This study investigates the leaching and purification processes for dunite slurry,a common mining waste material,and the carbonation processes for the mineralization of CO_(2) with Mg^(2+).Results indicate that HCl is...This study investigates the leaching and purification processes for dunite slurry,a common mining waste material,and the carbonation processes for the mineralization of CO_(2) with Mg^(2+).Results indicate that HCl is a promising leaching agent,and pH and temperature are major factors in controlling the efficiency of the leaching process,with leaching efficiencies of 82%achieved after 4 h using 2 M HCl solution at 75℃.The removal of other ions like Fe^(3+),Fe^(2+),and Al^(3+)through the purification of the leachate using ammonium hydroxide was also proven to be effective,completely removing iron and aluminum from the leachate from starting concentrations of 3.10 and 0.40 g/L,respectively.The carbonation of magnesium at room temperature was investigated with both purified leachate and pure MgCl_(2) aqueous solution.Nesquehonite crystals began to form after 1.5 h with a conversion of Mg^(2+)to nesquehonite of approximately 5%.The produced crystals possess a needle-like shape,which could be modified using the biopolymers pectin and xanthan.Pectin had a limited influence on the length of the crystals,reducing the needle length with increasing pectin concentration.Xanthan,on the other hand,shortened and widened the needle-like structure into a column shape as more xanthan was added.This study demonstrates the potential for this process to utilize mining wastes and sequester CO_(2),producing useful mineral products in the process.展开更多
Weathered crust elution-deposited rare earth ore is an important resource of rare earths, including grantic weathered crust elution-deposited rare earth ore and volcanic weathered crust elution-deposited rare earth or...Weathered crust elution-deposited rare earth ore is an important resource of rare earths, including grantic weathered crust elution-deposited rare earth ore and volcanic weathered crust elution-deposited rare earth ore. The development condition of the weathered crust, weathering degree and mineral composition of these ores will be different because of the differences between their parent rocks and weathered crust causes of mineralogy path. Therefore, mineral properties and leaching characteristics of volcanic weathered crust elution-deposited rare earth ore from Chongzuo（CZ）, Guangxi province were investigated. It was found that the CZ rare earth ore was a typical mid-yttrium and rich-europium ore, with the overall rare earth（REE） grade in ion-exchangeable phase of 0.15%. Partide size classification showed that finer particle had a higher REE grade. Column leaching tests showed that the leaching efficiency of REE was above 94% with leaching agent concentration of 0.20 mol/L, liquid-solid ratio of 4：3, flow rate of 0.60 mL/min, and initial pH value around 5.67. Compared to ammonium sulfate leaching, magnesium sulfate leaching was advantaged by nearly zero ammonia nitrogen emission while their REE leaching was almost equivalent.展开更多
Copper-nickel tailings(CNTs),consisting of more than 80wt%magnesium-bearing silicate minerals,show great potential for CO_(2)mineral sequestration.The dissolution kinetics of CNTs in HCl solution was investigated thro...Copper-nickel tailings(CNTs),consisting of more than 80wt%magnesium-bearing silicate minerals,show great potential for CO_(2)mineral sequestration.The dissolution kinetics of CNTs in HCl solution was investigated through a leaching experiment and kinetic modeling,and the effects of reaction time,HCl concentration,solid-to-liquid ratio,and reaction temperature on the leaching rate of mag-nesium were comprehensively studied.Results show that the suitable leaching conditions for magnesium in CNTs are 2 M HCl,a solid-to-liquid ratio of 50 g·L^(−1),and 90℃,at which the maximum leaching rate of magnesium is as high as 83.88%.A modified shrinking core model can well describe the leaching kinetics of magnesium.The dissolution of magnesium was dominated by a combination of chemical reaction and product layer diffusion,with a calculated apparent activation energy of 77.51 kJ·mol^(−1).This study demonstrates the feasibil-ity of using CNTs as a media for CO_(2)mineral sequestration.展开更多
基金supported by Fonds Wetenschappelijk Onderzoek-Vlaanderen(FWO).D.M.acknowledges support from FWO in the form of strategic basic research fellowships(File number:1S13924N).
文摘This study investigates the leaching and purification processes for dunite slurry,a common mining waste material,and the carbonation processes for the mineralization of CO_(2) with Mg^(2+).Results indicate that HCl is a promising leaching agent,and pH and temperature are major factors in controlling the efficiency of the leaching process,with leaching efficiencies of 82%achieved after 4 h using 2 M HCl solution at 75℃.The removal of other ions like Fe^(3+),Fe^(2+),and Al^(3+)through the purification of the leachate using ammonium hydroxide was also proven to be effective,completely removing iron and aluminum from the leachate from starting concentrations of 3.10 and 0.40 g/L,respectively.The carbonation of magnesium at room temperature was investigated with both purified leachate and pure MgCl_(2) aqueous solution.Nesquehonite crystals began to form after 1.5 h with a conversion of Mg^(2+)to nesquehonite of approximately 5%.The produced crystals possess a needle-like shape,which could be modified using the biopolymers pectin and xanthan.Pectin had a limited influence on the length of the crystals,reducing the needle length with increasing pectin concentration.Xanthan,on the other hand,shortened and widened the needle-like structure into a column shape as more xanthan was added.This study demonstrates the potential for this process to utilize mining wastes and sequester CO_(2),producing useful mineral products in the process.
基金supported by National Science and Technology Support Program of China(2015BAB16B01)Science and Technology Support Program of Guangxi(1598007-41)
文摘Weathered crust elution-deposited rare earth ore is an important resource of rare earths, including grantic weathered crust elution-deposited rare earth ore and volcanic weathered crust elution-deposited rare earth ore. The development condition of the weathered crust, weathering degree and mineral composition of these ores will be different because of the differences between their parent rocks and weathered crust causes of mineralogy path. Therefore, mineral properties and leaching characteristics of volcanic weathered crust elution-deposited rare earth ore from Chongzuo（CZ）, Guangxi province were investigated. It was found that the CZ rare earth ore was a typical mid-yttrium and rich-europium ore, with the overall rare earth（REE） grade in ion-exchangeable phase of 0.15%. Partide size classification showed that finer particle had a higher REE grade. Column leaching tests showed that the leaching efficiency of REE was above 94% with leaching agent concentration of 0.20 mol/L, liquid-solid ratio of 4：3, flow rate of 0.60 mL/min, and initial pH value around 5.67. Compared to ammonium sulfate leaching, magnesium sulfate leaching was advantaged by nearly zero ammonia nitrogen emission while their REE leaching was almost equivalent.
基金finacially supported by the National Key Research and Development Program of China(No.2022YFE0135100)the National Natural Science Found-ation of China(Nos.52378255,52278270,and 52008151).
文摘Copper-nickel tailings(CNTs),consisting of more than 80wt%magnesium-bearing silicate minerals,show great potential for CO_(2)mineral sequestration.The dissolution kinetics of CNTs in HCl solution was investigated through a leaching experiment and kinetic modeling,and the effects of reaction time,HCl concentration,solid-to-liquid ratio,and reaction temperature on the leaching rate of mag-nesium were comprehensively studied.Results show that the suitable leaching conditions for magnesium in CNTs are 2 M HCl,a solid-to-liquid ratio of 50 g·L^(−1),and 90℃,at which the maximum leaching rate of magnesium is as high as 83.88%.A modified shrinking core model can well describe the leaching kinetics of magnesium.The dissolution of magnesium was dominated by a combination of chemical reaction and product layer diffusion,with a calculated apparent activation energy of 77.51 kJ·mol^(−1).This study demonstrates the feasibil-ity of using CNTs as a media for CO_(2)mineral sequestration.
