Doctoral Dissertations

Alex Luyima

Keywords and Phrases

Printed Circuit Boards

Abstract

"Pyrolysis and leaching are the dominant techniques applied in the recycling of waste printed wiring boards (PWBs). Waste PWB pyrolysis is a highly polluting technology and produces brominated pyrolysis oils in addition to hydrogen bromide (HBr) gas. Moreover, leaching as a treatment process of waste PWBs is not well investigated. In this work, the pyrolysis of waste PWBs has been studied with the aim of reducing the amount of brominated oils and HBr gas evolved. The effects of powder inorganic chemicals (CaO, CaCO₃, Fe₂O₃, Al₂O₃, Y-Zeolite, and ZSM-5) additions on the pyrolysis of waste PWBs has been studied through experiments using a thermogravimetric-differential thermal analyzer connected to a mass spectrometer (TG-DTA-MS) and in a tube furnace at 900 ºC. It has been shown that the kinetic models by Friedman, Flynn-Wall-Ozawa, and Kissinger are applicable to waste PWB pyrolysis at temperatures below 400 ºC. Moreover, CaO, CaCO₃, Fe₂O₃, Y-Zeolite, and ZSM-5 show a potential to reduce the amount of HBr gas evolved during pyrolysis in TG-DTA-MS. However, in the tube furnace pyrolysis experiments, CaO and CaCO₃ were found to be the most effective chemical additions, with more than 90% reduction in total bromine (HBr and other brominated gases) evolved. It has also been demonstrated that the sequential leaching of waste PWBs with hydrochloric acid, nitric acid and aqua regia is capable of selective recovery of base and precious metals contained in waste PWBs"--Abstract, page iv.

Advisor(s)

Zhang, Lifeng (College teacher)
Peaslee, Kent D., 1956-2013

Committee Member(s)

Lekakh, S. N. (Semen Naumovich)
Schlesinger, Mark E.
Schuman, Thomas P.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Sponsor(s)

United States. Department of Energy

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2013

Journal article titles appearing in thesis/dissertation

  • Kinetic analysis of the thermal degradation of waste printed wiring boards.
  • Control of gas emission during pyrolysis of waste printed wiring boards.
  • Control of hbr and other pollutant gases during pyrolysis of waste printed wiring boards.
  • Leaching studies for metals recovery from waste printed wiring boards.
  • Leaching behavior of metals from waste printed wiring boards.

Pagination

xvi, 137 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Alex Luyima, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Electronic waste -- Recycling
Electronic waste -- Environmental testing
Electronic apparatus and appliances -- Environmental aspects
Electronic waste -- Management
Polymers -- Recycling
Pyrolysis -- Environmental aspects
Leaching -- Environmental aspects

Thesis Number

T 10365

Electronic OCLC #

858610186

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