Even in a normal civilian controlled demolition, explosive or vérinage, most of the dust is produced by the material crushing itself as the collapse hits ground.
The WTC buildings produced more dust because the buildings were much taller than any buildings that have been imploded. There was further for the rubble to fall, so it picked up more speed, more kinetic energy, which was all dissipated in the final crush.
There’s really no mystery. When ore or rubble is deliberately turned to dust it is done by crushing it in a mill. This process has been studied thoroughly and is well quantified. The same equations have been applied to the Twin Towers’ collapses, and the amount of dust produced was normal.