This study analyzed the prevalent physicochemical phases of smelting slag from the perspective of data science and chemistry.Findings delineated the silicate phase as the pivotal and predominant constraining phase for...This study analyzed the prevalent physicochemical phases of smelting slag from the perspective of data science and chemistry.Findings delineated the silicate phase as the pivotal and predominant constraining phase for the resource utilization of smelting slag.An intricate correlation between metallic elements and dominant phases was constructed.Typical silicate phase olivine(OL)was synthesized as a paradigm to examine alkali depolymerization,unveiling the optimal conditions for such depolymerization to be an alkali to olivine molar ratio of 1:5,a reaction temperature of 700℃,and a duration of 3 h.The underlying mechanism of alkali depolymerization within silicate phases was elucidated under these parameters.The reaction mechanism of alkali depolymerization within silicate phases can be encapsulated in three sequential steps:(1)NaOH dissociation and subsequent adsorption of OH^(-)to cationic(Mg or Fe)sites;(2)disruption of cation-oxygen bonds,leading to the formation of hydroxide compounds,which then underwent oxidation;(3)Na^(+)occupied the resultant cation vacancy sites,instigating further depolymerization of the intermediate Na_(2)(Mg,Fe)SiO_(4).The articulated mechanism is anticipated to furnish theoretical underpinnings for the efficacious recuperation of metals from smelting slags.展开更多
Hydrogenolysis has been explored as a promising approach for plastic chemical recycling.Noble metals,such as Ru and Pt,are considered effective catalysts for plastic hydrogenolysis,however,they result in a high yield ...Hydrogenolysis has been explored as a promising approach for plastic chemical recycling.Noble metals,such as Ru and Pt,are considered effective catalysts for plastic hydrogenolysis,however,they result in a high yield of low-value gaseous products.In this research,an efficient bimetallic catalyst was developed by separate impregnation of Ni and Ru on SiO_(2) support resulting in liquid products yield of up to 83.1 C%under mild reaction conditions,compared to the 65.5 C%yield for the sole noble metal catalyst.The carbon distribution of the liquid products from low density polyethylene hydrogenolysis with Ni-modified catalyst also shifted to a heavier fraction,compared to that with Ru catalyst.Meanwhile,the NiRu catalyst exhibited excellent performance in suppressing the cleavage of the end-chain C–C bond,leading to a methane yield of only 10.4 C%,which was 69%lower than that of the Ru/SiO_(2) catalyst.Temperature programmed reduction and desorption of hydrogen and propane were further conducted to reveal the detailed mechanism of low density polyethylene hydrogenolysis over the bimetallic catalyst.The results suggested that the Ni-Ru alloy exhibited stronger H adsorption properties indicating improved hydrogen coverage on the catalyst surface thus enhancing the desorption of reaction intermediates.The carbon number distribution was ultimately skewed toward heavier liquid products.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22006040 and 22376070)the National Key Research and Development Program of China(No.2019YFA0210404)the Research Project on Characteristic Innovation of University Teachers(No.2022XJZZ02)。
文摘This study analyzed the prevalent physicochemical phases of smelting slag from the perspective of data science and chemistry.Findings delineated the silicate phase as the pivotal and predominant constraining phase for the resource utilization of smelting slag.An intricate correlation between metallic elements and dominant phases was constructed.Typical silicate phase olivine(OL)was synthesized as a paradigm to examine alkali depolymerization,unveiling the optimal conditions for such depolymerization to be an alkali to olivine molar ratio of 1:5,a reaction temperature of 700℃,and a duration of 3 h.The underlying mechanism of alkali depolymerization within silicate phases was elucidated under these parameters.The reaction mechanism of alkali depolymerization within silicate phases can be encapsulated in three sequential steps:(1)NaOH dissociation and subsequent adsorption of OH^(-)to cationic(Mg or Fe)sites;(2)disruption of cation-oxygen bonds,leading to the formation of hydroxide compounds,which then underwent oxidation;(3)Na^(+)occupied the resultant cation vacancy sites,instigating further depolymerization of the intermediate Na_(2)(Mg,Fe)SiO_(4).The articulated mechanism is anticipated to furnish theoretical underpinnings for the efficacious recuperation of metals from smelting slags.
基金supported by the National Key R&D Program of China(Grant No.2022YFE0135400)the National Natural Science of China(Grant Nos.52376213 and 52236011)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LGG22E060004)the Fundamental Research Funds for the Central Universities(Grant No.2022ZFJH004).
文摘Hydrogenolysis has been explored as a promising approach for plastic chemical recycling.Noble metals,such as Ru and Pt,are considered effective catalysts for plastic hydrogenolysis,however,they result in a high yield of low-value gaseous products.In this research,an efficient bimetallic catalyst was developed by separate impregnation of Ni and Ru on SiO_(2) support resulting in liquid products yield of up to 83.1 C%under mild reaction conditions,compared to the 65.5 C%yield for the sole noble metal catalyst.The carbon distribution of the liquid products from low density polyethylene hydrogenolysis with Ni-modified catalyst also shifted to a heavier fraction,compared to that with Ru catalyst.Meanwhile,the NiRu catalyst exhibited excellent performance in suppressing the cleavage of the end-chain C–C bond,leading to a methane yield of only 10.4 C%,which was 69%lower than that of the Ru/SiO_(2) catalyst.Temperature programmed reduction and desorption of hydrogen and propane were further conducted to reveal the detailed mechanism of low density polyethylene hydrogenolysis over the bimetallic catalyst.The results suggested that the Ni-Ru alloy exhibited stronger H adsorption properties indicating improved hydrogen coverage on the catalyst surface thus enhancing the desorption of reaction intermediates.The carbon number distribution was ultimately skewed toward heavier liquid products.
