Slag Dumps Research Articles

Accumulation of Arsenic by Plants Growing in the Sites Strongly Contaminated by Historical Mining in the Sudetes Region of Poland.

The uptake of As by various plants growing in highly enriched sites was examined in order to identify potential As accumulators and to assess the risk associated with As presence in plant shoots. Representative samples of 13 plant species, together with soil samples, were collected from various sites affected by historical As mining: mine and slag dumps, tailings and contaminated soils with As concentrations in a range 72–193,000 mg/kg. Potentially and actually soluble As forms, extracted with 0.43 M HNO3 and, 1M NH4NO3 were examined in relation to As concentrations in plant roots and shoots. The latter differed strongly among the species and within them and were in the ranges 2.3–9400 mg/kg and 0.5–509 mg/kg, respectively. The majority (over 66%) of plant samples had As shoot concentrations above 4 mg/kg, an upper safe limit for animal fodder. The uptake of As by plants correlated well with total and extractable soil As, though As concentrations in plants could not be predicted based on soil parameters. Equisetum spp. and C. epigejos indicated a particularly strong accumulation of As in shoots, while A. capillaris, and H. lanatus showed a limited As root-to-shoot transfer, apparently associated with species-related tolerance to As.

Environmental Assessment of the Toxic Effect of Slagheap on Soil Continuum

This article shows the study of the toxicological state of soils in the areas of anthropogenic impact of slag dump industrial waste of aluminum casting in the Oryol region. The data obtained indicate a high impact of slag dumps as a result of waste storage in the production of aluminum casting [3]. The inter-elemental relationship between the studied toxic metals shows that heavy metals can also have the same anthropogenic origin, regardless of the sources of their origin. The results of the pollution index prove the moderately high level of pollution of the study areas. A comprehensive assessment of the degree of degradation of light gray forest soils and their ecological resistance to natural processes and regimes, anthropogenic loads occurring in the soil profile [5] is shown. Analysis of the isotopic composition of heavy metals proves their obvious anthropogenic origin, including industrial emissions from an aluminum casting plant, exhaust gases derived from regular exposure to vehicles, as well as from dust storms. Studies are made of the effect of slag dumps on the environment, in particular, the effect on soil, water and plant cover. As a result of the research performed, the local impact of the slag dump on the adjacent territory and its pollution with a complex of heavy metals were revealed.

TECHNOLOGY FOR THE COMPLEX RECYCLING SLAGS OF COPPER PRODUCTION

The article considers the inevitability of copper losses with slag and the possibility of reducing them by various methods and using local secondary technogenic formations. It has been established that the developed and widely used in industry technologies for decopperizing of slag only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the casualties are established, and suggestions for reducing their negative impact are recommended. The use of perfect mixing devices is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to make an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.

Recovery of rhenium from sulfuric acid solution by TOPO-impregnated silica sorbents

ABSTRACT A new solvent impregnated sorbent containing trioctylphosphine oxide was prepared using carriers from mesoporous silica, obtained by hydrometallurgical processing of Kola Mining-Metallurgical Company (Kola MMC, Russia) dump slag waste. The characterization of sorbent was performed using the SEM, FTIR and TGA techniques. Under static conditions, an sorption of rhenium onto impregnated sorbent in sulfuric acid solution was studied in a batch system with respect to contact time, sulfuric acid concentration, solid to liquid ratio and initial rhenium concentration. The recovery of rhenium from a sulfuric acid wash solution of the Kola MMC was demonstrated.

Исследование эффективности методов снижения пылеобразования на золошлакоотвалах

This research was aimed at analysing ash and slag dumps as objects of negative impact on atmospheric air, as well as at studying available methods for dust suppression. The existing ash and slag dump of the Novo-Irkutskaya combined heat and power plant, located in the forest park area between the cities of Irkutsk and Shelekhov, was considered. The territory adjacent to the ash dump is represented by forests in its south-eastern, eastern, and south-western parts, while the north-eastern part – by farmland. The operation of the ash and slag dump of the Novo-Irkutskaya thermal power plant leads to an increased level of atmospheric air pollution in the nearby residential area, which is situated outside the sanitary protection zone. This indicates the need to develop and implement measures to reduce dust formation from the surface of the ash and slag dump. In order to identify the most effective dust reduction method, it is important to calculate changes in emissions depending on the method used. To this end, we approximated the effective area of the dusting surface and the current ash particle outflow, which allowed determination of the surface concentrations of pollutants outside the ash dump area. Using a calculation method, we proved that the minimum rate of ash particle removal is observed when the water level in the nearby clarification pond is increased. It should be noted that, in addition to environmental aspects, economic factors should also be taken into account when developing environmental measures

Generalization of Tools for Internalization of Negative Externalities in the European Union: Conclusions for Ukraine

A comparative analysis of the tools of internalization of negative external. Based on the generalization and assessment of the possibilities of using the tools of internalization of negative externalities, the areas of application, as well as the strengths and weaknesses of direct regulation, economic (market) and institutional tools are identified. The tools of direct regulation are characterized, and it is found that they do not minimize economic costs and have high administrative costs. The economic (market) instruments of regulation are analyzed and it is revealed that in European practice such instruments as trade in permits (market instrument) and emission charges (Pig tax) are widely used. Institutional regulatory tools such as disclosure strategies and voluntary initiatives are considered and analyzed. It is substantiated that there is no universal tool that would provide full internalization of negative externalities. It is revealed that in modern conditions, the most successful solution will be the development and improvement of tools of direct state regulation of negative externalities in combination with economic (market) instruments, because both economic and market instruments can work effectively and purposefully only if environmental standards are established and observed. environmental quality. The characteristic of application of tools of internalization of negative external effects on an example of slag dumps is given.

ОЦЕНКА И АНАЛИЗ ГИДРОХИМИЧЕСКОГО РЕЖИМА ОБВОДНЕННЫХ КАРЬЕРОВ ПО ДОБЫЧЕ ФОСФОРИТОВЫХ РУД

Introduction. This article presents the results of studying the current environmental state of surface water bodies located in the affected area of phosphate mining enterprises and significantly altered as a result of technogenesis. Objects of accumulated environmental damage caused by mining enterprises contain the bulk (up to 85%) of waste accumulated in dumps, heaps and storages. In the Leningrad region, these are ash and slag dumps of the Slantsy Plant — about 35%, phosphogypsum of Fosforit Production Association and Volkhov Aluminum Smelter — about 18%, quartz sand with the content of phosphorite of Fosforit Production Association — about 17%, limestone — wastes from beneficiating oil shale of Leningradslanets Production Association — 12%, ash and slag dumps of CHPPs and state district power plants — 5%. In this regard, the authors assess the hydrochemical situation that has formed in the territory of the industrial site of ООО PG Fosforit in recent years. Methods. The article describes in detail a method for conducting field and laboratory studies for the period from 2017 to 2019, including a method for sampling and analysis. The authors analyze the content of basic anions and cations in a series of metals using high performance liquid chromatography and atomic absorption spectroscopy. Results. In the course of the studies, the authors revealed pollutants, the content of which in surface water bodies exceeds the maximum allowable concentrations. Conclusions. As a result of the studies, the authors identified sources of accumulated environmental damage and post-technological processes affecting the state of water bodies, and determined the trophicity of minor rivers in the affected area of decommissioned mining enterprises.

Неопределенность как средство повышения качества аналитического контроля металлургической продукции

Весь технологический процесс, начиная с добычи руды и заканчиваявыпуском готовой продукции, тесно связан с аналитическим контролем каждой стадии.В настоящее время в практику аналитических лабораторий крупных металлургическихпредприятий, к которым относится УК МК ТОО "Казцинк", прочно вошли физико-химическиеили инструментальные методы. Эти методы, отличающиеся экспрессностью, высокойизбирательностью и возможностью одновременного определения нескольких компонентов,вытеснили в большинстве случаев химические. В статье приводятся экспериментальныеданные анализа отвального шлака - отхода металлургического производства УК МКТОО "Казцинк" - методом атомной эмиссии с индуктивно-связанной плазмой. Атомныйспектральный анализ применяют в горнодобывающей промышленности и геологии,металлургической, металлообрабатывающей и химической промышленности и др. Результатыанализа были обработаны с позиций концепции неопределенности, что является весьмаактуальным в практике аналитической лаборатории.

Depletion of Slag from Almalyk Copper Plant with Aluminum Containing Waste

The article discusses the method of depletion of copper slag using local secondary technogenic formations. When performing this study, slag of secondary aluminum production was used as a reducing agent. It has been established that the developed and widely used in industry technologies for slag decontamination only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the losses are established and suggestions for reducing their negative impact are recommended. The use of melting units in laboratory conditions is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to achieve an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.

Analysis of the chemical safety state in the Luhansk region in the conditions of the warning conflict

The statistics of emergency situations in Ukraine for 2018 are analyzed. The total cost of damage caused by emergencies amounted to more than UAH 516 million. About 15% of the territory of Ukraine with a population of more than 10 million people is in a critical ecological state, in fact not favorable for living. It is shown that the most environmentally hazardous production (coke and metallurgical plants, power plants and chemical industry enterprises) are concentrated in the Donetsk and Luhansk oblasts. The production complex consists of 3995 enterprises, 7 of which are environmentally hazardous objects. Damage to technological installations can result in dangerous consequences for the population and the environment near the enterprises. Due to emergency emissions and discharges there is pollution of atmospheric air, surface and underground waters and soils. Storage tanks and sludges, storage sites for industrial waste, such as slag dumps, waste heaps, stocks of raw materials, etc. located on the territories of tailings storage facilities also cause environmental hazards. There is also the risk of contamination of the area outside the conflict zone and the Sea of Azov in the event of pollution of the Siversky Donets, Kalmius, Mius and Mokryy Yelanchyk rivers, which occur near the clash line and in areas beyond the control of the Government of Ukraine.
 As a result of the analysis of the state of chemical safety in Ukraine, the example of PrJSC «Severodonetsk Azot Association» shows the need to increase safety requirements and prepare new qualified personnel for radiation, chemical and biological protection. 
 The necessity of attracting additional funds for ensuring the effectiveness of the actions of the territorial subsystems of the EGS GZ in the region in the conditions of emergencies, enhancing the readiness of the specialized fire fighting service of the city's civil protection to the actions for appointment, ensuring the timeliness and quality of carrying out work to save people, extinguishing fires, eliminating the consequences of emergencies , creation of the possibility of conducting search, rescue, restoration and friend services around the clock their urgent work.

Development of energy-efficient method for processing industrial waste

An energy-saving method for processing technogenic waste has been developed — a smelt layer with inversion phase as a combination of “ideal” mixing and “ideal” displacement regimes. On its basis, a new generation of melting unit was created - the “reactor inversion phase - rotary kiln”. Experimental data show that in the inversion phase layer the specific fuel consumption for processing the “poor” on zinc and “rich” on zinc slags is approximately the same. The latter provision contradicts the prevailing opinion of metallurgists that the processing of slag with a zinc concentration of less than 5% is unprofitable. Сalculation results demonstrate that in case of implementation of an industrial sample of “reactor inversion phase - rotary kiln for processing “poor” slag, compared to the Waelz kiln processing “rich” slag, the specific consumption of fuel will be reduced by 1.5-1.7 times and specific productivity will increase 1.4-1.5 times. The industrial realization of “reactor inversion phase -rotary kiln” would allow cost-effective processing of fuming slag dumps, Waelz clinker, “poor” zinc ores, enrichment tails and other non-ferrous metal wastes.

Elements Distribution in Soil and Plants of an Old Copper Slag Dump in the Middle Urals, Russia

The elements concentration in soil and accumulation in plants growing spontaneously on an old copper slag dump were studied. The research object was a landfill site of the Polevskoy copper smelter (Middle Ural, Russia), which is about 200 years old. We investigated composite samples, consisting of soil blocks (20 x 20 cm) with growing plants. Samples were selected on a transect of 4–5 m at equal intervals. The composite sample was divided into slag fractions: stone, gravel, fine soil (particles smaller than 1 mm); plant fractions: moss and roots, stems and leaves. The microelement analysis of the samples was carried out at an analytical center of the Institute of Geology and Geochemistry, Ural Branch of RAS. The analyses were performed by inductively coupled plasma mass-spectrometry using Elan-9000 ICP massspectrometer. The formation of technogenic soil with a thickness of 10–15 cm on the dump of cast copper slag has begun two hundred years ago. Fine soil constitutes more than one third of the technogenic soil mass and acts as a sorption geochemical barrier. Fine soil accumulates elements mobilized from slag. The concentration of most elements in fine soil is 1–2 orders of magnitude higher than their concentration in slag stone. Pb, Cd, Bi are particularly effectively retained in fine soil: their content is 700-1000 times higher than in slag stone. In the conditions of unlimited supply of elements released from slag, plant reaches the upper threshold of accumulation. The aboveground plant parts compared to litter (roots and moss) have a lower concentration of all elements, but they show the stronger ability to accumulate selenium.

Technology of Processing Slags of Copper Production using Local Secondary Technogenic Formations

The article considers the inevitability of copper losses with slag and the possibility of reducing them by various methods and using local secondary technogenic formations. It has been established that the developed and widely used in industry technologies for slag decontamination only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the losses are established and suggestions for reducing their negative impact are recommended. The use of perfect mixing devices is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to achieve an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.

Determination of Optimum Production Parameters for Depletion of Balkhash Copper-Smelting Plant Dump Slags

Research is conducted on depletion of Vanyukov furnace (VF) slag of the Balkhash Copper Smelting Plant. It is proposed to carry out charge smelting and the depletion of slag in a two-zone VF furnace that has oxidizing and reducing zones separated by a partition. In order to determine the main production parameters of the operation of such a furnace laboratory studies are conducted making it possible to establish optimum conditions for smelting a copper charge. Optimum slag compositions are determined, slag obtained under oxidation and reduction conditions is studied thermogravimetrically, and the melting temperature is determined in each zone: 1285 and 1297 °C. It is established that a reduction in magnetite content to 2.0–2.3% makes it possible to reduce the copper content to 0.5–0.7% in dump slags.

Design and construction of precast reinforced concrete drain pipe in water conservancy project

At the bottom of slag dump site in water Conservancy projects, large diameter reinforced concrete drainage pipes are often used for drainage. Due to the large depth of burial, if the prefabricated reinforced concrete drainage pipe is damaged during construction or use, it will have a great negative impact on the safety of the project and it will be very difficult to repair. There is no relevant basis in the water Conservancy code and there are safety risks. Taking actual engineering as an example, the calculation results according to the design specifications and finite element analysis are compared and analyzed. the limitations of designing according to the water supply and drainage codes are explained. Some engineering solutions for the reinforcement design of prefabricated reinforced concrete drainage pipes with large buried depth are given out. These results can provide reference for hydraulic engineering designers.

Rainwater-induced migration of potentially toxic elements from a Zn–Pb slag dump in Ruda Śląska in light of mineralogical, geochemical and geophysical investigations

The Upper Silesia region of Poland is known for its concentration of heavy industry, including mining and smelting. Slag dumps scattered across the region are the sources of pollutants such as Zn, Mn, As, Cd and Pb. At the slag dump in Ruda Śląska, it is possible to distinguish three types of slag: (i) slag associated with the muffle/lining material, composed of olivine, pyroxene, iron oxide, feldspar and glass; (ii) glassy slag composed of glass and single crystals of melilite and wollastonite; and (iii) slag composed of aggregates of melilite, wollastonite and anorthite. These concentrate Potentially Toxic Elements (PTEs), reaching up to 6130 mg/kg of As, 36300 mg/kg of Mn, 21700 mg/kg of Pb, 53600 mg/kg of Zn and 105 mg/kg of Cd. Rainfall-induced weathering causes PTE mobilisation to secondary phases, mainly carbonates, sulphates, oxides and hydroxides. Leaching tests based on the Synthetic Precipitation Leaching Procedure (SPLP) prove the release of PTEs from slags and secondary phases, which was further confirmed by significant PTE concentrations in a water sample from effluent next to the dump: 2710 μg/l Mn, 163 μg/l Zn, 52.5 μg/l Pb, 20.1 μg/l As, 0.98 μg/l Cd. This study is the first attempt to apply a combination of electromagnetic (EM) measurements and mineralogical investigations to pyrometallurgical Zn–Pb slags, and to precisely describe links between the obtained conductivity and in-phase results and phases building soils and sediments of the studied area. Contamination mapping, using combined scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and EM methods, allowed to distinguish the main migration path of PTEs from the slag dump. This path is related to the effluent in which the presence of sulphides, oxides and hydroxides concentrating Cd, Zn, and Pb was determined to cause both high conductivity (>300 mS/m) and in-phase values (>6 ppt). On the other hand, soils from other areas outside the dump are not polluted by this migration path. Application of EM mapping confirmed its usefulness as a tool for tracking environmental contamination. For successful interpretation, however, it must always be used in combination with mineralogical/petrological methods.

Spatio-Temporal Dynamics of Soil Geochemical Anomalies in the Zone of Impact of Slag Residuals

The 13-year-old (from 2003 to 2016) dynamics of soil contamination for the content of heavy metals in the area of the village of Bolshoye Dumchino of the Mtsensk District in the territory adjacent to the slag dump of Mtsensk Foundry was studied. It is shown that on the territory of the placement of slag residuals a techno geochemical anomaly is formed, in which the contained heavy metals are of technogenic and genetic (natural geochemical) nature. To identify the effect of anthropogenic factor on soil pollution with heavy metals, was determined the refined enrichment factor of heavy metals (EFHM) in light gray forest soils at different distances from the slag dump, allowing to calculate the proportion of technogeneity of metals as a percentage of its total content. The technogenic origin of heavy metals as pollutants and the role of humus soil horizons in fixing these metals in the soil profile have been proven. Analysis of the results characterizing the degree of enrichment of the genetic horizons of light gray forest soils with heavy metals for the period 2003–2016 convincingly proves the effect of maximum accumulation of slag residuals in the dump on the accumulation intensity and fixation of the studied metals, both in the upper humus layer and their distribution in the profile soil. The established patterns in changing the degree of enrichment and technogenicity of heavy metals in the profile of light-gray forest soil are caused not only by the impact of the slag dump as a source of pollution, but also by the peculiarities of using the soils of the studied territories. It is shown that the toxic load for the analyzed period not only did not decrease, but even increased.

In situ bioremediation of hexavalent chromium in presence of iron by dried sludge bacteria exposed to high chromium concentration

Stability of chromium in the ferrochrome slag dumps and leachate are affected by pH, redox potential and the presence of other metallic species in the slag. It is desirable to keep chromium in slag dumps in the trivalent [Cr(III)] state because trivalent chromium is 1000 times less toxic to living organisms than the hexavalent form [Cr(VI)]. Due to the low toxicity and low mobility of Cr(III), it is recommended to convert Cr(VI) to Cr(III) wherever possible to protect the health of living organisms. In this study, the role of Cr(VI) reducing organisms for stabilising chromium in slag dumps was evaluated in the presence of iron [oxidation states Fe(II) and Fe(III)]. The study showed that stabilisation of chromium species in the trivalent state was most favourable under aerated conditions. Up to 100 mg/L Cr(VI) was reduced in less than 24 h by cultures grown under aerobic conditions in the presence of Fe(III). A much shorter time (6 h) was required to reduce the same amount of Cr(VI) in the presence of Fe(II). When oxygen was completely excluded, it was only possible to reduce 20 mg/L in about 48 h which was much slower than the removal of 100 mg/L in less than 24 h under aerated conditions. Fe(II) contributed directly to catalytic reduction of Cr(VI) reduction whereas Fe(III) was beneficial to Cr(VI) reduction up to an initial Cr(VI) concentration of 75 mg/L. Evaluation of Cr(VI) reduction kinetics showed that Cr(VI) reduction under aerobic conditions followed the non-competitively inhibited mixed-order reaction. Cr(VI) reduction in sealed reactor vessels, under anaerobic conditions, followed a modified non-competitive inhibition reaction model. The results indicate that chromium stabilisation in ferrochrome slag dumps would require maintenance of a fully aerated dump supplemented by a culture of Cr(VI) reducing organisms.

The impact of coal ash and slag dump on the quality of surface and ground waters - a case study

This paper presents the assessment of the impact of coal ash and slag from the ?Maljevac? dump on the quality of water of Paleski Creek, Montenegro. The obtained results confirm the negative influence of surface and groundwater from the dump on the water from the Paleski Creek. The results obtained by testing of the water samples, collected from Paleski Creek upstream of the dump, indicate that the water is qualified to be used for drinking, after simple physical treatment and disinfection. The results obtained for the water samples collected from the Paleski creek downstream from the dump indicate that the water could be safe for drinking only after the treatment that requires an intensive physical, chemical and biological processing, including some extended treatment.

Study of the Possibility of Obtaining Non-Decomposing Slag During Low-Carbon Ferrochrome Production

Methods are analyzed for stabilizing self-disintegrating slags in melting low-carbon ferrochrome, and the main reasons for breakdown are considered. Four methods are shown for stabilizing oxide melts of which a promising method for preventing breakdown under contemporary production conditions for chromium ferroalloys by mixing melts is a reduction in the content of dicalcium silicate with a reduction in the CaO/SiO2 ratio in oxide melt to a value of less than 1.4. However a reduction in CaO/SiO2 slag basicity to 1.33 is demonstrated by experiment (during melting low-carbon ferrochrome containing not less than 5% Si). However, according to the specifications of GOST 4757–91 and the international standard ISO 5448-81 the silicon content in low-carbon ferrochrome should not exceed 1.5%, in view of which the silicothermal process for process for preparing ferrochrome by a mixing method should be separated into two stages. The first stage is preparation of siliceous semiproduct (low-carbon ferrochrome containing Si ≈ 5%) and non-disintegrating slag with reduced basicity (CaO/SiO2 = 1.3–1.4). The second stage is refining the semiproduct with respect to silicon with preparation of highly basic slag (CaO/SiO2 = 1.8–1.9) and ferrochrome with the required silicon content (less than 1.5%). The possibility of obtaining a non-disintegrating slag during melting low-carbon ferrochrome with subsequent processing into building rubble will make it possible to improve the ecological situation in the vicinity of ferroalloy enterprises, to reduce slag dump and adjacent territory contamination and dust content, and also to reduce the amount of slag, loss of chromium, and to increase productivity of the process with a reduction in specific consumption of lime and electrical energy.