Journal articles: 'Leaching to minerals'

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Fowler, Ashley L., Mieke Brümmer-Holder, and Karl A. Dawson. "Dietary Trace Mineral Level and Source Affect Fecal Bacterial Mineral Incorporation and Mineral Leaching Potential of Equine Feces." Sustainability 11, no. 24 (December 11, 2019): 7107. http://dx.doi.org/10.3390/su11247107.

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Minerals excreted in feces have the potential to leach or runoff to water-ways, negatively impacting water quality. This study examined the effect of dietary trace mineral levels, and their source, on the leaching potential of minerals from equine feces. Nine horses were used in a replicated 3 × 3 Latin Square, with three dietary treatments provided as pellets: no added trace minerals (CON), added inorganic trace minerals (ING), and added organic trace minerals (ORG). Supplemental trace minerals included Co, Cu, Mn, and Zn. Horses were allowed ad libitum access to forage and fed their treatment pellets for 16 days prior to fecal sample collection. Estimated dietary mineral intake exceeded requirements for supplemented minerals. Regardless of the source, adding dietary trace minerals increased the fecal leaching potential of Cu, Zn, and P (p < 0.05). More Co leached from ORG compared to ING, while Zn leached in greater amounts from ING compared to ORG (p < 0.05). Fecal bacterial Zn content was greater (p < 0.05) for ORG compared to ING. Negative correlations were observed between bacterial mineral content and leaching for several minerals. Supplementing trace minerals in forms that increase microbial incorporation may provide a strategy to control fecal mineral leaching.

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Fowler, Ashley L., Mieke Brummer-Holder, and Karl A. Dawson. "Trace Mineral Leaching from Equine Compost." Sustainability 12, no. 17 (September 2, 2020): 7157. http://dx.doi.org/10.3390/su12177157.

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Mineral leaching from compost can be environmentally disruptive. Little information is available regarding trace mineral leaching from equine-sourced compost. The objective of this study was to quantify the mineral content and leaching potential of compost produced from feces of horses fed different amounts and forms (organic or inorganic) of trace minerals. Nine horses were fed three treatments in a 3 × 3 replicated Latin Square design. The dietary treatments were provided as a daily pellet: CON (pellet without added trace minerals), ING (added inorganic trace minerals), and ORG (added organic trace minerals). The added trace minerals were Co, Cu, Mn, and Zn. Feces were collected from each horse after a 16-day feeding period, combined with straw, composted, and then subjected to simulated rainfall to measure mineral mobility. Concentrations of Co, Cu, Mn, and Zn were greater in ING and ORG compared to CON compost (p < 0.05); additionally, ING had greater Zn than ORG compost (p < 0.05). More Cu leached from ING and ORG compared to CON (p < 0.05). The most Zn leached from ING, followed by ORG, and the least amount leached from CON compost (p < 0.05). Dietary trace mineral intake affected the trace mineral concentration in the compost and amount available to leach during rainfall events.

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Chen, Lingkang, Xiongwei Jin, Haixia Chen, Zhengwei He, Lanrong Qiu, and Hurong Duan. "Grain Size Distribution and Clay Mineral Distinction of Rare Earth Ore through Different Methods." Minerals 10, no. 4 (April 15, 2020): 353. http://dx.doi.org/10.3390/min10040353.

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Although clay mineral content in ion-absorbed rare earth ores is crucial for migrating and releasing rare earth elements, the formation, distribution, and migration of clay minerals in supergene rare earth ores have not been fully understood. Therefore, this study analyzes the characteristics of clay mineral type and content, soil particle size, pH value, leaching solution concentration, and leaching rate. This analysis was performed using different methods, such as regional rare earth mine soil surveys, in situ leaching profile monitoring, and indoor simulated leaching. The results showed that the grain size and volume curve of rare earth ore have unimodal and bimodal shapes, respectively. X-ray diffraction showed the differences in clay mineral types formed by different weathered bedrocks. The principal clay minerals were kaolinite, illite, chlorite, and vermiculite, with their relative abundance varying with parent rock lithology (granite and low-grade metamorphic rocks). In the Ganxian granite weathering profile, the kaolinite content increased from top to bottom. The decomposition of feldspar minerals to kaolinite was enhanced with an increase in the SiO2 content during weathering. The in situ leaching profile analysis showed that the kaolinite content increased initially and then decreased, whereas the illite/mica content exhibited the opposite trend. Under stable leaching solution concentration and leaching rate, clay mineral formation is favored by lower pH. Low pH, low leaching rate, and highly-concentrated leaching solution (12 wt%) resulted in a slow increase in kaolinite content in the upper part of the profile (30 cm). A lower concentration of the leaching solution (4 wt%) resulted in rapid enrichment of kaolinite after 15 days. Low pH, leaching solution concentration, and leaching rate promoted the formation of distinct kaolinite horizons. We suggest that by disregarding other control factors, rare earth recovery of over 90% can be achieved through leach mining with solutions of 8 wt% and a pH of 5 at a leaching rate of 5 mL/min.

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Nikkhou, Fatemeh, Fang Xia, Xizhi Yao, Idowu A. Adegoke, Qinfen Gu, and Justin A. Kimpton. "A Flow-Through Reaction Cell for Studying Minerals Leaching by In-Situ Synchrotron Powder X-ray Diffraction." Minerals 10, no. 11 (November 8, 2020): 990. http://dx.doi.org/10.3390/min10110990.

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A flow-through reaction cell has been developed for studying minerals leaching by in-situ time-resolved powder X-ray diffraction, allowing for a better understanding of the leaching mechanisms and kinetics. The cell has the capability of independent control of temperature (up to 95 °C) and flow rate (>0.5 mL min−1) for atmospheric pressure leaching. It was successfully tested at the powder diffraction beamline at the Australian Synchrotron. Galena powder was leached in a citrate solution under flow-through condition at a flow rate of 0.5 mL min−1, while diffraction patterns were collected during the entire leaching process, showing rapid galena dissolution without the formation of secondary mineral phases. The flow-through cell can be used to study leaching processes of other ore minerals.

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Cho, Kanghee, Hyunsoo Kim, Eunji Myung, Oyunbileg Purev, Nagchoul Choi, and Cheonyoung Park. "Recovery of Gold from the Refractory Gold Concentrate Using Microwave Assisted Leaching." Metals 10, no. 5 (April 28, 2020): 571. http://dx.doi.org/10.3390/met10050571.

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Microwave technology has been confirmed to be suitable for use in a wide range of mineral leaching processes. Compared to conventional leaching, microwave-assisted leaching has significant advantages. It is a proven process, because of its short processing time and reduced energy. The purpose of this study was to enhance the gold content in a refractory gold concentrate using microwave-assisted leaching. The leaching efficiencies of metal ions (As, Cu, Zn, Fe, and Pb) and recovery of gold from refractory gold concentrate were investigated via nitric acid leaching followed by microwave treatment. As the acid concentration increased, metal ion leaching increased. In the refractory gold concentrate leaching experiments, nitric acid leaching at high temperatures could limit the decomposition of sulfide minerals, because of the passive layer in the refractory gold concentrate. Microwave-assisted leaching experiments for gold recovery were conducted for the refractory gold concentrate. More extreme reaction conditions (nitric acid concentration > 1.0 M) facilitated the decomposition of passivation species derived from metal ion dissolution and the liberation of gangue minerals on the sulfide surface. The recovery rate of gold in the leach residue was improved with microwave-assisted leaching, with a gold recovery of ~132.55 g/t after 20 min of the leaching experiment (2.0 M nitric acid), according to fire assays.

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Kocaman, Ayse Tuba, Mustafa Cemek, and Katrina Jane Edwards. "Kinetics of pyrite, pyrrhotite, and chalcopyrite dissolution byAcidithiobacillus ferrooxidans." Canadian Journal of Microbiology 62, no. 8 (August 2016): 629–42. http://dx.doi.org/10.1139/cjm-2016-0085.

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The main objective of this study was to investigate the dissolution kinetics of pyrite, pyrrhotite, and chalcopyrite. Crushed minerals were reacted with Acidithiobacillus ferrooxidans (25 °C). The kinetics of dissolution was investigated by monitoring pH and Fe2+and Fe3+ion concentrations in the leaching solutions. Pyrite, pyrrhotite, and chalcopyrite dissolution by A. ferrooxidans was found to be a chemically controlled process. With bacteria, the dissolution rates of the minerals increased in the order of pyrrhotite, pyrite, and chalcopyrite. The number of cells attached to mineral surfaces increased in the same order. Acidithiobacillus ferrooxidans was found to enhance the dissolution rates of the minerals. The acid-insoluble trait of pyrite and acid-soluble trait of the other 2 minerals affected the pH changes in the leaching solutions.

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Oyun-Erdene, Gendenjamts, Dolgormaa Anudari, Luvsandagva Mandakhsaikhan, Tsoodol Zolzaya, and Jadambaa Temuujin. "Comparative Acid Leaching Study of Mongolian Muscovite and Montmorillonite Clay Minerals." Solid State Phenomena 323 (August 30, 2021): 21–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.323.21.

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Acid activation is the most commonly used method to enhance the chemical and physical properties of clay minerals. Porous structure formation behavior depends on the crystal structure of clay minerals. Within the same structure of clay minerals, their resistance to acid also varies. Acid leaching has been used to increase the surface area of clay minerals and obtain solids with high porosity and many acidic sites. This paper is focused on the results of acid leaching of Mongolian clay minerals (montmorillonite and muscovite). Both clay minerals belong to a group of phyllosilicates with the 2:1 crystal structure. The influence of acid concentration and leaching time on the porous properties of silica was studied. Initially, the montmorillonite was pre-treated by a simple physical purification methods. The montmorillonite and muscovite were acid leached by a 10% hydrochloric acid solution in an autoclave at 120°C for 10h. X-ray diffraction (XRD), X-ray fluorescence analysis (XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the surface area used for characterization of the raw and leached samples. The surface area of leached montmorillonite increased up to 77% and muscovite up to 63%. Clay mineral’s swelling character and isomorphic substitution of the octahedral layer show the main influence on porous structure formation.

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Mashifana, Tebogo, and Nastassia Sithole. "Leaching kinetics of gold mine tailings: the removal of manganese and iron by sodium carbonate." E3S Web of Conferences 96 (2019): 02005. http://dx.doi.org/10.1051/e3sconf/20199602005.

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South Africa is a mineral-rich country with numerous metals and minerals such as gold, copper, and platinum group metals which are exploited to a significant extent. In this study the leaching of heavy metals from gold tailings was studied using sodium carbonate using gold tailings from Sibanye gold. The effect of the key leaching parameters were studied: solvent concentration, temperature, leaching time and the kinetic models were used. Leaching is a hydrometallurgical process where metals are extracted by chemical dissolution, leaving behind a residue of inert minerals originally present as well as insoluble decomposition products of the reacted mineral. The effect of concentration and temperature was tested and it was found that highest Fe extracted(39%) was at 0.5 M and for Mn (46.3%) was at 0.25 M, both at 25 ºC. it was also found that an increase in metal extraction depends on leaching time. The data obtained was modelled to determine whether the kinetic model follows the chemical controlled process or controlled diffusion process and it was found that the controlled diffusion model best fits the kinetic model at all temperatures.

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Ranjbar, Mohammad, Mohammadreza Esmailbagi, and Mahin Schaffie. "Bioelectrochemical Leaching of Copper Sulfide Minerals." Solid State Phenomena 262 (August 2017): 16–19. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.16.

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The objective of this study is to improve the understanding of copper sulfides dissolution and to use this knowledge for optimization of process parameters for commercial application of electrochemical bioleaching of chalcopyrite concentrates in stirred bioreactors. From the results of this study, the importance of the oxidation reduction potential (ORP) on the catalytic interaction between chalcopyrite and pyrite can be pointed out as the main parameters for successful bioprocessing of chalcopyrite concentrates. Under these conditions, the optimization of the average particle size of feed (D80) and adjusting the ORP in the range between 400-450 mV are important criteria for increasing the electrochemical bioleaching rate of chalcopyrite concentrates. It seems that the main reason for the increased copper recovery could be the control and prevention of chalcopyrite passivation resulting from improved galvanic interaction between copper sulfide minerals, here especially chalcopyrite and pyrite in the selected ORP range and the right particle size distribution of feed. At optimum conditions, the copper extraction from chalcopyrite flotation concentrate during 7 days of continuous electrochemical bioleaching operations in stirred tanks was about 95%, which should be high enough to justify the process economically.

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Shakirullah, Mohammad, Imtiaz Ahmad, Mohammad Arsala Khan, Mohammad Ishaq, Habib ur Rehman, and Uzma Khan. "Leaching of Minerals in Degari Coal." Journal of Minerals and Materials Characterization and Engineering 05, no. 02 (2006): 131–42. http://dx.doi.org/10.4236/jmmce.2006.52009.

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11

Cho, Eung Ha. "Hypochlorous Acid Leaching of Sulfide Minerals." JOM 39, no. 1 (January 1987): 18–20. http://dx.doi.org/10.1007/bf03258089.

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Crundwell, F. K. "The dissolution and leaching of minerals." Hydrometallurgy 139 (July 2013): 132–48. http://dx.doi.org/10.1016/j.hydromet.2013.08.003.

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Dreisinger, David, Amanda Dreisinger, and Caleb Dreisinger. "The Production of Soluble Ferric Sulfate via Biological and Chemical Processing of Iron Sulfides." Advanced Materials Research 1130 (November 2015): 89–92. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.89.

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Ferric sulfate is a very useful reagent for mineral leaching and metal recovery. Ferric sulfate may be used as an oxidative leaching agent for uranium, zinc, copper, nickel and other ores. Ferric ion is a modestly strong oxidant. Similarly, the use of ferric co-precipitation to stabilize arsenic, selenium and other species is in wide use. The demand for ferric sulfate for this application is increasing. Pyrite and pyrrhotite represent minerals that are widely available as sources of soluble iron to provide ferric sulfate for leaching and for iron co-precipitation. The use of biological processes for oxidation of pyrite is well established. However, the common goal is to use biological oxidation to liberate a valuable material (eg. Gold locked in arsenopyrite or pyrite). Much less attention has been paid to production of soluble iron for leaching of other minerals or for use as a precipitant. The use of chemical processes such as atmospheric and pressure oxidation may also be used to generate ferric sulfate from iron sulfide minerals. In this paper the use of biological and chemical processing for production of ferric sulfate will be reviewed and discussed.

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Sokić, Miroslav, Slobodan Radosavljević, Branislav Marković, Vladislav Matković, Nada Štrbac, Željko Kamberović, and Dragana Živković. "Influence of chalcopyrite structure on their leaching by sodium nitrate in sulphuric acid." Metallurgical and Materials Engineering 20, no. 1 (March 31, 2014): 53–60. http://dx.doi.org/10.5937/metmateng1401053s.

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During the chalcopyrite leaching by sodium nitrate and sulfuric acid solution, leaching rate decreases with increasing the time and a part of chalcopyrite mineral grains remains in the leach residue. In chalcopyrite concentrate, 95.5 % of chalcopyrite mineral occurs as in liberated grains, and the rest is in association with gangue minerals, which is very favorably from the aspect of hydrometallurgical treatment. Complex forms, like impregnations and complex intergrowths, do not exist. After experiments carried out, leaching of copper achieved 84 % at temperature 80 o C and time 240 min. In the all leach residues, 97 % chalcopyrite mineral grains occur as liberated with highly corroded surfaces. Therefore, the structural assembly of chalcopyrite grains is favorable and no reason to reduce the leaching rate in the final stage of reaction. Reason for this is elemental sulfur, which was formed during the reaction, precipitated at the particle surfaces, and slowed down the leaching rate in the final stage of leaching process.

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Chen, Tao, Bo Yan, Li-li Li, Zi-Ang Yan, Jun Wang, and Xian-ming Xiao. "Mineralogy Characteristic Study and Exploration on the Valuable Metals Enrichment of Coal Fly Ash." Advances in Polymer Technology 2019 (October 27, 2019): 1–7. http://dx.doi.org/10.1155/2019/1839450.

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The separation and enrichment can be targeted to enrich in fly ash and reduce the cost of leaching and recovering of fly ash. Regarding their different properties, the single-component separation was used to obtain uncompleted burned carbon, glass microbeads, minerals, and other characteristic components from the ash. Also, the mineral composition of each component was analyzed by electron microscopy. The metal minerals were mainly concentrated in the mineral components. Besides, the electron probe microanalysis shows that the Pt content in the minerals of fly ash was significantly correlated with the metal contents of Ni and Cu. After the obtainment of the characteristics of fly ash metal enrichment, the heavy minerals with Cu, Ni, Pt, Pd, and other target metal elements were enriched by gravity separation and flotation. The enrichment coefficients of Cu, Ni, Pt, and Pd were 1.45, 1.33, 1.90, and 1.60, respectively, and the recovery rates were 77%, 81%, 97%, and 88%, respectively. Since the yield of heavy minerals obtained by separation was 62.24%, it indicated the physical separation method could significantly reduce the cost of leaching and recovering of fly ash metal resources.

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Toro, Norman, Yousef Ghorbani, Mehmet Deniz Turan, Pedro Robles, and Edelmira Gálvez. "Gangues and Clays Minerals as Rate-Limiting Factors in Copper Heap Leaching: A Review." Metals 11, no. 10 (September 27, 2021): 1539. http://dx.doi.org/10.3390/met11101539.

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Heap leaching is a firm extractive metallurgical technology facilitating the economical processing of different kinds of low-grade ores that are otherwise not exploited. Nevertheless, regardless of much development since it was first used, the process advantages are restricted by low recoveries and long extraction times. It is becoming progressively clear that the selection of heap leaching as an appropriate technology to process a specific mineral resource that is both environmentally sound and economically feasible very much relies on having an ample understanding of the essential underlying mechanisms of the processes and how they interrelate with the specific mineralogy of the ore body under concern. This paper provides a critical overview of the role of gangues and clays minerals as rate-limiting factors in copper heap leaching operations. We aim to assess and deliver detailed descriptions and discussions on the relations between different gangues and clays minerals and their impacts on the operational parameters and chemical dynamics in the copper heap leaching processes.

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Seifelnassr, Ahmed A. S., and Abdel-Zaher M. Abouzeid. "Exploitation of Bacterial Activities in Mineral Industry and Environmental Preservation: An Overview." Journal of Mining 2013 (December 29, 2013): 1–13. http://dx.doi.org/10.1155/2013/507168.

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Since the identification and characterization of iron and sulfur oxidizing bacteria in the 1940s, a rapid progress is being made in minerals engineering based on biological activities. Microorganisms can play a beneficial role in all facets of minerals processing, from mining to waste disposal and management. Some of the applications, such as biologically assisted leaching of copper sulfide ores, uranium ores, and biooxidation of refractory sulfide gold ores, are now established on the scale of commercial processes. A variety of other bioleaching opportunities exist for nickel, cobalt, cadmium, and zinc sulfide leaching. Recently, other uses of microorganisms are potentially possible. These include the bioleaching of nonsulfide ores, bioflotation, and bioflocculation of minerals, and bioremediation of toxic chemicals discharged from mineral engineering operations. These activities acquire considerable opportunities for further research and development in these areas. This paper is an attempt to provide a critical summary on the most important efforts in the area of bacterial activities in the mineral and mining industry.

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Kim, Rina, Heechan Cho, Jinan Jeong, Jihye Kim, Sugyeong Lee, Kyeong Woo Chung, Ho-Sung Yoon, and Chul-Joo Kim. "Effect of Sulfuric Acid Baking and Caustic Digestion on Enhancing the Recovery of Rare Earth Elements from a Refractory Ore." Minerals 10, no. 6 (June 12, 2020): 532. http://dx.doi.org/10.3390/min10060532.

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To improve the recovery of rare earth elements (REEs) from a refractory ore, this study investigated two different chemical decomposition methods, namely sulfuric acid baking and caustic digestion, with their respective leaching processes. The studied lateritic ore contained goethite (FeOOH) as a major constituent with REEs scattered around and forming submicron grains of phosphate minerals, such as apatite and monazite. Therefore, despite the substantially high content of REEs (3.4% total rare earth oxide), the normal acidic leaching efficiency of REEs reached only 60–70%. By introducing sulfuric acid baking and caustic digestion, the REE-leaching efficiency was significantly improved. After sulfuric acid baking at 2.0 acid/solid ratio and 200 °C for 2 h, the leaching efficiency reached 97–100% in the subsequent water-leaching. When the ore was digested with a solid/liquid ratio of 100 g/L in a 30 wt% NaOH solution at 115 °C and 300 rpm for 3 h, the REE-leaching efficiency of 99–100% was attained at 80 °C using a 3.0 M HCl solution. The correlation between the REE and the Fe-leaching was determined. The improvements in REE-leaching in both methods were mostly attributed to the mineral phase and crystallinity changes of Fe-bearing minerals due to the ore pretreatments. Such findings were also supported by X-ray diffraction and scanning electron microscopy analyses.

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Montross, Scott N., Jonathan Yang, James Britton, Mark McKoy, and Circe Verba. "Leaching of Rare Earth Elements from Central Appalachian Coal Seam Underclays." Minerals 10, no. 6 (June 26, 2020): 577. http://dx.doi.org/10.3390/min10060577.

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Rare earth elements (REE) are necessary for advanced technological and energy applications. To support the emerging need, it is necessary to identify new domestic sources of REE and technologies to separate and recover saleable REE product in a safe and economical manner. Underclay rock associated with Central Appalachian coal seams and prevalent in coal utilization waste products is an alternative source of REE to hard rock ores that are mainly composed of highly refractory REE-bearing minerals. This study utilizes a suite of analytical techniques and benchtop leaching tests to characterize the properties and leachability of the coal seam underclays sampled. Laboratory bench-top and flow-through reactor leaching experiments were conducted on underclay rock powders to produce a pregnant leach solution (PLS) that has relatively low concentrations of gangue elements Al, Si, Fe, and Th and is amenable to further processing steps to recover and produce purified REE product. The leaching method described here uses a chelating agent, the citrate anion, to solubilize elements that are adsorbed, or weakly bonded to the surface of clay minerals or other mineral solid phases in the rock. The citrate PLS produced from leaching specific underclay powders contains relatively higher concentrations of REE and lower concentrations of gangue elements compared to PLS produced from sequential digestion using ammonium sulfate and mineral acids. Citrate solution leaching of underclay produces a PLS with lower concentrations of gangue elements and higher concentrations of REE than achieved with hydrochloric acid or sulfuric acid. The results provide a preliminary assessment of the types of REE-bearing minerals and potential leachability of coal seam underclays from the Central Appalachian basin.

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Chen, Miao, Yi Yang, and Mikko Vepsalainen. "Characterization and Localized Insight into Leaching of Sulfide Minerals." Solid State Phenomena 262 (August 2017): 261–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.261.

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To improve the efficiency of sustainable recovery of valuable resources (such as copper, gold, uranium), advanced technologies of electrochemistry, surface chemistry and materials characterization, such as Synchrotron X ray-absorption spectroscopy (XAS), X-Ray photoelectron spectroscopy (XPS), and in situ X-ray Diffraction (XRD) have been employed to investigate the interactions between microbes and sulfide minerals in situ to gain a detailed understanding of the chemical reaction mechanisms operating in bioleaching. It has been demonstrated that alternating current Scanning Electrochemical Microscopy (ac-SECM) allows for straightforward characterization of sulfide mineral samples in aqueous solution. With the technology localized electrochemical properties of the mineral surface including the surface current mapping can be achieved. Robust chemical sensors have been developed for real time, in-situ monitoring of key leaching process parameters.

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Chen, Ci Yun, Shu Ming Wen, He Fei Zhao, Chao Lv, and Yi Jie Wang. "Using of Roasting Leaching Methods for Copper Recovery from a Flotation Concentrate of Yangla Copper Ore." Advanced Materials Research 868 (December 2013): 403–7. http://dx.doi.org/10.4028/www.scientific.net/amr.868.403.

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Through earliest experimental study to tailings of Yangla copper ore known that under the best conditions of the flotation process can be obtained a copper concentrate which copper grade of 1.43% and recovery was 29.71%. Due to copper minerals embedded in this materials at a very fine particle size, and closely symbiosis with iron content and quartz, lead to it difficult to enrichment through ore dressing methods. And copper minerals mainly exist in the form of sulfide copper mineral, it can not by leaching method for processing directly, thus put forward a process to deal with this materials of enriched concentrate conduct to sulfuric roasting-leaching, which on the premise of guaranteed cost is not high, ultimately achieve the goal of recycling all kinds of valuable elements. Through the test of low temperature sulphation roasting - leaching to the flotation of copper concentrate shows that under the conditions of temperature of 450 °C for copper concentrate roasting 135 minutes, and after the calcine cooling, then with concentration of 4% sulfuric acid and Liquid-solid ratio of 3:1 leaching of 80 minutes, ultimately available to the test targets of copper leaching rate of around 81%.

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Zhang, Meng, Shu Juan Dai, Lian Tao Yu, Jia Hong Han, and Guo Zhen Liu. "Experimental Research on a Cyanidation of Gold Ore Containing Arsenic." Advanced Materials Research 826 (November 2013): 53–56. http://dx.doi.org/10.4028/www.scientific.net/amr.826.53.

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The main metal minerals are magnetic pyrite arsenopyrite pyrites, galenite sphalerite,etc.The main gangue minerals are quarts,sericite,chlorite,carbonate,etc.Nature gold,electrum,bullion and nature silver are main gold silver minerals. The useful element is gold and silver and the impurity is arsenic. The experimental results of cyanide leaching crude and flotation concentrate show that the index of leaching rate of gold and silver being 93.90% and 81.38% are got on the condition of grinding fineness being 95.3%-0.074mm，pulp thickness being 33%，dosage if CaO being 2.5kg/t（pH≈11），dosage of NaCN being 3.0kg/t,leaching time being 24h by leaching crude of gold and silver grade being 0.82g/t、4.78g/t.

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Xiao, Junhui, Kai Zou, Wei Ding, Yang Peng, and Tao Chen. "Extraction of Lead and Zinc from a Rotary Kiln Oxidizing Roasting Cinder." Metals 10, no. 4 (April 2, 2020): 465. http://dx.doi.org/10.3390/met10040465.

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In this study, sulfuric acid leaching and gravity shaking-table separation by shaking a table are used to extract lead and zinc from a Pb-Zn oxidizing roasting cinder. The oxidizing roasting cinder—containing 16.9% Pb, 30.5% Zn, 10.3% Fe and 25.1% S—was obtained from a Pb-Zn sulfide ore in the Hanyuan area of China by a flotation-rotary kiln oxidizing roasting process. Anglesite and lead oxide were the main Pb-bearing minerals, while zinc sulfate, zinc oxide and zinc ferrite were the main Zn-bearing minerals. The results show that a part of lead contained in lead oxide is transformed to anglesite, and a 3PbO·PbSO4·H2O-dominated new lead mineral phase after acid leaching. A zinc leaching efficiency of 96.7% was obtained under the leaching conditions used: a leaching temperature of 55 °C; a leaching time of 90 min; a sulfuric acid dosage of 20%; a sulfurous acid dosage of 4%; a cinder particle size of <0.3 mm; and a solid-liquid ratio of R = 1:4. After the gravity shaking-table separation, a lead concentrate with 50.2% Pb, 2.33% Zn and lead recovery of 86.0% was produced. The main chemical compounds in leaching residue are anglesite, 3PbO·PbSO4·H2O, SiO2 and ZnFe2O4, while the main chemical compounds in lead concentrate are anglesite, 3PbO·PbSO4·H2O and SiO2.

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Cho, Kang Hee, Jong Ju Lee, and Cheon Young Park. "Liberation of Gold Using Microwave-Nitric Acid Leaching and Separation-Recovery of Native Gold by Hydro-Separation." Minerals 10, no. 4 (April 6, 2020): 327. http://dx.doi.org/10.3390/min10040327.

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The purpose of this study was to liberate gold from sulfide minerals in a gold concentrate through microwave-nitric acid leaching and to separate the light minerals in an insoluble residue using a hydro-separation process. The representative sulfide minerals in the gold concentrate were pyrite with minor galena. Mineralogical characterization was conducted on the gold concentrate using 1715.20 g/t based on lead-fire assays. During the leaching experiment, the effect of nitric acid concentration was studied. The results indicated that the metal leaching rate of the gold concentrate increased with increasing nitric acid concentration. After the microwave-nitric acid leaching, the resulting main feature was consistent with the increased exposure to reactive sulfide minerals and decrease in weight. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and scanning electron microscope backscattered electron imaging (SEM-BSE) were performed to characterize the minerals in the insoluble residue using microwave-nitric acid leaching and the hydro-separation process. The XRD patterns of the insoluble residues were compared. The intensities of the pyrite peak decreased and disappeared under different nitric acid concentrations, whereas intensities of the quartz peak increased. The hydro-separation process focused on the separation of heavy (e.g., native gold) and light (e.g., quartz) minerals from the insoluble residues. After the hydro-separation treatment process, the heavy minerals exhibited typical diffraction lines of gold, as obtained using the XRD analysis.

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Habashi, F. "Leaching mechanism of semiconducting minerals a historical note." Journal of Mining and Metallurgy, Section B: Metallurgy 48, no. 3 (2012): 477–81. http://dx.doi.org/10.2298/jmmb121109059h.

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mechanism of leaching of semiconducting minerals such as CuS, ZnS, UO2, etc., has been the subject of intensive speculation by hydrometallurgy researchers in the early 1950s who assumed the formation of intermediate surface complexes that could be neither separated nor identified by physico-chemical techniques. The electrochemical theory of leaching introduced in the late 1960s resolved this problem by comparing the leaching process to a corrosion phenomenon similar to the corrosion of metals. A historical summary of these proposals is presented.

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Feng, Qi Cheng, Shu Ming Wen, Ci Yun Chen, He Fei Zhao, Yi Jie Wang, and Chao Lv. "Extraction of Copper from a Refractory Copper Oxide Ore by Catalytic Oxidation Acid Leaching." Advanced Materials Research 734-737 (August 2013): 941–44. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.941.

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The study aimed to extract copper from copper oxide ores in which copper minerals had a complex association and dissemination with gangue minerals in the form of fine grain by catalytic oxidation acid leaching. Based on the research on the properties of the material and lots of experiments, the leaching process was performed. The optimum parameters of leaching process were determined as sulfuric acid dosage of 150 kg/t, KMnO4 dosage of 1500 g/t, liquid/solid mass ratio of 3 and leaching time of 45 minutes. Under such a condition, the leaching efficiency of 90.15% was achieved, which provided a way to improve leaching efficiency of copper for refractory copper oxide contained some copper sulphide using catalytic oxidation acid leaching.

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Koohestani, Babak, Ahmad Khodadadi Darban, Pozhhan Mokhtari, Esmaeel Darezereshki, Erol Yilmaz, and Elif Yilmaz. "Influence of Hydrofluoric Acid Leaching and Roasting on Mineralogical Phase Transformation of Pyrite in Sulfidic Mine Tailings." Minerals 10, no. 6 (June 1, 2020): 513. http://dx.doi.org/10.3390/min10060513.

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Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering possibility, it is advantageous to remove impurities and increase the pyrite content of mine tailings prior to the roasting procedure. In this case, hydrofluoric acid that has no influence on pyrite can be used to leach most inorganic minerals, including aluminosilicates. Therefore, this study investigated and compared the influence of the roasting process with and without hydrofluoric acid leaching pretreatment on mineralogical phase transformation of pyrite and magnetic properties of thermally generated minerals. Several tests and analyses were performed to study mineralogical phase transformation, morphology, elemental composition, surface characterization, and magnetic properties. Results of this study indicated that without acid leaching pretreatment, pyrite was mainly transformed to hematite. However, via acid leaching, fluorine, as a more electronegative element over oxygen, entered the compound and neglected the role of oxygen in thermal oxidation, instead reducing sulfur content of pyrite to only form pyrrhotite.

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Lu, Dian Kun, Li Fang Shi, and Zhe Nan Jin. "Research on Chloride Leaching of Cu, Zn and Ag from Flotation Tailings." Advanced Materials Research 391-392 (December 2011): 1138–42. http://dx.doi.org/10.4028/www.scientific.net/amr.391-392.1138.

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Mineralogical examinations of Asheler copper mine flotation tailings have been carried out. Results show that the major metal sulphide minerals are pyrite and the main gangue constituents are quartz, chlorite-serpentine and muscovite. The main valuable metals are Cu, Zn and Ag. Basic mineral compositions of copper and zinc have been identified through chemical phase analysis. On the basis of mineralogical examinations, leaching test has been carried out in about 240g/l NaCl solution. The optimum conditions for leaching are found as follows: temperature at 86°C, pulp concentration is 24.19%wt, [Cu2+] =19.22g/l, [HCl] initial =0.17mol/L. Under these conditions, chloride leaching can extract 83.35%Cu, 92.10%Zn, and 85.26%Ag after 8 hours leaching.

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Suzuki, Isamu. "Microbial leaching of metals from sulfide minerals." Biotechnology Advances 19, no. 2 (April 2001): 119–32. http://dx.doi.org/10.1016/s0734-9750(01)00053-2.

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Kirilchuk, Maksim, and Adam Mustapha. "Comparative experiments on the activation cyanide and chloride re-leaching of gold from the secondary mineral material of heaps of Aprelkovo mine." E3S Web of Conferences 192 (2020): 02016. http://dx.doi.org/10.1051/e3sconf/202019202016.

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This article presents the results of comparative experiments on the activation chloride and activation carbonate-cyanide leaching of gold from the secondary mineral material of heaps of Aprelkovo mine. A cyanide scheme with a gradual increase in the cyanide concentration in the pregnant solution was adopted as a control scheme for percolation leaching. To establish the maximum recovery of gold and associated components, preliminary experiments with agitational cyanide leaching were carried out. In the course of the experimental work, some of the problems of gold recovery according to the classical cyanide scheme applicable to this deposit were identified and, thanks to the use of activated solutions, were solved. The reasons for the insufficiently high recovery are clogging and limited access of the complexing agent to encapsulated and chemically bound gold inclusions due to their high dispersion in the crystal lattices of concentrating minerals and the presence in the ore of minerals that tend to absorb water with a pronounced hydration effect.

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Ovseychuk, V., and А. Zozulya. "Mining-geological and physico-chemical indicators determining the success of the use of block underground and heap leaching." Transbaikal state university journal 27, no. 3 (2021): 34–41. http://dx.doi.org/10.21209/2227-9245-2021-27-3-34-41.

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The success of the physico-chemical technologies’ application in the development of ore deposits, such as underground and heap leaching, depends on the petrographic and mineral composition of the ores and their host rocks, type of reagents leaching the useful component, technology of ore preparation and irrigation modes of lumpy ores. The efficiency of leaching of uranium-ore minerals is determined by the physico-chemical laws of the interaction of reagents with the ore material. In the course of the research, the relationship between the silica content in the rocks containing mineralization and their physical and mechanical properties was established. This makes it possible, knowing the type of rocks, to predict the conditions of ore preparation by drilling and blasting to obtain the optimal piece size for leaching. In addition, the influence of the ore texture on the leaching efficiency was proved experimentally. Previous researchers found that the rate of conversion of uranium to the mobile state during leaching depends on the rate of penetration of the leaching reagent into the piece, displayed by the effective diffusion coefficient (Kef). The analysis of mining and geological information made it possible to establish the relationship between the Kef and the type of host rocks through the SiO2 content and the type of uranium minerals through the uranium content. The obtained knowledge makes it possible to predict favorable conditions for the use of physico-chemical geotechnologies in the development of rock-poor uranium deposits

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Yepsen, Orlando, Eugenia Araneda, Rodrigo Yepsen, and Humberto Estay. "The Role of Solar Energy (UV-VIS-NIR) as an Assistant for Sulfide Minerals Leaching and Its Potential Application for Metal Extraction." Minerals 11, no. 8 (July 30, 2021): 828. http://dx.doi.org/10.3390/min11080828.

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The mining industry is facing emerging challenges as a result of the increase in energy consumption and environmental demands. These facts have promoted the use of renewable energy sources, such as wind, geothermal and, mainly, solar energy. This paper discusses the role of solar energy (UV-VIS-NIR) in leaching processes, evaluating its potential application in metal extraction from sulfide minerals, based on photochemical mechanisms that promote the regeneration of ferric iron or the so called ferrous iron cycling. The present paper discusses the possibility that ultraviolet, visible light and near infrared irradiation (e.g., sunlight provided) can assist the leaching processes in two main ways: by the oxidation of sulfide minerals through in-situ generated Fenton-like reactions, and by the photochemical activation of semiconductor minerals that contain transition metals (Fe, Cu, and Cr, among others). Thus, this paper provides theoretical support to move towards the future application of photoleaching, which consist of a leaching process assisted by UV, VIS, and NIR irradiation. This technology can be considered a promising mineral processing route, using direct photochemical solar energy that can reduce the energy consumption (electricity, fuels) and the environmental impact, opening an opportunity for an alternative method of metal extraction from sulfide ores.

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Zhou, Wen-bo, Kai Li, Yu-guang Wang, Li-juan Zhang, Hai-na Cheng, and Hong-bo Zhou. "Influence of particle size on copper recovery from sulfide ore by the moderately thermophilic microorganisms." Metallurgical Research & Technology 116, no. 1 (2019): 119. http://dx.doi.org/10.1051/metal/2018118.

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The bioleaching of copper ore by the defined moderately thermophilic consortium containing Leptospirillum ferriphilum and Acidithiobacillus caldus was carried out in the bench-scale column. Bioleaching experiments showed that the leaching rate was 25% higher than that of a conventional leaching and the acid consumption was reduced by 33% at the optimal leaching condition. Meanwhile, the effect of different particle sizes on the rate of the copper leaching was also investigated, and it was shown that the particle size affects the bioleaching rate significantly in the range of 5–25 mm, in which approximately 89.27% of copper was extracted at 5–10 mm, while only 57.08% at 15–25 mm. The results obtained by X-ray diffraction (XRD) analysis of the mineral samples before and after microbial and chemical leaching revealed that the decrease in particle size of the minerals resulted in an enhancement of complex microbial interactions. Especially for the particle size of 5–10 mm, a significant amount of elemental sulfur and jarosite formed on the surface of the mineral, while it was further confirmed that critical microbe-mineral interactions have taken place on the mineral surface. The results indicated that mineral particle size is an integral factor to improve the copper recovery from ore in heap leaching operation. This will provide a reference to the heap construction for the bioleaching.

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Ubaldini, Stefano. "Leaching Kinetics of Valuable Metals." Metals 11, no. 1 (January 19, 2021): 173. http://dx.doi.org/10.3390/met11010173.

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Zhang, Qi Dong, Xiao Li Li, Yong Sheng Song, and Gui Ying Zhou. "Experimental Research on Preparation Technics of High-Purity Quartz Material." Key Engineering Materials 748 (August 2017): 17–21. http://dx.doi.org/10.4028/www.scientific.net/kem.748.17.

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In order to make the natural quartz up to the standard of high purity quartz sands, quartz ores are processed to obtain high purity quartz sands by the purifying technologies which include grinding, high-intensity magnetic concentration, flotation and acid leaching, washed by deionized water. The phase, morphology and composition of the prepared quzrtz sands were determined by X-ray diffraction, scanning electron microscope and inductively coupled plasma spectrometers.The results show that impurity minerals adsorb onto the quartz mineral surfaces. Magnetic minerals were removed by magnetic concentration experiment, while other impurities were removed by flotation and acid leaching experiments and they show excellent cleaning effect. Finally a high purity quartz product which contains higher than 99.95% SiO2, less than 0.003% Fe2O3, and less than 0.01% Al2O3 was obtained.

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Svietkina, Olena, Kostiantyn Bas, Jamil Haddad, Kyrylo Ziborov, and Valentyna Olishevska. "Mechanochemical Activation of Polymetallic Ore and Further Selective Floatation." Key Engineering Materials 844 (May 2020): 65–76. http://dx.doi.org/10.4028/www.scientific.net/kem.844.65.

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It has been demonstrated that shock-vibrating activation of minerals is a prospective method to impact the ore; it may be used to intensify chemical and physical-chemical processes of mineral raw material processing and preparation. Differences in the composition and phase properties, obtained both in terms of continuous and periodic modes, are in the fact that in the first case loadings deal with interlayer space preserving layered nature of the mineral. When the mode is continuous, then the disturbances cover the octahedral layer though elementary constituent – tetrahedrons – are preserved. It has emerged that the most important advantage of high reacting capability of activated minerals is in the fact that leaching of some ores may be performed in chlorhydric acid at the expense of transformation of some silicate components into a specific state – loose packing of basic silicate chain. Consequently, shock-vibrating activation has become a basis to develop a method of leaching process intensification as well as a method to control phase formation.

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Cao, Long-hu, Cheng-jun Liu, Qing Zhao, and Mao-fa Jiang. "Analysis on the stability of chromium in mineral phases in stainless steel slag." Metallurgical Research & Technology 115, no. 1 (November 28, 2017): 114. http://dx.doi.org/10.1051/metal/2017071.

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Stainless steel slag from high alloy steel is hardly used in the construction industry. The chromium leaching in unstable phase is the limiting factor for the application in the slag. The aim of this study is to investigate the stability of mineral phases in stainless steel slag. In this work, the mineral phases were firstly confirmed through experimental results by SEM-EDS and XRD. Thermodynamic calculation and leaching test were adopted to characterize the theoretical stability of mineral phases in aqueous solution. The results showed that the main phases in the stainless steel slag were spinel, melilite [solid solution of gehlenite (Ca2Al2SiO7) and akermanite (Ca2MgSi2O7)], dicalcium silicate, merwinite and periclase phases. It can be concluded that the minerals behave differently when dissolving in aqueous solution and the dissolution of dicalcium silicate (Ca2SiO4), merwinite (Ca3MgSi2O8), akermanite (Ca2MgSi2O7) and periclase phase could be generally higher, especially at lower pH values. In addition, the solubility of chromium in the spinel phase is considered low. The leaching test demonstrated that the formation of spinel phase can limit the leaching of chromium and the chromium existing in the silicate and periclase phases can facilitate the chromium leaching.

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Hung, Nguyen Van. "STUDY ON THE USE OF ACIDOPHILIC IRON OXIDIZING BACTERIA FOR DISSOLVING IRON FROM LOW-GRADED CHALCOPYRITE ORES." Vietnam Journal of Science and Technology 54, no. 4A (March 21, 2018): 164. http://dx.doi.org/10.15625/2525-2518/54/4a/11990.

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Biomining is a microbiological-based approach to extract minerals from ores without adding acids and other extraction chemicals. Having biological nature, the process is considered environmental friendly and tends to be applied more widely nowadays, especially for low-graded ores, for which chemical extraction is no longer efficient. In this study, two iron oxidizing bacterial strains Acidithiobacillus sp. IOB1 and Leptospirillum sp. IOB2 originated from mining sites in Vietnam were used in laboratory leaching experiments for the recovering minerals from low-graded chalcopyrite ores. The obtained results showed that both strains could significantly accelerate the leaching process, the highest iron dissolution rate was estimated for 0.83 g×kg-1×d-1 within two weeks of incubation with strain IOB2, about 30 % and 50 % respectively higher than leaching with strain IOB1 or control without bacteria, respectively. The iron extraction from ores was also evidenced by EDX analyses comparing the ore particles before and after incubation with the bacteria. Microscopic observation of DAPI-stained ore particles also showed high cell density attached to the particles, instead of freely moving in the liquid extract. Furthermore, FISH analyses using a specific probe for the g-Proteobacteria GAM42a revealed that only ~50 % of DAPI-stained cells were Acidithiobacillus sp. IOB1 – like in the leaching experiment with this train as starting culture, indicating that other bacterial species have developed and contributed to the metal dissolution here; however very rare positive signals were observed in leaching experiment with strain IOB2 as starting culture or the control without added bacteria. Thus, the acidophilic iron oxidizing strains Acidithiobacillus sp. IOB1 and Leptospirillum sp. IOB2 could serve as potential microbial sources for the development of biologically based approaches to extract minerals from ores, especially for those having low mineral contents.

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Leelarungroj, Kittitat, Suched Likitlersuang, Thanakorn Chompoorat, and Dao Janjaroen. "Leaching mechanisms of heavy metals from fly ash stabilised soils." Waste Management & Research: The Journal for a Sustainable Circular Economy 36, no. 7 (June 12, 2018): 616–23. http://dx.doi.org/10.1177/0734242x18775494.

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Fly ash is an industrial waste material that is repurposed as a soil stabiliser worldwide. In Thailand, many ground improvement projects utilise mixtures of cement and fly ash to stabilise weak soils. In this study, leaching mechanisms of arsenic, chromium, lead, and zinc from cement and fly ash stabilised soils were investigated in the laboratory. Leaching tests were performed, with different leachants and pH conditions, on cement and fly ash stabilised soils used for soil improvement in road embankment construction projects in Northern Thailand. The results suggested that chemical compounds (CaO and MgO) on fly ash surfaces can control the pH of the fly ash and soil leachant. The dissolution of chromium and zinc was found to be amphoteric and controlled by oxide minerals at a high or low pH. Arsenic leaching was found to be oxyanionic where AsO43- prevented the adsorption of arsenic onto the negatively charged fly ash surface. Different types of leachant also leached out in different amounts of heavy metals.

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Gelhaar, Nadja, Simone Schopf, and Michael Schlömann. "Indium Extraction from Reiche Zeche Sphalerite and Community Analysis of Acidic Mine Water." Advanced Materials Research 1130 (November 2015): 392–95. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.392.

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During the process of industrialization, the world-wide demand for resources steadily increases. Significant amounts of crucial metals and metalloids remain in low grade mineral deposits, however using conventional metal extraction methods on these minerals is not environmentally feasible. To overcome these problems, biohydrometallurgy has become the focus of recent research. Biohydrometallurgy utilizes the activity of iron-oxidizing bacteria to catalyze the dissolution of sulfide minerals, in our case local sphalerite (ZnS), with the aim of winning zinc and indium. To achieve this enrichment cultures originating from waters of the Reiche Zeche mine in Freiberg, Germany, were used as inoculum for two acidic growth media. To explore the efficiency of the bioleaching process leaching tests have been performed in shaking-flasks under laboratory conditions. Ground ore from Reiche Zeche is mainly comprised of the sulfide minerals sphalerite, galena and pyrite. After the leaching process both the solution and the residue were analyzed either by ICP-MS or XRD.The results clearly show that it is possible to leach indium and zinc from natural sphalerite, but that leaching efficiency is hindered, and dissolved indium removed, by the formation of iron-hydroxy precipitates. Hence, optimal conditions for maximum indium recovery with minimal precipitation have to be determined by variation of physico-chemical parameters. Furthermore, the microbial diversity of Reiche Zeche mine waters were studied with cultivation dependent and independent methods.

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Sokic, Miroslav, Jovica Stojanovic, Branislav Markovic, Mladen Bugarcic, Nada Strbac, Zeljko Kamberovic, and Vaso Manojlovic. "Effects of structural and textural grain characteristics on leaching of sulphide minerals from a polymetallic concentrate by sodium nitrate and sulphuric acid solution." Chemical Industry 71, no. 6 (2017): 461–69. http://dx.doi.org/10.2298/hemind161130006s.

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In this paper, the influence of structural and textural characteristics of sulfide minerals on their leaching from a polymetallic concentrate by sulfuric acid and sodium nitrate solution is presented. The starting material was Pb?Zn?Cu sulphide polymetallic concentrate enriched during the flotation of a polymetallic ore in the "Rudnik" flotation plant (Rudnik ? Serbia). Leaching experiments were carried out in a closed glass reactor, which provides stable hermetic conditions and allows heating at constant temperature. Chemical, XRD, qualitative and quantitative microscopic and SEM/EDX analyses were used to characterizes samples of the polymetallic concentrate and leach residue. It was determined that chalcopyrite, sphalerite, galena, pyrrhotite and quartz were present in the polymetallic concentrate. The content of sulphide minerals was 69.5%, of which 60.9% occurred as liberated grains: 88.3% of chalcopyrite, 59.3% of sphalerite, 25.1% of galena and 51.6% of pirrhotite. The rest of chalcopyrite, sphalerite, galena and pirrhotite grains were in the forms of inclusions, impregnations, and simple and complex intergrowths. During the leaching process by sodium nitrate and sulphuric acid solution, it was shown previously that the leaching rate of sulphide minerals decreased with time while a part of the sulphide minerals remained in the leach residue. After leaching at 80?C for 120 min, the yields were 69.8, 82.7 and 67.1% for Cu, Zn and Fe, respectively. Lead, in the form of insoluble anglesite, remained in the leach residue. In addition to the anglesite, unleached sulfide minerals and quartz, elemental sulfur was found in the solid residue. The content of sulphide minerals was 35% of which 33.7% minerals occur independently. In specific, 54.7% of chalcopyrite, 31.9% of sphalerite, 8.2% of galena and 37.6% of pyrrhotite appear as separate grains with highly corroded surfaces. Therefore, the structural assembly of sulphide grains in the polymetallic concentrate is favourable and it is not the reason for the observed decrease in the leaching rate in the final process stages. The obtained findings may be explained by the presence of elemental sulphur that is formed during the reaction and precipitated at the grain surfaces, thus creating a diffusion barrier for the leach solution.

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Qin, Shu-Chen, Kai-Xi Jiang, Hai-Bei Wang, Bang-Sheng Zhang, Yu-Fang Wang, and Xue-Dong Zhang. "Research on Behavior of Iron in the Zinc Sulfide Pressure Leaching Process." Minerals 10, no. 3 (February 29, 2020): 224. http://dx.doi.org/10.3390/min10030224.

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Dissolved iron exerts significant effects on mineral leaching, impurity removal, and solution purification in the zinc hydrometallurgy process. To date, iron oxidation and migration behaviors are yet to be fully understood and further research on effective regulation mechanisms of iron is required. In this paper, zinc sulfide concentrate was used as the research object. The behaviors of both Zn and Fe during pressure leaching were investigated for varying temperature, acid addition, and leaching time. At temperature of 100~160 °C, H2SO4/Zn ratio of 0.9:1–1.25:1, and leaching time of 0.5–2.5 h, the zinc extraction increased with temperature, acidity and leaching time. The iron extraction, however, varied differently with increasing temperature, acidity and leaching time: (A) it increased with temperature to 150 °C and then decreased at higher temperature, and (B) displayed an initial increase followed by a decrease with respect to the leaching time. Based on the characteristics of the residue phase, chemical phase analysis was used to analyze the residue in detail. The extent of dissolution of iron-containing minerals and the extent of precipitation of ferric ions during the leaching process were quantitatively calculated.

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Rogozhnikov, Denis A., Andrey A. Shoppert, and L. M. Karimova. "Investigating of Nitric Acid Leaching of High-Sulfur Copper Concentrate." Solid State Phenomena 299 (January 2020): 968–73. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.968.

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This article describes the problems of deterioration of the quality of processed raw materials due to depletion of mineral resources. It is proposed to use nitric acid for the processing of complex refractory low-grade concentrates containing non-ferrous and noble metals. It was found that the studied concentrate contains: sphalerite (26.9 %), pyrite (22.0 %), chalcopyrite (19.9 %), silica (13.9 %), alumina (5.5 %), galena (1.7 %), oxidized forms of iron (Fe2O3) (12 %). Gold and silver are associated with sulfide minerals. Typical reactions of interaction of these minerals with nitric acid are considered. A sufficiently high thermodynamic probability of these reactions in a wide temperature range is established. With the use of mathematical methods, the optimal conditions of the process of nitric acid leaching are selected: the ratio of L:S = 5:1; the concentration of nitric acid 10 mol/L; the duration of the process is 60 minutes. In this case, the extraction of copper, zinc, iron and sulfur into the solution was 99.00 %, 99.84 % 98.60 %, 88.51 %, respectively.

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Sokić, Miroslav, Vladislav Matković, Branislav Marković, Vaso Manojlović, Nada Štrbac, Dragana Živković, and Željko Kamberović. "Complex sulphide-barite ore leaching in ferric chloride solution." Metallurgical and Materials Engineering 22, no. 2 (June 30, 2016): 81–90. http://dx.doi.org/10.30544/216.

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The results of research on the leaching process of complex sulphide-barite ore were presented in this paper. The leaching process was carried out in a laboratory autoclave by ferric chloride solution. Considering that those minerals are represented in complex structural-textural relationships, it is not possible to extract lead, zinc and copper minerals from ore by flotation methods. The obtained results confirmed possibility of the ore processing directly, by chemical methods. The effect of temperature, time and oxygen partial pressure on the lead, zinc and copper dissolution was studied. The maximal leaching degree was achieved at 100 °C and amount of 91.5 % for Pb, 96.1 % for Zn and 60.7 % for Cu). Leaching at temperatures above 100 °C is impractical.

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Naumov, K. D., K. A. Karimov, and A. M. Klyushnikov. "Complex Rare Earth Minerals Sulfate Decomposition Techniques Investigation." Materials Science Forum 946 (February 2019): 580–84. http://dx.doi.org/10.4028/www.scientific.net/msf.946.580.

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This article presents a study of Tomtor rare earth ore decomposition. This material contains a lot of valuable components such as REE and niobium (mas., %: 12,8 ΣREO (rare earth oxides), 0.039 Sc, 18.4 P2O5, 9.9 Fe, 9.0 Al, 0.24 ThO2, 8.2 Nb2O5). The study aims to find efficient ways of processing this deposit. Technologies using the sulfuric acid as the main reagent to leach are described in this article. Investigation has three trends. The first trend is agitation leaching at low sulfuric acid concentrations, temperatures up to 95 °C and atmospheric pressure. The second trend is pressure leaching at low sulfuric acid concentrations, high temperatures (up to 180 °C) and high pressure. The third trend is high temperature sulfatization with concentrated sulfuric acid at elevated temperature (up to 180 °C) and atmospheric pressure followed by aqueous leaching. The dependence of target components (rare earth elements, scandium, phosphorus) and the impurity (iron, aluminum, thorium) extractions into solution from major factors was studied.

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He, Hongye, and Hideaki Suito. "Leaching Behavior of Fluorine-containing Minerals in Seawater." ISIJ International 42, no. 2 (2002): 132–38. http://dx.doi.org/10.2355/isijinternational.42.132.

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Dutrizac, J. E. "The leaching of sulphide minerals in chloride media." Hydrometallurgy 29, no. 1-3 (June 1992): 1–45. http://dx.doi.org/10.1016/0304-386x(92)90004-j.

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Habashi, F. "The leaching of sulfide minerals in chloride media." Hydrometallurgy 38, no. 2 (July 1995): 219. http://dx.doi.org/10.1016/0304-386x(95)00003-y.

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Lapidus, Gretchen. "Mathematical modelling of metal leaching in nonporous minerals." Chemical Engineering Science 47, no. 8 (June 1992): 1933–41. http://dx.doi.org/10.1016/0009-2509(92)80311-y.

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Wang, Ruifeng, Xiong Wu, Yanliang Zhai, Yuxuan Su, and Chenhui Liu. "An Experimental Study on the Sources of Strontium in Mineral Water and General Rules of Its Dissolution—A Case Study of Chengde, Hebei." Water 13, no. 5 (March 5, 2021): 699. http://dx.doi.org/10.3390/w13050699.

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Chengde City boasts a wealth of high-quality mineral water resources characterized by a high level of strontium (Sr), a low level of sodium, and low alkalinity. In order to study the mechanism of formation of Sr-bearing mineral water in Chengde and to scientifically guide future mineral water exploration, taking three typical mineral water exploration areas in Chengde as examples, this paper studies the sources of Sr in mineral water and the general rules of its dissolution via a laboratory static leaching experiment and impact experiments, and it provides an analysis of the characteristics of typical rock samples. The research results indicate that the content of Sr in surrounding rock and the characteristics of minerals existing in surrounding rock jointly control the dissolution of Sr in water; that CO2 can promote the formation of mineral water containing Sr; and that temperature increases may boost the dissolution of Sr from carbonate minerals but also inhibit the dissolution of Sr from silicate minerals.

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Journal articles on the topic 'Leaching to minerals'

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