The results of some mechanical properties of four Mg-5Al-xRE-0.4Mn (x = 1 – 5) alloys are presented. The microstructure of

experimental alloys consisted of an α-Mg phase and an α+γ semi-divorced eutectic, Al11RE3 phase and an Al10RE2Mn7 intermetallic

compound. For gravity casting in metal mould alloys, Brinell hardness, impact strength, tensile and compression properties at ambient

temperature were determined. The performed mechanical tests allowed the author to determine the proportional influence of the mass

fraction of rare earth elements in the alloys on their tensile strength, yield strength, compression strength and Brinell hardness. The

impact strength of the alloys slightly decreases with a rise in the rare earth elements mass fraction.

Magnesium alloy with 5 wt% Al, 0.35 wt% Mn and 5 wt% rare earth elements (RE) was prepared and gravity cast into a sand mould.

Microstructure investigations were conducted. Analyses of the Mg-Al-RE alloy microstructure were carried out by light microscopy,

scanning electron microscopy and the XRD technique. In the as-cast condition, the alloy was composed of α-Mg, Al11RE3 and

Al10RE2Mn7 intermetallic phases. Additionally, due to non-equilibrium solidification conditions, an Al2RE intermetallic phase was

revealed.

The modification of the chemical composition of non-metallic inclusions by rare-earth elements in the new-developed microalloyed steels was discussed in the paper. The investigated steels are assigned to production of forged elements by thermomechanical treatment. The steels were melted in a vaccum induction furnace and modification of non-metallic inclusions was carried out by the michmetal in the amount of 2.0 g per 1 kg of steel. It was found that using material charge of high purity and a realization of metallurgical process in vacuous conditions result in a low concentration of sulfur (0.004%), phosphorus (from 0.006 to 0.008%) and oxygen (6 ppm). The high metallurgical purity is confirmed by a small fraction of non-metallic inclusions averaging 0.075%. A large majority of non-metallic inclusions are fine, globular oxide-sulfide or sulfide particles with a mean size 17 µm2 . The chemical composition and morphology of non-metallic inclusions was modified by Ce, La and Nd, what results a small deformability of nonmetallic inclusions during hot-working.

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.

Effects of additions of 0.00064, 0.001 and 0.0042 wt.% Bi on the graphite structure in the section thicknesses of 3, 12, 25, 38, 50, 75 and 100 mm of spheroidal graphite cast iron castings containing 2.11 wt.% Si and rare earth (RE) elements (Ce + La + Nd + Pr + Sm + Gd) in the range from 0.00297 to 0.00337 wt.% were analyzed in this paper. Addition of Bi was not necessary for obtaining high nodule count and nodularity higher than 80% in section thicknesses of 3, 12 and 25 mm. RE elements showed a beneficial effect on the nodule count and nodularity in these sections. Nodularity was below 80% in section thicknesses of 38, 50, 75 and 100 mm when Bi was not added. Detrimental effect of RE elements on graphite morphology in these sections was neutralized by adequate addition of Bi. Addition of 0.001 wt.% Bi (ratio of RE/Bi = 3.27) was enough to achieve nodularity above 80% in the section thickness of 38 mm. Nodularity was increased above 80% in section thicknesses of 50, 75 and 100 mm by addition of 0.0042 wt.% Bi (ratio of RE/Bi = 0.78). At the same time, Bi significantly increased the nodule count. Nodularity above 80% and the high nodule count in the section thicknesses of 75 and 100 mm were also achieved by using an external metallic chill in the mold. In this case, addition of Bi was not required.

The demand for REE was the background to include them to those consisting of the property of the State Treasury in Poland, enumerated in the Geological and Mining Law (Article 10). The PLN 500/kg REE payment for exploitation of REE (exploitation tax) was introduced. Both proposals will restrain the REE recovery from exploited domestic mineral commodities. The term REE is imprecise. Their deposits are rare and may be classified as “REE ore deposits”. The REE are often the accompanying constituents in varied mineral commodities and are recoverable during their processing, outside the mine. The application of an exploitation tax in such a case is inapplicable. The established value of the exploitation tax is incomparably high in respect to the value of the REE contained in mined mineral commodities. The analysis of introduced changes of mining and geological law allow to suggest the reevaluation of ownership based subdivision of mineral commodities: name the mineral commodities belonging to the land property owners and leave the list of mineral commodities consisting property of the State Treasury open. The more careful approach is also necessary in the formulation of Geological and Mining Law. It should be preliminary formulated by persons competent in geology and mining and subsequently adjusted to juridical exigencies.

Liquid metal extraction (LME) process results in 100% neodymium (Nd) extraction but the highest extraction efficiency reported for Dysprosium (Dy) so far is 74%. Oxidation of Dy is the major limiting factor for incomplete Dy extraction. In order to enhance the extraction efficiency and to further investigate the limiting factors for incomplete extraction, experiments were carried out on six different particle sizes of under 200 µm, 200-300 µm, 300-700 µm, 700-1000 µm, 1000-2000 µm and over 2000 µm at 900℃ with magnesium-to-magnet scrap ratio of 15:1 for 6, 24 and 48 hours, respectively. This research identified Dy2Fe17 in addition to Dy2O3 phase to be responsible for incomplete extraction. The relationship between Dy2Fe17 and Dy2O3 phase was investigated, and the overall extraction efficiency of Dy was enhanced to 97%.

The results of the Charpy impact test of AE-type magnesium alloys produced by the high pressure die casting method are presented. Three alloys with different weight fractions of rare earth elements (RE; e.g. 1, 3 and 5 wt%) and the same mass fraction of aluminium (5 wt%) were prepared. The casts were fabricated using a typical cold chamber high pressure die casting machine with a 3.8 MN locking force. Microstructural analyses were performed by means of a scanning electron microscope (SEM). The impact strength (IS) was determined using a Charpy V hammer with an impact energy equal to 150 J. The microstructure of the experimental alloys consisted of an -Mg solid solution and Al11RE3, Al10Ce2Mn7 and Al2RE intermetallic compounds. The obtained results show the significant influence of the rare earth elements to aluminium ratio on the impact strength of the investigated materials. Lower the RE/Al ratio in the chemical composition of the alloy results in a higher impact strength of the 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.