Jc. Choi et al., APPLICATION OF MINTEQA2 TO THE EVALUATION OF APATITE AS A PRECIPITANTFOR ACID-MINE DRAINAGE TREATMENT, ENVIRONMENTAL & ENGINEERING GEOSCIENCE, 3(2), 1997, pp. 217-223
The apatite drain system is a new method for acid mine drainage (AMD)
treatment. Laboratory tests and field experiments showed that this tec
hnique can remove high concentrations of iron and aluminum in AMD havi
ng a pH below 4.0. In addition, this system removes both ferric and fe
rrous iron, whereas a constructed wetlands system removes only ferric
iron when converted from the ferrous state in the wetland. A geochemic
al model, MINTEQA2, was used to simulate the changes in concentration
of aqueous constituents, and in the pH and the potential mineral phase
. Results of MINTEQA2 support the conclusions of the laboratory and fi
eld experiments. Apatite is effective in removing iron, sulfate, and a
luminum from AMD; pH was inversely proportional to the flow rate until
the equilibrium point was reached (pH = 4.09 at 25 degrees C). Also,
the role of apatite as a precipitant and pH buffer was limited by its
solubility.