Djiin Illuminatus + Dark Ritual

[Bahza]

Can you replicate a dark ritual with Djiin Illuminatus and let the copy resolve for mana then replicated it some more to gain infinite black mana?

[Apollyon]

Replicate is an additional cost that you pay upon playing the spell, which is done long before the Ritual resolves. While Illuminatus + Dark Ritual allows you to get a good amount of mana, you can't generate arbitrarily large amounts of mana.