Slate tile suitability for floors & walls
The simple answer is Yes these tiles are perfectly suitable for use on the walls as well as the floor.
As with any installation, it is the surface preparation which is the key factor.
Some surfaces may need to be primed, and the adhesive required may be different for each type of surface. However if you give us a call we can advise you on the correct products to use for your particular installation based on your substrate