I sent BTC from my Core Wallet to my BCC Wallet on my phone. The BCC wallet still shows a 0 balance. How can I recover it?
You can not unless you also have the same BTC address as BCC address.
Basically you need the private key for the address you sent it to.
So let's say your BTC address is A, and you sent it to BCC address B.
You now need to have the private key of B on the BTC network, and you need to import it into Core.
Look up the private key of your BCC address B, and see if you can import it t into Core. I don't think it will work, but i have never tried that.