Some magnetic field effects on in situ precipitated calcium carbonate

Magnetic field (MF) (B = 0.4 T) effects were studied on CaCO₃ precipitated from Na₂CO₃ and CaCl₂ solutions, which at 30°C were exposed for 30 min to the field. One of the impurity ions Mg²⁺, Zn²⁺, Fe²⁺, SO₄^2-, HPO₄^2- at 10^-5 mol l^-1 concentration was also added to CaCl₂ or Na₂CO₃, respectively. The changes of zeta potential, pH and light absorbance (at λ=543.2 nm) of the slurry after CaCO₃ precipitation were measured on the time. In some experiments changes in the deposited amounts of CaCO₃ due to MF treatment were determined on glass plates. MF affected all the parameters measured and the effects depended on the kind of impurity ion present.