Yes. MgCO3 and CaCO3 can be separated chemically by taking advantage of the different solubilities of their respective chlorides in ethanol. Here's a procedure to separate them:

1. Convert the carbonates to chlorides:

- Dissolve the mixture of MgCO3 and CaCO3 in dilute hydrochloric acid (HCl) to convert them into the corresponding chlorides, MgCl2 and CaCl2.

- Evaporate the solution to dryness to obtain the solid mixture of MgCl2 and CaCl2.

2. Recrystallize MgCl2 from ethanol:

- Dissolve the solid mixture in a minimum amount of hot ethanol.

- MgCl2 is soluble in ethanol, while CaCl2 is not. So, upon cooling the solution, MgCl2 will crystallize out, leaving CaCl2 in the solution.

- Filter the solution to separate the MgCl2 crystals from the remaining solution.

3. Recover CaCl2 from the solution:

- The filtrate from the previous step contains CaCl2, along with any remaining MgCl2.

- Evaporate the filtrate to dryness to obtain solid CaCl2.

By following this procedure, you can separate MgCO3 and CaCO3 chemically by selectively recrystallizing MgCl2 from ethanol.