The magnetic coagulation reaction between paramagnetic particles and iron ions coprecipitates

The relationship between the particle size of iron ion coprecipitates and magnetic coagulation reaction has been studied for application to water purification using magnetic separation system. The Fe(III) phosphate complex (IP) precipitate was used as a paramagnetic substance. At a high magnetic field of 8 T, the IP amount recovered by magnetic separation gradually increased with increasing Fe(III) ion concentration in the solution (by increasing the Fe/P mole ratio). However, at a low magnetic field of 0.8 T, it remained constant at about 30%. The magnetic coagulation reaction of the paramagnetic particles of the IP (Fe/P = 1.68) was enhanced by the addition of ferrimagnetic Fe3O4 particles, and that the recovery efficiency became higher with a smaller particle size of Fe3O4. (C) 2002 Elsevier Science B.V. All rights reserved.