I was going to mention the same thing Malcolm mentioned about separation. Are these Valencias? If so, then skip the rest of this note and enjoy your frozen OJ! If not, have you tried the juice after leaving in the fridge overnight? If it tastes fine the next day, you'll be good. If it tastes bitter, it may be a waste of your time to juice it all and then freeze it; it won't taste any less better when thawing it out later. Good luck to ya!

I know this is kinda an old thread but I have been concentrating tangerine and grapefruit juice lately. I juice the fruit and freeze in jugs (separately) and once the jugs freeze, I pull them out and allow to partially defrost. I can then prop them upside down to pour off the sweeter juice while the water stays frozen longer. Once the stuff dripping out of the previously frozen jug seems to be more water than fruit juice, stop and dispose of the rest of the ice. I've found that if I mix the two different concentrates together I get a really sweet strong juice that doesn't take up as much space in the freezer. I have not been diluting this juice before drinking but I suppose some people might want to. I guess it might be possible to freeze and do the thaw concentrate operation again and get an even stronger concentrate but I don't know how effective it will be in subsequent runs.

You could thaw it out and give it the sniff test. Those cardboard cartons do tend to pick up odors. Then if it smells fine, it's probably ok to drink.

When we were kids our mother made us ice pops with reconstituted frozen orange juice. i can't imagine it wouldn't also work with fresh juice. If the juice separates when it's thawed, I'd give it a quick whiz in the blender which both mixes and aerates it. That's how DW an I improved the taste of store brand frozen OJ in our early days.