Abstract:Bauxite is the main source of organic matter in the production process of alumina, and at present, organic matter has become a key common problem in the production of alumina, which urgently needs to be solved. In order to provide theoretical basis for the removal of organic matter in China's alumina production enterprises, applying two typical bauxites at home and abroad as the research object to study the influence of different leaching process conditions on the digestion of alumina, the reaction rate of organic carbon and the conversion rate of oxalate of the two bauxites. The results show that the appropriate leaching process conditions for domestic bauxite are: leaching temperature ≥ 265 ℃, leaching time of about 60 min, and lime addition of about 9%. Under these conditions, the alumina digestion rate of this bauxite is greater than 86.5%, the organic carbon reaction rate is about 33%, the sodium oxalate conversion rate is about 15%, and about one kilogram of organic carbon enters the system for the production of one ton of alumina, while about 2.63 kilograms of sodium oxalate is produced at the same time; When the low-temperature leaching process is used for imported bauxite, it is recommended to use a leaching temperature of 145 ℃ and leaching time of 30 min. Under these conditions, the digestion rate of alumina is about 89.5%, the conversion rate of organic carbon about 55%, the conversion rate of sodium oxalate is about 8%, and the conversion amount of sodium oxalate is about 1.5 kilograms per ton of Al2O3; When the high-temperature leaching process is used for imported bauxite, it is recommended to use a leaching temperature of 265 ℃ and leaching time of 5 to 10 minutes. Under these conditions, the conversion rate of organic carbon is about 60%, and the conversion rate of oxalate is about 15% to 16%, with a conversion amount of sodium oxalate of 2.9 to 3.05 kilograms per ton of Al2O3. Overall, the organic carbon reactivity of imported bauxite is significantly higher than that of domestic bauxite, with about two kilograms of organic carbon entering the system for every ton of alumina produced, which is twice that of domestic ore. However, the conversion rate of organic carbon to sodium oxalate is relatively high both types of ore. Therefore, whether using domestic ore or imported ore to produce alumina, it is necessary to pay attention to the changes in the content of organic and sodium oxalate in the system and make technical preparations for the removal of sodium oxalate.