阴极射线管锥玻璃碳热还原强化酸浸脱铅

通过碳热还原强化酸浸的方法高效去除CRT锥玻璃中的重金属铅,同时将脱铅残渣转变为玻璃微珠产品。实验考察了还原温度、碳粉加入量和保温时间对锥玻璃中铅浸出效果的影响。研究结果表明,经碳热还原预处理后锥玻璃中的氧化铅转变为单质铅并主要富集在玻璃微珠表面,通过酸浸处理可高效回收锥玻璃中的铅。当锥玻璃与10%碳粉混合均匀,在1 200℃条件下处理30 min,锥玻璃中铅的浸出效率可达94.80%,脱铅残渣为粒径范围1~15μm的玻璃微珠。     

废旧电视机CRT玻壳中Pb的浸出及豁免处置

采集黑白和彩色废旧电视机的阴极射线管(CRT)玻璃外壳(玻壳),利用X射线荧光分析了其化学组成,并采用浸出毒性浸出方法对玻壳中Pb的浸出进行了研究.结果表明,不同类型的CRT玻壳铅含量(以PbO计)差别较大,彩色CRT屏玻璃最低(0.07%),黑白CRT屏玻璃、锥玻璃次之(2.83%),而彩色CRT锥玻璃最高(22.6...     

机械活化对CRT锥玻璃浸出动力学的影响

通过研究CRT锥玻璃经机械活化后在硝酸溶液体系中浸出反应动力学规律,考察了机械球磨转速、浸出温度以及硝酸初始浓度对锥玻璃中铅的浸出效果影响。研究结果表明,锥玻璃经机械活化预处理后,反应活性显著增强,锥玻璃中铅浸出率大幅度提高。浸出反应的表观活化能和反应级数由109.4 kJ/mol和0.79降至54.3 kJ/mol和0.51。     

CRT锥玻璃碳热还原强化玻璃分相脱铅

通过碳热还原强化玻璃分相的方法实现CRT含铅锥玻璃高效脱铅的同时制备出高硅氧玻璃粉末。将锥玻璃与一定量B_2O_3混合后在还原气氛下进行热处理。在热处理过程中,锥玻璃中的部分氧化铅被还原成单质铅并从玻璃相中析出,剩下未被还原的氧化铅则主要富集在呈网状连通结构的富B_2O_3相中。析出的单质铅与富B_2O_3相通过5 mol·L~(-1)的硝酸高效去除。当锥玻璃与20%的B_2O_3混合均匀,在1 000℃还原气氛下保温30 min,铅的酸浸脱除效率可达99.80%,并得到SiO_2含量大于95%的高硅氧玻璃粉末。高硅氧玻璃粉末可作为催化剂载体、吸附剂或者重新熔炼制备成与石英玻璃类似的耐高温、透光性强的高硅氧玻璃,故为含铅玻璃的无害化与资源化利用提供了一条新的途径。     

利用CRT屏玻璃制备板状泡沫玻璃

以废旧阴极射线管(CRT屏)为主要原料,混合碳粉作为发泡剂,硼砂为助熔剂、稳泡剂,利用烧结法制备出的板状泡沫玻璃是一种高性能无机建筑保温材料。利用TG-DSC-MS研究分析了CRT屏玻璃的热性能与发泡剂协同作用的关系。配合料被预先压制成板块状,然后在发泡温度下进行烧成。研究了发泡剂碳粉的含量、发泡温度和发泡时间与其结构、性能的关系。研究分析表明,以废CRT屏玻璃为主要原料、碳粉为发泡剂,将混合料压制成块,烧制出板状泡沫玻璃。其较佳的发泡温度为850℃、碳粉的最佳用量范围为0.3%～0.5%,较好的发泡时间为30 min。烧制的板状泡沫玻璃的密度为0.292 g/cm3。在相同的制备条件下,随着发泡温度的升高,气泡孔径也呈现增大趋势,孔壁也逐渐变薄。随着发泡时间逐渐增加,气孔的直径迅速增大,并有形成连通孔。     

利用废CRT屏玻璃为原料制备泡沫玻璃

以废阴极射线管(CRT)屏玻璃为主要原料,碳黑为起泡剂,采用粉末烧结法制备了低密度保温泡沫玻璃。通过扫描电镜(SEM)、导热系数测定仪等分析手段,研究了起泡剂的用量、发泡温度和发泡时间对泡沫玻璃泡径、密度、热学性能以及机械力学性能的影响。结果表明,在相同烧制工艺条件下,随起泡剂掺加量增加,烧制所得的泡沫玻璃密度成"V"型变化;当其掺加量为0.20%时,泡沫玻璃在密度、孔径分布以及力学性能上均达到最佳。随着发泡温度的提高和发泡时间的延长,密度会逐渐减小,泡沫玻璃的气泡会逐渐增大,以致产生连通现象。当发泡温度为820℃、发泡时间为30min时烧制的泡沫玻璃密度为0.180 g/cm3,导热系数为0.0695 W/(m.K)。     

含锌铅废物碱法浸出工艺

各种工业过程中产生的大量含锌铅废物中含有大量的有毒重金属.必须在危险废物处置场所进行处置,这导致处置成本增加.采用强碱浸出的方法回收含锌铅废物中的Zn和Pb,考察了浸出温度、NaOH浓度、液固比(浸提液体积/原料质量)和搅拌速率等工艺参数对Zn、Pb和杂质金属浸出率的影响,得出其最佳工艺条件.在温度为70℃、液固比为13:1、搅拌速率为800r/min条件下.用5 mol/L的NaOH浸出含锌铅废物,浸出液中Zn和Pb的质量浓度分别达33.47、11.21 g/L,浸出率分别达到94.24%和93.47%.     

火焰原子吸收法测定酸洗废液中重金属的应用研究

针对采用火焰原子吸收法直接测定酸洗废液中铬、镍、铅3种重金属数据准确性较差的问题,研究了酸洗废液重金属测定存在的干扰因素及采用标准加入法消除干扰的可行性。结果表明,若用火焰原子吸收法直接测定酸洗废液会受到来自基体的干扰,铬、镍、铅的回收率分别为54.0%、84.9%、89.5%,均出现了回收率不达标的情况。通过干扰试验可知,铬主要受到Fe~(2+)的化学干扰及溶液的物理干扰,镍和铅主要受溶液的物理干扰作用,均使测定结果偏低。镍、铅可直接采用标准加入法测定,R~2分别可达0.999 1、0.999 7,镍、铅的回收率分别为97.5%、101.5%;但对于铬,需先优化测定条件和加入干扰抑制剂后,才能采用标准加入法测定,此时铬的相对标准偏差为1.41%,回收率为104.9%。该测定方法精确度和准确度良好,可用于酸洗废液中重金属的测定。     

玻璃分相法脱除CRT屏玻璃中重金属钡

玻璃分相的方法可以将重金属钡从CRT屏玻璃中高效脱除。该方法将CRT屏玻璃与一定量的B_2O_3混合后在空气气氛下进行热分相处理。在热分相处理过程中,屏玻璃中的B_2O_3与SiO_2逐渐分离,形成2个独立的相(富B_2O_3相和富SiO_2相)。CRT屏玻璃中的重金属钡和其他碱金属氧化物在分相过程中主要富集在呈网状连通结构富B_2O_3相中。将分相处理产物经5 mol·L~(-1)的硝酸在90℃条件下浸泡30 min,即可将富B_2O_3相以及其中包含的重金属钡一并去除,得到SiO2含量超过95%的高硅氧玻璃粉末。实验结果表明,当反应温度为1 100℃,B_2O_3添加量为30%,保温时间为30 min时,钡的脱除率可以达到98.84%,为废弃CRT屏玻璃无害化处理与资源化利用提供了一条新的途径。     

响应面法优化超临界CO_2流体处理油基钻屑工艺

采用超临界CO2流体处理油基钻屑,考察了萃取温度、萃取压力以及分离温度对油基钻屑油相回收率的影响,在单因素实验基础上,应用响应面法最终确定超临界CO2流体处理油基钻屑的最佳条件为:萃取压力21 MPa,萃取温度55℃,分离温度64℃。各因素对油相回收率的影响依次为:萃取压力分离温度萃取温度。在最佳条件下,油相回收率为99.65%,处理后废渣油相含量0.08%,满足《农用污泥中污染物控制标准》(GB 4284-84),同时达到GB18599-2001的Ⅱ类固废物要求,可安全处置。     

Rapid screening of different chelating agents in the lead extraction from cathode ray tube (CRT) funnel glass

The cathode ray tube (CRT) glass is one of the most important problem that afflicts the electronic waste disposal whose solution lies in the identification of efficient and ecofriendly processes to detoxify and reutilize lead-contained funnel glass. This study is focused on a rapid screening of different chemical and mechanochemical processes to reduce lead content in waste CRT glass downgrading the risk correlated to it. In particular, as a possibility to clean waste CRT glass, treatments of lead-containing glass with different chelating agents (EDTA, NTA, ATMP, EDTMP and HEDP) were performed to evaluate their extractive capabilities. Furthermore, the influence of the grinding, the chelating agent functional groups (polyamino-carboxylic acid, carboxylic acid, and polyamino phosphonic acid), and the time and the temperature on lead content reduction were analyzed. ESEM and EDS analysis were performed on all the samples to evaluate the lead amount before and after the treatments.     

Waste recycling of cathode ray tube glass through industrial production of transparent ceramic frits

ABSTRACT

Cathode ray tube (CRT) glass contains significant amounts of alkali and alkaline earth oxides, making it a useful by-product for use in the ceramics industry. Among the various alkali oxides present, those of strontium (SrO), calcium (CaO), and magnesium (MgO) are well known flux materials used widely in the ceramics industry. The most effective flux, SrO, is also a limited resource. In this study, we aimed to develop an environmentally friendly, low-cost method for recycling CRT waste by using it to produce transparent ceramic frits on an industrial scale. Four different samples were fabricated containing between 13 and 25 wt.% CRT panel glass. The color values, sintering behaviors, phases, and microstructural properties of the corresponding samples were analyzed and compared. The results indicate that a composition containing 25 wt.% CRT panel glass could pass the ISO 10545 test. Thus, the results confirm that CRT glass can be used to inexpensively produce transparent ceramic frits at an industrial scale.

Implications: The recycling of electronic waste (e-waste), including CRT waste, has increased by high rates of computer and TV consumption. This increase in consumption is likely to increase the rate at which CRTs are discarded. However, CRTs cannot be recycled in the desired amount. Owing to the high silicate, barium and strontium content of CRTs, it has great potential for glass ceramics such as frits. CRT panel glass to produce commercial transparent frit at low cost through an industrial production route for use in single-fire sintered products. Thus, CRT wastes can be recycled cost-effective, sustainable and environmentally friendly.     

废旧计算机CRT监视器的管理和资源化技术

分析了废旧计算机CRT监视器的材料组成 ,并且阐明了它对环境和人体健康的潜在危害 ,同时比较了国内外相关管理现状 ,总结了目前已有的资源化技术 ,主要是拆解技术 ,并且介绍了目前国内外的资源化实践 ,并提出有关建议。     

Evaluation of Biopolymer-Modified Concrete Systems for Disposal of Cathode Ray Tube Glass

Abstract

Cathode ray tubes (CRTs) from computer monitors and television sets, which contain significantly high percentage of lead (Pb) by weight, represent an enormous and growing hazardous waste problem in the United States and worldwide. As a result, new technologies are needed to cope with current CRT waste stream and increased hazard and build new markets for its recycled components, developing commercially viable concrete composites, as well as minimizing CRT disposal problems. In this study, commercially available biopolymers, such as xan-than gum, guar gum, and chitosan, were used to encapsulate CRT glass waste, reducing the Pb leachability. The biopolymers utilized contain a number of useful functional groups, such as carboxyl (xanthan), hydroxyl (guar), and amino groups (chitosan), which play important roles in binding and stabilizing Pb onto concrete structures. The use of biopolymers in concrete systems can create a stable interpenetrating cross-linking composite that will last for many years. Results from these new composites show 30% higher compressive strength than standard concrete and a sharp decrease in lead leachability from several thousand milligrams per liter initially to an amount of three-tenths milligrams per liter or lower values (much lower than the U.S. Environment Protection Agency standard for hazardous waste of 5 mg/L by the toxicity characteristic leaching procedure test), and for some of the composites leachability is below even the standard for drinking water. This efficient and cost-effective CRT–biopolymer-concrete composite is a new class of biopolymer-modified material that can potentially perform a significant role in relieving the current CRT issue.     

Evaluation of biopolymer-modified concrete systems for disposal of cathode ray tube glass

Cathode ray tubes (CRTs) from computer monitors and television sets, which contain significantly high percentage of lead (Pb) by weight, represent an enormous and growing hazardous waste problem in the United States and worldwide. As a result, new technologies are needed to cope with current CRT waste stream and increased hazard and build new markets for its recycled components, developing commercially viable concrete composites, as well as minimizing CRT disposal problems. In this study, commercially available biopolymers, such as xanthan gum, guar gum, and chitosan, were used to encapsulate CRT glass waste, reducing the Pb leachability. The biopolymers utilized contain a number of useful functional groups, such as carboxyl (xanthan), hydroxyl (guar), and amino groups (chitosan), which play important roles in binding and stabilizing Pb onto concrete structures. The use of biopolymers in concrete systems can create a stable interpenetrating cross-linking composite that will last for many years. Results from these new composites show 30% higher compressive strength than standard concrete and a sharp decrease in lead leachability from several thousand milligrams per liter initially to an amount of three-tenths milligrams per liter or lower values (much lower than the U.S. Environment Protection Agency standard for hazardous waste of 5 mg/L by the toxicity characteristic leaching procedure test), and for some of the composites leachability is below even the standard for drinking water. This efficient and cost-effective CRT-biopolymer-concrete composite is a new class of biopolymer-modified material that can potentially perform a significant role in relieving the current CRT issue.     

废弃等离子显示屏玻璃中重金属化学形态分布

通过BCR3步和BCR4步连续提取法,对等离子体显示屏玻璃中重金属的化学形态进行研究。结果表明,BCR3步连续提取法对废弃等离子体显示屏玻璃中重金属的提取比BCR4步连续提取法更稳定。废弃等离子体显示屏玻璃中Zn、Cu和Ag化学形态分布存在差异。BCR3步和BCR4步连续提取法均认为Ag以残渣态为主要赋存形态,对环境影响比较小;Cu的可交换与弱酸可溶态或交换态和碳酸盐结合态含量较少,潜在的环境风险也比较小;BCR3步和BCR4步连续提取法对Zn的形态分布结果评价不一致,BCR3步连续提取法表明Zn主要以可交换与弱酸可溶态为主,对环境影响较大,而BCR4步连续提取法结果认为Zn是以铁锰氧化态为主要存在形态。     

废电子电器回收处理体系研究

分析了废电子电器回收处理体系的问题,提出了一种适合我国国情的废电子电器回收处理体系模式,并对国家对废电子电器回收处理体系的支持问题进行了讨论。     

Pollution due to hazardous glass waste

Pollution resulting from hazardous glass (HG) is widespread across the globe, both in terms of quantity and associated health risks. In waste cathode ray tube (CRT) and fluorescent lamp glass, mercury and lead are present as the major pollutants. The current review discusses the issues related to quantity and associated risk from the pollutant present in HG and proposes the chemical, biological, thermal, hybrid, and nanotechniques for its management. The hybrid is one of the upcoming research models involving the compatible combination of two or more techniques for better and efficient remediation. Thermal mercury desorption starts at 100 °C but for efficient removal, the temperature should be >460 °C. Involvement of solar energy for this purpose makes the research more viable and ecofriendly. Nanoparticles such as Fe, Se, Cu, Ni, Zn, Ag, and WS₂ alone or with its formulation can immobilize heavy metals present in HG by involving a redox mechanism. Straight-line equation from year-wise sale can provide future sale data in comparison with lifespan which gives future pollutant approximation. Waste compact fluorescent lamps units projected for the year 2015 is 9,300,000,000 units and can emit nearly 9,300 kg of mercury. On the other hand, CRT monitors have been continuously replaced by more improved versions like liquid crystal display and plasma display panel resulting in the production of more waste. Worldwide CRT production was 83,300,000 units in 2002 and can approximately release 83,000 metric tons of lead.     

基于因特网的危险废物转移联单系统研究与开发

危险废物转移联单是跟踪危险废物转移和处理处置的基本方法 ,也是实施危险废物全过程管理的有效工具。然而 ,目前使用的纸质联单系统 ,运行过程繁杂、周期长、耗费人力和物力 ,与现代化管理不相适应。本文提出了符合中国国情的电子化转移联单解决方案 ,论述了系统的设计开发过程和运行情况。这一系统采用了因特网技术 ,能实现联单运行的电子化和自动化 ,简化运行过程 ,提高效率 ,为我国危险废物转移的电子化管理奠定了基础