Rare earth metals including yttrium and europium are one of several critical raw materials, the use of which ensures the development of the so-called high technology. The possibility of their recovery in Europe is limited practically only to secondary materials such as phosphogypsum and electronic waste.
The article presents the results of our research concerning the development of recovery technology of yttrium and europium from luminophore CRT used lamps. It describes the principle of separation of elements and the test results of cleaning the concentrate. It was shown that the costs of preparing the concentrate according to the proposed technology are lower than the phosphogypsum processing technology and the composition of the resulting product does not contain hazardous substances.
Using methods of physical material studies (scanning electron microscopy and micro X-ray spectral analysis), a study was carried out with focus on alteration of structure and phase composition in surface layers of Al-Si alloy (silumin АК10М2N) treated in electroexplosive alloying with a multiphase plasma jet formed in the process of aluminum foil explosion and carrying particles of Y2O3 weighted powder portion. It was revealed that a porous surface layer with non-homogeneously distributed alloying elements (silicon, yttrium) in it is formed in any conditions of electroexplosive alloying of silumin. Thickness of the modified layer is different, varying 50 to 160 µm, depending on the zone to be examined. The modified surface consists basically of Al, Si and Y. Yttrium in the modified layer is thought to be an indirect evidence of better physical and mechanical properties of the surface layer in comparison with the base material.
The Neogene basaltoid intrusions found in the S-7 borehole in the Sumina area (USCB) caused transformations of the adjacent Carboniferous rocks. The mineral and chemical compositions of the basaltoides are similar to those of the Lower Silesian basaltoides. The transformations that took place in the vicinity of the intrusion were manifested in the formation of natural coke, the secondary mineralization of these rocks (calcite, chlorite, zeolites and barite) and in the specific distribution of rare earths (REY). Among REY, the light elements (LREY) had the highest share, while the heavy elements (HREY) had the lowest share. Regardless of the lithological type of the analyzed rock, with increasing distance from the intrusion, the percentage of MREY and HREY elements increases at the expense of the light elements LREY. All analyzed distribution patterns of the REYs are characterized by the occurrence of anomalies, which often show a significant correlation with the distance of sampling points from the basaltoid intrusion. The specific distribution of REYs in the vicinity of the intrusion of igneous rocks is an indication of the impact of hydrothermal solutions associated with the presence of basaltoides on the rocks closest to them located at a temperature of over 200°C.
This paper presents results of a study of the effect of inoculation of yttrium on the microstructure of AZ91 alloy. The concentration of the inoculant was increased in samples in the range from 0.1% up to 0.6%. The influence of Y on the thermal effects resulting from the phase transformations occurring during the crystallisation at different inoculant concentrations were examined with the use of Derivative and Thermal Analysis (DTA). The microstructures of the samples were examined with the use of an optical microscope; and an image analysis with a statistical analysis were also carried out. Those analyses aimed at examining oh the effect of inoculation of the Y on the differences between the grain diameters of phase αMg and eutectic αMg + γ(Mg17Al12) in the prepared examined material as well as the average size of each type of grain by way of measuring their perimeters.
In this work, we developed the lanthanum strontium cobalt ferrite and it’s composite with yttrium iron cobaltite (mass ratio of 1:1) cathodes as a thin layer on Ce0.8Sm0.2O1.9 electrolyte. Two kinds of electrode pastes were prepared, with and without 6 mm polystyrene beads as an additional pore former. The performance of cathode materials was investigated by electrochemical impedance spectroscopy as a function of electrode morphology, oxygen partial pressure, potential, and temperature. The polarization resistance of the more porous electrodes was lower than those electrodes prepared without additional pore former in the whole potential range at 800°C, slightly lower at 700°C and 600°C. The addition of yttrium iron cobaltite decreased the performance of both types of cathodes. The lower polarization resistance of porous cathodes is due to the facilitated gas diffusion through their structure.
Potential sources of rare earth elements are sought after in the world by many researchers. Coal
ash obtained at high temperatures (HTA ) is considered among these sources.
The aim of the study was an evaluation of the suitability of the high temperature ash (HTA ) formed
during the combustion of bituminous coal from the Ruda beds of the Pniówek coal mine as an
potential resource of REY . The 13 samples of HTA obtained from the combustion of metabituminous
(B) coal were analyzed.
The analyses showed that the examined HTA samples varied in their chemical composition.
In accordance with the chemical classification of HTA , the analyzed ash samples were classified
as belonging to the following types: sialic, sialocalcic, sialoferricalcic, calsialic, fericalsialic,
ferisialic.
The research has shown that the rare earth elements content (REY ) in examined HTA samples
are characterized by high variability. The average REY content in the analyzed ashes was 2.5 times
higher than the world average (404 ppm).
Among rare earth elements, the light elements (LREY ) were the most abundant. Heavy elements
(HREY ) had the lowest share.
A comparison of the content of the individual rare earth elements in HTA samples and in UCC
showed that it was almost 20 times higher than in UCC.
The distribution patterns of REY plotted for all samples within their entire range were positioned
above the reference level and these curves were of the M-H or M-L type. The data presented indicate, that the analyzed ash samples should be regarded as promising REY
raw materials. Considering the fact that in 7 out of 13 analyzed ash samples the REY content was
higher than 800 ppm, REY recovery from these ashes may prove to be economic.