Dual Ecosystem Enhancement: In-Situ Pit Lake Remeidation By Silicate-Slag
Addition
Principal Investigator: Dr. Courtney Young
cyoung@mtech.edu
This project investigated the potential for treating acid rock drainage
using smelter slag from various inactive smelter sites in Montana.
Thermodynamic calculations show that the silicates within basic
smelter slags will increase the pH and, thereby, induce precipitation
reactions. However, the level of remediation is dependent on the
slag-silicates that are used. Three smelter slags were examined:
a fayalite slag, a pseudowallastonite/rankanite slag, and an olivine
slag. Berkeley Pit water was used as the mine waste water, and initial
work tested each slag’s ability to raise the pH of the water.
All three slags were able to increase the pH, with the pseudowallastonite/rankanite
slag yielding the highest equilibrium pH (6.0-7.8). A Box-Behnken
design matrix was used to test the response of the variables pH,
and arsenic, iron, and manganese concentrations to changes in iron
stiochiometry, particle size, and mass of slag used. It was found
that although responses were satisfactory for pH, arsenic concentration,
and iron concentration, the slags were not successful at removing
manganese from the mine water.
MWTP Activity IV, Project 36
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