Well. Guessing it is the 32gig /dev/sdb.
Not really sure how to check if the back-up kernel sees it. I know it used to work before I updated the kernel.
If you did not uninstall the new kernel. Use the shift key on power up to get into grub menu and the previous kernel will be in the menu.
Since fdisk sees it. The reader is working. Ubuntu is just not auto mounting it for you. I don't know how a kernel change can screw up a auto mount feature but
you can mount it manually as sudo in terminal
I don't run Ubuntu . I am posting in AntiX.
I don't even run a Desktop Enviornment like you do but just a Window Manager called Icewm instead. To tell the truth. I am stumped how a kernel change could
screw up automount on a Desktop Environment. I don't even know what version
of Ubuntu you are running.
Like I'll show you how to below. The inxi command I used won't work for you though in Ubuntu. You need to install that on your own.
Edit: It's Friday and I am not all here. My Bad. Mint has INXI in it. I totally spaced out the KDE Mint statement in your original post. Sorry.
$ cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux jessie/sid"
$ cat /etc/issue
Debian GNU/Linux jessie/sid \n \l
$ uname -a
Linux biker 3.12-6.towo-siduction-686-pae #1 SMP PREEMPT Fri Dec 20 22:11:05 UTC 2013 i686 GNU/Linux
$ inxi -S
System: Host: biker Kernel: 3.12-6.towo-siduction-686-pae i686 (32 bit)
Desktop: IceWM 1.3.7 Distro: antiX-13_386-full Luddite 01 June 2013