Laboratory evaluation of limestone and lime neutralization of acidic uranium mill tailings solution. Progress report [electronic resource]
Experiments were conducted to evaluate a two-step neutralization scheme for treatment of acidic uranium mill tailings solutions. Tailings solutions from the Lucky Mc Mill and Exxon Highland Mill, both in Wyoming, were neutralized with limestone, CaCO₃, to an intermediate pH of 4.0 or 5.0, followed b...
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Online Access |
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| Corporate Authors: | , |
| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Richland, Wash. : Oak Ridge, Tenn. :
Pacific Northwest National Laboratory (U.S.) ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy,
1984.
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| Summary: | Experiments were conducted to evaluate a two-step neutralization scheme for treatment of acidic uranium mill tailings solutions. Tailings solutions from the Lucky Mc Mill and Exxon Highland Mill, both in Wyoming, were neutralized with limestone, CaCO₃, to an intermediate pH of 4.0 or 5.0, followed by lime, Ca(OH)₂, neutralization to pH 7.3. The combination limestone/lime treatment methods, CaCO₃ neutralization to pH 4 followed by neutralization with Ca(OH)₂ to pH 7.3 resulted in the highest quality effluent solution with respect to EPA's water quality guidelines. The combination method is the most cost-effective treatment procedure tested in our studies. Neutralization experiments to evaluate the optimum solution pH for contaminant removal were performed on the same two tailings solutions using only lime Ca(OH)₂ as the neutralizing agent. The data indicate solution neutralization above pH 7.3 does not significantly increase removal of pH dependent contaminants from solution. Column leaching experiments were performed on the neutralized sludge material (the precipitated solid material which forms as the acidic tailings solutions are neutralized to pH 4 or above). The sludges were contacted with laboratory prepared synthetic ground water until several effluent pore volumes were collected. Effluent solutions were analyzed for macro ions, trace metals and radionuclides in an effort to evaluate the long term effectiveness of attenuating contaminants in sludges formed during solution neutralization. Neutralized sludge leaching experiments indicate that Ca, Na, Mg, Se, Cl, and SO₄ are the only constituents which show solution concentrations significantly higher than the synthetic ground water in the early pore volumes of long-term leaching studies. |
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| Item Description: | Published through the Information Bridge: DOE Scientific and Technical Information. 02/01/1984. "nureg/cr-3449" " pnl-4809" "DE84007401" Serne, R.J.; Dodson, M.E.; Opitz, B.E. |