共查询到20条相似文献,搜索用时 109 毫秒
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氟碳铈矿提取稀土的绿色化学进展 总被引:15,自引:0,他引:15
氟碳铈矿是稀土工业的重要原材料,目前从氟碳铈矿提取稀土主要采用酸法工艺,该工艺虽然稀土回收高,但流程长,试剂消耗长,成本较高,同时酸法产生HF及废酸碱污染环境。因此寻找低成本,低污染的绿色化学处理工艺是近几十年中人们一直努力的方向。本文系统介绍了氟碳铈矿分解工艺的发展,并着重介绍邓氯化铵法提取氟碳铈矿稀土的的新工艺。该工艺采用盐类分解并氯化氟碳铈矿,直接用水浸取回收稀土,不引入酸和碱,提高了反应选择性,减轻了稀土在稀土杂质分负荷,降低了化工材料消耗,简化了工艺,提高了回收率,是符合绿色化学要求的工艺。 相似文献
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复合氨基酸微量元素螯合物制备新工艺的研究 总被引:19,自引:0,他引:19
本文报道了以废羽毛为原料,采用矿物质硫酸盐的制备与中和脱酸、螯合反应结合的新工艺,以金属盐类作催化剂和硫酸水解法,制得了复合氨基酸微量元素螯合物。复合氮基酸生成率为71.7%,微量元素螯合率达到98%以上。该工艺简单易行,生产成本低。 相似文献
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系统总结了以工业固体废料为原料合成沸石分子筛材料的最新研究进展, 讨论了以粉煤灰、 珍珠岩工业废料、 煤矸石、 流体催化裂化(FCC)废催化剂、 锂矿渣、 铝土矿渣、 废瓷料和废弃玻璃等工业固体废料为原料, 合成LTA, FAU, MFI, CHA, GIS, SOD, ANA和KFI沸石分子筛材料的工艺方法, 及其在污水中重金属离子的脱除、 空气中CO2的捕获、 氮氧化物的选择性还原等实际应用中的性能, 并对未来工业固体废料合成沸石分子筛的发展趋势进行了展望. 相似文献
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随着我国社会主义建设事业的发展,三废治理的重要性日益突出。溶剂萃取法具有高选择性,高萃取率及从低浓度溶液中提取分离有机及无机化合物的特点,它既可直接处理工业废水,回收化工原料,化害为利,又可用于工艺改革代替沉淀法或代替原来需用有毒物质的化工操作,从而杜绝三废产生,成为无公害工艺。近年来由于三槽充气器,培纳油水分离器及微粒浮集设备的应用,使有机相的夹带大幅度降低,为萃取技术在三废治理中的应用创造了有利条件。改革冶炼工艺,消除三废应用萃取流程来改革冶炼工艺是冶金工业中治理三废的重要途径。如在有色金属的经典冶炼过程中,经常有大量氧化硫等腐蚀性废气、酸性有害废水及废 相似文献
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Fred W. Mader 《Macromolecular Symposia》1992,57(1):15-31
Environmental concern about waste problems and regulatory measures from the governments have increased during the last decade. Plastics waste management has become a major strategic issue for the European plastics industry. A statistical study provides data on plastics consumption, post-users plastics waste arisings based on a life-time analysis and plastics recovery in the year 1989. An end-use sectorial split-up into sectors like municipal solid waste, automotive waste, agricultural waste, construction, as well as large distribution waste, will serve as a base for an integrated plastics waste management concept including recycling of mono-material and co-mingled waste, chemical recycling, energy recovery and landfill. An overview gives examples for ongoing plastics recycling activities in Western Europe and an outlook to the year 2000 is presented. 相似文献
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Chen Chong Lin 《Macromolecular Symposia》1998,135(1):129-135
Poly(ethylene terephthalate) (PET) has become one of major post consumer plastics wastes, in addition to polyethylene (PE), polypropylene (PP), polystyrene (PS) and poly(vinyl chloride) (PVC). The challenge to large-volume plastics companies is to learn how to collect, separate, reprocess and market their low-cost products and make a profit, too. The effort of PET recycling, however, is the most successful story in the plastic recycling technology, including both reclaim and upgrade of PET waste. Beverage bottles made of PET are recycled more than 20% of the total production. The technology of today can reclaim the post-consumer PET bottles to produce high-quality granulated PET with better than 99% purity. A practical reclaim process for recycling PET bottles (including bottle, HDPE base cup, aluminum cap, liner, label and adhesive) is available by the Center for Plastics Recycling Research in USA. PET recycling process, like for other plastics, can be divided into three categories: incineration, physical recycling, and chemical recycling. To make the plastic recycling business pay requires more than simple recovery and marketing. Greatest profit potential is in upgraded and value-added reclaim products. Upgrading involves compounding with additives to make material more processable, adding reinforcement, or producing extrusions or finished parts from reclaim resins. For instance, a modified injection-moldable resin made from PET bottle scrap is claimed to provide high impact and processability at less cost than competitive materials. It is foreseen that chemical recycling of waste PET bottle becomes feasible if the price of raw material goes up. Three economical processes are involved in this technology: pyrolysis, hydrocracking, and hydrolysis. The hydrolysis process is presently employed to recover the raw material for unsaturated polyester resin manufacture or polyols for the production of polyurethane resin. It is reported in this presentation that polymer concrete could be a huge potential market for chemical reclaim of PET materials, especially for green or mixed-color PET, which are priced lower than colorless PET reclaim materials. 相似文献
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Richard A. Fleming 《Macromolecular Symposia》1992,57(1):75-93
The technology of separating plastics from the municipal waste stream for reuse is reviewed, with emphasis on the key role played by the bottle sorting step. Experience gained in the first year's operation of two large commercial recycling plants provides a better understanding of practical problems encountered, their relative importance, and technical advances needed for improved operation. It is concluded that purity of feedstock and processing rate are two critical independent variables requiring technical and business understanding and management. Hypothetical examples illustrate the interplay of these with dependent variables of yield and sorting cost. 相似文献
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大量废弃塑料引发了一系列的环境和生态问题,其转化和利用一直受到广泛关注.塑料中含有丰富的碳元素,但这些碳元素往往以惰性的C–C键和C–H键形式存在,因此如何利用这些碳资源成为一大难题和挑战.以往部分研究已经提供了塑料催化转化制备碳材料、化学品和燃料的可能性,但是自然界中的废弃塑料总量庞大,需要考虑其转化过程中的能量来源.地球上有丰富的太阳能资源,光催化过程有可能利用太阳能来实现温和条件下的废弃塑料转化.在以往的研究中,光催化塑料降解和光催化塑料重整过程主要关注的目标产物分别是CO2和H2.相较而言,光催化塑料转化制备低碳数有机化合物的过程有望助力碳循环经济的发展.近年来报道了一些光催化塑料转化制备低碳数有机化合物的研究工作,这些研究为获取和利用塑料中的碳资源提供了新的研究思路和策略.本文概括对比了光催化塑料降解、光催化塑料重整和光催化塑料转化制备低碳数有机化合物三种过程的差异,包括其中的目标产物和相应的反应活性物种.此外,本文总结了光催化塑料转化制备低碳数化合物的反应方法.简要地说,塑料可以经过光催化选择性氧化、氧化偶联和水解脱氢等策略来得到低碳数的化学品和燃料,涉及利用光催化氧化过程断裂塑料中的C–C键,利用水解过程断裂塑料的C–N和C–O键,以及利用光催化脱氢过程断裂中间产物的O–H键和N–H键等关键步骤.在光催化塑料转化到低碳数有机产物的文献报道中,主要涉及液固相反应体系和反应器,需要考虑反应溶剂的选择.水是理想的溶剂,但对塑料的溶解能力有限.当使用其他有机溶剂时,需要利用同位素标记实验验证产物中的碳物种来源.此外,实际废弃塑料上残留的其他杂质会影响光催化剂的吸光过程,降低光催化反应效率,因此亟需设计和开发合理的光反应器来提高对光能的利用率,实现塑料的高效转化.虽然塑料制备低碳数化学品和燃料的光催化转化策略已有研究报道,但未来仍需探索更加高效的转化路线.此外,塑料主要呈现高分子聚合物的结构,未来的研究可以借鉴对生物质等天然聚合物分子的转化策略. 相似文献
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The management of packaging waste is a significant issue covered by European Union legislation which sets demanding targets for the recycling of all materials, including plastics. Significant progress has been made by an industry consortium, led by BP Chemicals, in developing technology to help meet the recycling targets. 相似文献
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TGA技术研究城市生活垃圾燃烧特性 总被引:15,自引:0,他引:15
采用TGA(热解重量分析法)技术,考察了山西省晋城市区生活垃圾不同组分的着火及燃烧特性,实验室出了原生垃圾中不同组分(包括废塑料类,废纸类,废弃织物类,植物类,厨余类和细粒类)垃圾的TG/DTG曲线,着火温度及其它燃烧特征参数,通过对TG/DTG曲线,着火温度及燃烧特征参数的分析,首次提出了一种在TGA技术中确定着火温度的新方法,给出上述不同垃圾组分的开始热分解温度,着火温度,燃尽温度以及平均燃烧速率等重要参数,并对各种垃圾的着火及燃烧特性进行了对比研究,为垃圾焚烧工业化应用提供了基础数据。 相似文献
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