Tiberiobardiite, Cu9Al(SiO3OH)2(OH)12(H2O)6(SO4)1.5·10H2O, a new mineral related to chalcophyllite from the cretaio Cu prospect, massa marittima, grosseto (Tuscany, Italy): Occurrence and crystal structure

The new mineral species tiberiobardiite, ideally Cu9Al(SiO3OH)2(OH)12(H2O)6(SO4)1.5·10H2O, has been discovered in the Cretaio Cu prospect, Massa Marittima, Grosseto, Tuscany, Italy, as very rare, light green, vitreous, tabular 0001, pseudo-hexagonal crystals, up to 200 µm in size and 5 µm in thickness, associated with brochantite. Electron microprobe analysis gave (in wt %, average of 5 spot analyses): SO3 10.37, P2O5 3.41, As2O5 0.05, SiO2 8.13, Al2O3 5.54, Fe2O3 0.74, CuO 62.05, and ZnO 0.03, for a total of 90.32. Based on an idealized O content of 42 atoms per formula unit, assuming the presence of 16 H2O groups and 13.5 cations (without H), the empirical formula of tiberiobardiite is (Cu8.69Al0.21Fe0.10)Σ9.00Al1.00(Si1.51P0.54)Σ2.05S1.44O12.53(OH)13.47·16H2O. The main diffraction lines, corresponding to multiple hkl indices, are [d in Å (relative visual intensity)]: 9.4 (s), 4.67 (s), 2.576 (m), 2.330 (m), and 2.041 (mw). The crystal structure study revealed tiberiobardiite to be trigonal, space group R 3, with unit-cell parameters a = 10.6860(4), c = 28.3239(10) Å, V = 2801.0(2) Å3, and Z = 3. The crystal structure was refined to a final R1 = 0.060 for 1747 reflections with Fo > 4σ (Fo) and 99 refined parameters. Tiberiobardiite is the Si-analogue of chalcophyllite, with Si4+ replacing As5+ through the coupled substitution As5+ + O2− = Si4+ + (OH)−. The name tiberiobardiite honors Tiberio Bardi (b. 1960) for his contribution to the study of the mineralogy of Tuscany

Crystal-chemistry of sulfates from apuan alps (Tuscany, Italy). i. Crystal structure and hydrogen bond system of melanterite, Fe(H2O)6(SO4)·H2O

Melanterite, ideally Fe(H2O)6SO4·H2O, from the pyrite+iron oxide ore deposit of Fornovolasco (Apuan Alps, Tuscany, Italy) has been fully characterized through electron microprobe analysis, micro-Raman spectroscopy, and X-ray diffraction. Melanterite occurs as cm-sized greenish fibrous efflorescences on pyrite or rare pseudo-octahedral colorless crystals, up to 5 mm in size. Electron microprobe analysis (in wt% - average of ten spot analyses normalized to 100 wt% without H2O) gave: SO3 52.98, FeO 45.53, MgO 1.49, sum 100.00. Assuming the occurrence of 7 H2O groups per formula unit, the chemical formula can be written as (Fe0.95Mg0.06)Σ1.01(SO4)·7H2O. The Raman spectrum of melanterite is characterized by bending and stretching modes of (SO4) and H2O groups. Melanterite crystallizes in the space group P21/c, with unit-cell parameters a=14.0751(8), b=6.5014(4), c=11.0426(6) Å, β=105.632(3)°, V=973.11(10) Å3, Z=4. The crystal structure of melanterite refined to R1 = 0.024 on the basis of 3457 unique reflections with Fo>4σ(Fo) and 179 refined parameters. It can be described as formed by undulating layers showing the alternation, along a, of SO4 groups and Fe-centered octahedra coordinated by H2O groups. The occurrence of a complex hydrogen bond system plays a fundamental role in the crystal structure of melanterite

New data on metacinnabar from Tuscany (Italy)

New crystallographic data collected on samples of metacinnabar from the Levigliani mine (Apuan Alps), Niccioleta mine (Metalliferous Hills), and the Monte Amiata Hg ore district are reported. The study of the samples from Levigliani completes the characterization of this phase, integrating the data already available in literature. Its crystal structure has been refined on the basis of single-crystal X-ray diffraction data, achieving a R1 factor = 0.044 on the basis of 43 reflections with Fo > 4σ(Fo). The crystal structure refinement confirms the substitution of Hg by Zn and Fe as well as the contraction of the unit-cell parameter [a = 5.7966(8) Å]. Samples from southern Tuscany do not show any significant chemical substitution. Metacinnabar from the Niccioleta mine was identified on the basis of X-ray powder diffraction only, due to the microcrystalline nature of the available material. The unit-cell parameter was refined on the basis of powder data [a = 5.859(1) Å]. Samples from the Monte Amiata Hg ore district were collected in the Bagnore and Pietrineri mines. Their unit-cell parameters, refined on the basis of single-crystal X-ray diffraction data, are a = 5.8358(14) Å (Bagnore) and 5.8355(5) Å (Pietrineri). The refinement of the crystal structures of samples from Bagnore and Pietrineri converged to R1 = 0.037 and 0.026, respectively. The occurrence of metacinnabar in the ore deposits from Tuscany can be interpreted as an evidence for relatively high temperatures (> 315°C) locally attained during Hg ore formation

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO4)F(H2O)5

AbstractKhademite, ideally Al(SO4)F(H2O)5, from the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy, has been characterised through quantitative electron microprobe analysis, micro-Raman spectroscopy and single-crystal X-ray diffraction. Khademite occurs as colourless to whitish tabular crystals, up to 5 mm. Electron microprobe analysis (in wt.%, average of 20 spot analyses) gave: SO3 35.43, Al2O3 21.27, F 6.92, H2Ocalc 39.73, sum 103.35, –O = F 2.92, total 100.43. On the basis of 10 anions per formula unit, assuming the occurrence of 5 H2O groups and 1 (F+OH) atom per formula unit, its chemical formula can be written as Al0.96S1.02O4[F0.84(OH)0.16]Σ1.00⋅5H2O. The Raman spectrum of khademite is characterised by the occurrence of vibrational modes of SO4 groups and by broad and strong bands due to the O–H stretching modes. Khademite is orthorhombic, space group Pcab, with unit-cell parameters a = 11.1713(2), b = 13.0432(3), c = 10.8815(2) Å, V = 1585.54(5) Å3 and Z = 8. The crystal structure refinement converged to R1 = 0.0293 on the basis of 2359 unique reflections with Fo > 4σ(Fo) and 152 refined parameters. The crystal structure of khademite is characterised by the alternation, along b, of two distinct kinds of {010} layers, one formed by [001] rows of isolated Al-centred octahedra, connected to each other through H bonds, and the other showing isolated SO4 groups. Along b, oxygen atoms belonging to SO4 groups act as acceptor of H bonds from H2O groups coordinating Al atoms. The new data improved the description of the H bonds in khademite and led us to discuss about the possible existence of its (OH)-analogue, rostite. In addition, Raman spectroscopic data were collected on the same crystal used for the crystal-chemical characterisation, allowing a comparison with previous results

The crystal structure of svabite, Ca5(AsO4)3F, an arsenate member of the apatite supergroup

The crystal structure of svabite, ideally Ca5(AsO4)3F, was studied using a specimen from the Jakobsberg mine, Värmland, Sweden, by means of single-crystal X-ray diffraction data. The structure was refined to R1 = 0.032 on the basis of 928 unique reflections with Fo > 4σ(Fo) in the P63/m space group, with unit-cell parameters a = 9.7268(5), c = 6.9820(4) Å, V = 572.07(5) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%, average of 10 spot analyses): SO3 0.49, P2O5 0.21, V2O5 0.04, As2O5 51.21, SiO2 0.19, CaO 39.31, MnO 0.48, SrO 0.03, PbO 5.19, Na2O 0.13, F 2.12, Cl 0.08, H2Ocalc 0.33, O (= F+Cl) -0.91, total 98.90. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.66Pb0.16Mn0.04Na0.03)Σ4.89(As2.96S0.04Si0.02P0.02)Σ3.04O12 [F0.74(OH)0.24Cl0.01]. Svabite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. The crystal structure of synthetic Ca5(AsO4)3F was previously reported as triclinic. On the contrary, the present refinement of the crystal structure of svabite shows no deviations from the hexagonal symmetry. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas

‘Hartite’ renamed branchite

Historical samples of branchite, described by the Tuscan naturalist Paolo Savi (1798–1871) at the end of the 1830s, were re-examined through single-crystal X-ray diffraction, showing their identity with hartite, C20H34, a hydrocarbon mineral described by Haidinger in 1841. The refined unit-cell parameters are a = 11.4116(7), b = 20.9688(12), c = 7.4100(4) Å, α = 93.947(2), β = 100.734(2), γ = 80.524(2)°, V = 1716.99(17) Å3 and Z = 4; space group P1. The crystal structure was solved and refined up to R1 = 0.0424 for 13512 reflections with Fo > 4σ(Fo) and 1265 refined parameters. As the name ‘branchite’ has priority over ‘hartite’, the reinstatement of the former name and the discreditation of the latter were approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA–CNMNC). Branchite is one of only eleven minerals formed by C and H listed in the official IMA List of Minerals. The type locality of branchite is the Botro di Lavajano, Monte Vaso, Chianni, Pisa, Tuscany, Italy. Neotype material is kept in the Natural History Museum of the Pisa University under catalogue number 14426

Tetrahedrite-(Hg), a new 'old' member of the tetrahedrite group

AbstractTetrahedrite-(Hg), Cu6(Cu4Hg2)Sb4S13, has been approved as a new mineral species using samples from Buca della Vena mine (hereafter BdV), Italy, Jedová hora (Jh), Czech Republic and Rožňava (R), Slovakia. It occurs as anhedral grains or as tetrahedral crystals, black in colour, with metallic lustre. At BdV it is associated with cinnabar and chalcostibite in dolomite veins. At Jh, tetrahedrite-(Hg) is associated with baryte and chalcopyrite in quartz–siderite–dolomite veins; at R it is associated with quartz in siderite–quartz veins. Tetrahedrite-(Hg) is isotropic, greyish-white in colour, with creamy tints. Minimum and maximum reflectance data for Commission on Ore Mineralogy wavelengths in air (BdV sample), R in %) are 32.5 at 420 nm; 32.9 at 546 nm; 33.2 at 589 nm; and 30.9 at 650 nm. Chemical formulae of the samples studied, recalculated on the basis of 4 (As + Sb + Bi) atoms per formula unit, are: (Cu9.44Ag0.07)Σ9.51(Hg1.64Zn0.36Fe0.06)Σ2.06Sb4(S12.69Se0.01)Σ12.70 (BdV), Cu9.69(Hg1.75Fe0.25Zn0.06)Σ2.06(Sb3.94As0.06)S12.87 (Jh) and (Cu9.76Ag0.04) Σ9.80(Hg1.83Fe0.15Zn0.10)Σ2.08(Sb3.17As0.58Bi0.25)S13.01 (R). Tetrahedrite-(Hg) is cubic, I$\overline 4$3m, with a = 10.5057(8) Å, V = 1159.5(3) Å3 and Z = 2 (BdV). Unit-cell parameters for the other two samples are a = 10.4939(1) Å and V = 1155.61(5) Å3 (Jh) and a = 10.4725(1) Å and V = 1148.55(6) Å3 (R). The crystal structure of tetrahedrite-(Hg) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.019 on the basis of 335 reflections with Fo > 4σ(Fo) and 20 refined parameters. Tetrahedrite-(Hg) is isotypic with other members of the tetrahedrite group. Mercury is hosted at the tetrahedrally coordinated M(1) site, along with minor Zn and Fe. The occurrence of Hg at this position agrees both with the relatively large M(1)–S(1) bond distance (2.393 Å) and the refined site scattering. Previous occurrences of Hg-rich tetrahedrite and tetrahedrite-(Hg) are reviewed, and its relations with other Hg sulfosalts are discussed

Comparison of Genetic and Reinforcement Learning Algorithms for Energy Cogeneration Optimization

Large process plants generally require energy in different forms: mechanical, electrical, or thermal (in the form of steam or hot water). A commonly used source of energy is cogeneration, also defined as Combined Heat and Power (CHP). Cogeneration can offer substantial economic as well as energy savings; however, its real-time operation scheduling is still a challenge today. Multiple algorithms have been proposed for the CHP control problem in the literature, such as genetic algorithms (GAs), particle swarm optimization algorithms, artificial neural networks, fuzzy decision making systems and, most recently, reinforcement learning (RL) algorithms.This paper presents the comparison of a RL approach and a GA for the control of a cogenerator, using as a case study a thermal power plant serving a factory during the year 2021. The two methods were compared based on an earnings before interest, taxes, depreciation, and amortization (EBITDA) metric. The EBITDA that could be obtained using the RL algorithm, exceeds both the EBITDA that could be generated using a per-week genetic algorithm and the one from the manual scheduling of the CHP. Thus, the RL algorithm proves to be the most cost-effective strategy for the control of a CHP

Manganiakasakaite-(La) and Ferriakasakaite-(Ce), Two New Epidote Supergroup Minerals from Piedmont, Italy

Two new monoclinic (P21/m) epidote supergroup minerals manganiakasakaite-(La) and ferriakasakaite-(Ce) were found in the small Mn ore deposit of Monte Maniglia, Bellino, Varaita Valley, Cuneo Province, Piedmont, Italy. Manganiakasakaite-(La) occurs as subhedral grains embedded in pyroxmangite. Its empirical formula is A(1)(Ca0.62Mn2+0.38) A(2)(La0.52Nd0.08Pr0.07Ce0.07Y0.01Ca0.25) M(1)(Mn3+0.52Fe3+0.28Al0.18V3+0.01) M(2)Al1.00 M(3)(Mn2+0.60Mn3+0.27Mg0.13) T(1−3)(Si2.99Al0.01) O12 (OH), corresponding to the end-member formula CaLaMn3+AlMn2+(Si2O7)(SiO4)O(OH). Unit-cell parameters are a = 8.9057(10), b = 5.7294(6), c = 10.1134(11) Å, β = 113.713(5)°, V = 472.46(9) Å3, Z = 2. The crystal structure of manganiakasakaite-(La) was refined to a final R1 = 0.0262 for 2119 reflections with Fo > 4σ(Fo) and 125 refined parameters. Ferriakasakaite-(Ce) occurs as small homogeneous domains within strongly inhomogeneous prismatic crystals, where other epidote supergroup minerals coexist [manganiandrosite-(Ce), “androsite-(Ce)”, and epidote]. Associated minerals are calcite and hematite. Its empirical formula is A(1)(Ca0.64Mn2+0.36) A(2)(Ce0.37La0.17Nd0.06Pr0.03Ca0.35□0.02) M(1)(Fe3+0.61Al0.39) M(2)Al1.00 M(3)(Mn2+0.64Mn3+0.33Fe3+0.02Mg0.01) T(1−3)Si3.01 O12 (OH), the end-member formula being CaCeFe3+AlMn2+(Si2O7)(SiO4)O(OH). Unit-cell parameters are a = 8.9033(3), b = 5.7066(2), c = 10.1363(3) Å, β = 114.222(2)°, V = 469.66(3) Å3, Z = 2. The crystal structure of ferriakasakaite-(Ce) was refined to a final R1 = 0.0196 for 1960 unique reflections with Fo > 4σ(Fo) and 124 refined parameters