Preparation and thermal analysis of synthetic malachite CuCO3·Cu(OH)2

Tanaka, Haruhiko; Yamane, Masayuki

doi:10.1007/bf01979390

Cited by 25 publications

(20 citation statements)

References 11 publications

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“…Pushcharovskite was synthesized by a modified wet chemical procedure after Majzlan et al (2015), Guillemin (1956) and Toman (1978). All solutions were prepared with deionized water.…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic properties, crystal structure and phase relations of pushcharovskite [Cu(AsO3OH)(H2O) ⋅ 0.5H2O], geminite [Cu(AsO3OH)(H2O)] and liroconite [Cu2Al(AsO4)(OH)4 ⋅ 4H2&

et al. 2020

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Abstract. The phases pushcharovskite, geminite and liroconite were synthesized or acquired and characterized by powder X-ray diffraction, infrared spectroscopy, electron microprobe analysis, thermogravimetric analysis and optical emission spectrometry, as needed. Their thermodynamic properties were determined by a combination of acid-solution calorimetry and relaxation calorimetry, resulting in Gibbs free energies of formation (ΔfGo, all values in kilojoules per mole) of -1036.4±3.8 (pushcharovskite, Cu(AsO3OH)(H2O)⋅0.5H2O) and -926.7±3.2 (geminite, Cu(AsO3OH)(H2O)). For the natural liroconite (Cu2Al[(AsO4)0.83(PO4)0.17](OH)4⋅4H2O), ΔfGo=-2996.3±9.2 kJ mol−1. The estimated ΔfGo for the endmember Cu2Al(AsO4)(OH)4⋅4H2O is −2931.6 kJ mol−1. The crystal structure of liroconite was refined (R1=1.96 % for 962 reflections with I>3σ(I)) by single-crystal X-ray diffraction and the positions of H atoms, not known previously, were determined. Liroconite is a rare mineral, except for several localities, notably Wheal Gorland in England. Thermodynamic modelling showed that liroconite will be preferred over olivenite if the Al(III) concentration in the fluid reaches levels needed for saturation with X-ray amorphous Al(OH)3. We assume that such fluids are responsible for the liroconite formation during contemporaneous oxidation of primary Cu–As ores and pervasive kaolinization of the host peraluminous granites. pH had to be kept in mildly acidic (5–6), and the activities of dissolved silica were too low to form dioptase. The main stage with abundant liroconite formation was preceded by an acidic episode with scorodite and pharmacosiderite and followed by a late neutral to mildly basic episode with copper carbonates. Geminite and pushcharovskite, on the other hand, are minerals typical for very acidic solutions. At the studied site in Jáchymov (Czech Republic), extremely acidic water precipitates arsenolite; sulfate is removed by formation of gypsum. Geminite associates with other acidic minerals, such as slavkovite, yvonite and minerals of the lindackerite group. Pushcharovskite is metastable with respect to geminite and probably converts quickly to geminite under field conditions.

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“…Pushcharovskite was synthesized by a modified wet chemical procedure after Majzlan et al (2015), Guillemin (1956) and Toman (1978). All solutions were prepared with deionized water.…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic properties, crystal structure and phase relations of pushcharovskite [Cu(AsO3OH)(H2O) ⋅ 0.5H2O], geminite [Cu(AsO3OH)(H2O)] and liroconite [Cu2Al(AsO4)(OH)4 ⋅ 4H2&

et al. 2020

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“…e . the copper-to-carbonate concentration ratio is fixed at [CO 3 2− ]/[Cu 2+ ] = 1.0 29 . Accordingly, solutions were prepared by mixing stoichiometric amounts of fresh aqueous 15 mM copper acetate (Sigma Aldrich) and 15 mM ammonia carbonate (Alfa Aesar) solutions at room temperature, while continuously stirring the mixed solution 30 .…”

Section: Methodsmentioning

confidence: 99%

Cost-effective sol-gel synthesis of porous CuO nanoparticle aggregates with tunable specific surface area

Dörner

Cancellieri

Rheingans

et al. 2019

Sci Rep

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CuO nanoparticles (NPs) are applied in various key technologies, such as catalysis, energy conversion, printable electronics and nanojoining. In this study, an economic, green and easy-scalable sol-gel synthesis method was adopted to produce submicron-sized nanoporous CuO NP aggregates with a specific surface area > 18 m²/g. To this end, a copper-carbonate containing precursor was precipitated from a mixed solution of copper acetate and ammonia carbonate and subsequently calcinated at T ≥ 250 °C. The thus obtained CuO nanopowder is composed of weakly-bounded agglomerates, which are constituted of aggregated CuO NPs with a tunable size in the range of 100–140 nm. The CuO aggregates, in turn, are composed of equi-axed primary crystallites with a tunable crystallite size in the range of 20–40 nm. The size and shape of the primary CuO crystallites, as well as the nanoporosity of their fused CuO aggregates, can be tuned by controlled variation of the degree of supersaturation of the solution via the pH and the carbonate concentration. The synthesized submicron-sized CuO aggregates can be more easily and safely processed in the form of a solution, dispersion or paste than individual NPs, while still offering the same enhanced reactivity due to their nanoporous architecture.

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“…Numerous papers ,,,,− have described the batch (integral in pH) precipitation of copper(II) and zinc(II) salts to form colloidal precipitates, which, together with those of magnesium(II), are our present concern. These are largely amorphous, and upon aging, especially at higher temperature (Ostwald ripening), broadened XRD lines appear , that have been assigned to the patterns of hydrozincite, malachite, etc.…”

Section: Resultsmentioning

confidence: 99%

Fast Diffusion Reaction in the Composition and Morphology of Coprecipitated Carbonates and Nitrates of Copper(II), Magnesium(II), and Zinc(II)

Davidson

Sefiane

Wood

2015

Ind. Eng. Chem. Res.

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The role of membrane formation, diffusion, and segregated reaction in determining the composition and morphology of copper, magnesium, and zinc carbonate and nitrate precipitates has been investigated. Photography of the coalescence of drops of divalent nitrate solutions into a shallow pool of sodium carbonate, at millisecond intervals, shows the formation of lamellae of fixed diameter comprised of a network of membranes separating the solutions. Segregated reaction within a lamella yields basic nitrates internally and mainly basic carbonates externally. On the macroscopic scale, with stirring, the precipitates are gels and, as precipitated, have been investigated by chemical analysis, IR spectroscopy, and microscopy through narrow pH ranges. Such gels are complexes of water, sodium carbonate, and metal basic carbonates corresponding to typical alkali complex carbonates, Na m M(CO 3 ) (n+0.5m) (OH) (2−2n) (m and n are the ratios of sodium and carbonate ions with respect to divalent cations), together with basic nitrates. Hydrolysis during washing changes the composition and yields basic carbonates having low values of n as reported hitherto.

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Preparation and thermal analysis of synthetic malachite CuCO3·Cu(OH)2

Cited by 25 publications

References 11 publications

Thermodynamic properties, crystal structure and phase relations of pushcharovskite [Cu(AsO<sub>3</sub>OH)(H<sub>2</sub>O) ⋅ 0.5H<sub>2</sub>O], geminite [Cu(AsO<sub>3</sub>OH)(H<sub>2</sub>O)] and liroconite [Cu<sub>2</sub>Al(AsO<sub>4</sub>)(OH)<sub>4</sub> ⋅ 4H<sub>2&

Thermodynamic properties, crystal structure and phase relations of pushcharovskite [Cu(AsO<sub>3</sub>OH)(H<sub>2</sub>O) ⋅ 0.5H<sub>2</sub>O], geminite [Cu(AsO<sub>3</sub>OH)(H<sub>2</sub>O)] and liroconite [Cu<sub>2</sub>Al(AsO<sub>4</sub>)(OH)<sub>4</sub> ⋅ 4H<sub>2&

Cost-effective sol-gel synthesis of porous CuO nanoparticle aggregates with tunable specific surface area

Fast Diffusion Reaction in the Composition and Morphology of Coprecipitated Carbonates and Nitrates of Copper(II), Magnesium(II), and Zinc(II)

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