EMPLOYEE WAS CHANGING BURNER NOZZLES ON #2 GAS SUSPENSION CALCINER IN AN ATTEMPT TO CONTROL FLUE GAS NOX. AS HE REMOVED THE NOZZLE, THE CALCINER PUFFED AND BLEW OUT HOT GASES (1000 DEG C) AND BURNED THE EMPLOYEE'S FACE AND BOTH FOREARMS. THESE BURNS DEVELOPED INTO SECOND DEGREE, MAKINGTHIS A RECORDABLE INCIDENT. NO LOST TIME OR RESTRICTED DUTY.