Browsing by Subject "strontium"

Now showing 1 - 3 of 3

Access status: Open Access ,
Metallurgical processing of Al-Si alloys with increased iron content using sodium, strontium, and tellurium
(AGH University of Science and Technology Press, 2018) Pokusová, Marcela; Berta, Igor; Murgašová, Marta
This paper presents the results of research focused on the processing of the hypoeutectic Al-Si alloy with an increased iron content of 1.75 wt.%. The physical-metallurgical method was used to eliminate the undesirable effect of the iron rich b-phase on the mechanical properties of the casting material using liquid metal modification by strontium, sodium, and tellurium. The chemical composition of an experimental material didn't contain any elements for the solid-solution strengthening of a matrix, therefore, the presented results can document the capabilities of modifying the ?-phase under a minimum influence on the properties of the basic Al-Si system.
Access status: Restricted ,
Mineralogical characteristic of the Czarkowy sulphur deposit
(Data obrony: 2016-09-28) Nowicka, Małgorzata
Wydział Geologii, Geofizyki i Ochrony Środowiska
The Czarkowy sulphur deposit located in the northern part of Polish Carpathian Foredeep is aged Badenian. Sediments originated in the evaporite basin contain mainly carbonates with gypsum , native sulphur and significant amount of strontium within the sulphur-bearing ore. High concentration of strontium in the Czarkowy sulphur deposit could be associated with epigenetic enrichment, related with change of chemical conditions in the coastal marginal zones of Badenian basin. Presence of geochemical barrier in the mixing zone between aquifers and saline brines allowed for precipitation of strontium minerals. Euhedral well-developed bipyramidal crystals of strontium sulphates are found in cavities and pores of limestones with gypsum. Moreover, study of heavy and secondary minerals shows that celestine crystals occur in the overburden of the deposit as well.
Access status: Open Access ,
New data on celestine-rich salts in the Wieliczka salt deposits
(Wydawnictwa AGH, 2017) Nowińska, Justyna
Pale brownish celestine-rich salt rocks were found near the Franciuszek Müller gallery, in the chambers of the 3rd level in the Wieliczka Salt Mine. The complex of rock salts subjected to exploration occurred within a large seam approximately 15 m thick. Detailed research revealed that the salt has the form of a block incorporated within the gray salts body and being similar to other blocks of green salts, well known in the upper part of the deposit. A characteristic petrographical feature of the pale brown rock salt owed to the presence of celestine ($SrSO_{4}$). That strontium mineral was re-examined, using X-ray powder data, and scanning microscope observations, with EDS analysis. The investigated rock salts exhibited a mineral association of halite (main component), anhydrite, celestine, calcite, gypsum, clay materials, iron compounds and a small amount of bitumen. Interrigenous sediments and the insoluble part of salt occurred higher content of strontium that in halite. Celestine crystals were observed in two forms: elongated platy crystals, forming fan-shaped aggregates and granular aggregates, strongly associated with anhydrite. On carbonate and sulphate strontium usually appearing as needle shaped aggregates of celestine. No barium minerals were observed. The development and paragenesis of celestine suggested a post-sedimentary origin of these rocks that ought to be connected with diagenetic processes. An important observation that confirmed that thesis was the transformation of fine crystalline anhydrite into platy crystals, recrystallization and primary accumulation of strontium, as a result of evaporation processes.