Minerals and rocks

Haldar, S.K.

doi:10.1016/b978-0-12-820585-3.00001-6

Cited by 13 publications

(17 citation statements)

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“…The chemical composition of the sample before leaching shows that except for main elements (Cu, Fe, and S), a slight amount of Ag, Pb, Zn, Ni, Mn, and C are present. The results also indicated a greater Fe and S content than would appear from the CuFeS2 stoichiometry (pure CuFeS2 should contain approximately 34.5% Cu, 30.5% Fe, and 35% S [19]). This fact can be explained by the phase analysis results indicating that magnetite (Fe3O4) and pyrite (FeS2) (Figure 3a,b) are also present in the material.…”

Section: Resultsmentioning

confidence: 86%

Chalcopyrite Leaching in the Presence of Isopropanol—The Kinetic and Mechanistic Studies

Michałek,

Pacławski,

Fitzner

2024

Materials

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Oxidative leaching, as a basic step of the hydrometallurgical process of pure copper production from chalcopyrite, is a slow process in which mineral acids with strong oxidants addition are usually used as a leaching medium. It was found experimentally that the copper leaching from chalcopyrite in the H2SO4–H2O2–H2O system, in the presence of isopropanol (IPA) and under other conditions (H2O2 concentration, rate of mixing and temperature), takes place with satisfactory rate and efficiency. To quantify how much the change of these crucial variables affects the rate of the process, experimentally obtained kinetic curves (conversion over time) were analyzed using a Shrinking Core Model (SCM). The determined values of the copper leaching rate constants (kobs) confirmed the positive influence of increasing IPA and H2O2 concentrations as well as the temperature on the kinetics and efficiency of the leaching. The kinetic studies were also supported by using X-ray diffraction (XRD), 57Fe Mössbauer spectroscopy, scanning electron microscopy (SEM), and adsorption measurements. The positive influence of IPA was explained by its stabilizing role for iron compounds (hematite , magnetite, and pyrite), which are catalysts during the Cu dissolution, as well as H2O2 protection from decomposition during free radical reactions. Finally, the optimal conditions for efficient leaching, the rate-limiting step as well as the mechanism suggestion of the copper dissolution, were given.

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Section: Resultsmentioning

confidence: 86%

Chalcopyrite Leaching in the Presence of Isopropanol—The Kinetic and Mechanistic Studies

Michałek,

Pacławski,

Fitzner

2024

Materials

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“…Nonetheless, the present study provides strong circumstantial evidence associating arsenic accumulation with the progression of the gallbladder carcinogenesis. Arsenic in the Gangetic plains of Bihar is also found in the form of arsenopyrite (FeAsS) 95 . It has very high affinity to bind with these two elements, hence it easily binds with endogenous sulfhydryl compounds including metallothioneins.…”

Section: Discussionmentioning

confidence: 99%

Arsenic causing gallbladder cancer disease in Bihar

Kumar

Ali

Raj

et al. 2023

Sci Rep

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In recent times Gallbladder cancer (GBC) incidences increased many folds in India and are being reported from arsenic hotspots identified in Bihar. The study aims to establish association between arsenic exposure and gallbladder carcinogenesis. In the present study, n = 200 were control volunteers and n = 152 confirmed gallbladder cancer cases. The studied GBC patient’s biological samples-gallbladder tissue, gallbladder stone, bile, blood and hair samples were collected for arsenic estimation. Moreover, n = 512 gallbladder cancer patients blood samples were also evaluated for the presence of arsenic to understand exposure level in the population. A significantly high arsenic concentration (p < 0.05) was detected in the blood samples with maximum concentration 389 µg/L in GBC cases in comparison to control. Similarly, in the gallbladder cancer patients, there was significantly high arsenic concentration observed in gallbladder tissue with highest concentration of 2166 µg/kg, in gallbladder stones 635 µg/kg, in bile samples 483 µg/L and in hair samples 6980 µg/kg respectively. Moreover, the n = 512 gallbladder cancer patient’s blood samples study revealed very significant arsenic concentration in the population of Bihar with maximum arsenic concentration as 746 µg/L. The raised arsenic concentration in the gallbladder cancer patients’ biological samples—gallbladder tissue, gallbladder stone, bile, blood, and hair samples was significantly very high in the arsenic exposed area. The study denotes that the gallbladder disease burden is very high in the arsenic exposed area of Bihar. The findings do provide a strong link between arsenic contamination and increased gallbladder carcinogenesis.

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“…According to the data from the existing research, similar results have been obtained because of the low intensity of clay contents. 36,37 3.3. FTIR Spectra.…”

Section: Xrd Spectramentioning

confidence: 99%

Investigation of the Temperature Dependence of the Chemical–Mechanical Properties of the Wufeng–Longmaxi Shale

Zhai

et al. 2022

ACS Omega

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Shale rocks have been widely investigated to evaluate the productivity of oil/gas. The high temperature generated by the explosive fracturing to stimulate the gas reservoir has a significant impact on the chemical−mechanical properties of shale rocks. Pioneering works have been carried out at temperatures below 500 °C, but little has been done to quantify the correlation between the chemical and mechanical properties of shale at temperatures above 500 °C. Therefore, an experimental study on the effect of temperature on the chemical−mechanical properties of shale rocks is presented in this paper. The temperatures used in our experiments are between 0 and 800 °C. Results indicate that there exist strong chemical reactions leading to a big reduction in the sample's weight and mechanical strength for a temperature over 500 °C. Thermogravimetric analysis data demonstrates that the weight of shale powders has little change below 400 °C and largely decreases after 600 °C. It shows that the chemical reaction rate corresponding to shale compositions varies with temperature. X-ray diffraction and Fourier transform infrared are integrated to quantify the occurrence of contained reactions including the decomposition of kerogen, carbonates, and quartz transition. This can provide a temperature range for all possible reactions. Changes in the compositional information of shale samples have been proven to significantly influence the mechanical properties. A 25% decrease in dynamic Young's modulus emerges as the temperature approaches 700 °C. As the brittle minerals, for instance, carbonates, decrease with temperature, a brittle-ductile transition happens in shale. This work provides very meaningful results different from that at low temperatures to help people better understand the effects of high temperatures in many fields, such as explosive fracturing and radioactive waste disposal.

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Minerals and rocks

Cited by 13 publications

References 0 publications

Chalcopyrite Leaching in the Presence of Isopropanol—The Kinetic and Mechanistic Studies

Chalcopyrite Leaching in the Presence of Isopropanol—The Kinetic and Mechanistic Studies

Arsenic causing gallbladder cancer disease in Bihar

Investigation of the Temperature Dependence of the Chemical–Mechanical Properties of the Wufeng–Longmaxi Shale

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