Kinetics of limestone neutralization of acid waters.

The rate of neutralization of sulfuric acid by limestone particles is shown to be controlled by hydrogen diffusion in the pH range of 2 to 6. The first-order rate constant is 10 to 4l./(cm)2(S) at 298 K for a limestone containing 87 wt % carbonates, using as a driving force the hydrogen concentration in the bulk phase minus that at equilibrium at the end of the neutralization. A shrinking particle model physically described dissolution of the limestone. Particle sizes investigated vary from 0.037 to 0.044 mm to 0.500 to 0.595 MM. Effects of temperature (274-348 K), stoichiometry, turbulence, and carbon dioxide pressure are analyzed.