Pyrolusite is a LV-tier material, it has to be processed in LV-tierElectrolyzer in order for its chemical components to be obtained. It can also be smelted in any furnace, which allows to obtain Manganese from it in 1:1 ratio, which is more efficient.
Due to the excessive bulk of including all GregTech 5 blocks and items this navigation box only holds ~10% of all. The reader can view This and This navigation boxes to access the rest.