Effect on the calcium carbonate scale in circulating cooling water: constant magnetic and pulsed magnetic fields

The scale inhibition and the different effect on calcium carbonate scale treated by magnetic fields were studied by using a home-made equipment, which simulates circulate cooling water, similar to that of power plant in Inner Mongolia. The scale inhibition rate, water viscosity, crystal phases, calcium ion concentration, and crystal morphologies of scale samples were discussed under the pulsed magnetic field and the constant magnetic field. The effect of pulsed magnetic field is more evident than that of constant magnetic field. Treated by the pulsed magnetic field, average scale inhibition rate is up to 49.47%, and the concentration of Ca2+. and water quality of viscosity slightly changes. The X-ray diffraction results confirmed that pulsed magnetic field is more advantageous to restrain the formation of scale, and makes the grain size small and the non-adherent scale loose. The results indicated that the appropriate setting of frequencies for pulsed magnetic field is very important for scale inhibition.