Did somebody say ballista?
Aesystrofi's Poliánthion: In our efforts to find new uses for Orichalcum, we have stumbled across a manner of treating it such that it develops springiness- that is, it is somewhat flexible, but will always 'spring' back to its original form.
However, it requires too much force to make bows out of. Perhaps as a single layer in a composite, but that's not what we seek to use it for (today). Instead, we have developed an ingenious engine capable of projecting stones and bolts across vast distances- far greater than bows or sun staves, more equivalent to Sun Temples in range.
This 'Poliánthion' is made out of wooden components, reinforced with regular metal (or Orichalcum if needed). It somewhat resembles a (very) large bow, with two prods attached to a (thick) string, which is pulled back before being released, firing a projectile. Unlike a bow, the Poliánthion stores its energy in 'torsion springs', made out of the new Orichalcum, which can store exponentially more energy than a bow of equivalent size could. A crank is needed to reload the weapon, as no human could hope to pull back the string.
It fires either stone shot, or wooden bolts tipped with metal. The bolts are more accurate, but the stones can do more damage in certain situations. It is primarily intended to be used as a siege weapon or mounted on ships, but battlefield use is not impossible. Indeed, it should give commanders a way to deal with the sand-dwellers' "Sky Temple", and anti-infantry use is also an option.
The weapon may be disassembled and transported in pieces, or placed on a cart (if we have them) and moved whole. (Or put on a ship)