China has about 98%of the diasporic bauxite ores,with around 70%being low-grade.These low-grade bauxites containing high silica pose significant challenges in alumina recovery,as their reaction with sodium aluminate i...China has about 98%of the diasporic bauxite ores,with around 70%being low-grade.These low-grade bauxites containing high silica pose significant challenges in alumina recovery,as their reaction with sodium aluminate in the Bayer process leads to alumina loss and increased caustic consumption.This study presents a novel,sustainable process for upgrading low-grade bauxite with an initial alumina-to-silica mass ratio(A/S)of 2.39.The process involves muffle furnace heating and water quenching,as well as fragmentation of bauxite.In this process,low-grade bauxite was first treated in a muffle furnace at 350℃ for 50 min,using a particle size of 355–425µm,and then suddenly cooled in cold water for fragmentation.Subsequently,a separation of the parts into smaller sizes is needed.The results demonstrate a 130%increase in the A/S mass ratio,with 67%concentrate recovery for alumina extraction.This method offers a promising solution for efficiently using low-grade bauxites without further treatments,contributing to more sustainable alumina production practices.The process is adaptable to different bauxite sources and could significantly impact alumina refineries'economics and environmental footprint worldwide.展开更多
基金supported by“Low-carbon Transformation Technologies and Demonstration in Chemical Engineering and Metallurgical Processing”,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0390201).
文摘China has about 98%of the diasporic bauxite ores,with around 70%being low-grade.These low-grade bauxites containing high silica pose significant challenges in alumina recovery,as their reaction with sodium aluminate in the Bayer process leads to alumina loss and increased caustic consumption.This study presents a novel,sustainable process for upgrading low-grade bauxite with an initial alumina-to-silica mass ratio(A/S)of 2.39.The process involves muffle furnace heating and water quenching,as well as fragmentation of bauxite.In this process,low-grade bauxite was first treated in a muffle furnace at 350℃ for 50 min,using a particle size of 355–425µm,and then suddenly cooled in cold water for fragmentation.Subsequently,a separation of the parts into smaller sizes is needed.The results demonstrate a 130%increase in the A/S mass ratio,with 67%concentrate recovery for alumina extraction.This method offers a promising solution for efficiently using low-grade bauxites without further treatments,contributing to more sustainable alumina production practices.The process is adaptable to different bauxite sources and could significantly impact alumina refineries'economics and environmental footprint worldwide.
