The use of coal spoils as feed materials for alumina recovery by acid-leaching routes. 1. The suitability and variability of the feed materials

Academic Article

Abstract

  • The suitability of fine tailings from eight British collieries and a number of coal ash materials as feeds for alumina recovery by acid leaching routes has been studied. The rates of extraction of aluminium and of the major impurities, iron and potassium, have been measured under standard calcination and leaching conditions using HCl as the leaching agent, and the results have been interpreted in terms of the chemical, mineralogical and physical properties as well as the thermal histories of the feed materials. Coal ashes, where combustion had occurred at temperatures in excess of 1123-1173 K, are not suitable for alumina recovery. Controlled calcination in the temperature range 923-1123 K was necessary for acceptable yields in the leaching stage. Aluminium recovery values of 50-70% after 2 hours, and 75-90% after 7 hours were achieved by leaching the calcined tailings with boiling 6 molar HCI. The extraction rates of both iron and potassium were greater than those of aluminium. Tailings with low iron content and high kaolinite content were found to be the most suitable for alumina recovery. An ash material produced from colliery tailings by a fluidised bed combustion process which has been developed by the National Coal Board of the U.K. (N.C.B.) was found to have particularly attractive leaching and physical properties. © 1983.
  • Authors

    Published In

  • Hydrometallurgy  Journal
  • Digital Object Identifier (doi)

    Author List

  • Livingston WR; Rogers DA; Chapman RJ; Bailey NT
  • Start Page

  • 79
  • End Page

  • 96
  • Volume

  • 10
  • Issue

  • 1