Aluminum Plant Research Articles

Investigation of the Emission Higher Harmonics into the Generator Grid

The article considers a section of the grid with generator voltage busbars (GRU-10 kV) of one of the hydroelectric power plants HPP-I of a large cascade HPP, which supplies electricity to an aluminium plant via two busbars. It is described that the plant load includes converter units, including: transformers, bridge rectifier blocks and saturation chokes, which are powerful sources of harmonic disturbances. An overview of the developed model and the principles of its construction for studying the influence a powerful non-linear load on the generator is given. Analysis of the results calculations on the model showed that the load of an industrial enterprise creates current and voltage distortions in the electrical s not only of the plant itself, but also in urban grids, and on the busbars of the generator voltage HPP-I. The article analyzes the influence of the current effects of a large industrial enterprise load in asymmetric modes on hydrogenerators by evaluating torsional vibrations and tangential vibrations in generators. It is shown that tangential forces of double frequency (100 Hz) practically do not create significant vibration displacements when the natural frequency of the frontal parts basket is adjusted.

Production of red mud based nanofibers and their potential in arsenate removal from waste water

In this study, it was aimed to utilize red mud (RM, an industrial waste material) as a nanofiber adsorbent in arsenate removal from waste water. RM, obtained from Seydişehir Aluminum Plant (Konya, Turkey), was leached using nitric acid in order to recover metallic elements such as Fe, Al, and Ti. Oxides and hydroxides of these elements are known to have a high affinity toward arsenic. Metallic salt solution, obtained after leaching treatment, was used to produce nanofibers via electrospinning method to get an adsorbent material with high surface area. Compositional, phase structural, microstructural, and thermal analyses were conducted using AAS, XRF, XRD, SEM, and DT/TGA. Organic removal from nanofibers were conducted at 600 °C for 5 h, based on the DT/TGA results. After heat treatment, nanofibers with diameters ranging from 45 to 58 nm were obtained. Performance of nanofibers in As(V) (arsenate) removal from waste water was also evaluated with different amount of nanofibers (1-3 mg/L), arsenate concentration (5-100 ppm), and contact time (10-120 min). Experimental results showed that the fastest and highest removal efficiency (∼80.2%) was obtained for 3 mg/L nanofiber and 10 ppm arsenate concentration at 90 min. Kinetic studies revealed that the pseudo-second-order kinetic model was dominantly active in the adsorption process.

The lichens in aluminum plants vicinities of Irkutsk region

The aim of our work was to assess the diversity of lichens in the forests polluted by the air emissions fromthe Bratsk (BRAZ), Irkutsk (IRKAZ) and Taishet (TAZ) aluminum smelters, as well as in the background (non-polluted)territories, similar to those by natural and forest-growing conditions. 102 wide-distributed lichen species were found onplots. This amount is due to the fact that the wood tier is sparse and forophytes composition is depleted. The lichen diversity varies in different types of vegetation and according to the influence of anthropogenic factors. Species diversity in vicinities of smelters and in buffer zones are similar, excluding control zones with dark-conifers forests. It’s established that as wemove closer to the aluminum plants – to the IRKAZ and especially BRAZ, the projective cover, the total number of speciesdecreases, and their species composition changes. Clear morphological changes of lichen thalloma were observed in theimpact zone of the BRAZ. Relatively resistant to atmospheric pollution lichens are found in the impact and buffer zonesin vicinities of plants. Lichens are absent in the crowns and trunks, but their abundance increases on bases of trees trunks.

Innovational Construction Materials of LLP “EcostroyNII-PV” Production

The article discusses the experience of recycling industrial waste from the electric power industry and metallurgy. Based on the experience of Ecostroy NII-PV LLP. The proposed technology for manufacturing building products from ash and slag waste provides innovative compositions of raw mixtures. What provides an increase in operational characteristics and labor productivity in construction. The applied technology, in comparison with the existing analogues, provides for the use of local waste (ash and slag waste from the combustion of Ekibastuz coal, bauxite sludge from the Pavlodar aluminum plant, steel-making slags), differing in chemical and granulometric composition. as well as binding properties from other analogs and prototypes. In the manufacture of building products introduced mixture, including, wt %: slag Portland cement - 14.32-17.00; sand - 18.74-25.52, crushed stone - 46.50-49.71, sludge from alumina production obtained during the recycling of bauxite from Kazakhstan - 5-7; self-disintegrating steelmaking slag - 5-7; ash and slag waste from thermal power plants from burning Ekibastuz coals - 5-7. According to the test results, the average tensile strength of building products (paving slabs, curbs, hollow bricks) is 3.2 - 3.8 MPa (strength class V2.5).

Occurrence State of Carbon and Electrolyte in Anode Carbon Residue From Electrolytic Aluminum

Anode carbon residue is produced in the production of electrolytic aluminum. Its properties need to be studied for secondary utilization. In this paper, mineralogy of anode carbon residue from an electrolytic aluminum plant in Guizhou was studied. The anode residue chemical composition, structure, mineral composition, occurrence state of main elements, etc, was investigated. The results show that: Anode carbon residue is mainly composed of 14 minerals such as cryolite, cryolithionite, elpasolite and graphite. Among them, the opaque minerals are mainly graphite and the transparent minerals are mainly cryolite. Carbon in the form of independent mineral occurrence in graphite; fluoride in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite and fluorite; aluminum in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite, aluminium oxide and magnesium aluminate; sodium in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite. The mineralogical characteristics and occurrence state of carbon and electrolyte were studied, which provided a basis for the separation and recovery of carbon and electrolyte in anode carbon residue.

Characterization of the submarine disposal of a Bayer effluent (Gardanne alumina plant, southern France): II. Chemical composition of the clarified effluent and mineralogical composition of the concretions formed by its discharge in the Mediterranean Sea

The Gardanne alumina plant (Marseille region, Southeast France) has disposed its residues as a slurry (red muds) in the Mediterranean Sea up to 2015 when new regulations allowed the sole discharge of a clarified effluent. This reduced the quantity of suspended material from ~300 g/L to less than 10 mg/L. The detailed chemical composition of this clarified effluent has been determined by ICP-OES, ionic chromatography, 1H NMR spectroscopy and carbon analysis. It is a Na–Al–OH aqueous solution at pH 12.5 having a solute load of 1.5 g/L and an organic carbon content of about 100 mg/L, all other elements being in minor or trace amounts. A X-ray diffraction and SEM study showed that the submarine concretions forming at the outfall upon mixing the effluent with seawater are predominantly composed of a Mg–Al–OH double layer hydroxide of the hydrotalcite supergroup that contains Ca and S (wermlandite subgroup), along with minor calcite, bayerite, and rarely brucite and akaganeite (an iron hydroxide). The investigation of the stability of standard hydrotalcite in the marine environment through solubility calculations showed that hydrotalcite minerals are not stable in normal seawater and as such are prone to dissolve and release their components to the environment.

Recovery of bauxite ore particles -1mm from tailings of the Tan Rai bauxite processing plant by mechianical classifiers

Tailings of the Tan Rai bauxite mineral processing plant contain a relatively high proportion of fine bauxite ore particles of less than 1mm. This amount of discarded fine bauxite particles necessarily leads to a high loss of valuable bauxite mineral and also require more tailings dam space. Recovery of such fine bauxite ore particles may produce certain economic and environmental effects to the current processing plant. The paper presents results of the study on recovery of fine bauxite ore particles -1 mm from tailings of the Tan Rai - Lam Dong bauxite mineral processing plant by the use of mechanical classifiers. The obtained +0.5 mm bauxite concentrate are suitable for blending with the +1 mm concentrate of the current plant. The study results showed that recovery of fine bauxite ore particles -1mm from the plant tailings may produce additional amount of valuable concentrate to ensure the supply requirements to the alumina plant and also add some values to the effective mineral resource utilization and bring some economic efficiency.

Technology and equipment for isolated aluminum melt overflow from a vacuum transport ladle with using the siphon

The work was performed at the Sayanogorsk aluminum plant UC RUSAL in the technological scheme from an aluminum cell to an alloying furnace. The article presents comparative results of studies of the dynamics of saturation of aluminum with hydrogen when using a vacuum transport ladle with a closed (siphon) cast metal overflow and the existing technology of overflow. The basic design of a vacuum transport ladle with a removable siphon is presented. It is shown that one of the main sources of saturation of aluminum melt with hydrogen is its interaction with air moisture during open overflows of metal during its movement from the cell to the alloying furnace. During the study, it was found that pouring aluminum from the cell using traditional technology increases the hydrogen content by an average of 0.045 cm3/100 g Al, and pouring aluminum from the cell with an experimental ladle with a siphon increases the concentration of hydrogen in the metal by an average of 0.029 cm3/100 g Al. It was found that when pouring aluminum from the ladle into the alloying furnace using traditional technology, the hydrogen content increases from 0.220 cm3/100 g Al to 0.297 cm3/100 g Al, and when using a vacuum transport ladle with a closed (siphon) overflow, the hydrogen content decreases from 0.189 cm3/100 g Al to 0.161 cm3/100 g Al. It is shown that an additional advantage of pouring aluminum melt with an experimental vacuum transport ladle with a closed (siphon) overflow is to reduce the amount of dross removed from the metal surface, as well as to reduce metal losses due to oxidation of the melt. The specific dross formation according to the existing overflow technology was 1,962 kg/t Al, and when using an experimental vacuum pump with a closed (siphon) overflow, the specific formation of dross was 1,204 kg/t Al.The work was performed using the results of research conducted during the implementation of project 14.578.21.0193 from October 3 for the period 2016–2018. “Development of theoretical and technological solutions for reducing hydrogen in aluminum and low-alloy aluminum alloys” in the framework of the Federal target program “Research and development in priority areas of development of the scientific and technological complex of Russia for 2014–2020” with financial support from the Ministry of education and science of Russia.

Study of the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan

Background: The emission and presence of air pollutants such as fluorides has over burdenized the public healthcare issues. The current study aimed to determine the content of fluorides in atmospheric air in Bokhtar region and Tursunzade city of Tajikistan. Methods: Based on the direction of wind, two zones were selected in the current study: experimental and control. In the first (experimental) zone, those areas were selected where the western, northern and northeastern directions of wind was significant. Dzhura Rakhmonov was assigned to the control zone with the shortest time for the eastward winds. In general, 72 samples of atmospheric air were taken in 12 settlements of the city of Tursunzade and 90 samples of atmospheric air in the Bokhtar region of the Khatlon province. To determine fluorine in air, a potentiometric method with an ion-selective electrode was used, which makes it possible to measure the potential concentrations of fluorides in atmospheric air. Results: Compounds of gaseous (hydrogen fluoride) and solid fluorine (salts of hydrofluoric acid), which are the main emission from various sources, were found in the atmospheric air of the populated areas of the city of Tursunzade, where the aluminum plant industry is located. The maximum amount of hydrogen fluoride in the experimental zone (Jamoat and Navobod) with a western wind direction was found in the autumn, which exceeded the MPC. However, the amount of solid fluorides in the western direction of the wind ranged from 0.01 to 1.0 mg / m3, which did not exceed the MPC value and was not significant. In control zone (Dzhura Rakhmonov) the said pollutants hydrogen fluoride and solid fluorine were not significant in autumn within accordance to MPC limit. The results of the study of atmospheric air in 15 administrative cities and districts of the Bokhtar region showed a complete absence of solid fluorides in all samples of atmospheric air. Conclusion: Compounds of gaseous fluorine and salts of hydrofluoric acid were found in the atmospheric air of populated areas of the city of Tursunzade, and no significant amounts in the Bokhtar region according to MPC and control. The maximum amount of fluorine compounds was found in the experimental zone (Jamoat Navobod) of the city of Tursunzade.

Investigation on ash fusion behavior modification of wheat straw by sludge addition

Energy utilization of biomass has attracted great interests. To decrease ash-related issues during straw gasification and mitigate sludge environmental pollution, the influences of three sludges [aluminum plant sludge (APS), paper-making sludge (PMS), and municipal waste-water sludge (MWS)] on the ash fusion behaviors of wheat straw (WS) and their variation mechanisms under reducing atmosphere were investigated. The ash fusion temperatures (AFTs) of mixed WS increased following APS > PMS > WMS when they were equal. The ratio of bridging-oxygen bonds and nonbridging-oxygen bonds of WS mixture decreased more obviously with APS addition than that of MWS, causing the WS-APS mixture AFT increased more quickly than that of WS-MWS. The formations of high melting-point (MP) KAlSiO4, MgAl2O4 and their increasing contents by APS addition resulted in the AFT increased obviously; the increase in relative high MP Ca3MgSi2O8 caused the AFT increase moderately with increasing PMS percentage; with MWS addition, the increasing CaMgSiO4 content led to a slow increase in the AFTs. The variations in liquid-phase content in the WS mixtures based on FactSage calculation were also explained the AFT variations.

Improving the efficiency of the carbothermal reduction of red mud by microwave treatment

In this work, we studied the effect of microwave treatment of red mud briquettes containting more than 48% of Fe on the process of iron reduction under various conditions of heat treatment. Research samples were collected from red mud formed during the production of alumina from bauxite at the Ural Aluminum Smelter. The chemical composition of mud samples was examined by X-ray fluorescence analysis. The composition of initial mud and that of agglomerates obtained after treatment in microwave and muffle furnaces was studied using the X-ray diffraction method. Phase transitions and structural changes occurring under the effect of heating were studied by scanning electron microscopy. The experimental briquettes comprising red mud and charcoal were treated at 850°C and 1000°C in a microwave furnace (under the frequency of 2.45 GHz and the power of 900 W). For reference, briquettes of analogous composition were heat-treated in a muffle furnace under the same conditions. It was found that, under the conditions of microwave heating to 1000°C for 10 min, hematite is completely reduced to metallic iron after the addition of wustite. An analysis of the m i-crostructure of the samples after microwave treatment showed that the particles of metallic iron in the as-obtained pellet-agglomerates have a larger size than in those after conventional thermal heating in a muffle furnace. The metallized phases of reduced iron at the end of heat treatment in a microwave furnace create a stable durable body of agglomerates. The evidence-based parameters of the process can become a basis for designing a technology for recycling such an industrial material as red mud. The obtained high-strength pellets from red mud with a high content of reduced iron (up to 85%) may be used as an alternative charge material for ferrous metallurgy. The proposed technology for recycling red mud into pellet-agglomerates can be applied in various industries to reduce environmental impact on the production areas of alumina plants.

The Study of the Magnetic Properties of Red Mud from Alumina Production after Alkaline Treatment

In Russia, the main feedstock for producing aluminum is bauxite. During the processing of 1 ton of bauxite into alumina (Al2O3), up to 0.5–0.6 ton of techno-genic waste is formed, that is red mud. It is not currently disposed of and accumulated in mud tailing dumps. It contains valuable components: Al – 8 %; Fe – 25 %; Ti – 2.4 % and it can be considered as a potential raw material for ferrous metallurgy and as a source of vanadium, titanium, and rare-earth elements (REE) Sc, Y, La. The paper shows the possibility of obtaining red mud with an increased iron content of up to 36 %, with an additional extraction of aluminum. Red mud from the Ural Aluminum Plant (Russia) is considered. It is proposed to direct this mud to the production of pellets for the production of cast iron. To extract aluminum from red mud, it is proposed to process the mud in a highly alkaline medium by sintering in the temperature range 300–600 °C. The resulting sinter is leached with water or a slightly alkaline solution with the conversion of aluminum compounds into solution. The red mud, obtained this way, exhibits magnetic properties. A magnetic separation was carried out, and the yield of the magnetic fraction is 79.87 %. The iron content increases by 25 % and amounts to 51.88 % of Fe2O3.

Evaluation of red sludge use efficiency for water purification from sulphates

In this work the reagent purification of aqueous solutions from sulfates with the use of red sludge of the Nikolaev alumina plant processes were investigated. This sludge, according to chemical analysis, contains a sufficiently large amount of alumina (up to 18 %) and calcium oxide (up to 10 %) and along with calcium silicate and iron oxides contains sodium and calcium aluminates. The ability of sodium aluminate to be deposited from a solution of sulfates in the form of calcium sulfoaluminates was used in the work to purify water from sulfate anions. The process takes place when treating the solution with sludge and lime suspension. It is shown that when red sludge is applied in the amount of 1–50 g/dm3 during magnesium sulfate solutions liming, water is purified from sulfate anions. The degree of water purification reaches 50–70 %. It was found that the efficiency of sulfate extraction is significantly dependent on the consumption of lime and increases slightly with increasing sludge consumption over 1 g/dm3. The dependence of the efficiency of sulfate extraction from water on their initial concentration is determined. It was found that at the initial concentration of sulfates up to 1000 mg/dm3 at the expense of lime 3–12 mg-eq/dm3 the residual concentration of sulfates decreases to 236–460 mg/dm3, and at the concentration of sulfate anions about 2000 mg/dm3 their concentration decreases to 550–830 mg/dm3 at a lime consumption of 30 mg-eq/dm3 regardless of the sludge consumption. The degree of extraction of sulfates from solutions reaches 40–73 %.

Preparation of a mixed Al/Sc nano-oxide derived from the bauxite residue (red mud) via the sulfuric acid roasting–leaching–precipitation process

In this study, three methods were used and compared for the selectable extraction of aluminum/ scandium with the least amount of iron in red mud (RM) samples from the Iran alumina plant in Jajarm as follows: 1) RM direct acid leaching with H2SO4, 2) RM washing with hydrochloric acid and oxalic acid before leaching with H2SO4, and 3) RM sulfuric acid roasting-leaching-precipitation. The aim was to extract the highest amount of scandium while preventing the leaching of other metals, especially iron. Due to any discriminative features, the selective separation of Al/Sc with methods 1 and 2 was impossible practically. While, method 3 resulted in 73.7% of extracted scandium under optimal conditions with only 0.6% of iron found in the final product. The characterization of the final oxide product was done via inductively coupled plasma mass spectrometry (ICP-MS) and energy-dispersive X-ray analysis (EDX). The morphology of the oxide product was examined by field emission scanning electron microscopy (FE-SEM). This mixture oxide had a nanosize spherical shape and was distributed uniformly. The pH of the remaining red mud after the acid roasting-leaching-precipitation method was 8, which was far more environmentally desirable than the primary red mud with a pH = 12.

The frequency of chromosomal aberrations in individuals chronically in contact with excess dosages of fluorides

BACKGROUND: Chronic excess human exposure to fluorides is an underestimated problem. There is information that fluorides are capable of exerting a genotoxic effect in vitro and in vivo. The data obtained on human populations are limited and contradictory. More research is needed.
 MATERIALS AND METHODS: The material for the study was peripheral venous blood taken from residents of the city of Novokuznetsk. The material was selected in four groups: workers of the Novokuznetsk Aluminum Plant (NkAZ) with fluorosis, NkAZ workers without pathology, residents of the area adjacent to NkAZ, residents of the city living away from the industrial zone. The frequency of chromosomal abnormalities in blood leukocytes was estimated using the method of accounting for metaphase chromosomal aberrations, as well as the concentration of fluoride ion in blood plasma by direct potentiometry.
 RESULTS: A significant increase in the frequency of aberrant metaphases in blood leukocytes was observed among workers at an aluminum smelter compared to control, workers with fluorosis compared to workers without pathology, and residents of the area adjacent to the plant compared to residents of the city living far from the industrial zone. A correlation of the frequency of chromosomal aberrations with the concentration of fluoride ion in blood plasma was noted.
 CONCLUSION: The results obtained confirm the ability of the industrial factor of the aluminum smelter to exert a genotoxic load on the human population. The presence of an association of fluoride factor with chromosomal abnormalities in blood leukocytes is likely.

Degradation of STOP1 mediated by the F-box proteins RAH1 and RAE1 balances aluminum resistance and plant growth in Arabidopsis thaliana.

The C2H2-type zinc finger transcription factor sensitive to proton rhizotoxicity 1 (STOP1) is crucial for aluminum (Al) resistance in Arabidopsis. The F-box protein Regulation of AtALMT1 Expression 1 (RAE1) was recently reported to regulate the stability of STOP1. There is a unique homolog of RAE1, RAH1 (RAE1 homolog 1), in Arabidopsis, but the biological function of RAH1 is still not known. In this study, we characterize the role of RAH1 and/or RAE1 in the regulation of Al resistance and plant growth. We demonstrate that RAH1 can directly interact with STOP1 and promote its ubiquitination and degradation. RAH1 is preferentially expressed in root caps and various vascular tissues, and its expression is induced by Al and controlled by STOP1. Mutation of RAH1 in rae1 but not the wild-type (WT) background increases the level of STOP1 protein, leading to increased expression of STOP1-regulated genes and enhanced Al resistance. Interestingly, the rah1rae1 double mutant shows reduced plant growth compared with the WT and single mutants under normal conditions, and introduction of stop1 mutation into the double mutant background can rescue its reduced plant growth phenotype. Our results thus reveal that RAH1 plays an unequally redundant role with RAE1 in the modulation of STOP1 stability and plant growth, and dynamic regulation of the STOP1 level is critical for the balance of Al resistance and normal plant growth.

Increased aluminum and lithium and decreased zinc levels in plasma is related to cognitive impairment in workers at an aluminum factory in China: A cross-sectional study

BackgroundPrevious studies have shown that multiple imbalances of metal ions in the brain are closely associated with the neurodegenerative disorders. Our studies have shown that long-term working exposure to aluminum induces increased plasma aluminum levels and causes cognitive impairment in workers at aluminum factories. ObjectiveTo explore the levels of nine metals in plasma and the effect on cognitive function among in-service workers. MethodsIn this cross-sectional study, cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), which included seven subitems: executive/visuospatial abilities; naming; attention and calculation; language; abstract; recall; and orientation. The plasma levels of nine kinds of metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS). A multivariate generalized linear regression model and Bayesian kernel machine regression (BKMR) were selected to estimate the relationship between metal plasma level and MoCA scores with adjustment for confounders. ResultsOne hundred and eighty-seven workers participated in this study. In the multivariable generalized linear model, among these nine metals studied, five were related to the MoCA score: aluminum, lithium, cobalt, zinc and chromium. In the BKMR model, a significantly negative correlation between the plasma aluminum, lithium and the total MoCA score was observed. Moreover, for subitems on the MoCA scale, the plasma levels of lithium, aluminum, and zinc had a significant correlation with the executive/visuospatial abilities, naming, and orientation abilities, respectively. The log-transformation concentrations of plasma aluminum and lithium were negatively correlated with the executive/visuospatial abilities and naming abilities, respectively. The log-transformation plasma zinc concentration was positively correlated with orientation abilities. ConclusionBased on the results, we determined that increased aluminum and lithium and decreased zinc levels in plasma were associated with the incidence of mild cognitive impairment (MCI) in workers at a Chinese aluminum plant.

Ecological monitoring in the impact zone of an industrial enterprise producing alumina

Ecological monitoring in the impact zone of an industrial enterprise that produces alumina will ensure effective management of production processes. In the course of monitoring in the area of sludge farm near Achinsk alumina plant in Russia, systematic observations and timely detection of underground water contamination, determining the size of the contamination area, as well as studying the development of the underground water contamination area in time and space is carried out. In wells located in the immediate proximity of the sludge storage, maximum values of alkalinity, potassium and bicarbonate are observed and away from the sludge storage, the values of these indicators decrease. It is established that the zone of negative impact is located within 300-500 m from the contour of the sludge storage, outside of which the chemical composition of underground water almost corresponds to the background. Monitoring studies of the soil in the area adjacent to the sludge storage showed their recovery after reclamation and phytosanation. The analysis has shown that the ecological monitoring system at JSC “RUSAL Achinsk” combines all the necessary components: instrument and hardware maintenance, a measurement organization system, and a set of methods for analyzing the results of observations, providing all the necessary conditions for its implementation in practice.

Improved Molten Metal Sampling Method for Hydrogen Content Analysis

The main disadvantage of the existing sampling method of metal for hydrogen content analysis is the contact of metal with air moisture during an open overpour from a metal scoop to the ingot mold. In response, a novel method is proposed for sampling molten aluminum and its alloys for hydrogen content analysis by dipping a conical ingot mold sampler into the melt. The work was performed at the Sayanogorsk aluminum plant UC RUSAL in the technological workflow from a transport ladle to the casting machine. Hydrogen analysis results using the proposed method are compared to those of the sampling method using the Rensley chill mold. The error in the hydrogen content measurement of the sample under the existing sampling scheme with overpour of metal from a metal scoop into the ingot mold was confirmed. The hydrogen concentration in the samples taken in the Rensley chill mold is less, on average, by 0.019 cm3/100 g Al, than in the samples obtained using the newly developed ingot mold sampler. Results of the study reveal that the proposed sampling method provides an additional advantage when sampling molten metal.

Environmental Challenges in Regions: Analysis and Measures to Reduce Potential Risks

The environmental deterioration in Russia requires the identification and analysis of the main challenges facing the country and its individual regions in this sphere. Additionally, it is necessary to find ways to overcome these problems. Th e issu e is particularly relevant for resource regions where new economic activities develop. the Lower Angara region in Krasnoyarsk krai is one of such regions. The study considers the environmental problems in connection with the socio-economic conditions of a particular territory. I used the method of economic and mathematical modelling based on the author’s models for optimising environmental protection measures. The research combines the obtained results to built a comprehensive model of the future ecological situation that may develop in the region. The analysis discovered various causes of environmental challenges. The first reason is planning exxessive output at individual facilities. In particular, calculations have shown that in the conditions of the Lower Angara region, the unit capacity of the pulp and paper industry should not exceed 300–350 thousand tonnes (instead of the planned 720 thousand tonnes); the capacity of the aluminum plant should not exceed 200–250 thousand tonnes (instead of 600 thousand tonnes). Second, an excessive concentration of production in certain areas (primarily, in Boguchansky and Kodinsky industrial hubs) increases the environmental burden. Third, pollution control is complicated by unique production capacities of various facilities that require special purification systems. The fourth reason is the effects of synergism and additivity of contaminants. The fifth cause is the actual and potential negative consequences of the construction of hydropower plants on the Angara and Yenisei rivers. The results of this research can be used for creating a strategy for the integrated development of territorial economic systems to organise environmental protection activities and substantiate management decisions at the regional and local levels of governance.