The leaching behaviors of calcium and magnesium in the rare earth tailings leached with magnesium sulfate using deionized water,CaCl2 solution and lime water were investigated.Experimental data indicated that magnesiu...The leaching behaviors of calcium and magnesium in the rare earth tailings leached with magnesium sulfate using deionized water,CaCl2 solution and lime water were investigated.Experimental data indicated that magnesium in the tailings was easy to be leached out since most of the magnesium was in the form of water-soluble phase.Most of calcium in the lime water was electrostatically adsorbed on the clay mineral of the tailings,and the water-soluble magnesium was also gradually converted into exchangeable phase because of back-adsorption of Mg2+on the clay mineral with increasing the pH values.When the liquid-to-solid ratio was 0.80,the contents of readily-available magnesium and calcium were 104.4−207.6 and 201.7−1426.3 mg/kg,respectively,which could meet the requirements for plants.These results suggest a promising route for the environmental remediation of ion-adsorption rare earth ore after in-situ leaching.展开更多
Sludge as the by-product of wastewater treatment usually accumulates toxic substances that require specific treatment before disposal.With the increase of sludge production,the safe and economic treatment of sludge ha...Sludge as the by-product of wastewater treatment usually accumulates toxic substances that require specific treatment before disposal.With the increase of sludge production,the safe and economic treatment of sludge has become a global issue.Construction filed provides a solution for consuming huge volumes of sludge and sludge ash owing to the similar chemical composition with cementitious materials.This paper critically reviewed the current status of recycling sludge and sludge ash into low-carbon construction materials and highlighted the future perspectives of sludge-derived construction materials.Furthermore,the immobilization mechanisms of heavy metals in sludge-derived construction materials were elaborated to promote the actualization of sustainable management of sludge and sludge ash.展开更多
基金The authors are grateful for the financial supports from the National Key Research and Development Program of China(2018YFC1801803)the Major Research Plan of the National Natural Science Foundation of China(91962211).
文摘The leaching behaviors of calcium and magnesium in the rare earth tailings leached with magnesium sulfate using deionized water,CaCl2 solution and lime water were investigated.Experimental data indicated that magnesium in the tailings was easy to be leached out since most of the magnesium was in the form of water-soluble phase.Most of calcium in the lime water was electrostatically adsorbed on the clay mineral of the tailings,and the water-soluble magnesium was also gradually converted into exchangeable phase because of back-adsorption of Mg2+on the clay mineral with increasing the pH values.When the liquid-to-solid ratio was 0.80,the contents of readily-available magnesium and calcium were 104.4−207.6 and 201.7−1426.3 mg/kg,respectively,which could meet the requirements for plants.These results suggest a promising route for the environmental remediation of ion-adsorption rare earth ore after in-situ leaching.
基金support from the National Natural Science Foundation of China(No.52236008)the Zhejiang Provincial Natural Science Foundation of China(LZ23E060004)for this study.
文摘Sludge as the by-product of wastewater treatment usually accumulates toxic substances that require specific treatment before disposal.With the increase of sludge production,the safe and economic treatment of sludge has become a global issue.Construction filed provides a solution for consuming huge volumes of sludge and sludge ash owing to the similar chemical composition with cementitious materials.This paper critically reviewed the current status of recycling sludge and sludge ash into low-carbon construction materials and highlighted the future perspectives of sludge-derived construction materials.Furthermore,the immobilization mechanisms of heavy metals in sludge-derived construction materials were elaborated to promote the actualization of sustainable management of sludge and sludge ash.
