Device and method for comprehensive treatment of construction wastes

The invention relates to a device and a method for the comprehensive treatment of construction wastes and relates to the field of construction waste recycling and utilization. The device comprises a crushing device used for crushing the construction wastes and a separating device used for separating metal from the crushed construction wastes, wherein the output end of the crushing device is provided with a first conveying belt used for conveying the crushed construction wastes; the separating device comprises a frame body; the first conveying belt is arranged on the frame body; a second conveying belt is arranged on the frame body and located above the first conveying belt; a rubber magnetic plate is wound on the second conveying belt and fixedly connected to the second conveying belt; a flattening device used for flattening the crushed construction wastes is arranged on the frame body and located above the belt surface of the first conveying belt; and the flattening device is locatedbetween the input end of