General Adus not dropping Trarthan Powder

After killing General Adus I opened the furnace or whatever it is for the Trarthan Powder and its not dropping. I've tried creating a new instance and everything and it still won't drop. I'm out of ideas and can't progress farther in the game.

If you can't get the Powder, you might've already gotten it and turned it in to Sin?

Have you double checked whether or not you've collected and turned in the Basilisk Acid? And talking to Sin in the Quarry still doesn't open the path?