Copper tailing is a widespread and intractable solid waste in copper production. Traditional leaching and recovery technology for copper tailing focuses on copper but neglects the leaching of iron. With the increase in applications and demands of iron-containing materials for environment, understanding the leaching behaviors of iron can promote the utilization of copper tailings. In this study, the kinetics and mechanism of the leaching of iron from copper tailings using sulfuric acid were studied. Under optimal conditions (40 °C, sulfuric acid concentration of 0.53 mol L, stirring speed of 400 rpm, solid/liquid ratio of 1 : 10 and leaching time of 120 min), 66.45% of Fe, along with 65.32% of Zn and 59.95% of Cu, were leached from the tailings. The leaching of iron was confirmed to be controlled by solid-film diffusion. The reaction orders for sulfuric acid concentration, solid/liquid ratio, and stirring speed were found to be 0.85, -0.70, and 0.40, respectively. Results from XRF, XRD, and SEM indicated that oxides (including CaO, CuO, and ZnO) were leached first, after which FeSiO was preferentially reacted compared to FeO. The accumulation of CaSO and SiO inhibited the further leaching of iron.
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http://dx.doi.org/10.1039/d0ra08865j | DOI Listing |
Environ Res
January 2025
School of Creative Science and Engineering, Faculty of Science and Engineering, Waseda University, Tokyo 169-8050, Japan; Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan. Electronic address:
Layered double hydroxides (LDHs) can effectively stabilize Se oxyanions, yet the thermal stability of Se oxyanions incorporated into LDHs remains unclear. In this study, calcination products of three types of LDHs loaded with SeO2- 3 or SeO2-4 were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray absorption fine structure spectroscopy (XAFS) and leaching tests. It has been found that SeO2-4 can be reduced to SeO2- 3 in the Fe-containing LDHs after calcination at temperatures above 450 °C.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Academic Area of Earth and Materials Sciences, Autonomous University of Hidalgo State, Mineral de la Reforma 42184, Mexico.
Mine tailings are a byproduct of mineral extraction and often pose an environmental challenge due to the contamination of soil and water bodies with dissolved metals. However, this type of waste offers the opportunity for the recovery of valuable metals such as silver (Ag). In the present investigation, an integral analysis of a sample of tailings was carried out, addressing granulometry, elemental composition, neutralization potential (NP), and acid potential (AP), as well as mineralogy, for the dissolution of silver from this type of waste.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Laboratory of Sorption Methods, Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, 119991 Moscow, Russia.
The use of reduction leaching in the production of alumina from bauxite by the Bayer process in order to decrease the amount of waste (bauxite residue) by adding elemental iron or aluminum, as well as Fe salts and organic compounds in the stage of high-pressure leaching, requires the purchase of relatively expensive reagents in large quantities. The aim of this study was to investigate the possibility of the use of electrolytically reduced bauxite residue (BR) as a substitute for these reagents. Reduced BR was obtained from Al-goethite containing BR using a bulk cathode in alkaline suspension.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy.
This study introduces a sustainable approach for enhancing the fire retardancy and smoke suppression of poly(lactic acid) (PLA) composites, contributing to addressing one of the major challenges in biocomposites that limits their application in various engineering fields, as automotive and construction sectors. Flax fibers (FF) were surface functionalized with a novel organic-inorganic hybrid flame retardant (FR), offering a sustainable bioinspired approach that mitigates potential mechanical properties impairment and FR leaching, which can cause environmental concerns and reduced composite durability. The process involves a three-step coating procedure.
View Article and Find Full Text PDFChemSusChem
January 2025
Spanish Scientific Research Council: Consejo Superior de Investigaciones Cientificas, Metalurgia Primaria y Reciclado de Materiales, SPAIN.
This work aims to recover rare earths from wind turbines NdFeB magnets through pyrometallurgical and hydrometallurgical techniques. First, a NdFeB hydride powder is obtained by decrepitation with hydrogen. Subsequently, this powder was subjected to a chlorination roasting process and successive leaching with water to bring the metals into solution.
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