Chromium slag usually contains various heavy metals,making its safe treatment difficult.Glassceramic sintering has been applied to resolve this issue and emerged as an effective method for metal immobilization by inco...Chromium slag usually contains various heavy metals,making its safe treatment difficult.Glassceramic sintering has been applied to resolve this issue and emerged as an effective method for metal immobilization by incorporating heavy metals into stable crystal structures.Currently,there is limited knowledge about the reaction pathways adopted by multiple heavy metals and the co-stabilization functions of the crystal structure.To study the Cu/Cr co-stabilization mechanisms during thermal treatment,a simulated system was prepared using a mixture with a molar ratio of Al_(2)O_(3):Fe_(2)O_(3):Cr_(2)O_(3):CuO=1:1:1:3.The samples were sintered at temperatures 600–1300℃ followed by intensive analysis of phase constitutions and microstructure development.A spinel phase(CuFe_(x)Al_(y)Cr_(2–x–y)O_(4))started to generate at 700℃ and the incorporation of Cu/Cr into the spinel largely complete at 900℃,although the spinel peak intensity continued increasing slightly at temperatures above 900℃.Fe_(2)O_(3)/Cr_(2)O_(3) was more easily incorporated into the spinel at lower temperatures,while more Al_(2)O_(3) was gradually incorporated into the spinel at higher temperatures.Additionally,sintered sample microstructures became more condensed and smoother with increased sintering temperature.Cu/Cr leachability substantially decreased after Cu/Cr incorporation into the spinel phase at elevated temperatures.At 600℃,the leached ratios for Cu and Cr were 6.28%and 0.65%,respectively.When sintering temperature was increased to 1300℃,the leached ratios for all metal components in the system were below 0.2%.This study proposes a sustainable method for managing Cu/Cr co-exist slag at reasonable temperatures.展开更多
基金supported financially by the National Natural Science Foundation of China(Grant No.21707063)the National Key R&D Program of China(Grant No.2018YFC1902904)the Natural Science Foundation of Guangdong Province in China(No.2019A15150-11836)。
文摘Chromium slag usually contains various heavy metals,making its safe treatment difficult.Glassceramic sintering has been applied to resolve this issue and emerged as an effective method for metal immobilization by incorporating heavy metals into stable crystal structures.Currently,there is limited knowledge about the reaction pathways adopted by multiple heavy metals and the co-stabilization functions of the crystal structure.To study the Cu/Cr co-stabilization mechanisms during thermal treatment,a simulated system was prepared using a mixture with a molar ratio of Al_(2)O_(3):Fe_(2)O_(3):Cr_(2)O_(3):CuO=1:1:1:3.The samples were sintered at temperatures 600–1300℃ followed by intensive analysis of phase constitutions and microstructure development.A spinel phase(CuFe_(x)Al_(y)Cr_(2–x–y)O_(4))started to generate at 700℃ and the incorporation of Cu/Cr into the spinel largely complete at 900℃,although the spinel peak intensity continued increasing slightly at temperatures above 900℃.Fe_(2)O_(3)/Cr_(2)O_(3) was more easily incorporated into the spinel at lower temperatures,while more Al_(2)O_(3) was gradually incorporated into the spinel at higher temperatures.Additionally,sintered sample microstructures became more condensed and smoother with increased sintering temperature.Cu/Cr leachability substantially decreased after Cu/Cr incorporation into the spinel phase at elevated temperatures.At 600℃,the leached ratios for Cu and Cr were 6.28%and 0.65%,respectively.When sintering temperature was increased to 1300℃,the leached ratios for all metal components in the system were below 0.2%.This study proposes a sustainable method for managing Cu/Cr co-exist slag at reasonable temperatures.
