<< wav is not cd audio although it can be written as so just like mp3s can be. >>
Not to be picky but the data part of CD audio IS IDENTICAL to a .wav file. Both are Pulse-Code Modulated (PCM) digital data. No data coversion is required to write a .wav as a .cda. Only the file header is different (and of course CD audio discs have a different way of organizing the data on the disc, but that's a function of the CD standard, not .wav vs. mp3). MP3 involves an extensive conversion of the data. Which leads to...
<< generally a small amount of data is lost in converting CDA to mp3 >>
More like a huge amount of data is lost. An mp3 retains only about 12-15% of the original data. The rest is discarded according to the rules established by the mp3 encoding algorithm.
So, when you convert the mp3 to .wav, even though the file size is 12-15 times larger, you are still missing just as much data.