Rare Earth Oxalate Precipitation (2D)

This 2D companion drives the same oxalate precipitation chemistry as the 3D version but through a genuine per-ion mass-action simulation instead of an aggregate dial: a pH-speciation curve sets how much of your reagent dose actually exists as free, reactive oxalate ion, individual REE³⁺ and C₂O₄²⁻ particles drift and react on collision, and Fe/Al impurity ions co-precipitate into the same growing crystal bed, so purity and yield emerge from the particle count instead of a formula.