Thermochemical reduction of pelletized gypsum mixed with carbonaceous reductants

Authors

  • SR Motaung 1. DST/CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, Pretoria 0001, South Africa; 2.Department of Environmental, Water and Earth Science, Tshwane University of Technology, Pretoria 0001, South Africa
  • JN Zvimba CSIR Natural Resources and the Environment, Council for Scientific and Industrial Research, Pretoria 0001, South Africa
  • JP Maree Department of Environmental, Water and Earth Science, Tshwane University of Technology, Pretoria 0001, South Africa
  • AV Kolesnikov Department of Chemical and Metallurgical Engineering, Tshwane University of Technology, Pretoria 0001, South Africa

DOI:

https://doi.org/10.4314/wsa.v41i3.08

Keywords:

waste gypsum, binders, pelletization, tube furnace

Abstract

The recovery of better quality waste gypsum during acid mine drainage (AMD) neutralization is one step closer to achieving downstream waste gypsum beneficiation for recovery of valuable materials. This can facilitate recovery of treatment costs and prevention of environmental pollution from gypsum waste-dumps. Thermal reduction using rotary kilns to recover valuable materials from waste gypsum remains a critical and controversial process because of waste gypsum handling problems, environmental pollution due to dust and gaseous emissions and poor conversion yields. In order to mitigate these problems and improve waste gypsum conversion yields, pelletization of waste gypsum in the presence of binders (starch and cellulose) was investigated. A laboratory-scale disc pelletizer was used to produce pellets from a mixture of coal and commercial gypsum or waste gypsum, generated during AMD neutralization, with starch and micro-crystalline cellulose used as binders. The pellets were subjected to high-temperature thermal treatment in a tube furnace to generate calcium sulphide (CaS), an important intermediate for waste gypsum beneficiation. The kinetics of thermal conversion of pelletized waste gypsum to CaS were found to be highly dependent on furnace temperature. Results also showed that pelletization affords improved handling of waste gypsum while use of binders as additives significantly improved the CaS yield, with starch giving the better yield compared to cellulose.

Downloads

Download data is not yet available.

Downloads

Published

2015-04-21

Issue

Vol. 41 No. 3 April (2015): Water SA

Section

Research paper

License

Copyright (c) 2022 SR Motaung, JN Zvimba, JP Maree, AV Kolesnikov

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Creative Commons License

The content of this journal is licensed under a Creative Commons Attribution Licence.  Users are permitted to read, download, copy, distribute, print, search or link to the full texts of the articles in this journal under the terms of this Licence, without asking prior permission from the publisher or the author, provided the source is attributed. Copyright is retained by the authors.

How to Cite

SR Motaung (2015) “Thermochemical reduction of pelletized gypsum mixed with carbonaceous reductants”, Water SA, 41(3 April). doi:10.4314/wsa.v41i3.08.