Distribution of rare earth elements in Ruska Poliana granites and accessory fluorites

Fluorite is one of the main concentrators of rare earth elements (REE) in the granites of the Ruska Polіana massif of the Korsun-Novomyrhorod pluton of the Ukrainian Shield. Despite its distribution in the granites of the massif, the geochemical features of the fluorites have not yet been investigated. The aim of this work was to determine the content of REE in the fluorites, the granites and to study the distribution of REE in the fluorites and granites containing this mineral. The content of REE in 4 samples of the granites and 4 monofraction the fluorites from these granites (well № 8568) was determined by the ICP MS method on the Element-2 device at M. P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the NAS of Ukraine (Kyiv). The well № 8568 was drilled in the southeastern part of the Ruska Polіana granite massif of the Korsun-Novomyrhorod pluton of the Ukrainian Shield (Ruska Polіana Village). In this part, the researchers revealed granites with rare metal mineralization. The investigated granites of well are represented by 3 types: the gray-pink fine-medium-grained granites (type I) (156,1–158,0 m), the gray-pink porphyriform granites (type II) (174,6–176,5 m), the gray medium-coarse-grained granites (type III) (225,0–227,0 m) and the pink-gray medium- coarse granites (type III) (239,6–242,0 m). According to the results of the ICP MS analysis, the highest content of lanthanides (26933 ppm) and yttrium (11 705 ppm) was observed in fluorites from the gray-pink fine-medium granites of the upper part of the well. But the gray-pink fine-medium granites have the lowest total lanthanide content (218 ppm). The lowest levels of lanthanides (692 ppm) and yttrium (831 ppm) were determined in the fluorites of the pink-gray medium-coarse grained granites of the deepest part of the well. The pink-gray medium-coarse granites are characterized by high lanthanide content (797 ppm). The fluorites from Ruska Poliana of the gray-pink fine-medium grained granites can be compared with the fluorite from Perga granite by the total content of lanthanides. Among the rock-bearing minerals in biotites from the Ruska Poliana granites of different depths of the well, there is a high content of REE, almost at the level of the granites themselves. Such a high level indicates the presence of inclusions of accessory minerals enriched with REE in the biotites, especially fluorites.

Bio-mining of Lanthanides from Red Mud by Green Microalgae

Red mud is a by-product of alumina production containing lanthanides. Growth of green microalgae on red mud and the intracellular accumulation of lanthanides was tested. The best growing species was Desmodesmus quadricauda (2.71 cell number doublings/day), which accumulated lanthanides to the highest level (27.3 mg/kg/day), if compared with Chlamydomonas reinhardtii and Parachlorella kessleri (2.50, 2.37 cell number doublings and 24.5, 12.5 mg/kg per day, respectively). With increasing concentrations of red mud, the growth rate decreased (2.71, 2.62, 2.43 cell number doublings/day) due to increased shadowing of cells by undissolved red mud particles. The accumulated lanthanide content, however, increased in the most efficient alga Desmodesmus quadricauda within 2 days from zero in red-mud free culture to 12.4, 39.0, 54.5 mg/kg of dry mass at red mud concentrations of 0.03, 0.05 and 0.1%, respectively. Red mud alleviated the metal starvation caused by cultivation in incomplete nutrient medium without added microelements. Moreover, the proportion of lanthanides in algae grown in red mud were about 250, 138, 117% higher than in culture grown in complete nutrient medium at red mud concentrations of 0.03, 0.05, 0.1%. Thus, green algae are prospective vehicles for bio-mining or bio-leaching of lanthanides from red mud.

Development of Borosilicate Glass Compositions for the Immobilisation of the UK's Separated Plutonium Stocks

The UK inventory of separated civil plutonium is expected to exceed 100 tonnes by 2010. Whilst the majority of this could be used in the manufacture of MOx (Mixed Oxide) fuel in future power generation scenarios, options for the disposal of surplus plutonium are currently being investigated by Nexia Solutions Ltd on behalf of the UK's Nuclear Decommissioning Authority (NDA). One of the options being considered is immobilisation in a durable glass matrix followed by long term storage and subsequent final repository disposal.A preliminary experimental survey assessed a selection of potential glass systems on the basis of Pu-surrogate (cerium) loading, durability, and ease of processing. Following this, a number of borosilicate compositions have been taken forward into a more detailed investigation in order to fully qualify their potential for Pu-immobilisation. The selected compositions are lanthanide borosilicate (LaBS), alkali tin silicate (ATS) and high-lanthanide alkali borosilicate (modified-MW). For this second series of experiments, hafnium was selected as the Pu surrogate, and a study of the potential waste loading as a function of temperature for the three selected compositions is described in this paper. Furthermore, several variations of the LaBS composition were fabricated in order to investigate the effect of total lanthanide content on melting temperature. The benchmark of 10 wt% HfO2 incorporation is achievable for all three glasses with temperatures of 1200, 1300 and 1400 °C required for ATS, modified-MW and LaBS respectively.

Determination of Trace Elements in Opium by Means of Activation Analysis

SummaryMany methods have been advocated for the determination of the origin of opium, but so far no research has been reported on the possibilities of such studies by means of radiochemical methods applied to the opium ash.In the present investigation the gold and lanthanide content in samples of opium ash has been studied using neutron activation analysis. The gold content was found to vary from about 0,5 to 10 ppm and the total rare earths content from about 20 to 150 ppm. Large variations are found in the distribution pattern of the individual rare earths in opium samples from different origin. The results are discussed and indicate that activation analysis may be used to indentify the origin of opium samples.