废旧塑料鉴别与回收技术研究进展

介绍了近年来废旧塑料鉴别技术的研究现状和最新进展,并分析了各自的优缺点,并对典型塑料的回收利用现状进行了综述,指出高效、复合型鉴别与回收技术将成为今后废旧塑料处理方法发展的主要方向。     

废旧塑料的识别与回收技术

在科学技术日新月异的现代社会，世界各国都越来越重视废旧塑料的回收与利用问题。中国一方面废旧塑料满山遍野，造成大量的资源浪费和环境污染，另一方面由于技术落后，不能很好地回收利用。本文主要从常见废旧塑料的种类、一般辨别方法和几种回收利用的方法几个方面对废旧塑料回收利用的技术进展进行论述。     

我国废旧塑料的回收现状与发展分析

从废旧塑料回收对节约能源和保护环境的意义入手，分析了我国废旧塑料回收的现状及存在的问题。并提出了解决问题所应采取的措施，指出废旧塑料回收利用的发展方向。     

废塑料的再生利用

介绍了废旧塑料再生利用的方法、国外发泡聚苯乙烯、聚苯乙烯和聚酯等废旧塑料的再生利用情况，以及废旧塑料作为固体燃料和油品化的情况；指出了废旧塑料回收利用中值得注意的几个问题。     

废塑料的再生利用

介绍了废旧塑料再生利用的方法，国外发泡聚苯乙烯，聚苯乙烯和聚酯等废旧塑料的再生利用情况，以及废旧塑料作为固体燃料和油品化的情况；指出了废旧塑料回收利用中值得注意的几个问题。     

塑料撕碎机

广东开平雅琪塑胶机械模具厂最近制成获得中国实用新型专利权，与塑料破碎机配套，可将体积较大的废旧塑料制品进行解体的塑料撕碎机。 目前，未见有可适用于将体积较大的废旧塑料制品进行回收解体的设备。现有的塑料破碎机只能对体积较小的废旧塑料制品进行破碎，却无法对体积较大的废旧塑料制品直接回收处理，而通常的处理方式是：首先将体积较大的废旧塑料制品用手工锯或电工锯锯成条块状，再将这些条块状的物料送进塑料破碎机才能进行破碎。这样，存在着既不利于安全加工、回收效率低，又有排放废尘污染的弊端。     

鉴别废旧塑料的先进近红外技术

介绍了用于鉴别废旧塑料的近红外技术的原理、优点及局限性，重点综述了已在国外(主要是欧洲)获得工业应用的几套近红外鉴别废旧塑料系统的工艺流程、操作参数及特性。     

塑料的生命周期评价（LCA）

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,尤其是消费后的废旧塑料是回收利用的重点。本文从回收方法和途径阐述了有关废旧塑料各类最新的塑料循环周期模型,进而说明积极的研究废旧塑料循环利用的新方法、新工艺具有十分重要的意义。     

废旧塑料回收及其综合利用

本文简要叙述了废旧塑料回收利用的重要性和主要方法;介绍了世界发达国家回收利用废旧塑料的现状,并结合我国国情提出了废旧塑料回收利用的改进意见。     

我国塑料回收技术的发展现状

2004年我国的塑料制品产量超过2500万t。按照我国的《再生资源回收利用“十五”规划》规定，到2005年，国内要达到回收废旧塑料500-600万t的水平，实际上，我国2004年回收的废旧塑料只有约200多万t。     

Plastic Waste Utilization via Chemical Recycling: Approaches,Limitations, and the Challenges Ahead

Chemical recycling offers the opportunity to foster the transition towards a circular economy for plastics as a complementary strategy for mechanical recycling. For the implementation of chemical recycling technologies, there are still significant challenges ahead that – besides the definition of binding legal frameworks – need for intensified research: knowledge-based methods for both the identification of suitable process technologies considering decentralized waste conditions and the design of conversion steps and downstream processing are strongly needed for process development and process evaluation.     

物理法再生涤纶鉴别方法初探

初步研究了物理法再生涤纶和原生涤纶的鉴别方法。通过“溶解-沉淀法”提取涤纶中游离齐聚物,用高效液相色谱(HPLC)法检测聚酯齐聚物的分布;在HPLC数据预处理中,依次采用小波变换法、相关性优化规整法和主成分分析方法达到基线校正、信号对齐和数据降维目的;建立反向传播人工神经网络模型,实现物理法再生涤纶的自动识别。该模型不能识别化学法再生涤纶,仅对物理法再生涤纶有效。研究结果表明:采用化学模式识别方法处理涤纶中齐聚物分布可用于鉴别物理法再生涤纶。     

化学法再生涤纶鉴别方法初探

为了探究化学法再生涤纶和原生涤纶间的差异,应用"醇解-过滤"的方法将聚酯大分子异质链节解聚出来,并经高效液相色谱测试;测试数据经基线校正、信号对齐和数据降维后,转变为两类纤维的特征向量;建立反向传播人工神经网络模型,实现化学法再生涤纶的计算机自动识别。结合所建立的物理法再生涤纶鉴别方法,可以建成一个再生涤纶"两步法"鉴别流程。尽管其存在步骤繁琐的缺点,但势必启发出更为高效的再生涤纶鉴别方案。     

废旧混合塑料识别分离与清洗技术研究进展

针对废旧混合塑料工业化回收循环利用过程中分类识别和高效清洗两大关键技术难题,本文主要综述了系列可工业用废旧混合塑料分类识别方法;讨论了浮沉分离、浮选分离、电选分离、近红外光谱精准识别技术在废旧塑料识别中的应用;介绍了清洗工艺除污提高分离效果的重要性和清洗剂主要成分——碱性物质、助剂和表面活性剂以及其作用;并提出了将超声波清洗以及浮沉分离、浮选分离、近红外光谱识别分离用于废旧塑料精准识别与分离的集成技术工艺路线。由于国内近红外光谱识别技术与超声波清洗技术相对落后,指出研究此两项技术、设备并将两者结合应用于废旧塑料回收是今后的发展方向。     

废旧PET瓶盖及标签材料的分析与鉴别

文章采用DSC和FTIR方法对废旧PET瓶盖及标签进行了测试分析和鉴别,结果表明,PET瓶盖材料均为高密度聚乙烯(HDPE),测得其MI在3 g/10 min左右,表明其分子量较高,可以作为高性能HDPE材料回收使用;PET瓶标签大部分为聚丙烯(PP)材料,但仍有少部分为聚氯乙烯(PVC)改性材料。上述结果为废旧PET瓶的分类回收和高值化利用提供了基础数据。     

Qualitative and quantitative contaminants assessment in recycled pellets from post-consumer plastic waste by means of spectroscopic and thermal characterization

The complexity of any plastic recycling initiative lies in the heterogeneous nature of the post-consumer commingled plastic waste stream: recycling treatments are challenging without prior reliable sorting. A suitable identification system should be able to recognize different plastics and blends. Nowadays, the main technique used as quality control in plastic waste sorting centers is differential scanning calorimetry, whose result can be purely qualitative or semi-quantitative, since only the crystalline fraction is evaluated. Moreover, the time required for data acquisition is relatively long. Infrared spectroscopy is an alternative, faster technique extensively used in applied research, but not widely utilized in industry. In this work, the cross-use of infrared spectroscopy and calorimetry is tested in a real, practical case: the quality control of recycled pellets (namely composed of polyolefins only), which represent the output of a commingled plastic recycling plant and are used as secondary raw materials for different applications. Appropriate infrared spectroscopy calibration curves were built to allow the quantitative analysis with respect to the most common polymers found in the commingled plastic waste stream; the composition and contaminants in the recycled pellets were thereby determined and tracked through different production batches through the cross-use of the two techniques outlined above.     

Plastic identification and comparison by multivariate techniques with laser‐induced breakdown spectroscopy

The classification of plastics is very important in the recycling industry. A quick online classification allows the installation of the equipment in this line of work. Whether qualitative or quantitative analysis, the basic component of any laser‐induced breakdown spectroscopy (LIBS) measurement is the emission spectrum recorder from single plasma. Each fire of the laser atomizes a portion of the sample in the pulse focal volume and produces plasma that excites and re‐excites the atoms to emit light. The plasma light is collected and recorded in an ensuing measurement. In this sense, the LIBS technique offers all possible advantages: speed, the possibility of online analysis, nondestructive analysis, and so on. In this article, we discuss details related to the analysis of the emission spectrum. The plastics used in this study were low‐density polyethylene (PE), high‐density PE, polypropylene, polystyrene, and poly(ethylene terephthalate). Hierarchical cluster analysis was proven to be the best method because the four polymers could be divided into two clusters, which allowed their identification and classification in a fast and easy way that could be carried out with commercial software and could be implanted online in a recycling factory, as conventional data analysis techniques are limited to the qualitative identification and calculation of elemental abundances. Principal component analysis on LIBS spectra can be used to better describe the chemical variations in the samples and to extract a greater understanding of the chemical structure. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

浅谈工业遗产的保护与再利用

中国的工业遗产保护与再利用工作起步较晚,尚未对其形成较完善的研究、认定与再利用体系。本文深入阐述了工业遗产的概念,并从国际、国内两个层面对其进行分析界定;然后从分析工业遗产具有的多重价值出发,如：历史研究价值、科学技术价值、人文社会价值、建筑艺术价值和经济价值等,进一步揭示了工业遗产保护与再利用工作的重要性与意义。