Lijia Zhu,Yimin Zhu,Wenliang Xiong,Zheng Zhou,Peng Gao,Yuexin Han
Metal ions, naturally present in flotation pulp, are commonly employed in flotation reagents, serving as vital reagents in mineral separation processes. This study investigated the impact of ASS, a blend of AlCl 3 , sulfuric acid, and sodium silicate (SS), on the flotation separation efficiency of fluorite from dolomite, as well as the underlying interaction mechanism. Micro flotation tests revealed that ASS significantly decreased the flotation recovery of dolomite while exerting negligible influence on that of fluorite. The difference in flotation recovery rates among the two minerals reached 92.00 % with the addition of 103 mg/L of ASS. The artificial mixed mineral flotation tests were also carried out, the recovery rate and grade of F in the concentrate were 86.47 % and 42.79 %, respectively. The formation of the metal complex ASS, resulting from the combination of Al with Si(OH) 4 , facilitated the adsorption of their hydrolysis products on the surface of dolomite. Within the flotation pulp system, the Ca 2+ and Mg 2+ on the dolomite surface selectively interact with the –OH groups in ASS. At the same time, the Al 3+ in ASS selectively bonds with the O atom of the carbonate group exposed on the dolomite surface. This interaction promotes the adsorption of ASS onto the dolomite surface, thereby hindering the adsorption of sodium oleate. The fluorite surface exhibited weaker interactions with ASS, leading to more sodium oleate adsorbed on the surface of fluorite, thereby increasing the hydrophobicity of the fluorite particles, which floated up. As a result, the selective adsorption of the reagents facilitated the flotation separation of fluorite from dolomite.
Single-atom catalysts (SACs), with precisely controlled metal atom distribution and adjustable coordination architecture, have gained intensive concerns as efficient oxygen reduction reaction (ORR) electrocatalysts in Zn-air batteries (ZAB). The attainment of a monodispersed state for metallic atoms anchored on the carbonaceous substrate remains the foremost research priority; however, the persistent challenges lie in the relatively weak metal-support interactions and the instability of captured single atom active sites. Furthermore, in order to achieve rapid transport of O 2 and other reactive substances within the carbon matrix, manufacturing SACs based on multi-stage porous carbon substrates is highly anticipated. Here, we propose a methodology for the fabrication of carbon aerogels (CA)-supported SACs utilizing papermaking nanofibers , which incorporates advanced strategies for N -atom self-doping, defect/vacancy introduction, and single-atom interface engineering. Specifically, taking advantages of using green and energy-efficient feedstocks, combining with a direct pore-forming template volatilization and chemical vapor deposition approach, we successfully developed N -doped carbon aerogels immobilized with separated iron sites (Fe-SAC@N/CA-Cd). The obtained Fe-SAC@N/CA-Cd exhibited substantially large specific surface area (S BET = 1173 m 2 /g) and a multi-level pore structure, which can effectively mitigate the random aggregation of Fe atoms during pyrolysis. As a result, it demonstrated appreciable activity and stability in catalyzing the ORR progress (E 1/2 = 0.88 V, E onset = 0.96 V). Furthermore, the assembled liquid electrolyte-state Zn-air batteries (LES-ZAB) and all-solid-state Zn-air battery (ASS-ZAB) also provides encouraging performance, with a peak power density of 169 mW cm −2 for LES-ZAB and a maximum power density of 124 mW cm −2 for ASS-ZAB.
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