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Reclamation of Phosphatic Clay Waste Ponds by Capping: Volume 5: Centrifugal Model Evaluation of the Consolidation Behavior of Phosphatic Clays and Sand/Clay Mixes

02-030-075Final

Abstract

The consolidation behavior of phosphatic clays taken from 19 sites located in central and northern Florida is investigated to address the problem of disposal of waste clays generated in the beneficiation process within the Florida phosphate industry. Uncapped, capped, and sand/clay mix centrifuge tests were run on each waste clay. Atterberg limits and x-ray diffraction tests were also conducted. Objectives were, first, to determine if the Atterberg limits or the mineralogy of the waste clays could be related to their settling behavior in the uncapped tests and, second, to examine the effects of sand caps and sand/clay mixes on the settlement characteristics of the clays.

Atterberg limits predicted the consolidation behavior of the clay fairly well. A relationship was observed between liquidity index and effective stress for the uncapped clays, while no definite trends were observed between clay mineralogy and consolidation behavior. Both sand/clay mixes and sand caps improved the settlement characteristics of the clays. Sand/clay mixes enhanced the time rate of consolidation more than the sand caps, while the sand caps generated a higher final clay solids content than the sand/clay mixes.

Reclamation of Phosphatic Clay Waste Ponds by Capping.
Other Volumes

FIPR Publication No. 02-030-056
Volume 1: Centrifugal Model Evaluation of Reclamation Schemes for Phosphatic Waste Clay Ponds. University of Florida. April, 1988.

FIPR Publication No. 02-030-061
Volume 2: Centrifugal Modeling of the Consolidation Behavior of Phosphatic Clay Mixed with Lime or Gypsum. University of Florida. April, 1988.

FIPR Publication No. 02-030-062
Volume 3: Evaluation of the Use of Geotextiles for Capping Phosphatic Waste Clay Ponds. University of Florida. April, 1988.

FIPR Publication No. 02-030-063
Volume 4: Piecewise Linear Computer Modeling of Large Strain Consolidation. University of Florida. April, 1988.

FIPR Publication No. 02-030-073
Volume 6: Consolidation Properties of Phosphatic Clays from Automated Slurry Consolidometer and Centrifugal Model Tests. University of Florida. February, 1989.