Sending mail in batches

[Akhil Sahu]

I need to send approx 40 - 50000 mails depending upon user selection. These mail id are stored in database. There can be any number of mail. A dedicated mail server is setup for this. I don't want them to end up in spam. I want to send mail of approx 5000 per hour so as to avoid getting blacklisted. I want to schedule a batch mail job where all mails are send and failed mails are retried. So as to avoid. The batch job is scheduled when user start it and he has control to stop and also log of mails sent.

Note: This is not related to the spamming.

Something like a chunk batch job where chunks are processed hourly.