Yes and no. Yes, you may get some taxes back. However:

- Fuel surcharges are generally not refunded ("Carrier surcharge")
- If you officially cancel the return, which is needed to get taxes back, the price for the ticket will most probably be re-calculated. That means that your ticket will change into a one-way. And one-ways are often more expensive than return tickets. Which may even mean that, by initiating this process, you will owe them money!