China Nonferrous Metallurgy

Red mud is a strong alkaline solid residue produced in the process of alumina production, which limits its large-scale application in cement and other fields. It is urgent to develop efficient alkali removal technology of red mud and support sodium content analysis and detection technology. In this paper, sodium in Bayer red mud was measured by flame atomic absorption spectrophotometry. The existing method was improved. The red mud sample was digested by hydrochloric acid (1+1) without using precious metal crucible. The digestion time of the sample was optimized. The ionization interference of sodium was effectively eliminated by KCl, and the effective concentration range of KCl in the literature was corrected. Under the optimized measurement conditions, the recovery rate of standard addition was 99.17 %~105.00%, and the relative error of red mud standard sample was -0.22%~0.29%. The relative standard deviation (n=10) of red mud was 1.28%, and the relative standard deviation (n=3) of red mud standard sample was 0.85%~2.72%. The method has high sensitivity, good accuracy and precision, and the conventional laboratory can meet the analysis and detection conditions, which can provide reliable analysis and detection support for the development of efficient alkali removal and comprehensive utilization technology of red mud.