Hey guys,
Quick question: is it correct to say that when I mint a zerocoin I convert a basecoin (say Bitcoin) to a zerocoin and when I spend that zerocoin I convert it back to the basecoin (Bitcoin), which then looks like a newly minted (Bit)coin?
Yes, currencies that use zero knowledge proofs (not bitcoin 
) have this feature that when you mint a zerocoin, you will get special (zerocoin) version of the same coin, usually in some denominations that you can later spend.
Once you spend them you will create back a newly minted coin that seems as it doesn’t have any history.