Re-Use of Silico-Manganese Slag

The world’s rapidly growing demand for raw manganese has made it increasingly important to develop methods for the economic recovery of manganese from secondary sources. The current study aims to present possible ways for the recycling and reuse of silico-manganese slag landfilled in Tulcea, City on the Danube River close to the Danube Delta Biosphere Reserve in order to save the natural resources raw of manganese. In the last three decades, the ferroalloy production plant has over 2.6 million tons of slag. Slag dumping constitutes a significant source of air, water and soil pollution, which adversely affects the environment and human health. Mn present in the slag dump is an environmental pollutant with potentially toxic effects. The results obtained with a leaching method to recover manganese from slag shows two efficient ways to valorize manganese from solid fraction (54%) with size particles between 80 and 315 µm and/or reuse the leaching medium (56% Mn) with a slag size of <80 µm. The motivation of our research is the possibility to recover manganese from slag by saving natural resources of raw of manganese and the remaining fraction can be used as aggregate sources (construction and road rehabilitation by saving extract mineral aggregates and agriculture), in order to decommission the slag dump. The proposed research is in concordance with the sustainable use of natural resources for the achievement of sustainable development of the 2030 Agenda and Waste Management Legislation due of the huge ecological costs regarding non-conforming waste dumping. If we consider the cost-benefit analysis, the environmental future is more important the human health and the benefits on the quality of the population’s health and the environment which are not non-measurable in monetary value.

Survival of forest strips in ash and slag dump territory of Chita combined heat and power plant

This article is a continuation of research on creation of forest protective strips on the territory of sanitary protection zone with intensive influence of ash and slag dump of the Chita CHPP-1 (TGC-14). Earlier (2017-2019), plantings were made focused on reducing atmospheric pollution, improving soil properties, regulating surface runoff that prevents erosion, fixing ground cover, reducing wind speed and retaining small solid particles. The aim of the research was to analyze survival rate and health of woody and shrubby plant species in protective forest strips; to obtain linear indicators of plant growth and development in experimental plots. In the course of the research, it was found that the overall survival of plants in the experimental plots differed by year. Survival rate of woody and shrubby plant species also differed. Larix gmelinii, Betula pendula, Hippophae rhamnoides, Crataegus sanguinea, Caragana spinosa and Elaeagnus commutata had the highest survival rate in the experiment. The survival of shrubs was generally better than that of trees. Among shrub species, Caragana spinosa (92 and 81 %) and Elaeagnus commutata (95 and 86 %) were characterized by good survival in plantings in 2017 and 2018, respectively. Rosa acicularis (20 %), Spiraea media and Sorbaria sorbifolia (28 %) showed low survival in 2019. The plant survival varies significantly depending on the planting season, types of seedlings and planting technology. The use of planting material (wildfowl) with a large earthen lump increases plant survival in forest protection strips. Unfavorable factors that have a negative impact on the transplanted plants are man-made landscapes, harmful atmospheric impurities from the ash and slag dump. Moreover, competitive relations with herbaceous plants, intensive grazing of animals, insect and disease damage have an additional impact. For healthy growth of plants, it is necessary to perform care for plantings, and organizational measures (fencing of experimental plots with signal tapes). It is important to continue observations and repeat plantings to clarify the adaptive ability of plant species grown in protective plantings, improve planting technology.

Soil Heavy Metals Contamination of a Typical Calcium Carbide Slag Dump Sites: Source Apportionment and Risk Assessment

Source identification and risk assessment of heavy metals were the necessary preliminary work for the contaminated sites remediation. In this report, the As, Cd, Cr, Cu, Hg, Ni, Pb and Zn concentration in a typical calcium carbide slag dump site of thirty-four soil samples were collected to test. The source of heavy metals was analyzed by PMF model, and the apportionment of ecological risk and health risk with different pollution sources were calculated. The results show that Hg was the main polluted heavy metal in the site, with a maximum concentration of 112.19 mg.kg-1, and the soil in the site was accompanied by As, Cu and Pb co-contamination. The average Hg concentration in farmland samples was 0.13 mg.kg-1, which also exceeded the local soil background values, indicating that soil Hg contamination in the site had spread outwards. The sources of eight heavy metals were divided into oil refinery waste water and parent material mixed source (As, Cr, Cu and Pb), vinyl chloride waste source (Hg) and parent material source (Cd, Ni and Zn), respectively. The average potential ecological risk of soil in the site was 22344.39 and vinyl chloride waste source contributed 99.85% to ecological risk. The average CR of oil refinery waste-water and parent material mixed source for children and adults were 9.06×10-6 and 6.36×10-6, accounting for 99.9% and 99.48% of the total average CR for children and adults, respectively. The average HI of vinyl chloride waste source to children and adults were 0.6 and 0.38, accounting for 64.13% and 52.34% of the average total HI of child and adult, respectively. This indicates that children were more vulnerable to heavy metals. Compared with adults, the major pollution sources were more harmful to children.

Key technologies of ecological restoration and analysis of slope stability of spontaneous combustion of slag dumps in gullies

There are potential safety hazards such as spontaneous combustion, high temperature explosion, rainfall-induced landslide, and others within slag dumps in gullies, which seriously endanger the lives and property of surrounding residents. In this paper, the slag dump on the north side of Yumen River in Ximing Mine was taken as the project background. Aimed at the existing problems of environmental pollution and slope stability of the spontaneous combustion of slag dumps in gullies, the key technology of fire extinguishing by shallow jet deep hole grouting and the technology of foreign soil spray seeding with multiple soil fixation measures were put forward. The safety factor of gangue hill slopes under natural conditions, earthquakes and rainstorms was calculated by Lizheng Slope Stability Analysis Software, and the displacement field and the stress field of dangerous sections were analyzed by MIDAS GTS NX, a finite element simulation software. The calculation and analysis results show that the slope of the slag dump is in a stable state under natural conditions. Under the working conditions during earthquakes and rainstorms, the safety factor of the slope of the slag dump is decreased obviously, but the slope is still in a basically stable state. After 2 years' follow-up monitoring, the ecological restoration effect of the slag dump is good and the slope is stable.

COMPARATIVE ANALYSIS OF THE STATE OF FRAGMENTS COENOPOPULATIONS OF CHAMAECYTISUS RUTHENICUS (FISCH. EX WOL.) KLASS.

Статья посвящена комплексной оценке состояния ракитника русского Chamaecytisus ruthenicus на основе онтогенетических, популяционных, морфометрических и виталитетных параметров данного вида в природных и антропогенных ландшафтах Режевского района Свердловской области. В индивидуаль- ном развитии Chamaecytisus ruthenicus выделены 3 периода и 6 онтогенетических состояний. Характер- ным типом онтогенетического спектра является одновершинный центрированный спектр. Особенностью в условиях антропогенного воздействия на шлаковом отвале и в водоохраной зоне р. Реж является пол- ное отсутствие прегенеративных особей, о чем свидетельствуют индексы восстановления и замещения. По совокупности всех параметров установлено, что оптимальные условия для существования складыва- ются в природном ландшафте в водоохранной зоне р. Бобровки, несмотря на низкие организменные зна- чения. Преобладающая часть изученных местообитаний ракитника отличается высокой численностью и не- полночленным онтогенетическим спектром, связанным с быстрым отмиранием растений после заверше- ния генеративного периода. По нашим наблюдениям, состояние фрагментов ценопопуляции не только зависит от эколого-ценотических условий в местообитаниях, но связано в первую очередь с антропоген- ными воздействиями. Отсутствие антропогенного влияния способствует увеличению плотности особей в ценопопуляции, и за счет регулярной смены поколений ракитник русский способен удерживать занятую им территорию. The article is devoted to a comprehensive assessment of the condition of Chamaecytisus ruthenicus on the basis of ontogenetic, population, morphometric and vital parameters of this species in natural and anthropogenic landscapes of the Rezhevsky district of the Sverdlovsk region. There are 3 periods and 6 ontogenetic States in the individual development of Chamaecytisus ruthenicus. A characteristic type of ontogenetic spectrum is a single-vertex centered spectrum. Especially in the conditions of anthropogenic impact on the slag dump and in the water protection zone of the river. However, we can distinguish the complete absence of pregenerative individuals, as evidenced by the recovery and replacement indices. Based on the totality of all parameters, it was found that the optimal conditions for existence are formed in the natural landscape in the water-protected zone of the Bobrovka river, despite the low organizational values. The predominant part of the studied Chamaecytisus ruthenicus habitats are characterized by a high number and incomplete ontogenetic spectrum associated with the rapid death of plants after the generative period. According to our observations, the state of coenopopulation fragments not only depends on the ecological and coenotic conditions in the habitats, but is primarily associated with anthropogenic impacts. The absence of anthropogenic infl uence contributes to an increase in the density of individuals in the coenopopulation and due to the regular change of generations, the Chamaecytisus ruthenicus is able to hold the territory occupied by it.

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.

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.