specific ioninteraction
theory [21], etc. While the Pitzer equation (as shown in Eq. (1a))
can be applied in the whole concentration range [22]. The work by
Wang has proved that the Pitzer equation can give a good description
of MgCl2 solution from -30 to 350 °C at pressures to 100 MPa and molalities
to 25 mol · kg−1 [23].