How to control mineral precipitation during kinetic reactions

[bessie000]

Hi,

I have a fairly complicated mineral system, I wonder how to control secondary mineral formation (mineral precipitation) during kinetic reactions? I know during equilibrium process, Phreeqc will calculate SI, but does this work for kinetic reactions? Do I need specify which minerals to precipitate to begin with? And how do I know the amount of minerals precipitated?

Thanks.

[dlparkhurst]

You will use a RATES definition for each kinetic reactant. A rate definition will calculate the number of moles of a reactant that enters/leaves solution over an internally generated time step (Basic function TIME). As a kinetic reaction proceeds, the moles of kinetic reaction (Basic function M or KIN("rate_name")) is increased or decreased, which gives the total amount of reactant available. KIN_DELTA("rate_name") gives the amount reacted during a reaction step.

Normally, a mineral reaction would include a factor that goes to zero when equilibrium is reached, typically something like (1 - SR("mineral")).