Mathematical Modeling on Open Limestone Channel

TL;DR

This paper develops a mathematical model to predict pH and calcium concentration variations in open limestone channels used to neutralize acid mine drainage, aiding in understanding and optimizing this passive treatment method.

Contribution

It introduces a differential equation model for calcium dissolution and diffusion in open limestone channels, providing insights into their neutralization process.

Findings

Model predicts pH increase and calcium concentration over time.

Diffusion of calcium due to iron precipitates is effectively modeled.

Results support the design and optimization of passive AMD treatment systems.

Abstract

Acid mine drainage (AMD) is the outflow of acidic water from metal mines or coal mines. When exposed to air and water, metal sulfides from the deposits of the mines are oxidized and produce acid, metal ions and sulfate, which lower the pH value of the water. An open limestone channel (OLC) is a passive and low cost way to neutralize AMD. The dissolution of calcium into the water increases the pH value of the solution. A differential equation model is numerically solved to predict the variation of concentration of each species in the OLC solution. The diffusion of Calcium due to iron precipitates is modeled by a linear equation. The results give the variation of pH value and the concentration of Calcium.