Solubility of Fe(III) Al in AMD by modelling and experiment
- Radian Corp., Oak Ridge, TN (United States)
- Colorado School of Mines, Golden, CO (United States)
Studies of Fe(III) and Al species in acid mine drainage (AMD) alone and in contact with limestone were conducted by MINTEQA2 modelling and by experiments. The objectives of these studies were to: (1) determine at what pH Fe(III) and Al would be in solution in AMD such that the water would be harmful to an anoxic limestone drain (ALD), and (2) evaluate the theoretical limits to the amount of alkalinity that could be generated by an ALD. Using Fe(OH){sub 3} as the primary species and the standard values for MINTEQA2, Fe(III) precipitates at pH 2.90 when the concentration is over 453 mg/L. Al precipitates at a pH of 4.00 when the concentration is over 108 mg/L. Experiments found that over 90 % of Fe(III) and 45% of Al were precipitated at these pH`s. Experimental verification of Fe(III) concentrations of pH`s from 2.90 to 4.0 found that modelling agreed with experiment when ferrihydrite is the primary solid and the log Ksp (solubility product) is -38.9. For Al, gibbsite would be the primary solid and log Ksp is -34.1. For AMD in contact with CaCO{sub 3} when CO{sub 2} is conserved, final alkalinity is higher when mineral acidity is higher even though pH of the final solution is lower. This modelling result was confirmed by experiment. Higher mineral acidity causes generation of more CO{sub 2} that reacts with CaCO{sub 3} to generate more dissolved HCO{sub -3}.
- OSTI ID:
- 588857
- Report Number(s):
- CONF-9605286-; TRN: 98:001296-0059
- Resource Relation:
- Conference: 13. annual meeting of the American Society for Surface Mining and Reclamation (ASSMR), Knoxville, TN (United States), 18-23 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of Successes and failures: Applying research results to insure reclamation success; Daniels, W.L.; Burger, J.A.; Zipper, C.E. [Virginia Tech, Blacksburg, VA (United States). Depts. of Crop and Soil Environmental Sciences and Forestry] [eds.]; PB: 889 p.
- Country of Publication:
- United States
- Language:
- English
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