The viability of physico-chemical purification methods such as selective flocculation for the separation of two components having similar chemical compositions and the same crystal structure but different surface properties is demonstrated. A loss of selectivity was observed in a dolomite-dolomite mixture when polyethylene oxide (PEO) (five million molecular weight) was used as the flocculant. Heteroflocculation was minimized using a low molecular weight PEO (MW ≈ 105) as a site blocking agent (SBA). Near complete separation was achieved at pH 10.5 at the 100% recovery level.