The Qt wallet is simply just a wallet. If you want to solo mine you can download the iridium daemon from https://github.com/iridiumdev/iridium/releases/tag/v1.0.0
Once it's downloaded, install libtools with the command "sudo apt-get install libboost-all-dev" then configure the iridium daemon permissions with the command "chmod u+x iridiumd" Then finally run the iridium daemon with the command "./iridiumd"

Make sure you change into the directory that iridiumd is located with the "cd" command.

To start solo mining once running iridiumd, type the command "start_mining YOUR WALLET ADDRESS NUMBER_OF CORES" eg. start_mining ir... 2