Liquid oil and residual characteristics of printed circuit board recycle by pyrolysis

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• 作者：Kuo-Hsiung Lin^a ; Hung-Lung Chiang^b ; ^{hlchiang@mail.cmu.edu.tw" class="auth_mail}
• 关键词：Pyrolysis oil ; Residues ; Water-soluble ionic species
• 刊名：Journal of Hazardous Materials
• 出版年：30 April, 2014
• 年：2014
• 卷：271
• 期：Complete
• 页码：258-265
• 全文大小：941 K

文摘

Non-metal fractions of waste printed circuit boards (PCBs) were thermally treated (200-500 掳C) under nitrogen atmosphere. Carbon, hydrogen, and nitrogen were determined by elemental analyzer, bromine by instrumental neutron activation analysis (INAA), phosphorus by energy dispersive X-ray spectrometer (EDX), and 29 trace elements by inductively coupled plasma atomic emission spectrometer (ICP-AES) and mass spectrometry (ICP-MS) for raw material and pyrolysis residues. Organic compositions of liquid oil were identified by GC (gas chromatography)-MS, trace element composition by ICP system, and 12 water-soluble ions by IC (ionic chromatography). Elemental content of carbon was >450 mg/g, oxygen 300 mg/g, bromine and hydrogen 60 mg/g, nitrogen 30 mg/g, and phosphorus 28 mg/g. Sulfur was trace in PCBs. Copper content was 25-28 mg/g, iron 1.3-1.7 mg/g, tin 0.8-1.0 mg/g and magnesium 0.4-1.0 mg/g; those were the main metals in the raw materials and pyrolytic residues. In the liquid products, carbon content was 68-73%, hydrogen was 10-14%, nitrogen was 4-5%, and sulfur was less than 0.05% at pyrolysis temperatures from 300 to 500 掳C. Phenol, 3-bromophenol, 2-methylphenol and 4-propan-2-ylphenol were major species in liquid products, accounting for >50% of analyzed organic species. Bromides, ammonium and phosphate were the main species in water sorption samples for PCB pyrolysis exhaust.