China's Refractories

Abstract:

Copper smelting furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type, and slag system is dictated by the specific ore type available; which will determine the individual refractory wear. This paper evaluates the common refractory wear mechanisms as observed in the copper Peirce-Smith converter and in the copper anode furnace. The chemical factors include corrosion caused by fayalite type slag and sulphur supply, as well as by Cu-oxide attack. Changes in the temperature during the furnace operation (thermal shock) create stresses in the brick lining which can only be absorbed to a limited extent. Mechanical factors include erosion, caused primarily by the movement of the metal bath, slag and charging material, as well as stresses in the brickwork due to punching. Finally, improper lining procedures can also affect the service life. All these wear parameters lead to severe degeneration of the brick microstructure and a decreased lining life, and in the worst case overheated furnace structures and possibly dangerous hot spots or even breakouts. Therefore, a detailed investigation and understanding of the wear mechanisms through “post-mortem studies” together with thermochemical calculations by FactSage ^TM software is an important prerequisite for the refractory producer. Based on these research results, combined with specific process knowledge, appropriate brick lining solutions for copper processing furnaces can be recommended. In addition to the described efforts to investigate refractory wear and optimise lining qualities, it is also essential to monitor the process and the effect on the refractories to further improve both safety and process. For this purpose, technologies using sensors and novel digital solutions can be applied.

Key words: wear phenomena, copper vessel, monitoring technologies