CaCO₃ dissolves upon the addition of HCl. The CaCO₃ can now be separated from SiO₂ by ___ (evaporation, decantation, or filtration), as the CaCO₃ is now found in the ( residue, supernatant). The CaCO₃ is reconstituted by (the addition of potassium carbonate, evaporation, decantation).