Integrated iron(II) oxidation and limestone neutralisation of acid mine water

Volumetric iron(II) oxidation rates exceeding 100 g/(l.d) were achieved by dosing powdered limestone to a bio-reactor treating artificial acid mine water. Neutralisation and partial sulphate removal were achieved as well. The rate is highly dependent on the surface area exposed to the liquid (RSA) and the OH−, oxygen, CaCO3, suspended solids and iron(II) concentrations, and less dependent on specific surface area (SSA) and pressure in the pH range 5 to 6. The chemical oxidation rate (pH greater than 6) is dependent on the OH−, oxygen, and iron(II) concentrations and the reactor surface area (RSA).