What was found
(CAN) IMMEDIATELY FOLLOWING MAIN WHEELS LEAVING THE GROUND STICK SHAKERS AND STALL WARNING ACTIVATED. CREW CONTINUED WITH TAKEOFF, THE AIRCRAFT RETURNED TO AIRPORT. CREW REPORTED THAT DURING SLAT RETRACTION THAT THEY COULD NOT FULLY RETRACT THE SLATS (DUE TO STALL WARNING). STALL WARNING CONTINUED THROUGH OUT FLIGHT & DID NOT STOP UNTIL AIRCRAFT TOUCHED DOWN ON THE RUNWAY. MAINTENANCE FOUND THAT THE STALL WARNING SYSTEM #2 WAS ACTIVATING PREMATURELY, SYSTEM #2 STALL WARNING WAS DEACTIVATED AND THE AIRCRAFT DISPATCHED AS PER MEL WITH NO FURTHER FAULTS.