The employee involved was working at the Process Tanks to remove a 12"" spool pipe on slurry cooler #3 at phase II. When tapping the spool piece out the Vic coupling failed to hold Vic 741 in place. The valve popped out of its groove releasing acidic slurry into the work area. The employee received 1st and 2nd degree burns to the wrist, neck area and right elbow.