Influence of the Al2O3/SiO2 mass ratio and gas composition on the viscous behavior and structure of Cr-containing stainless steel slags

Selective elemental concentration during the solidification of stainless steel slags for increased Cr recovery with MnO addition

“…With the core Cr 2 O 3 phase and sufficient time at the moderately high temperature of 1300°C, diffusion occurs, and the Ca 3 Cr 2 Si 3 O 12 phase forms. Since Al 3+ and Cr 3+ ions can form similar tetrahedral structures that require additional charge compensation to reach electroneutrality, Cr 3+ ions can be partially replaced with Al 3+ ions to form a new crystal phase, identified as Ca 3 Cr 1.75 Al 0.25 Si 3 O 12 4,40 . The dissolution of Cr2O3 and the formation of Ca 3 Cr 2‐x Al x Si 3 O 12 in the same sample can also be estimated from the FactSage calculation results, as shown in the previous Figure 1.…”

“…Approximately 15 million tons of Cr‐containing slags classified as environmentally hazardous byproducts are generated annually worldwide during the production of stainless steel, and most of the slags are directly discharged to the environment 1‐4 . Under typical weathering conditions, the direct discharge of Cr‐containing slags into the environment will eventually result in Cr dissolution into water and soil (4Cr 3+ + 10H 2 O + 3O 2 = 4CrO 4 2− + 20H + ), damaging the ecology, hindering animal and plant growth and causing various diseases as Cr 6+ enters the human body through the digestive tract and skin 5‐7 .…”

“…Approximately 15 million tons of Cr-containing slags classified as environmentally hazardous byproducts are generated annually worldwide during the production of stainless steel, and most of the slags are directly discharged to the environment. [1][2][3][4] Under typical weathering conditions, the direct discharge of Cr-containing slags into the environment will eventually result in Cr dissolution into water and soil (4Cr 3 + + 10H 2 O + 3O 2 = 4CrO 4 2− + 20H + ), damaging the ecology, hindering animal and plant growth and causing various diseases as Cr 6+ enters the human body through the digestive tract and skin. [5][6][7] Due to the greater demand for high-performance stainless steels and growing emphasis on sustainability, cost-effective treatments of Cr-containing stainless steel slags to improve the recovery efficiency of the Cr in the slag to minimize the outbound elemental content have been extensively studied.…”

Immobilizing chromium in stainless steel slags with MnO addition

“…As the main by-product during stainless steel smelting, the global generation of stainless steel slags is approximately 15 million tons per year. [1][2][3][4][5] Since Cr-containing stainless steel slags are potentially hazardous Cr-containing materials, its recycling has been severely restricted. 6 Most stainless steel slags worldwide are landfilled, 7 where the Cr 3+ can potentially oxidize to Cr 6+ under long-term environmental exposures.…”

“…As the main by‐product during stainless steel smelting, the global generation of stainless steel slags is approximately 15 million tons per year 1‐5 . Since Cr‐containing stainless steel slags are potentially hazardous Cr‐containing materials, its recycling has been severely restricted 6 .…”