https://www.gsmarena.com/asus_padfone_mini-5891.php
It sounds like the Android OS has become corrupted and that's why your phone is going through the startup procedure but fails when it comes to actually loading up the operating system. Hopefully others will comment with more optimistic viewpoints but this does not bode well for recovering data stored in your phone's internal storage at this point.
You referred to removing the battery but how long did you leave it out? If you just removed it and put it right back in, try removing it again but this time leaving it out for several minutes, and then put it back in and see if your phone boots up properly. (By leaving it out for an extended period, that allows any residual power that might be left in any of your phone's internal components to drain away.)
You might also want to try wiping the system cache partition. While this is not a likely solution to this particular problem it doesn't hurt anything to at least try. The system cache resides in its own dedicated partition, completely separate from the data partition, where all your files are stored, so it won't affect any of your data. You need to boot your phone up into its Recovery Mode to do this:
http://www.hardreset.info/devices/asus/asus-pf451cl-padfone-mini/recovery-mode/
Once running in Recovery Mode select the 'wipe cache partition' option, and then reboot.
There's also the option of taking your phone in to trusted repair facility. Explain your situation (emphasizing you need to save your stored files), and be sure to get something in writing for a price quote and that they won't do something like a Factory Reset.
.... and be sure from this point onward to set up a reliable backup solution. Were you saving anything to your microSD card? (That's more of a half-measure as backup media since cards are tend to have limited reliability for long-term storage.)