Physicochemical properties of arsenic sulfide sludge(ASS) from copper smelter(ASS-I) and lead-zinc smelter(ASS-II) were examined by XRD, Raman spectroscopy, SEM-EDS, TG-DTA, XPS and chemical phase analysis method. The...Physicochemical properties of arsenic sulfide sludge(ASS) from copper smelter(ASS-I) and lead-zinc smelter(ASS-II) were examined by XRD, Raman spectroscopy, SEM-EDS, TG-DTA, XPS and chemical phase analysis method. The toxicity characteristic leaching procedure(TCLP), Chinese standard leaching tests(CSLT), three-stage sequential extraction procedure(BCR) and batch leaching experiments(BLE) were used to investigate the environmental stability. The ASSs from different smelters had obviously different physicochemical and environmental properties. The phase composition and micrograph analysis indicate that ASS-I mainly consists of super refined flocculent particles including amorphous arsenic sulfide adhered with amorphous sulfur and that ASS-II mainly consists of amorphous arsenic sulfide. The valence state of arsenic in both sludges is trivalent, but the valence composition of sulfur is quite different. The ASSs have thermal instability properties. The results of TCLP and CSLT indicate that the concentrations of As and Pd in the leaching solution exceed the standard limits. More than 5% and 90% of arsenic are in the form of acid soluble and oxidizable fractions, respectively, which explains the high arsenic leaching toxicity and environmental activity of ASS. This research provides comprehensive information for the disposal of ASS from copper and lead-zinc smelter.展开更多
The vitrification characteristics of municipal solid waste incinerator (MSWI) fly ash were investigated. Effects of temperature on the binding efficiency of heavy metals, the change of chemical compositions and the we...The vitrification characteristics of municipal solid waste incinerator (MSWI) fly ash were investigated. Effects of temperature on the binding efficiency of heavy metals, the change of chemical compositions and the weight loss of fly ash in the range of 800-1350 ℃ were studied. Toxicity Characteristic Leaching Procedure (TCLP) of the United States was used to analyze the leaching characteristics of heavy metals in fly ash and molten slag. Results indicate that chemical compositions, the weight loss of fly ash and the binding efficiency of heavy metals in fly ash have a tremendous change in the range of 1150-1260 ℃. The percentage of CaO, SiO2 and Al2O3 increases with the increasing temperature, whereas it is contrary for SO3, K2O, Na2O and Cl; especially when the temperature is 1260 ℃, the percentage of these four elements decreases sharply from 43.72% to 0.71%. The weight loss occurs obviously in the range of 1150-1260 ℃. Heavy metals of Pb and Cd are almost vaporized above 1000 ℃. Cr is not volatile and its binding efficiency can reach 100% below 1000 ℃. Results of TCLP indicate that the heavy metal content of molten slag is beyond stipulated limit values.展开更多
基金Projects(51904354,51634010)supported by the National Natural Science Foundation of ChinaProject(51825403)supported by the National Science Fund for Distinguished Young Scholars,ChinaProjects(2018YFC1903301,2018YFC1900301)supported by the National Key R&D Program of China。
文摘Physicochemical properties of arsenic sulfide sludge(ASS) from copper smelter(ASS-I) and lead-zinc smelter(ASS-II) were examined by XRD, Raman spectroscopy, SEM-EDS, TG-DTA, XPS and chemical phase analysis method. The toxicity characteristic leaching procedure(TCLP), Chinese standard leaching tests(CSLT), three-stage sequential extraction procedure(BCR) and batch leaching experiments(BLE) were used to investigate the environmental stability. The ASSs from different smelters had obviously different physicochemical and environmental properties. The phase composition and micrograph analysis indicate that ASS-I mainly consists of super refined flocculent particles including amorphous arsenic sulfide adhered with amorphous sulfur and that ASS-II mainly consists of amorphous arsenic sulfide. The valence state of arsenic in both sludges is trivalent, but the valence composition of sulfur is quite different. The ASSs have thermal instability properties. The results of TCLP and CSLT indicate that the concentrations of As and Pd in the leaching solution exceed the standard limits. More than 5% and 90% of arsenic are in the form of acid soluble and oxidizable fractions, respectively, which explains the high arsenic leaching toxicity and environmental activity of ASS. This research provides comprehensive information for the disposal of ASS from copper and lead-zinc smelter.
基金Sponsored by the Chinese Postdoctoral Fund(Grant No.023205030)National Natural Science Foundation of China(Grant No.20577047)
文摘The vitrification characteristics of municipal solid waste incinerator (MSWI) fly ash were investigated. Effects of temperature on the binding efficiency of heavy metals, the change of chemical compositions and the weight loss of fly ash in the range of 800-1350 ℃ were studied. Toxicity Characteristic Leaching Procedure (TCLP) of the United States was used to analyze the leaching characteristics of heavy metals in fly ash and molten slag. Results indicate that chemical compositions, the weight loss of fly ash and the binding efficiency of heavy metals in fly ash have a tremendous change in the range of 1150-1260 ℃. The percentage of CaO, SiO2 and Al2O3 increases with the increasing temperature, whereas it is contrary for SO3, K2O, Na2O and Cl; especially when the temperature is 1260 ℃, the percentage of these four elements decreases sharply from 43.72% to 0.71%. The weight loss occurs obviously in the range of 1150-1260 ℃. Heavy metals of Pb and Cd are almost vaporized above 1000 ℃. Cr is not volatile and its binding efficiency can reach 100% below 1000 ℃. Results of TCLP indicate that the heavy metal content of molten slag is beyond stipulated limit values.
