A system and method for increasing the amount of oxygen in a kiln chamber is disclosed. The radial surface of a rotatable kiln is provided with at least one oxidant injection port extending through the radial surface into the kiln chamber. A cam is connected to the radial surface adjacent the oxidant injection port. A valve assembly including a valve chamber in fluid communication with an oxidant supply is mounted adjacent the kiln substantially in fixed spatial relation with the rotatable kiln body. The valve assembly includes a follower member adapted to contact a surface to the cam to actuate the valve assembly. Rotation of the kiln body brings the cam into contact with the follower member, thereby actuating the oxidant injection assembly, and injecting oxidant through the injection port into the kiln chamber.