Sulfur hexafluoride recovery device for magnesium alloy low-pressure casting

A sulfur hexafluoride recovery device for magnesium alloy low-pressure casting comprises a negative-pressure air suction pipeline which is connected with a vacuum tank, an air inlet pipe, an air suction pipe, a first vacuum pressure switch and a first sulfur hexafluoride concentration sensor are arranged on the vacuum tank, an air inlet electromagnetic valve is arranged on the air inlet pipe, andthe air suction pipe is connected with a vacuum pump through a pressure regulating valve. Wherein the vacuum tank is connected with the slow-release tank through a compressed air pipeline, a compressor and a pressure reducing valve are arranged on the compressed air pipeline, a second vacuum pressure switch and a second sulfur hexafluoride concentration sensor are arranged on the slow-release tank, and the slow-release tank is connected with the return pipeline. The sulfur hexafluoride mixed gas discharged during pressure relief of low-pressure casting equipment can be recycled and recycled back to the casting equipme