Granulation of molten material

A granulator comprising:

• a chamber,
• a rotary atomizer for receiving molten slag within the chamber and mounted to spin about a substantially vertical axis within the chamber and adapted to project droplets of the molten slag along a trajectory, wherein the trajectory is at an angle to the substantially vertical axis;
• and
• the chamber having an impact surface disposed within the trajectory of the droplets upon which all or substantially all of the droplets impact, and
• the chamber having an air cooling arrangement which creates an airflow of cooling air in the chamber to enhance cooling of the molten slag droplets, said airflow being of an annular nature with substantially no net upward velocity component when in steady state,
• wherein the impact surface is cooled by water or other refrigerant and is disposed above the rotary atomizer, the angle at which the impact surface is disposed relative to the trajectory of the droplets being greater than 30 and less than 60 degrees;
• and wherein the impact surface being at a distance from the rotary atomiser in combination with the angle at which the impact surface is disposed relative to the trajectory of the droplets leaving the rotary atomiser being such that:
• all or substantially all of the droplets impact the impact surface, and
• (ii) a portion of the droplets are not fully solidified prior to contact with the impact surface.