The answer is in the link you provided, and is alluded to by u/SirHerald. Black body radiation is the idealized emissions due to heat from a "black body." Any specific material will have a different actual emission spectrum when heated, depending on the difference in electron shell energy levels of its atoms or molecules. The energy levels that the electrons fall from in heated Thorium tend to release more photons that are in the visible spectrum of humans that the idealized black body radiation at the given temperature would.
LexiconDul t1_jarhdv8 wrote
Reply to Why does a Thorium gas mantle, when incandescent, emit more light in the visible spectrum than in infrared, when compared with a black body with the same temperature? by [deleted]
The answer is in the link you provided, and is alluded to by u/SirHerald. Black body radiation is the idealized emissions due to heat from a "black body." Any specific material will have a different actual emission spectrum when heated, depending on the difference in electron shell energy levels of its atoms or molecules. The energy levels that the electrons fall from in heated Thorium tend to release more photons that are in the visible spectrum of humans that the idealized black body radiation at the given temperature would.