Thermal power plants have produced insulating bricks for boiler with fly ash.

This brick won a high appreciation for its economic value in raising the heat effect of boiler.

The Pyongyang Thermal Power Complex remodeled its heat-insulating material production base to produce tens of thousands of quality insulating bricks every month with white fly ash.

Similar successes were made at the Pukchang Thermal Power Complex and the Sunchon Thermal Power Plant, too.