The granite water film dust collector is mainly composed of a Venturi tube, a main pipe, an overflow tank, and a secondary cylinder. Its working principle is that the dusty airflow enters the Venturi tube through the flue, and water is evenly sprayed into the flue gas at the inlet of the throat, causing the flue gas to dissolve the water into small water droplets. In this process, the ash in the flue gas is wetted, increasing its weight and facilitating centrifugal separation. In high-speed turbulent flow, due to the large difference between water droplets and dust particles, the ash particles collide and condense with the water droplets, especially the fine dust particles that can be dissolved by the water droplets. These are all sufficient preparations for the separation of ash, and then enter the main cylinder. The main cylinder is a circular cylinder, and water enters the main cylinder from the overflow groove on the dust collector, causing a layer of water film to flow from top to bottom along the entire inner wall of the cylinder. Gas enters from the lower part of the cylinder tangentially and rises as it rotates. The dust containing gas always rubs against the water film on the cylinder wall under the action of centrifugal force. In this way, the dust containing gas is wetted by the water film, and the dust particles flow with the water to the dust collector and are discharged from the drainage outlet. There is a water seal groove at the bottom of the cylinder to prevent smoke from being discharged from the bottom. The wastewater after dust removal flows into the sedimentation area from the bottom, and is neutralized by the sedimentation for recycling. The purified gas is dehydrated through the upper conical part of the main cylinder and enters the secondary cylinder for settling. After separation and dehydration, the purified flue gas is discharged into the induced draft fan through the lower part of the secondary cylinder, completing the entire working process.