Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased ca...Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.展开更多
A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-co...A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.展开更多
刚果(金)SICOMINES低铜高钴氧化铜钴矿铜品位为0.519%,钴品位为0.541%,矿石中主要含铜矿物为硅孔雀石和铜蓝,含钴矿物主要为水钴矿,使用“浮选+高梯度磁选”工艺进行选别,钴金属损失严重。因此,对该低铜高钴矿石进行系统浸出试验研究。...刚果(金)SICOMINES低铜高钴氧化铜钴矿铜品位为0.519%,钴品位为0.541%,矿石中主要含铜矿物为硅孔雀石和铜蓝,含钴矿物主要为水钴矿,使用“浮选+高梯度磁选”工艺进行选别,钴金属损失严重。因此,对该低铜高钴矿石进行系统浸出试验研究。试验结果表明,溶液终点酸度和磨矿粒度对其铜、钴浸出率影响均不大,钴浸出率较低,不到10%,钴浸出率较低可能与其电位高有较大关系,较高的溶液电位难以满足矿石中相关含钴物相的反应。通过加入焦亚硫酸钠降低溶液电位,将电位调到350 m V以下,再升高温度至60℃,可使Co浸出率升高到74.43%。展开更多
基金supported by National Natural Science Foundation of China (Nos.52131003 and 42007180)Special Research Assistant Program of Chinese Academy of Science, Natural Science Foundation of Chongqing (No.cstc2020jcyj-msxm X0775)+1 种基金Scientific Research Instrument Development Project of Chinese Academy of Sciences (No.YJKYYQ20200044)Outstanding Scientist of Chongqing Talent Program (No.CQYC20210101288)。
文摘Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.
文摘A sulphuric acid bake–leach method for the treatment of mixed copper-cobalt oxide minerals was investigated as an alternative to the reductive leaching method. Sulphuric acid bake-leach process of the mixed copper-cobalt oxide ore was carried out by mixing the sample with sulphuric acid followed by baking of the mixture in a muffle furnace. Baking tests were conducted at different conditions such as temperature, time, and varying amounts of acid. The reacted samples were then subjected to water leaching at room temperature to determine the leachability of copper and cobalt from the baked material. The dissolutions of copper and cobalt were dependent on acid concentration with cobalt showing more sensitivity to the amount of acid. Both copper and cobalt were extracted from the baked material within short leaching times and without the addition of reducing agents. The outcome of this work has shown that the sulphuric acid bake-leach process is a possible alternative to the reductive leaching method for copper-cobalt oxide ores.
文摘刚果(金)SICOMINES低铜高钴氧化铜钴矿铜品位为0.519%,钴品位为0.541%,矿石中主要含铜矿物为硅孔雀石和铜蓝,含钴矿物主要为水钴矿,使用“浮选+高梯度磁选”工艺进行选别,钴金属损失严重。因此,对该低铜高钴矿石进行系统浸出试验研究。试验结果表明,溶液终点酸度和磨矿粒度对其铜、钴浸出率影响均不大,钴浸出率较低,不到10%,钴浸出率较低可能与其电位高有较大关系,较高的溶液电位难以满足矿石中相关含钴物相的反应。通过加入焦亚硫酸钠降低溶液电位,将电位调到350 m V以下,再升高温度至60℃,可使Co浸出率升高到74.43%。
