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Improving clay‐based tailings disposal: Case study on coal tailings

1997; Wiley; Volume: 43; Issue: 7 Linguagem: Inglês

10.1002/aic.690430724

1547-5905

Ross de Kretser, Peter J. Scales, David V. Boger,

Landfill Environmental Impact Studies

Abstract The role of swelling clays in hindering the compressional dewatering characteristics of coal‐mine tailings is examined. The effects of electrolyte concentration and ion exchange in improving the shear and compressional rheology are compared. Suspensions studies include actual mine tailings (thickener feed and thickener underflow) as well as synthetic clay dispersions made from clay collected from the coal seam. It was shown that the most important parameter in controlling the properties of the tailings suspension is “controlled” dispersion in the presence of a Ca 2+ electrolyte concentration in excess of that required to (1) prevent initial swelling and (2) provide full cation exchange of the clay. Under these electrolyte conditions, complete delamination of the clay did not occur, and both the dewatering and handling characteristics of the resultant suspensions improved dramatically.