🧪 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 — the Henderson–Hasselbalch equilibrium for diprotic oxalic acid — sets how much of your reagent dose actually exists as free, reactive C₂O₄²⁻ ion at the chosen pH; individual REE³⁺ and oxalate particles then drift through the bath by Brownian motion (faster with higher bath temperature) and react on collision, sinking into a growing crystal bed at the bottom, while Fe/Al impurity ions co-precipitate alongside them and dilute the bed's purity. The precipitation yield, purity and mother-liquor loss readouts update live from the actual particle counts rather than a fixed formula.