而随着电子工业的发展，大量寿命已到的印刷线路板已开始报废。印刷线路板材料构成复杂，若不及时有效的分离处理，不仅造成严重的环境污染，还导致大量宝贵资源的浪费。发达国家采用物理的或化学的方法对稀贵金属进行回收，积累了一些经验，而我国还几乎是空白。实践证明，先用物理方法进行稀贵金属的富集，然后进行冶炼提纯比较有效。     

废线路板跨区域回收系统模拟与环境影响评价

针对废线路板在收集与处置过程中,各区域存在跨地区协调性弱、处置能力不匹配等问题,使用最小距离最大流（MDMF）模型对废线路板跨区域最优流动路径及流量进行模拟,并对优化结果进行环境影响评价。结果表明：随着废线路板产生量逐年增加,根据模拟优化的跨区域回收路径,拥有典型废线路板处理技术的地区,如广东、湖北等都能达到其最大产能,且该条件下环境影响程度较小。本研究为废线路板回收系统的区域协调规划提供了理论支撑。     

从废弃印刷线路板中回收金的试验研究

试验研究了采用硫脲法有效地从废弃印刷线路板中回收金。试验结果表明，硫脲回收金的主要影响因素有：温度、硫脲质量浓度、Fe^3＋质量分数、浸出时间、硫酸体积分数；合适的浸出条件是：固液比为1：5，浸出温度为35℃，硫脲质量浓度为10g／L，Fe^3＋质量分数为0．3％，浸出时间为1h。硫酸体积分数为5％。     

侧吹熔池熔炼废线路板工艺及装置

通过分析国内外处置废线路板技术的优缺点,提出了采用侧吹熔池熔炼技术协同处置废线路板,分析了该技术在处理废线路板等含铜多金属固废上的技术优势,详细描述了协同处置工艺流程、工艺特点及侧吹炉结构特征,侧吹熔池熔炼废线路板具有原料适应性强、能耗低、环境友好及金属回收率高等技术特点。     

带元件废印刷线路板中金的回收工艺

带元件的废印刷线路板多种金属共存,在采用氰化法浸取金的过程中,金的质量浓度随浸取时间的变化呈先升高后降低的曲线特征。如果反应时间控制不当,已经溶解的金就会被废印刷线路板上锌、镍等金属还原。为了提高金的回收率,研究了低氰化物质量浓度、短浸出时间的两次逆流浸金工艺,使金的回收率达到99%以上,废印刷线路板表层残余Au品位在3 g/t以下。     

废催化剂中铜锌的回收

迄今为止,我国石油农药化肥等化工领域中用过的铜锌催化剂,大都当成垃垃废弃,有的倒入江河,有的用于铺路填坑。大厂一次卸下的废催化剂上百吨,小厂也有两吨多。国内目前尚未公开发表铜锌催化剂用后回收再用的报道。。由于用来制造催化剂的铜锌原料不仅量大而且要求纯度很高,为此,我们对合成甲醇使用过的铜锌铝系催化剂。回收再制进行了实验室和生产上应用的     

从废催化剂中回收钼的研究

研究了从含钼、镍废催化剂中回收钼的方法及生产工艺流程.该流程简单,生产效益高.钼产品质量达到了国际标准,钼回收率大于90%.     

从废催化剂中回收钼的工艺流程研究

介绍了采用加碱氧化焙烧—水浸—溶剂萃取—酸沉等过程从废催化剂中回收钼酸铵的工艺,考察了加碱量、焙烧温度对钼的浸出率的影响,对影响钼溶剂萃取过程的因素进行了初步分析。实验研究结果表明该工艺钼总回收率大于８５％,产品钼酸铵质量达到ＧＢ３４６０－８２工业一级标准。     

Hydrometallurgical Process for Copper Recovery from Waste Printed Circuit Boards (PCBs)

Present paper focuses on the selective recovery of copper from the enriched ground printed circuit boards (PCBs) using leaching and solvent extraction. The metal-enriched ground sample obtained from the beneficiation of the sized PCBs in a laboratory scale column type air separator contained mainly 49.3% Cu, 3.83% Fe, 1.51% Ni, 5.45% Sn, 4.71% Pb, and 1.85% Zn. The leaching of the enriched sample with 3.5 mol/L nitric acid dissolved 99% copper along with other metals at 323 K temperature and 120 g/L pulp density in 1 h time. The composition of the leach liquor with wash solution was found to be 42.11 g/L Cu, 2.12 g/L Fe, 4.02 g/L Pb, 1.58 g/L Zn, and 0.4 g/L Ni. The McCabe–Thiele plot indicated the requirements of three counter-current stages for maximum extraction of copper from the leach liquor at pH 1.5 using 30, 40, and 50% (v/v) LIX 984 N at the phase ratios (A/O) of 1:3, 1:2, and 1:1.5, respectively. The counter-current simulation studies show the selective extraction of 99.7% copper from the leach liquor feed of 1.5 pH in three stages with 50% LIX 984 N at A/O phase ratio of 1:1.5. The stripping of copper from the loaded organic with sulfuric acid produced copper sulfate solution from which copper metal/powder could be recovered by electrolysis/ hydrogen reduction.     

过硫酸钠直接回收废电路板金属富集体中的铜

考察了过硫酸钠浓度、硫酸加入量、搅拌速度、温度和固液比对过硫酸钠直接回收废电路板金属富集体中铜的影响。结果表明,增加过硫酸钠浓度、搅拌速度和升高温度有利于铜的回收。在45℃、固液比0.004(g/mL)、搅拌速度500r/min、过硫酸钠浓度0.2mol/L、时间60min的条件下,铜的回收率达96.5%。     

空气氧化—氨浸出废旧电路板中的铜

提出了在氨水—硫酸铵体系下鼓入空气浸出废旧电路板中铜的新工艺。考察了氨水浓度、硫酸铵浓度、固液比、反应温度、通入空气流量和浸出时间对铜浸出率的影响。结果表明,在下述最佳浸出条件下,渣计铜浸出率达到96.67%:氨水浓度2mol/L,硫酸铵浓度2mol/L,固液比1∶20,反应温度25℃、通入空气量8m3/h、浸出时间4h。     

以废旧印刷电路板为原料制备超细铜粉的研究

介绍了一种以废旧印刷电路板为原料经物理分选、NH3-(NH4)2SO4-H2O体系浸出铜、萃取提纯、H2SO4反萃得到CuSO4溶液,而后蒸发冷却结晶获得CuSO4.5H2O晶体,以此为原料制备超细铜粉的方法。制备超细铜粉的最佳试验条件为:先制备出Cu2O沉淀配制成100 mL悬浊液,在PVP加入量为6 g(200 mL溶液)、搅拌速度为400 r/min、NaH2PO2.H2O加入量是理论量的4倍,加料方式为将NaH2PO2.H2O分两次加入100 mL的Cu2O悬浊液中,50℃时加入40mL后以1.2℃/min的速度升温到75℃时加入剩下的60 mL,用2 g/L的苯并三氮唑溶液浸泡清洗后的超细铜粉0.5 h进行表面改性,在此条件下制备的铜粉粒度均匀,结晶度高,无团聚现象,该超细铜粉可以用于多层功能陶瓷电容器(MLCC)的电极上。     

废旧印刷电路板中铜的回收生产现状

铜是电路板中含量最高的金属,也是资源化回收废旧电路板时研究和关注的重点。本文主要阐述废旧印刷电路板中有价金属铜的回收生产现状,并给出了对策及建议。     

硫氰酸盐—双氧水体系回收废电路板中的金

采用硫氰酸盐—双氧水浸金体系从废电路板中回收金和银,详细考察了硫氰酸盐浓度、双氧水浓度、溶液pH、固液比、温度和搅拌速度等对金银浸出率的影响。结果表明,在0.05 mol/L H2O2、0.4mol/L SCN-、固液比1/250、搅拌速度200r/min、室温(~15℃)浸取8h的条件下,金、银浸出率分别超过90%和79%,铅浸出率为9.7%。     

用N902萃取废印刷线路板浸出液中的铜

以N902为萃取剂,从废弃印刷线路板氨性浸出液中萃取回收铜,研究萃取剂浓度、相比(O/A)、萃原液初始pH和时间对铜萃取率的影响。结果表明,室温下N902萃取铜最优条件为:萃取剂浓度15%、O/A=1∶2、料液初始pH=10、萃取时间2.5min。在此条件下Cu2+萃取率98.62%,用2mol/L硫酸溶液对负载有机相进行一级反萃4min,Cu2+反萃率达89.91%,其溶液可满足电积提铜的要求。     

废旧印刷电路板回收利用的研究进展

简要介绍了印刷电路板的组成及特点,重点分析了常规方法和新技术在废旧印刷电路板回收利用中的应用及研究进展,并展望了废旧印刷电路板回收利用技术的发展方向。     

Precious Metals Recovery from Waste Printed Circuit Boards by Gravity Separation and Leaching

ABSTRACT

This study focuses on the recovery of valuable metals, such as gold, silver, and copper, from the printed circuit boards of waste computers, using physical separation followed by leaching methods. Characterization studies revealed that resins and glass fibers were attached as grain together with base and precious metals. A hammer mill was employed as a second stage crusher to disintegrate the different components of the printed circuit board, thus improving the selectivity and recovery of metals. Separation studies using a laboratory-scale shaking table showed that 33% of the feed was removed as a light product and 96.8% of Au, 96.7% of Ag, and 97.7% of Cu were recovered in heavy fraction. Leaching the light fraction using 3 M H₂SO₄ and 0.33 M HNO₃ at 80°C for two h resulted in greater than 90% extraction of Cu. Au and Ag were dissolved at room temperature with a leaching solution of 0.2 M S₂O₃ ^2-, 0.02 M CuSO₄, and 0.2 M NH_3.H₂O, which provided a recovery of more than 59% of Au and 98% of Ag within eight h. Direct leaching tests using optimized conditions were also implemented on the crushed sample, and 45% of Au, 87.6% of Ag, and 70.8% of Cu were extracted.     

A Review on Recovery of Copper and Cyanide From Waste Cyanide Solutions

The mainstream technology for leaching gold from gold ore is still leaching in aqueous alkaline cyanide solution. However, when copper minerals are present in the gold ore, high levels of free cyanide must be maintained during leaching because many common copper minerals react with cyanide, forming copper cyanide complexes that deplete the solution of free cyanide. This results in a significant economical penalty through excessive cyanide consumption and loss of valuable copper in tails. Environmental constraints controlling the discharge of cyanide from mining industry are being tightened by local governments worldwide. The solution chemistry of copper in cyanide solution and various technologies for the recovery of copper and cyanide from barren gold cyanide solutions were reviewed in the paper. Direct recovery methods are mainly based on the acidification–volatilization–reneutralization (AVR) process or its modifications. These processes are not very efficient for treating low cyanide solutions and high metal cyanide solutions due to their substantial operational cost. Indirect recovery technologies by activated carbon, ion-exchange resins (IX) and solvent extraction (SX) have been extensively studied. The basic principle of these technologies is to pre-concentrate copper (and part of cyanide) into a small volume of eluant or stripping solution. The copper and cyanide in the resulted solutions can be further recovered by AVR or similar processes or by the electrowinning process. Activated carbon is only suitable for use as a polishing process to remove cyanide to lower levels from those cyanide solutions where the cyanide content is already low. Compared to activated carbon, ion exchange resins are less easily poisoned by organic matter and can usually be eluted at room temperature, and selectivity for particular metals can be achieved by the choice of the functional group incorporated into the bead or by the selective elution process. Solvent extraction process developed base on guanidine and modified quaternary amines exhibit relative fast extraction kinetics and can be operated in a continuous manner. It will be necessary to thicken and wash the solids in order to produce a clarified feed solution while treating the slurry from operations using carbon-in-pulp (CIP) for the recovery of gold. Other copper and cyanide recovery technologies such as biosorption or direct electrowinning were also proposed, but they have still not found their way to practical application.