Mercury pollution resulting from artisanal gold mining is a serious environmental problem in many developing countries. In this study, we analyzed heavy metal(loid) contamination in mine wastes from a Carlin-type gold...Mercury pollution resulting from artisanal gold mining is a serious environmental problem in many developing countries. In this study, we analyzed heavy metal(loid) contamination in mine wastes from a Carlin-type gold mine in southwestern Guizhou, China. Highly elevated levels of As, Hg, Tl, Sb, and Cd—up to 5844, 28,29, 581 and 3.0 mg/kg, respectively—were observed in the mine wastes, but no significant accumulation of Cr, Ni, Cu,Zn, and Pb was found. The smelting process of gold ores had significant impacts on the enrichment of As, Tl, and Hg in the mine wastes. Due to the significant metal(loid)pollution in this gold mine, the ecological risks are classified as ‘‘very high.'' Hg and As are the major pollutants with a relative contribution of 55.9 % and 24.2 % to the risk index, respectively. Phytoremediation could be used to reduce heavy metal contamination and recycle the gold simultaneously. Hg–As–Tl pollution should be considered in gold extraction at Carlin-type gold mines.展开更多
As indispensable strategic materials for high-tech industries,rare earth elements and yttrium(REY)have become particularly important in recent years,raising the demand of developing new approaches for reclamation of R...As indispensable strategic materials for high-tech industries,rare earth elements and yttrium(REY)have become particularly important in recent years,raising the demand of developing new approaches for reclamation of REY from REY-rich materials such as coal combustion products(CCPs).In this study,five coal-fired power plants(CFPPs)in Guizhou of southwest China were selected for investigating REY concentrations of solid samples,atmospheric emissions,and recovery potentials.REY concentrations of feed fuels are higher in this study(147.2-468.6 mg/kg)than what have been reported previously for coals in China and the world.REY atmospheric emissions are extremely low(38.70-180.11 mg REY/t coal).REY are enriched in bottom ash and fly ash,with average of 658±296 mg/kg and maximum of 1257 mg/kg from the five CFPPs.Relative enrichment factors(REF)of REY in bottom ash and fly ash compared with the feed fuel are 0.86-1.02 and 0.91-1.04,respectively.REY concentrations in desulfurized gypsum are very low(6-17 mg/kg),and that is mostly inherited from limestone.Critical REY(Nd,Eu,Tb,Dy,Y,and Er)in bottom/fly ash account for 34%-39%of the total REY and the outlook coefficients(Cout1)are in the range of 0.89-1.11.This study indicates a promising prospect to reclaim REY from REYrich CCPs(bottom and fly ash)in CFPPs in Guizhou,especially in the central-north Guizhou,although such practices require further technology advancement.展开更多
基金funded by the West Light Foundation of the Chinese Academy of Sciencesthe Social Development Project of Guizhou Province (2012–3044)+1 种基金the Natural Science Foundation of Guizhou Province (2009–2003)the National Natural Science Foundation of China (21007068 and 41373135)
文摘Mercury pollution resulting from artisanal gold mining is a serious environmental problem in many developing countries. In this study, we analyzed heavy metal(loid) contamination in mine wastes from a Carlin-type gold mine in southwestern Guizhou, China. Highly elevated levels of As, Hg, Tl, Sb, and Cd—up to 5844, 28,29, 581 and 3.0 mg/kg, respectively—were observed in the mine wastes, but no significant accumulation of Cr, Ni, Cu,Zn, and Pb was found. The smelting process of gold ores had significant impacts on the enrichment of As, Tl, and Hg in the mine wastes. Due to the significant metal(loid)pollution in this gold mine, the ecological risks are classified as ‘‘very high.'' Hg and As are the major pollutants with a relative contribution of 55.9 % and 24.2 % to the risk index, respectively. Phytoremediation could be used to reduce heavy metal contamination and recycle the gold simultaneously. Hg–As–Tl pollution should be considered in gold extraction at Carlin-type gold mines.
基金Project supported by the K.C.Wong Education FoundationNational Natural Science Foundation of China(U1612442)+3 种基金Key Grant for Creative Research Groups of Guizhou Provincial Education Department(Qian-Jiao-He KY Zi2016047)Young Scientific Talents Growth Project of Guizhou Provincial Education Department(Qian-Jiao-He KY Zi 2016252)Doctoralof Zunyi Normal University(Zun-Shi BS 201815)Science and Technology Project of Guizhou Provincial Science and Technology Department(Qian-Ke-He-Ping-Tai-RenCai 20175727-07)。
文摘As indispensable strategic materials for high-tech industries,rare earth elements and yttrium(REY)have become particularly important in recent years,raising the demand of developing new approaches for reclamation of REY from REY-rich materials such as coal combustion products(CCPs).In this study,five coal-fired power plants(CFPPs)in Guizhou of southwest China were selected for investigating REY concentrations of solid samples,atmospheric emissions,and recovery potentials.REY concentrations of feed fuels are higher in this study(147.2-468.6 mg/kg)than what have been reported previously for coals in China and the world.REY atmospheric emissions are extremely low(38.70-180.11 mg REY/t coal).REY are enriched in bottom ash and fly ash,with average of 658±296 mg/kg and maximum of 1257 mg/kg from the five CFPPs.Relative enrichment factors(REF)of REY in bottom ash and fly ash compared with the feed fuel are 0.86-1.02 and 0.91-1.04,respectively.REY concentrations in desulfurized gypsum are very low(6-17 mg/kg),and that is mostly inherited from limestone.Critical REY(Nd,Eu,Tb,Dy,Y,and Er)in bottom/fly ash account for 34%-39%of the total REY and the outlook coefficients(Cout1)are in the range of 0.89-1.11.This study indicates a promising prospect to reclaim REY from REYrich CCPs(bottom and fly ash)in CFPPs in Guizhou,especially in the central-north Guizhou,although such practices require further technology advancement.
