Direct Observation of the Combustion Behavior of Copper Concentrate Using a Micro-Drop Tube Furnace

In the reaction shaft of the flash furnace, particle-particle interactions are known to be significant, and collision and coalescence of the droplets are thought to dominate the matte yield in the settler. Although it is essential to understand this behavior for efficient copper recovery and sustainable production, the mechanisms of concentrate combustion, particle collision, and coalescence have not yet been fully understood due to a phenomenon based on very fast reactions of fine concentrates. In this study, to reveal the mechanisms of combustion, collision, and coalescence of the concentrate, a microscopic observation method was developed using high-speed imaging. A small, vertical laminar flow furnace made of quartz, the micro-drop tube furnace, was supplied with heated oxygen, and a small amount of concentrate was continuously fed from the top of the furnace and combusted. Using a high-speed camera and microscope lens, direct observation of the combustion behavior and morphological change of single particle in the concentrate was successfully achieved. The knowledge obtained from this direct observation would be highly useful for estimating concentrate combustion behavior and matte droplet growth in the reaction shaft of the flash furnace.