scholarly journals Influence of Temperature on the Formation of Ag Complexed in S2O32--O2 System

Author(s):  
Aislinn M. Teja-Ruiz ◽  
Julio C. Juárez-Tapia ◽  
Leticia E. Hernández-Cruz ◽  
Martín Reyes-Pérez ◽  
Francisco Patiño-Cardona ◽  
...  

Metallic elements of higher economic value occurring in the mineralogy of Zimapán are Pb, Zn, Cu and Fe, said elements are sold as concentrates, which, even after processing, generally include significant concentrations of Mo, Cd, Sb, Ag and As that could recover through different leaching methods. In this work the influence of temperature was studied in the complexation of silver in the S2O32--O2 system. Chemical and mineralogical characterization of concentrated Zn from the state of Hidalgo confirmed the presence of the silver contained in a sulfide of silver arsenic (AgAsS2) through the techniques of Atomic Absorption Spectrophotometry (AAS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). The mineralogical species identified allowed the construction mineralogical species Pourbaix diagrams in the range of 298 K to 333 K, through which the Eh-pH conditions to obtain silver in solution were determined. The formation of Ag(S2O3)23- complex was confirmed by characterizing liquors leached using the technique Infrared Spectroscopy Fourier Transform (FTIR).

2015 ◽  
Vol 820 ◽  
pp. 13-17
Author(s):  
Neila Gondim Azeredo ◽  
Euzébio Barnabé Zanelato ◽  
Jonas Alexandre ◽  
Afonso Rangel Garcez de Azevedo ◽  
Gustavo de Castro Xavier ◽  
...  

The physical, chemical and mineralogical characterization of a precursor clay body before firing is of relevance for understanding the technological performance of the fired clay ceramic. In particular, structural clay ceramic blocks used in building construction need to attend standard properties specified by the norms. In the present work the precursor clay body, typically used to fabricate structural blocks in Campos dos Goytacazes, state of Rio de Janeiro, Brazil, was characterized in terms of particle size distribution, X-ray diffraction, chemical composition and Atterberg limits. In addition, the performance of structural ceramic blocks, fabricated from the extruded clay body and fired at 850oC, was evaluated. The results indicated that the ceramic mechanical strength complies with the Brazilian norm but the water absorption is higher than the maximum specified by the norm. The characteristic of the clay body contribute to justify the structural blocks performance.


Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 311 ◽  
Author(s):  
Graciela Ponce-Antón ◽  
Maria Cruz Zuluaga ◽  
Luis Angel Ortega ◽  
Juantxo Agirre Mauleon

Mortars from the cistern in Amaiur Castle (Navarre, Spain) were analysed to assess the mortar manufacturing process and application techniques. To this end, optical microscopy, scanning electron microscopy (SEM), thermogravimetric analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman microspectroscopy, and Fourier transform infrared spectroscopy (FTIR) were performed. The study of both structural and plaster mortars from Amaiur Castle cistern show patterns/rules in the mortar manufacture according to the specific construction requirements. A multilayer application technique was used for the construction of the cistern tank. Deliberate selection of the aggregate nature and grading contributed to mortar impermeability. Ceramic and silico-aluminous rock fragments were used as aggregates in the cistern tank to confer hydraulicity to the mortars, instead of carbonated aggregates as used in the vault. Aluminosilicated phases present in the aggregates led to the formation of amesite, which is a magnesium aluminosilicate hydrate (M-A-S-H) phase conferring hydraulicity to the mortar. Two types of additives were identified in the outer pigmented layer of plaster. Beeswax was the identified organic additive used to improve the impermeability of mortar, while hematite was the identified inorganic additive giving rise to the reddish colour of the layer.


2015 ◽  
Vol 820 ◽  
pp. 56-59
Author(s):  
F.K.A. Sousa ◽  
I.A. Silva ◽  
W.S. Cavalcanti ◽  
Gelmires Araújo Neves ◽  
Heber Carlos Ferreira

Used in various branches of the industry, bentonitic clays are considered a valuable mineral, used specially in the petroleum industry for manufacturing of fluids used the drilling of petroleum wells in long depth. Recently, a deposit of this valuable mineral was discovered in the town of Olivedos-PB. There are data that prove that this is a very poor and underdeveloped town. So, this work aims at the physico-mineralogical characterization of clays recently discovered and, this way, verify if they present similar characteristics which allow them to replace the clays from Boa Vista-PB, and if they can be used by the industry, thus bringing social development for that town. The characterization was made by means of the analysis of chemical composition by X-ray fluorescence (EDX), thermogravimetric and thermal differential analyses (TG and DTA), X-ray diffraction (XRD), cation-exchange capacity (CEC) and specific area (SA). The results show that the clays recently discovered in Olivedos-PB are polycationic clays, presenting MgO, CaO and K2O content, and that they are constituted by smectitic clay mineral, by quartz and kaolinite.


Mining Revue ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 78-82
Author(s):  
Nurudeen Salahudeen ◽  
Aminat Oluwafisayo Abodunrin

Abstract Local clay mineral was mined from Okpella Town, Etsako Local Government Area of Edo State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer and the pH analysis of the clay was carried out using pH meter. The mineralogical analysis revealed that the clay was majorly a dolomite mineral having 72% dolomite. The impurities present are 18% cristobalite, 4.1% garnet, 5% calcite and 1% quicklime. The pH analysis of the clay revealed that the clay was acidic having average pH value of 3.9. The pH determined for the 1:1, 1:2, 1:4, 1:8 and 1:10 samples were 3.61, 3.85, 3.85, 4.05 and 4.09, respectively.


2007 ◽  
Vol 50 (2) ◽  
pp. 169-181 ◽  
Author(s):  
Ana Christina Duarte Pires ◽  
Vander de Freitas Melo ◽  
Valmiqui Costa Lima ◽  
Antônio Carlos Vargas Motta

The aim of this work was to evaluate the mineralogical and chemical characteristics of most representative soils of the Region of Curitiba, Paraná State. Samples were collected at different depths. The results showed: (a) the quartz was the only identified mineral at the silt and sand fractions. The dominant clay mineral was Kaolinite, with contents ranging from 676.7 to 820.8 g kg-1. The gibbsite was also an important constituent of the most weathered horizons and the hematite and goethite contents were low, mainly in the Histosol; (b) at the C horizon of the Inceptisol, high intensity of vermiculite/smectite reflections were detected (X-ray diffraction), justifying the high capacity of expansion and contraction, normally showed for this soil horizon; (c) was observed a good relation between pedogenetic degree and crystallographic mineral characteristics.


2019 ◽  
Vol 9 (20) ◽  
pp. 4422 ◽  
Author(s):  
Jianjun Hu ◽  
Chuan He ◽  
Xian Yang ◽  
Hui Li ◽  
Hongbin Xu ◽  
...  

The FeS solid lubricating coatings were prepared on the AISI 5140 steel by chemical bath deposition (CBD) coating technique at various temperatures from 30 to 90 °C. The influence of temperature on microstructure, microcracks, and tribological properties was characterized and studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometry (EDS). The results show that the coating mainly consists of FexSy (FeS, FeS2, and Fe1−xS), and has a chrysanthemum-shaped (CS) morphology composed of the FeS crystal petals. The CS particles nucleate at about 30 °C, rapidly grow and reach a peak thickness at about 50–70 °C, and finally disappear and are replaced by disordered thick petals at 90 °C. The wear resistance of the steel was improved obviously after introducing of FeS coatings, owing to that the coatings can provide better lubrication and improve the wear resistance.


2020 ◽  
Vol 74 (10) ◽  
pp. 1280-1286
Author(s):  
Lucas Train Loureço ◽  
Celso de Araujo Duarte ◽  
Dietmar William Foryta ◽  
Bruno Guimarães Titon ◽  
Eleonora Maria Gouvêa Vasconcellos

The present work reports the results of structural and optical investigations in samples of natural dolomite, subjected to thermal treatment at different temperatures (500 ℃ to 700 ℃) and times (one up to three hours). The motivation is the evaluation of the changes that may occur in carbonaceous asteroids and meteorites, respectively, subjected to the action of the solar radiation and heated during the fall in the atmosphere. We carried out scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, optical reflectance and photoluminescence measurements


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