The wear of the nozzle ring and damage to the upper cover of the nozzle ring cause the wind speed in vertical roller mill to not reach the design wind speed, and the material cannot be lifted in time, causing spitting.

The grinding disc ring is severely worn, the gap is enlarged, and the air leakage is serious, causing slag spitting.

The guide cone is severely worn and cannot effectively play the role of guiding logistics and airflow.

The grinding roller skin and the grinding disc liner are severely worn, which causes the grinding pressure to drop, the grinding effect is not good, and the internal circulation load of vertical roller mill increases and causes slag spitting.