When you Azure AD join your device and activate Bitlocker, you get the option to store the Recovery Key in Azure AD.
If you ever wonder where to find them, they are all available from the Details Window for your registered devices in the Azure AD Management Portal.
A few easy steps to get there
- Open Azure AD in the Management Portal
https://manage.windowsazure.com - Open the Users tab and search/browse for the account you need to find recovery key for, then open it.
- Go to the Devices tab, and in the View box, select Devices.
- Select the affected device, and click View Details.
All registered keys should be visible