Steam in the vapor state will not separate from air in a cyclone or any other such device. You could condense the steam into tiny droplets and those would separate. If you have both steam and dust, you will get some sort of sludge, which is a challenge to work with, especially on a continuous basis. That's why we design systems that avoid this combination and why you readily don't find solutions on the Web. [Is this the same 700°C flue gas thing?]

Thanks, Dudley J Benton ! This is different from the flue gas stream at 700 deg C- much colder, and hence not planning to recover the energy from this one.

Magnetize the flu particles and then cross the flu inside the magnetic field.