All-Russian Scientific-Research Institute Of Mineral Resources named after N.M. Fedorovsky

The promising methods of preliminary activation of spodumene concentrate are shown (mechanoactivation, energy impact, high-frequency electromagnetic processing). An increase in the reactivity of α-spodumene was found during sulfatization of activated spodumene concentrate.

The article shows prospects of processing ores of national deposits of carbonatite weathering crusts, which are one of the main raw materials sources of niobium. The variability of the proposed technological solutions for their processing makes it possible to obtain a wide range of niobium products in demand.

2 -

The composition of microbial communities in rock samples, reservoir water, and enrichment cultures from subsurface horizons of an uranium deposit (Russia) was determined. The studied horizons were located in the zone of hindered water exchange at a depth of 513–544 m, characterized by moderate salinity (up to 15 g/L) of reservoir water and the presence of charry plant organic matter. The biodiversity of autochthonous subsurface prokaryotes was determined by high-throughput sequencing of the V4 region of the 16S rRNA gene. Bacterial phyla predominant in the rock samples were Firmicutes (24.2%), Fusobacteriota (23.0%), Proteobacteria (18.7%), Actinobacteriota (15.5%) and Bacteroidota (9.0%). The predominant bacterial phylum in the reservoir water was Proteobacteria (90.7%), including representatives of the genera Methylophaga, Porphyrobacter, Roseovarius, Pseudomonas, and Methylococcus. Sequencing of the internal transcribed spacer (ITS) revealed occurrence of lower fungi of the genera Mucor and Thamnidium (phylum Mucoromycota) and of the genus Penicillium (phylum Ascomycota) in the rock samples; members of these genera are known for their resistance to heavy metals and the ability to use complex organic substrates. The functional characteristics of bacterial communities of the rock and reservoir water samples, predicted by the iVicodak program and the KEGG database, showed that reservoir water bacteria had a higher potential ability to carry out the pathways of carbohydrate, nitrogen, and sulfur metabolism, degradation of xenobiotics, benzoate, polycyclic aromatic hydrocarbons and chlorinated organic compounds than the rock microbiota. Enrichment cultures of iron-reducing and sulfate-reducing bacteria and pure cultures of denitrifying bacteria of the genera Bacillus, Paenibacillus, and Acinetobacter were obtained. These results indicate the presence of a small but viable microbial community that can participate in the processes of transformations of carbon, nitrogen, sulfur, and metals in the subsurface horizon when water exchange is activated.

The article provides an overview and analysis of seismicity within the boundaries of the Arctic region for 2014, a description of seismic station networks and processing methods. The catalog of earthquakes in the Arctic region was compiled on the basis of catalogs of several organizations and seismological centers. In total, 452 earthquakes with ML≥1.5 are included in the earthquake catalog. Most of the earthquakes occurred in 2014, including all the strongest earthquakes, werelocated within the mid-ocean ridges of Mon, Knipovich and Gakkel. In the offshore territories, most of the earthquakes were confined to the Svalbard archipelago, in particular, to the seismically active zone in the Sturfjord strait. The renewal of instrumental seismological observations in 2011 (station ZFI) on Alexandra Land Island in the Franz Josef Land archipelago made it possible to record weak earthquakes in the north of the shelf of the Barents and Kara Seas. For seven earthquakes, the focal me-chanism parameters are presented according to Global CMT catalog.

In recent years, geologists have found peatlands extremely rich in uranium. They can be considered an example of the efficient operation of natural organic geochemical barriers in the humid zone. They also open up the possibility of determining the age of these peatlands by t he isotopic ²³⁰Th/²³⁴U method. The deposition of uranium in peat is due to the U(VI) bioreduction controlled by several geochemical factors: the composition of organic matter and soil solution, the redox potential, and the capacity of uranyl ions to make complexes with organic ligands. By the nature of uranium enrichment, peatlands can be subdivided into two groups: (a) peatlands enriched in uranium carried by soil and groundwater from peripheric sources and (b) peatlands enriched in uranium from underlying uraniferous rocks. The data on geography, genesis, and physicochemical conditions of positive uranium anomalies in peatlands of the humid zone are collected and analyzed in this review.

The results of the research and tests in production of beryllium concentrate of the superior and commercial grades as well as the marketable fluorite concentrate from ore and waste of the Ermakovsky deposit are presented. The ore and waste contain a mineral complex which is hard to separate using fat acids and features an increased content of fluorite. Production of the marketable flotation concentrate is based on fixation of calcium in pulp using sodium carbonate, caustic soda and sodium tripolyphosphate. The autoclave-membrane electrolysis technology is developed for the production of marketable beryllium hydroxide from beryllium concentrates. The technology consists of a set of successive operations: dissociation in autoclave, separation of the suspension after the autoclave dissociation, removal of admixtures from the solutions, membrane electrodyalysis of alkaline solutions, hydrolysis of sodium beryllate and separation of beryllium hydroxide. The processing data of the test beryllium concentrates obtained using the autoclave-membrane electrolysis technology are given.

Ti-bearing iron ore of the Pudozhgorsky deposit has been studied in detail using laboratory mineralogical analytical methods in order to determine the morphostructural and constitutional features of titanomagnetite. The genesis of the ore and gangue mineral intergrowths has been established, as well as typomorphic attributes of three titanomagmetite varieties differing in degree of heterogeneity. The behavior of ore in technological processes is controlled by exsolution structures of titanomagnetite with ilmenite formation. The possibility of the complex development of this ore has been shown. Titanomagnetites of major mineral assemblages pertaining to various types of Tiand V-bearing iron ores are compared.