Can we stay in Shanghai without the check-in for our next flight?

Hello, we have two separate tickets :
1) Copenhagen - Shanghai, Shanghai - Copenhagen
2) Shanghai - Australia, Australia - Shanghai
My question is if we could stay in Shanghai for 2 days without the check-in for our second flight to Australia?
I see that I could make the check-in online and get the CONFIRMED SEATS only before 24 hours we board. But if we don't have it yet can we still go out of the airport before we make the check-in? Thank you