Sulphuric Acid Bake-Leach Process for the Treatment of Mixed Copper-Cobalt Oxide Ores

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.

Extraction and recycling technologies of cobalt from primary and secondary resources:A comprehensive review

Cobalt has excellent electrochemical,magnetic,and heat properties.As a strategic resource,it has been applied in many hightech products.However,the recent rapid growth of the battery industry has substantially depleted cobalt resources,leading to a crisis of cobalt resource supply.The paper examines cobalt ore reserves and distribution,and the recent development and consumption of cobalt resources are summarized as well.In addition,the principles,advantages and disadvantages,and research status of various methods are discussed comprehensively.It can be concluded that the use of diverse sources(Cu-Co ores,Ni-Co ores,zinc plant residues,and waste cobalt products)for cobalt production should be enhanced to meet developmental requirements.Furthermore,in recovery technology,the pyro-hydrometallurgical process employs pyrometallurgy as the pretreatment to modify the phase structure of cobalt minerals,enhancing its recovery in the hydrometallurgical stage and facilitating high-purity cobalt production.Consequently,it represents a promising technology for future cobalt recovery.Lastly,based on the above conclusions,the prospects for cobalt are assessed regarding cobalt ore processing and sustainable cobalt recycling,for which further study should be conducted.

纯铜、纯钴电极和铜钴合金电极在碱性介质中的光电化学研究

用动电位伏安法对纯铜电极、纯钴电极以及含钴量 5 1%、9 7%、15 %、2 5 %和 40 %的铜钴合金电极在硼砂—硼酸缓冲溶液 (pH8 5 )中的光电化学行为进行了研究。纯铜电极、纯钴电极和铜钴合金电极均显示P 型光响应 ,纯铜电极的光响应来自Cu2 O ,纯钴电极的光响应主要来自Co3O4 ,铜钴合金电极的光响应来自Cu2 O和Co3O4 的共同作用。纯铜电极在阳极氧化过程中存在着Cu的阳极溶解和电极表面生成Cu2 O膜的反应 ,温度升高有利于Cu2 O膜的生成 ,除氧与否影响纯铜电极的成膜反应。纯钴电极电位正向扫描时不显示光响应 ,负向扫描时显示阴极光电流。铜钴合金电极的光响应随含钴量而变化。

STRUCTURE AND PROPERTIES OF Cu-Co MULTILAYER FILMS PRODUCED BY ELECTRODEPOSITION

Multilayer Cu-Co film has been produced from a single bath by the method of pulse electrodeposition. Its structure and some magnetic properties were analysed by TEM,AES, XRD and VSM. The results indicated that the film was layed structure, consisted of alternating pure copper and copper-cobalt alloy layers. The results have shown the possibility of producing multilayer films with perpendicular magnetic anisotropy byelectrodeposition.

Efficient electroreduction of nitrate via enriched active phases on copper-cobalt oxides

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.

Non-metallic electronic regulation in CuCo oxy-/thio-spinel as advanced oxygen evolution electrocatalysts

Developing cost-effective and high-performance oxygen evolution reaction(OER)electrocatalysts has become the intense research on pursuing emerging renewable energy conversion,in which exploring and investigating the intrinsic nature of efficient and stable Cu Co spinel catalysts toward OER in alkaline media is highly desirable.Herein,Cu1–xCo2+xO4oxy-spinel nanoflakes are fabricated by a facile hydrothermal method with the oxidation of ammonia water.In the same condition,Cu1–xCo2+xS4thio-spinel nanospheres are formed without oxidation.In OER process,the as-obtained Cu1–xCo2+xO4nanoflakes and Cu1–xCo2+xS4nanospheres possess the anodic overpotential of 267 and 297 m V in alkaline media to drive the current density of 10 m A/cm^2,respectively,outperforming the state-of-the-art noble metal catalyst of RuO2.X-ray photoelectron spectroscopy analysis exhibits the higher ratio value of Co(Ⅲ)/Co(Ⅱ)in Cu1–xCo2+xO4than that in Cu1–xCo2+xS4,suggesting that the stronglyelectronegative oxygen efficiently predominates in regulating valence states of Co active sites in spinel structures.Remarkably,density functional theory simulation further reveals that the increased valence state of Co could accelerate the electron exchange between catalysts and oxygen adsorbates during electrocatalysis,thus contributing to the higher OER activity of Cu1–xCo2+xO4catalysts.This work provides deep insight regarding the significance of non-metal element(O and S)in Cu Co spinel structure catalysts,as well as presents a promising approach to exploit higher performance and grasp the mechanism of various non-noblemetal spinel catalysts for water oxidation.