China
Africa
Explore chapters and articles related to this topic
Carbon Dioxide Conversions
Published in Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda, 1 Chemistry, 2022
Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda
Choi et al. (2017) reported the production of heavy hydrocarbons on a novel Cu-Fe catalyst prepared by reduction of delafossite (a copper iron oxide mineral with the formula CuFeO2 ). In their catalyst, χ-Fe5C2 ( Hägg iron carbide), as active catalytic phase for heavier hydrocarbon production, was formed by reduction and in-situ carburization of CuFeO2 . Delafossite is a precursor to Cu-Fe catalysts for the production of higher liquid hydrocarbons with 65% selectivity, methane selectivity of 2%–3% and olefin/paraffin ratio of 7.3.
Methods of fabrication
Published in R. F. Tylecote, The Prehistory of Metallurgy in the British Isles, 2017
The sulphur present in some slags (Table 59) arises, no doubt, from the oxidation of the residual sulphide or matte phase from the smelting process. Phases detected by X-ray diffraction are iron oxides and double oxides such as the spinel type phase CuFe2O4, or the oxide delafossite (CuFeO2). It seems that these slags are essentially alkali silicates or alkali aluminium silicates with some iron and copper. But the main components that give the reddish colour to relatively unoxidized examples of these slags are metallic copper and Cu2O which are not in solution. These red glassy slags resemble ruby glasses in their composition.
Bioleaching for Recovery of Metals from Spent Batteries – A Review
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Farhad Moosakazemi, Sina Ghassa, Mohammad Jafari, Saeed Chehreh Chelgani
Zeng et al. (2013) investigated the Ag-catalyzed bioleaching of LiCoO2 cathodes with A. ferrooxidans cultures. With 20 mg/L Ag+, cobalt leached to 98% in 7 d at 1% pulp density, compared to 43% without Ag. Ag+ was proposed to form an intermediate AgCoO2 on LiCoO2 surfaces, with subsequent decay-causing a release of Ag+ and dissolution of Co2+ (Equations (13)–(14)) (Zeng et al. 2013). A polytype of AgCoO2 is an efficient catalyst of Co oxidation (Dey et al. 2018), and several modifications of physical and chemical properties of this complex with delafossite (copper iron oxide mineral) formula have been described (Iwase et al. 2011; Muguerra et al. 2008). Like Equations (11)and (14) also cannot be correct. Again, correct reactions will be suggested in section 3.4.4.
Acid Bioleaching of Copper from Smelter Dust at Incremental Temperatures
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Shahram Ebrahimpour, Hadi Abdollahi, Mahdi Gharabaghi, Zahra Manafi, Olli H. Tuovinen
Copper was dissolved from smelter dust in shake flask bioleaching tests with microbial consortia of mesophiles, moderate thermophiles, and extreme thermophiles. Bioleaching tests were conducted at three incremental temperatures of 35°C, 50°C, and 70°C, with each step inoculated with the specific microbial consortium. In the initial acid demand test, 68% of the copper content was leached from the smelter dust within 2 h. Cumulative copper recovery was increased to 84% with the three-step bioleaching, starting with mesophilic consortia (35°C), followed by moderate thermophiles (50°C) and extreme thermophiles (70°C) for 2 d each. Additional bioleaching experiments at 35°C and 50°C over 16 days yielded results that were generally comparable to the three-step bioleaching tests. Delafossite and chalcopyrite, both in the monovalent copper class, were more recalcitrant than the sulfate phase chalcocyanite. Further increases in the yield of copper bioleaching from smelter dust require extended contact times or an extremely thermophilic process and stirred bioreactor conditions for process control.
Regulation of Cr3+ doping on the defect characteristics and magnetic order in the CuFe1-xCrxO2 ceramics
Published in Journal of Asian Ceramic Societies, 2021
Mingsheng Xu, Yu Sun, Tao Li, Bin Zhao, Haiyang Dai, Zhenping Chen
Figure 1 shows the XRD patterns of CuFe1-xCrxO2 (x = 0.0–0.4) series at room temperature. All the diffraction peaks can be well indexed as a delafossite structure with space group (PDF#01-085-0605), without any detectable secondary phase. Rietveld refinement of XRD dates is carried out to obtain the lattice information. As an example, the Rietveld refinement of CuFe0.6Cr0.4O2 sample is shown in Figure 1(b). Figure 1(c) displays the plot of the a and c values and the values decrease monotonously with increasing Cr3+ content x, which is ascribed to the smaller ionic radius of Cr3+ (rCr3+ = 0.605 Å) than that of Fe3+ (rFe3+ = 0.645 Å). It should be noted that the c/a ratio shown in Figure 1(d) increases with rising x, in spite of the reduction among both a and c values. This increment of c/a ratio implicates a noticeable change occurring along the a-axis than that of c-axis. All these variations in lattice parameters along a- and c-axis accord with Vegard’s law and signify that Cr3+ ions have successfully entered into the CuFeO2 lattice sites and formed the homogeneous CuFe1-xCrxO2 solid solution.