The fraction analysis of chromium in manganese slag

• The fraction distributions of chromium in manganese slag have been analyzed using Tessier method.
• Cr (total) and Cr (III) fraction distributions have the same trend.
• The main fraction of residual is stable and Cr (III) of low toxicity is the main ingredient.
• The chromium release in the manganese slag stacking process has low impact on environment.

In present research, Tessier method was used to explore the fraction distributions of Cr (total) and Cr (III) in manganese slag. Nano-TiO2 was used to concentrate and separate out Cr (III) from manganese slag. Meanwhile, the contents of various fraction compounds of chromium were determined by atomic absorption spectrophotometer. The experimental results showed that fraction distributions of Cr (total) and Cr (III) have the same trend, which was residual [Cr (total) 88.7%/Cr (III) 86.71%] > bound to Fe–Mn oxides [Cr (total) 5.16%/Cr (III) 6.47%] > exchangeable [Cr (total) 3.93%/Cr (III) 4.29%] > bound to organic matter [Cr (total) 1.88%/Cr (III) 2.20%] > bound to carbonates [Cr (total) 0.35%/Cr (III) 0.33%]. Because the main fraction of residual is stable and Cr (III) of low toxicity in each fraction is the main ingredient, the chromium release in the manganese slag stacking process has a low impact on environment.