A novel approach to recycling of glass fibers from nonmetal materials of waste printed circuit boards

The printed circuit boards (PCBs) contain nearly 70% nonmetal materials, which usually are abandoned as an industrial solid-waste byproduct during the recycling of waste PCBs. However those materials have abundant high-value glass fibers. In this study, a novel fluidized bed process technology for recycling glass fibers from nonmetal materials of waste PCBs is studied. The recycled glass fibers (RGF) are analyzed by determination of their purity, morphology and surface chemical composition. This process technology is shown to be effective and robust in treating with nonmetal materials of waste PCBs. The thermoset resins in the nonmetal materials are decomposed in the temperature range from 400 °C to 600 °C. And the glass fibers are collected at high purity and recovery rate by the cyclone separators without violating the environmental regulation. This novel fluidized bed technology for recycling high-value glass fibers from nonmetal materials of waste PCBs represents a promising way for recycling resources and resolving the environmental pollutions during recycling of waste PCBs.     

探究聚氨酯废弃软泡的资源化利用技术(上)

软质聚氨酯泡沫塑料废旧物的回收利用无疑对环境保护和资源利用是有利的,由于聚氨酯的用量较大,而近期原料价格居高不下,其废弃物回收资源化利用市场前景看好。针对废旧聚氨酯软泡塑料的循环利用形势所迫,分别论述了废旧聚氨酯软泡塑料的物理回收利用技术;废旧聚氨酯软泡塑料的化学回收利用技术;废旧聚氨酯软泡回收利用的粘结加压成型和挤出成型技术,以及废旧聚氨酯软泡回收利用热解法制作填料技术等的工艺特点、加工方法,同时指出其社会效益、经济效益和市场前景。     

A model for simulating the grinding and classification cyclic system of waste PCBs recycling production line

Crushing and separating technology is widely used in waste printed circuit boards (PCBs) recycling process. A set of automatic line without negative impact to environment for recycling waste PCBs was applied in industry scale. Crushed waste PCBs particles grinding and classification cyclic system is the most important part of the automatic production line, and it decides the efficiency of the whole production line. In this paper, a model for computing the process of the system was established, and matrix analysis method was adopted. The result showed that good agreement can be achieved between the simulation model and the actual production line, and the system is anti-jamming. This model possibly provides a basis for the automatic process control of waste PCBs production line. With this model, many engineering problems can be reduced, such as metals and nonmetals insufficient dissociation, particles over-pulverizing, incomplete comminuting, material plugging and equipment fever.     

包装废弃 PET 瓶的处理及再生资源化技术 研究进展

废弃 PET 作为生活与工业中随处可见的固体废弃物之一,因其具有 稳定的物理化学特性而难以在自然界中降解,是目前需要回收处理的重要固 体废弃物之一。概括了废弃 PET 主要有三种回收技术,即物理回收法、化学 回收法和生物回收法,并分别简述三种回收法的原理、优缺点和研究现状。 可见,回收废弃 PET 主要采用物理回收法,化学回收法作为辅助技术,生物 回收法仍处于研究阶段。化学回收法能有效实现废弃 PET 资源的高效利用, 因而我国在废弃物处理技术发展进程中的关键是通过化学回收法将废弃 PET 进行高效率降解转化,再将产物用于制备新型的高纯度化工原料,以提高废 弃 PET 的再生资源化利用率,使利用率达到 90% 以上。     

废旧塑料的回收利用进展

塑料的回收利用是近些年来再生资源研究的一个非常重要的方向.废旧塑料,尤其是消费后废旧塑料是回收利用的重点.从回收方法和途径阐述了有关废旧塑料的各类最新的回收利用技术和塑料循环周期模型,进而说明积极研究废旧塑料循环利用的新方法和新工艺具有十分重要的意义.     

Optimizing the operating parameters of corona electrostatic separation for recycling waste scraped printed circuit boards by computer simulation of electric field

The printed circuit board (PCB) has a metal content of nearly 28% metal, including an abundance of nonferrous metals such as copper, lead, and tin. The purity of precious metals in PCBs is more than 10 times that of rich-content minerals. Therefore, the recycling of PCBs is an important subject, not only from the viewpoint of waste treatment, but also with respect to the recovery of valuable materials. Compared with traditional process the corona electrostatic separation (CES) had no waste water or gas during the process and it had high productivity with a low-energy cost. In this paper, the roll-type corona electrostatic separator was used to separate metals and nonmetals from scraped waste PCBs. The software MATLAB was used to simulate the distribution of electric field in separating space. It was found that, the variations of parameters of electrodes and applied voltages directly influenced the distribution of electric field. Through the correlation of simulated and experimental results, the good separation results were got under the optimized operating parameter: U=20-30 kV, L=L(1)=L(2)=0.21 m, R(1)=0.114, R(2)=0.019 m, theta(1)=20 degrees and theta(2)=60 degrees .     

塑料包装废弃物的化学回收技术研究进展

目的 以聚烯烃和聚对苯二甲酸乙二醇酯(PET)为研究对象综述近5年来塑料包装废弃物的化学回收技术,以期为塑料包装废弃物的资源化技术发展趋势提供参考。方法 通过收集与整理相关文献,阐述聚烯烃类以及PET包装废弃物的化学回收方法、常用催化剂、反应装置等,分析催化剂、反应装置、反应温度等条件对产物收率、成分的影响。结论 未来短期内柔性包装材料仍然会以聚烯烃、聚酯等传统石油基材料为主。化学回收是废塑料资源化的一种重要手段,传统催化剂的改良、新型催化剂的开发以及反应装置的优化将是该领域未来的研究重点。     

Critical rotational speed model of the rotating roll electrode in corona electrostatic separation for recycling waste printed circuit boards

Waste printed circuit board (PCB) is increasing worldwide. The corona electrostatic separation (CES) was an effective and environmental protection way to recycle resource from waste PCBs. The aim of this paper is to analyze the main factor (rotational speed) that affects the efficiency of CES from the point of view of electrostatics and mechanics. A quantitative method for analyzing the affection of rotational speed was studied and the model for separating flat nonmetal particles in waste PCBs was established. The conception of "charging critical rotational speed" and "detaching critical rotational speed" were presented. Experiments with the waste PCBs verified the theoretical model, and the experimental results were in good agreement with the theoretical model. The results indicated that the purity and recycle percentage of materials got a good level when the rotational speed was about 70 rpm and the critical rotational speed of small particles was higher than big particles. The model can guide the definition of operator parameter and the design of CES, which are needed for the development of any new application of the electrostatic separation method.     

废弃氧化铟锡中铟的回收技术综述

废弃氧化铟锡(ITO)的回收利用对我国铟资源的可持续发展与环境保护具有重要意义。本文首先对废弃ITO的回收潜能进行了初步评估;进而系统概述了废弃ITO回收技术的研究进展,回收工艺主要包括湿法与火法,分析比较了现有回收技术的优缺点;在此基础上,指出了当前废弃ITO资源化处理过程中存在的主要问题及相应的解决对策;最后展望了废弃ITO资源化利用未来的研究趋势,开发高效、环境友好型回收工艺是今后重要的研究课题。     

我国农村废弃物分类资源化利用战略研究

本文围绕我国农村废弃物分类资源化利用问题,论述了农村废弃物的产生、危害以及资源化利用的重要意义,评估了我国农村废弃物的产生量、地区分布特征及资源化利用情况,深入分析了农村废弃物资源化利用存在的突出问题,结合美丽乡村建设及农村废弃物资源化利用的发展趋势,制定了农村废弃物资源化利用的发展战略及分阶段目标,提出了我国未来农村废弃物资源化开发利用的保障措施和政策建议。     

生物粘合剂在废旧沥青材料再生应用中的研究进展

为充分利用道路行业以及建筑行业每年产生的大量废旧沥青材料,改善传统路面再生技术对旧料利用率低且对环境造成的不良影响,介绍了一种将生物粘合剂用于废旧沥青材料再生的方法。重点阐述了由猪粪热解得到的生物粘合剂对回收的废旧沥青材料和回收沥青瓦的改性再生方法,以及再生后材料的路用性能,指出存在的问题和未来进一步研究建议。现有研究表明,生物粘合剂加入到废旧沥青材料中能有效降低其粘度,改善其和易性,显著提高废旧沥青材料含量大的混合料的低温抗裂性和抵抗疲劳开裂性能,且其水稳定性和抗车辙性能均能满足规范要求,相比传统沥青路面旧料的再生利用方法具备优良的环境、经济和实施效益。将生物粘合剂用于废旧沥青材料再生行业具有广阔的发展前景,可以为在我国铺面工程中的研究应用提供参考。     

我国电子废弃物回收工艺研究进展

总结了处理电子废弃物的传统基本技术及其特点。针对传统工艺的缺陷综述了我国具有处理流程简单、成本低、资源利用率较高等优点的电子废弃物回收新工艺的研究进展,重点介绍了机械物理复合工艺处理废旧家电、废旧电池及废旧PCB板。同时提出了我国电子废弃物资源化方面的一些新动向和潜在的问题。     

乡村废弃蛋壳资源设计再造应用研究

目的 废弃蛋壳属于典型乡村废弃物,而乡村废弃物的累积会导致生态环境问题。因此,对此类资源进行有效利用是乡村生态文化建设的重要内容。方法 本文通过对乡村废弃蛋壳资源设计的再造工艺进行研究,将废弃蛋壳转化为一种新型塑合物材料。同时,本研究对该材料的可加工性能、稳定性能,以及外观表现效果进行了初步的测试,以研究材料的产品设计应用方向。在此基础上开展设计应用,并以问卷的形式,调研用户对设计成果的使用满意度。结果 开展基于乡村场景的设计应用实践,将废弃蛋壳设计再造为装饰品和生活用品。结论 设计再造的工艺将废弃蛋壳制成易于加工的新材料,使其具有独特的外表肌理、透光性、一定的稳定性,且能够自然地降解。设计应用流程简单,不需要专业设备,成本低、能耗少、对环境友好,适合于乡村场景下的小批量手工艺产品,展现乡土美感,具有一定应用前景。     

Theoretic model and computer simulation of separating mixture metal particles from waste printed circuit board by electrostatic separator

Traditionally, the mixture metals from waste printed circuit board (PCB) were sent to the smelt factory to refine pure copper. Some valuable metals (aluminum, zinc and tin) with low content in PCB were lost during smelt. A new method which used roll-type electrostatic separator (RES) to recovery low content metals in waste PCB was presented in this study. The theoretic model which was established from computing electric field and the analysis of forces on the particles was used to write a program by MATLAB language. The program was design to simulate the process of separating mixture metal particles. Electrical, material and mechanical factors were analyzed to optimize the operating parameters of separator. The experiment results of separating copper and aluminum particles by RES had a good agreement with computer simulation results. The model could be used to simulate separating other metal (tin, zinc, etc.) particles during the process of recycling waste PCBs by RES.     

Electrokinetic recovery of Cd, Cr, As, Ni, Zn and Mn from waste printed circuit boards: Effect of assisting agents

The printed circuit boards (PCBs) contains large number of heavy metal such as Cd, Cr, As, Ni, Zn and Mn. In this study, the use of electrokinetic (EK) treatment with different assisting agents has been investigated to recover the heavy metals from waste PCBs, and the effectiveness of different assisting agents (HNO₃, HCl, citric acid) was evaluated. The PCBs were first pre-treated by supercritical water oxidation (SCWO) process, then subjected to EK process. The heavy metal speciation, migration and recovery efficiency in the presence of different assisting agents during EK process were discussed. The mass loss of Cd, Cr, As and Zn during the SCWO process was negligible, but approximately 52% of Ni and 56% of Mn were lost in such a process. Experimental results showed that different assisting agents have significant effect on the behavior and recovery efficiency of different heavy metals. HCl was highly efficient for the recovery of Cd in waste PCBs due to the low pH and the stable complexation of Cl⁻. Citric acid was highly efficient for the recovery of Cr, Zn and Mn. HNO₃ was low efficient for recovery of most heavy metals except for Ni.     

废旧塑料再利用生产新材料的研究进展

废旧塑料的回收利用作为一项节约能源、保护环境的措施,普遍受到重视.本文概述了废旧塑料的再生利用途径,着重介绍了利用废旧塑料生产建筑、涂料等新材料的方法和工艺流程,并对废旧塑料的回收利用进行了展望.     

Evaluation of cleaner production audit in pharmaceutical production industry: case study of the pharmaceutical plant in Dalian,P. R. China

The pharmaceutical industry in China makes an important contribution to the national economy. However, the associated pollution problems cause gradual deterioration of the environment and impact adversely on the local community. Cleaner production (CP) technology, an effective way to reduce waste emission and save resources, has been widely employed in the pharmaceutical industry in the developed countries. Such technologies have been applied in a number of factories in China, although there is no integrated assessment and implementation procedure for implementing CP technologies in pharmaceutical plants. To solve such problems, a series of CP options are proposed and assessed here. CP is a powerful tool for decreasing waste production, limiting environmental pollution and natural resource depletion. Moreover, the return on investment in CP is quick, so it would seem that CP activities should be very much in demand by enterprises. Reality is less optimistic: frequently only limited interest is expressed, even after an explanation; business people hesitate to become actively involved. The processes in the pharmaceutical production industry produce a vast amount of waste, including wastewater with high concentrations of organic substances (the principal component), solid waste, and organic off-gas. To solve such problems, a series of CP options are proposed and assessed in this study. Having consideration to environmental impacts and economic efficiency, four groups of medium/high cost CP options were screened in an integrated assessment. To verify the proposed options, a case study was conducted in Degussa Luyuan, Northeast China. The characteristics of resource consumption and waste emission during the production process were identified. The proposed options were evaluated according to different aspects. An integrated CP system based on the proposed options was designed and then implemented in the factory. In three years of practical use, the productivity and quality of alcohol product were improved, with a reduction in waste and pollution and a marked increase in water/energy savings. This study provides theoretical and practical support for the extensive application of CP technologies and sustainable development in China’s pharmaceutical industry. These methods include ways to clean up production that are incorporated in the process design, reforming present production technologies, updating the equipment, exploiting new producing flowcharts, using cleaner energy, building recycling into the manufacturing process, recycling waste, enhancing management, developing environmental protection technology, and ensuring satisfactory end-of-pipe disposal.     

国内外生活垃圾焚烧发电技术进展

随着人们对环境方面要求的日益增长,垃圾合理处理在践行绿色发展理念和推动生态文明建设进程中发挥着越来越重要的作用。生活垃圾焚烧发电技术作为固废资源利用的一种方法,如今已经演变成为一种成熟的资源利用技术。分别从垃圾焚烧发电行业的上、中、下游,即从垃圾焚烧的原料性质、燃烧发电技术以及烟气控制方面对国内外生活垃圾焚烧技术进行了比较分析,认为随着生活垃圾量日益增长,生活垃圾焚烧技术仍是一种实现减量化、资源化必不可少的手段,但是需要提升焚烧技术,改进国产焚烧工艺,严格控制焚烧烟气中污染物的排放,建立实时监测点,避免造成二次污染。     

我国报废汽车回收利用现状分析与对策建议

从资源节约、环境保护、交通安全三方面论述提高我国报废汽车回收利用水平的重要意义。从报废汽车回收率、法律法规、监督管理、回收拆解等方面分析我国报废汽车回收利用的现状与问题,并提出解决问题的若干对策与建议,最后给出汽车报废回收阶段的生态效益评价模型。