grate-kiln furnace

The grate-kiln system is a method used in iron processing, specifically for pelletizing iron ore concentrates. This system combines a horizontal traveling grate with a rotating kiln and a cooler. In this process, iron ore concentrates are formed into soft, spherical agglomerates, then dried and hardened by firing at high temperatures. The grate-kiln system allows for separate stages of drying, firing, and cooling, producing finished pellets that are nearly ideal in shape for use in a blast furnace.1

A blast furnace is a vertical shaft furnace used to produce liquid metals, primarily pig iron from iron ore, for subsequent steel production. It operates by reacting a flow of air under pressure with a mixture of metallic ore, coke, and flux fed from the top. The process involves preheating the charge as it descends the shaft, where it reacts with ascending reducing gases. Hot air, often preheated, is blown into the bottom, reacting with coke to create high temperatures that melt the iron and form slag.2