I can't help you as with mini 1 there were several mini's built for different markets. I don't know what frequencies are used in Spain for LTE and if the Sprint model matches what you need. If you know what frequencies your carrier uses. I can check to see what the sprint mini included if that will help.
----------
Here are the specifications on the Sprint mini.
This specific iPad mini A1455 model also has support for A-GPS and GLONASS, CDMA EV-DO, GSM/EDGE, UMTS/HSPA+/DC-HSDPA, and LTE bands 1, 3, 5, 13, and 25. In the US, it is intended to run on the Verizon or Sprint network.
From what I understand, it should work.