Sustainable Mining and Metallurgy

Aiming at the lime digestion residue of alumina enterprises, this paper proposed a new process of recycling the digestion residue instead of lime to return to the alumina production process. The digestion residue was mixed with lime milk for causticization of sodium carbonate after crushing and grinding. The results of causticization test showed that the causticization efficiency increased gradually with the increase of lime digestion residue, indicating that the effective component CaO in lime digestion residue could carry out causticization reaction, and it was feasible to replace lime with digestion residue. Therefore, the traditional treatment process was reformed and the residue treatment process was added, so that the residue was changed from completely open storage and transportation treatment to continuous closed retreatment. The process was applied to an alumina enterprise, and good economic benefits were obtained. The process avoids the anti-causticization of the residue returning to the front end of the production system, reduces the sodium carbonate entering the system, reduces the salt discharge consumption, realizes the online continuous closed treatment of the residue, solves the shortcomings of the traditional complete open treatment of the residue, and achieves better economic and social benefits. It has certain application value.