System for coal blowing in iron oxide reducing kilns

A method for feeding solid carbonaceous reducing agent through the discharge end of a rotary kiln directly reducing materials containing metal oxides using a supply of solid carbonaceous reducing agent, a portion of which is fed through the charge feed end and the remaining portion of which is fed through the discharge end of the kiln, the interior barrel of which has two upper and two lower quadrants defined by a vertical plane and a plane perpendicularly intersecting said vertical plane along the kiln axis, comprising the steps of:

• forming said remaining portion of the solid carbonaceous reducing agent into particles of about 1/2 inch diameter and less;
• injecting the particles through the discharge end of the kiln in the form of a stream of particles;
• and
• spreading said particles over the gas/bed interface by directing said stream into one of the upper quadrants in the kiln barrel and bouncing it off the kiln wall in the region between about 40% and 90% of the kiln length from the charge feed end.

A system for controlling heat transfer to the charge bed in a rotary kiln directly reducing materials containing metal oxides using a supply of solid carbonaceous reducing agent, a portion of which is fed through the charge feed end and the remaining portion of which is fed through the discharge end of the kiln, which kiln has an interior barrel with two upper and two lower quadrants defined by a vertical plane and a plane perpendicularly intersecting said vertical plane along the kiln axis and which bed has a working zone over at least a third of the kiln length from the discharge end, comprising:

• first means for injecting metered amounts of oxygen-containing gas axially within the kiln at locations spaced along its length;
• second means for injecting said remaining portion of the solid carbonaceous reducing agent through the discharge end of the kiln in particulate form over the surface of the charge bed, said second injecting means comprising:
• a pipe disposed at the discharge end of the kiln;
• and
• fireman means for feeding the solid carbonaceous reducing agent to said pipe;
• and means for adjusting the rate of injection of said reducing agent and the direction of injection to spread reducing agent over at least the gas/bed interface in the working zone of the kiln comprising:
• means connected to said second injecting means for blowing the particulate reducing agent from said fireman means through said pipe using low pressure air to form a stream of reducing agent, said blowing means comprising a positive displacement blower;
• and means for orienting said pipe such that said stream is directed into one of the upper quadrants within the kiln barrel and bounces off the kiln wall in the region between about 40% and 90% of the kiln length from the charge feed end.