Device and method for co-producing potassium sulphate compound fertilizer from tripolycyanamide tail gas

The invention belongs to the technical field of chemical production, and particularly relates to a device and method for co-producing a potassium sulphate compound fertilizer from a tripolycyanamide tail gas. The device comprises a potassium chloride dechlorination reaction unit, an HCl tail gas absorbing unit, an ammonium chloride crystallization and separation unit, a potassium sulphate compound fertilizer neutralizing unit and a potassium sulphate compound fertilizer granulating and screening unit. The invention further discloses a method for producing the potassium sulphate compound fertilizer by using the device. According to the device and the method, by using the tail gas produced by adopting the tripolycyanamide device, co-production is performed by the tripolycyanamide device and the compound fertilizer device, thus the difficulty in treating the tail gas produced by the tripolycyanamide device is solved, the additional value of the tripolycyanamide tail gas is increased, the production cost of the c