working of phreeqc

[rimsi]

hello sir
hello sir
While reading the working of PHREEQC in version 2 manual, i came across the equation f p=(lnKp + [ln(10)]SI p, target )-sumof(cmp^(am)). For finding the amount of a mineral/element leached out at equilibrium conidtions, what should be the SIp traget value to be entered in the EQUILIBRIUM PHASES input block ?

[dlparkhurst]

A target saturation index of zero will produce equilibrium with the mineral, except in the case when the solution is undersaturated and there is not enough of the mineral present (second entry in EQUILIBRIUM_PHASES) to attain equilibrium.

A target saturation other than zero could represent a slightly more soluble or less soluble form of the mineral.

It is also possible that a target saturation index other than zero indicates a system where complete equilibrium is not attained. Precipitation to a given supersaturated state or dissolution to a given undersaturated state could represent kinetic processes, but precipitation to undersaturation or dissolution to supersaturation would be difficult to defend.

[rimsi]

thank you sir