China
Africa
Explore chapters and articles related to this topic
Sandstone-hosted stratabound copper deposits of the south Pyrenean foreland basin
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
I. Subías, I. Fanlo, J. García-Veigas
Non-opaque minerals that have been identified in cupriferous sandstones include clastic grains of quartz, feldspar, ilmenite, anatase, rutile, monazite, zircon, biotite, muscovite and fossil plant material. Calcite, chlorite and sulphides are present in the form of authigenic cements. Reflected light examination of polished sections shows that the ores consist primarily of a variety of Cu-S minerals and smaller amounts of pyrite, chalcopyrite, bornite, galena, sphalerite and argentite. In some cases the primary copper minerals are cuprite, tenorite and native Cu. They are all present as replacements of calcite cement, of fossil plant material and even of clastic grains.
Copper and copper alloys
Published in R. F. Tylecote, The Prehistory of Metallurgy in the British Isles, 2017
In pure air the stable form of copper is the oxide tenorite (CuO). More acid conditions can produce malachite. If corrosion is not complete and some copper metal is left, then the red cuprous oxide (cuprite – Cu2O) is normally present. A sulphurous urban atmosphere will produce brochantite (CuS04.3Cu(OH)2), but this hardly ever forms in soils.
Recent progress in the development of backplane thin film transistors for information displays
Published in Journal of Information Display, 2023
Gwon Byeon, Seong Cheol Jang, Taewan Roh, Ji-Min Park, Hyun-Suk Kim, Yong-Young Noh
Copper oxide has two common forms: cuprous oxide or cuprite (Cu2O) and cupric oxide or tenorite (CuO). Both copper oxides are generally p-type semiconductors, and Cu2O shows higher mobility than CuO. By doping Ga, which presents high-oxygen affinity, the Cu2O film decreases oxygen vacancy (Vo) during the reduction [27]. By reduction, Cu2O TFT improved overall TFT performance, such as field effect mobility, on/off ratio, threshold voltage, and subthreshold swing. Also, there are some reports about copper oxide TFT fabricated by ALD. Wanjoo et al. examine the CuOx TFT fabricated by the ALD process with the precursor of hexafluoroacetylacetonate Cu(I)(3,3-dimethyl-1-butene)[(hfac)Cu(I)(DMB)] and reactant of ozone gas (O3) [28]. The XPS results indicate that the Cu2+ bonding state increases during the annealing temperature of 300 °C, which means the formation of Cu2O. Here, the mobility of CuOx TFT results in 5.64 cm2/Vs.
Synthesis of nanostructured cupric oxide for visible light assisted degradation of organic wastewater pollutants
Published in Cogent Engineering, 2021
David Dodoo-Arhin, Etchu E. Mbu, Seteno K. Ntwampe, Edward N. Malenga, Elvis Fosso-Kankeu, Benjamin Agyei-Tuffour, Emmanuel Nyankson, Abu Yaya, Henry Agbe
When investigating complex cuprates, copper oxides can be used as reference materials, since most cuprates have shown high-Tc superconductivity due to a Jahn-Teller distortion associated with the structural characteristics of their divalent copper monoxide structure. This phenomenon tends to introduce strong electron–phonon interactions for the impartation of the required superconductivity and photocatalytic dye degradation process (Kamimura et al., 2005). To fully understand the origin and mechanism of this phenomenon, numerous studies have ensued on simple and complex copper oxides (Elwell et al., 2017). Cupric oxide (CuO) is unique amongst many of the oxides within the 3d transition series. This is largely because of its unique monoclinic structured planar square coordination. The copper bonds with oxygen in a four coplanar arrangement within a distorted tetrahedral environment, and at the same time being coordinated by four other copper atoms. Two sets of chains directed along the [110] and staggered along the [001] planes then form a three dimensional crystal structure of the CuO (Åsbrink & Norrby, 1970; Tunell et al., 1935). Overall, some research interest on Tenorite (CuO), a p-type semiconductor, is based on its ease of synthesis, benignity to organisms and ease of engineering to give it a variety of morphologies at the nanoscale level which can be enhanced for high catalytic activity by narrowing the energy band-gap within 1.2–1.8 eV (Bhattacharjeea & Ahmaruzzaman, 2016). in view of these, CuO has found applications in catalysis, solar energy systems, super-capacitors, and as electrode material for lithium-ion batteries (Shaikh et al., 2011).
Removal of nitrates from copper-containing aqueous acidic leach solutions by electrodialysis
Published in Mineral Processing and Extractive Metallurgy, 2021
Felipe Riveros, Nicolas guajardo, Marcelo Bravo Valenzuela, Andréa Moura Bernardes, Jane Zoppas Ferreira, Gerardo Cifuentes
Considering that leaching is the first stage in the process, it is responsible for many problems in terms of impurities, which, in turn, will depend on the mineralogy of the ore. Copper oxides, for instance cuprite (Cu2O) and tenorite (CuO), and some sulfides such as chalcocite (Cu2S) and covellite (CuS), are typically the main ore minerals involved in this process. In the case of Chilean copper mining, mineral deposits are found mainly in the north of the country, specifically in the Antofagasta region. In fact, in 2015 this region was responsible for more than 50% of the total copper production and for 82% of the production of copper cathodes at the national level (Servicio Nacional de Geología y Minería 2015). This zone is also characterised by a large content of caliche minerals which represent high amounts of sodium and potassium nitrates (Wisniak and Garcés 2001; Torres et al. 2015). These nitrates are leached with the copper ores, resulting in high contents of nitrates in the PLS (up to 30 g L−1 depending on the soil mineral), which cause several problems in the next stage, SX. One of the problem occurs when the organic and aqueous phase come in contact, especially at nitrate levels higher than 10 g L−1. In this case, nitration and/or hydrolysis of the oximes (the main functional group of extractant) can take place, causing large losses of extractant. Furthermore, nitrated oximes form a strong complex of copper, which cannot be effectively stripped in the typical operating conditions, producing losses of copper as well (Virnig et al. 2004). Besides the degradation caused over SX reagents, recent studies have shown detrimental effects over bioleaching microorganisms. Thus, in spite of the high microorganism adaptability, lower growth cell and higher microbial lag times are some of the problems due to the presence of nitrates (Blight and Ralph 2008; Schlesinger et al. 2011; Shiers et al. 2014).