Abstract：Argon-oxygen decarburization furnace (AOD) slag will undergo a series of aging effects such as hydration, carbonation, and oxidation during the long-term storage process. These reactions can affect the properties and leaching characteristics of aged AOD stainless steel slag, and then change its potential for safe resource utilization. The short-term static leaching test was carried out on the ten-year-aged AOD slag by controlling the initial leaching solution pH and leaching atmosphere, and the electrochemical characteristics and chromium concentration of the leachate were tested during the leaching process to study the effect of leaching conditions on chromium leaching characteristics in the aged AOD slag. Mineralogical identification and microscopic morphology observation were used to analyze the effect of leaching on the mineral phase in AOD slag. The results showed that during the leaching process, the mass fraction of dicalcium silicate in the aged AOD slag decreased due to hydration reaction. The pH of the leachate obtained under the condition of opening and the leachate's initial pH=2 was the lowest, but it still showed strong alkalinity. The pH of the leachate under the sealed atmosphere was 8%-14% higher than that under the open condition. When the initial leaching solution pH is the same, the leached solution Eh under closed condition is 6-37 mV lower than that under open condition. During the long-term aging process, part of the Cr(Ⅲ) in the AOD slag was oxidized to Cr(Ⅵ). These Cr(Ⅵ) were more sensitive to the leaching environment and had the strongest leachability in the open acidic leaching condition. The aging products had physical sequestration on the remaining Cr(Ⅲ) in the aged AOD slag, so that the leachability of this part of Cr(Ⅲ) was weak.
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WANG Wei, LI Jun-guo, WANG Ya-jun, ZENG Ya-nan, GAO Ai-min. Properties of aged AOD slag and its leaching characteristics[J]. China Metallurgy, 2021, 31(8): 104-110.
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