The hot off-gases exit the bed at a temperature of around 200-400°C and are mixed with a cross stream of cold air. This stream of air reduces the off-gas temperature.
The gases from the kiln pass through a drop-out box where coarser particles are dropped out and discharged. From the drop-out box, the off-gases are collected in a bag house and discharged by an exhaust fan. The dust from the drop-out box and the bag house is collected in a dust bin. This dust is transported back to the mine or can be used in the production of agricultural MgO.