AFAIK, takes at least a couple of weeks. The only one I ever personally submitted was several years ago - it took exactly 4 weeks and they didn't send me a reply, the site just "reappeared" one day. My site has been solidly positioned ever since but there was residual flakiness for +6 months after reinclusion, like pages disappearing for a few days during algo updates - a little unsettling.
Before you submitted the reconsideration request, did you check your site point-by-point against Google's webmaster guidelines, especially the quality guidelines section? Your site will be subject to a very picky manual inspection and it doesn't meet all those requirements your request will go straight in the trash.
You should check all of those things every time you launch a new site - it's a LOT easier to stay indexed than it is to get back in!