废旧聚苯乙烯塑料的回收和利用

本文介绍了以废旧聚苯乙烯泡沫塑料为原料,经裂解、蒸馏工序制取苯乙烯,同时副产混合苯溶剂的工艺。该法回收利用了废弃的资源,具有明显的经济、社会、环境效益。     

聚苯乙烯泡沫塑料无害化环保再生技术研究

聚苯乙烯(PS)泡沫塑料的回收再生主要是采取熔融挤出造粒的生产工艺,在加工过程中塑料易发生受热降解,大大降低了塑料的使用性能和利用价值。在聚苯乙烯泡沫塑料的回收生产中加入自主创新研发的一种分子量调节剂,可以修复断裂的塑料分子链,最大限度恢复再生塑料的性能,回收的再生聚苯乙烯粒子可替代新料作为建筑保温XPS板、仿木装饰板(线)材、橡胶改性等行业的原料,和新料相比,本创新产品具有极高的性价比优势。     

废聚苯乙烯泡沫塑料的回收利用

本文以从事工程设计和开发新产品的研究试验为基础,并参考有关文献资料,对废聚苯乙烯泡沫塑料回收利用的四种可行性工艺进行了论述。文中还对推广实施这些工艺的生产流程,城乡环卫条件的改善,化工原料资源渠道的开拓,及国外回收利用废聚苯乙烯泡沫塑料的概况均作了介绍。     

废旧聚苯乙烯泡沫材料的再生

通过简单的工艺过程－消泡除杂，造粒，后处理，使废旧聚苯乙烯泡沫材料获得再生。采用本法，消耗原，辅料较少，生产成本较低，生产过程中不产生废气和废渣，仅排出含少量Ｃａ＾＋和Ｈ＾＋的废水，经简单处理后即可达到国家排放标准。     

用废聚苯乙烯泡沫塑料生产乳胶漆

近些年来,聚苯乙烯泡沫塑料在各种商品的包装上得到越来越广泛地使用,但这些包装材料大都是一次性使用,用后即作为无法处理的废料扔掉,占用土地。这种泡沫塑料200年也不会降解,造成了严重的环境污染。因此,有效合理地利用这些废料,不但可解决环境污染问题,而且可变废为宝。 针对聚苯乙烯塑料比重轻、耐水、耐光、耐化学腐蚀等特点,将回收的废聚苯乙烯泡沫塑料经过加工、溶制改性、乳化等工序,可制成用于内外墙使用的乳胶漆涂料。通过试验和初步应用证明,它具有成本低、耐擦洗、装饰效果好等特点。因此,采用废聚苯乙烯泡沫塑料生产乳胶漆涂料,不但生产技术上可行,而且还具有较好的经济效益和社会效益。     

非溶剂型热介质法消泡回收聚苯乙烯泡沫塑料

回收利用聚苯乙烯泡沫塑料可用不同的消泡减容方法。非溶剂型热介质法分别采用20%氯化钙水溶液作水性介质,液体石蜡和固体石蜡混合物作油性介质,消泡操作温度110℃～130℃,可减容30倍,回收物料密度达到0.9g/cm3,适于下游产品加工应用。     

关于编制《供销合作社废旧商品回收体系建设规划（2012—2015年）》的通知

各省、自治区、直辖市、计划单列市及新疆生产建设兵团供销合作社,中国供销集团及中国再生资源开发有限公司：为深入贯彻落实《国务院办公厅关于建立完整的先进的废旧商品回收体系的意见》（国办发[2011]49号）精神,中华全国供销合作总社（以下简称总社）成立了以杨传堂同志为组长,顾国新、戴公兴同志为副组长的废旧商品回收体系建设工作领导小组,把建立完整的先进的废旧商品回收体系作为供销合作社系统当前和今后一个时期的重大工程来推进。     

废旧锌锰电池及其回收过程中汞载体的研究

针对目前一些回收废旧锌锰电池工艺在汞回收处理上存在的问题,集中对废旧锌锰电池中汞的载体以及回收处理废旧锌锰电池过程中汞载体的变化进行了研究,为废旧锌锰电池回收处理中汞的完全回收提供了依据.     

从废旧锌锰电池中回收汞和铵的工艺研究

针对废旧锌锰电池中汞分散存在给回收处理废旧锌锰电池工作完全回收汞所带来的困难,利用汞和铵的性质特点,找到了从废旧锌锰电池中集中回收汞和铵的工艺条件,为废旧锌锰电池的资源化和防止二次污染创造了有利条件.     

关于加快推进供销合作社废旧商品回收利用体系建设的意见

供销经字[2012]28号各省、自治区、直辖市及计划单列市、新疆生产建设兵团供销合作社,中国供销集团及中国再生资源开发有限公司：为深入贯彻落实《国务院办公厅关于建立完整的先进的废旧商品回收体系的意见》（国办发[2011]49号）（以下简称国办49号文件）,加快推进供销合作社废旧商品回收利用体系建设,促进供销合作社废旧商品回收利用企业健康快速发展,现提出如下意见：     

Processing scheme based on selective dissolution to recycle food packaging and other polymeric wastes and its economic analysis

This investigation proposes the development of the selective dissolution process for recycling food packaging and other polymeric wastes. This process takes into account that the specific solvent of a particular polymer which is to be separated, must be a non-solvent for the remaining polymers. Likewise, taking into account the solubility of each polymer into various solvents as well as its production costs, the order of the polymers produced can be polyvinylchloride (PVC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polybutadiene (PB), polyacrylnitrile (PAN), polyesters (PES), nylon and polyurethanes (PU). However, cost analysis of the process revealed that the recycling of food packaging polymers in the order of PE, PVC, PP, and PS is more cost-effective.     

Rheological Behavior Under Shear and Non-Isothermal Elongational Flow of Biodegradable Polymers for Foam Extrusion

The production of many items, in particular for food packaging applications, is based on foam extrusion and thermoforming. These operations require the use of polymers which can grant some specific rheological properties, both under shear and elongational flow. In this work, the behavior of some biodegradable polymers [Mater-Bi^® and poly(lactic acid)] under shear and non-isothermal elongational flow was investigated and compared with a traditional, non-biodegradable polymer, in order to assess their suitability for industrial-scale foam extrusion and thermoforming. The rheological characterization evidenced the differences between the different biodegradable polymers and the reference polystyrene (PS), as well as the effect of humidity on their main rheological properties. This can be of great interest in helping to find an optimum solution in replacing PS for the production of food packaging items.     

Microstructural and Physical Properties of Thermoplastic Corn Starch/Polystyrene Blend Foams Affected by Different Contents and Combinations of Plasticizers

Journal of Polymers and the Environment - A comprehensive study was performed on thermoplastic corn starch (TPS)/polystyrene (PS) blend foam to optimize the formulation from the aspects of...     

Recycling of extruded polystyrene wastes by dissolution and supercritical CO2 technology

Polystyrene (PS) is currently used as packaging, insulating and storing material in various industrial or domestic fields. As a result, a large quantity of PS wastes is produced. Plastic wastes are not usually biodegradable, so it is necessary to suggest a technology to recycle them. Landfills and incineration are reasonably cheap methods but are not environmentally acceptable, therefore, alternative methods for polymer recycling are required. The general purpose of PS foam recycling is to recover a more compact polymeric material without degradation. Dissolution with terpenic solvents is presented here as an efficient and cheap alternative that is developed at room temperature; among the oils studied, limonene was selected because of its intermediate solubility and its abundance. The solvent removal is possible thanks to supercritical technology that provides a high solubility in limonene and almost a complete PS insolubility at moderated pressures (77?bar) and low temperatures (30?°C). Thus, based on the results of thermogravimetric and chromatographic analysis, we propose that.supercritical antisolvent precipitation is an ideal technique for carrying out the separation of PS and limonene, providing a recycled polymer with a reduced volume, almost completely free of solvent and without degradation of the polymeric chains.     

Boiling treatment of ABS and PS plastics for flotation separation

A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile–butadiene–styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling.     

Development of a catalytic dehalogenation (Cl,Br) process for municipal waste plastic-derived oil

Dehalogenation is a key technology in the feedstock recycling of mixed halogenated waste plastics. In this study, two different methods were used to clarify the effectiveness of our proposed catalytic dehalogenation process using various carbon composites of iron oxides and calcium carbonate as the catalyst/sorbent. The first approach (a two-step process) was to develop a process for the thermal degradation of mixed halogenated waste plastics, and also develop dehalogenation catalysts for the catalytic dehydrochlorination of organic chlorine compounds from mixed plastic-derived oil containing polyvinyl chloride (PVC) using a fixed-bed flow-type reactor. The second approach (a single-step process) was the simultaneous degradation and dehalogenation of chlorinated (PVC) and brominated (plastic containing brominated flame retardant, HIPS–Br) mixed plastics into halogen-free liquid products. We report on a catalytic dehalogenation process for the chlorinated and brominated organic compounds formed by the pyrolysis of PVC and brominated flame retardant (HIPS–Br) mixed waste plastics [(polyethylene (PE), polypropylene (PP), and polystyrene (PS)], and also other plastics. During dehydrohalogenation, the iron- and calcium-based catalysts were transformed into their corresponding halides, which are also very active in the dehydrohalogenation of organic halogenated compounds. The halogen-free plastic-derived oil (PDO) can be used as a fuel oil or feedstock in refineries.     

Application of fluidization to separate packaging waste plastics

The objective of the experimental work described in this paper is the study of the separation of PS (polystyrene) from PET (polyethylene terephthalate) and PVC (polyvinyl chloride) from drop-off points using a fluidized bed separator. This is a low-cost process commonly used in the hydro-classification of mineral ores. Firstly, experimental tests were carried out with artificial granulated samples with different grain sizes, types and sources of plastic ("separability tests"). The particle settling velocities were determined under different operating conditions. Then, based on the results, the laboratory tests continued with real mixtures of waste plastics ("separation tests") and the efficiency of the process was evaluated. From a PET-rich mixture, a concentrate of PS with a 75% grade in PS was produced while the underflow was quite clear from PS (grade less than 0.5% in PS).     

Melt Flow Behavior and Processability of Polylactic Acid/Polystyrene (PLA/PS) Polymer Blends

The present investigation dealt with the flow behavior and processability of polylactic acid/polystyrene (PLA/PS) polymer blends using a capillary rheometer. For this purpose, PLA/PS blends with different ratios of the concentrations were prepared using a single screw extruder. The shear viscosity, shear stress, shear rate, power-law index, viscous activation energy at a constant shear stress, and elongational stress were determined. PLA/PS blends exhibited a typical shear-thinning behavior over the entire range of shear rates tested, and the viscosity values of the blends would tend to decrease with increasing amount of PLA. In addition, the polymer blend of 70 % PLA and 30 % PS was found to be relatively less sensitive to the processing temperature, implying that the extrusion process was more desirable for fabrication of PLA/PS polymer blend than the injection process.     

The ecological relevance of transport in waste disposal systems in Western Europe

With the development of modern waste management systems in Western Europe, a remarkable increase in the distances for waste transportation has been observed. The question thus arises whether recycling with longer transport distances is ecologically advantageous or whether disposal without recycling is to be preferred. This situation was analysed using selected product and waste streams. This included refrigerators, paper, polyethylene films and expanded polystyrene. For each of these streams, a life cycle analysis was conducted with an emphasis on waste transport. The system boundaries were set in terms of the generation of waste to recycling or landfilling. The comparison included several scenarios with recycling and different transport distances. Landfilling was used as the reference scenario. The results obtained demonstrated how transport distances influence the ecological benefit of recycling. In the case of expanded polystyrene, the ecological boundaries are reached in practical situations, while with other materials these boundaries are far from being attained. In these cases, more complex and elaborate collection schemes, such as kerbside collection, which is economically convenient and shows the highest collection rates, can also be recommended.     

聚氯乙烯生产中副产高沸物的综合利用

介绍了以ＰＶＣ生产中副产的高沸物精制后作溶剂,降解后的废聚苯乙烯泡沫塑料的作主料,制造塑化防腐漆的工艺流程,产品性能及经济效益。