Recently, the complete set of technologies for time-temperature coordination and intelligent control of super-large alumina roasting furnaces, independently developed by China Aluminum International Shenyang Aluminum & Magnesium Design and Research Institute Co., Ltd., has achieved large-scale implementation. The overall technology has reached the internationally leading level, overcoming long-standing technical bottlenecks in the thermal engineering systems of roasting furnaces.
The roasting furnace is a core link in alumina production, accounting for one-third of the total heat consumption in production. "The mainstream gas suspension roasting furnaces in the industry have short high-temperature residence times for materials and insufficient gas-solid heat exchange efficiency, and the systems are also highly dependent on manual experience-based operation. Previous domestic and international research mostly remained at auxiliary stages such as backend waste heat recovery," said Zhou Fenglu, head of the project leadership group.
In response to the above bottlenecks, the team carried out coordinated research from three dimensions: in terms of process, it pioneered a new low-temperature roasting process with buffered time extension to prolong the high-temperature reaction residence time of materials; in terms of equipment, it pioneered gas-solid guided dispersion-type heat and mass intensification cyclone separation technology, developed a super-large single-unit cyclone separator, and applied it in support of the gas suspension roasting furnace with the world's largest single-unit capacity of 6,000 tons/day; in terms of intelligent control, it built a four-dimensional coordinated system of "grey-box modeling—predictive feedforward—flexible execution—rule constraints," controlling main furnace temperature fluctuations within ±2% and achieving oxygen content control accuracy of ±1.6%.
At present, this complete set of technologies has been implemented in a number of large alumina enterprises in China, and the heat consumption of the alumina production system can be reduced to 2.7 GJ/t.