The story you may have heardWiktionary passes on the claim that tartarum comes from Arabic durdī 'dregs' (from Persian durd). This is impossible on dates: Latin tartarālis is found in the 4th–5th century, long before Arabic contact, as Etymonline and TLFi note. Paracelsus's explanation of the name, tying it to Tartarus, is also judged fanciful (Etymonline).