ISSN 0798 1015

Vol. 38 (Nº 43) Año 2017. Pág. 29

New Method’s Development of Industrial Waste Recycling to Reduce Environmental Stress around Lake Baikal

Nuevo Método Desarrollo del Reciclaje de Residuos Industriales para Reducir el Estrés Ambiental alrededor del Lago Baikal

Sergey BUYANTUEV 1; Vladimir SAKTOEV 2

Recibido: 15/06/2017 • Aprobado: 28/06/2017

Content

1. Introduction

2. Materials and Method

3. Data, Analysis, and Results

4. Discussion

5. Conclusion

Acknowledgement

References

1. Introduction

Due to the industrial activity of humankind, fresh water is becoming one of the most crucial and difficult to renew natural resources (Nekhoroshkov, 2016, pp. 1761-1771; Ravera, 2013).

Lake Baikal is one of the world’s largest lakes that contains about twenty per cent of the world’s fresh water (Jakob, et al., 2016). The development of various industries (mining, metallurgy, energy, etc.) and infrastructure (railway and roads construction, pipelines and power lines construction, etc.) changed environmental situation in the region, and not for the better. In this regard, various Russian and international organizations and fund were founded that work hard to establish protected reserves and to attract attention of the world community in order to improve lake’s ecology (Hosaka, et al., 2016, pp. 61-67). As a result of their activities following acts were adopted: the UNESCO and the UN decision to assign Lake Baikal the status of World Heritage; the Law of the Russian Federation on Lake Baikal, and the concept of the target program “Protection of Lake Baikal and Socioeconomic Development of the Baikal Natural Territory up to 2020” (Bychkov, Maksimova, & Kuznetsova, 2015, pp. 350-357; Hosaka, et al., 2016, pp. 61-67; Jakob, et al., 2016). These acts laid foundation for the strategy and tactics of solving Lake Baikal environmental issues on state and international levels. Along with that, the issues of systematic monitoring and analysis of Lake Baikal ecology, the search for financial, technical, and innovative technological solutions to further insure the reduction of environmental stress around the lake remain pressing problems. Continuous independent monitoring of the ecological status of Lake Baikal could use the experience of the USA and Canada, which established the International Joint Commission (IJC) for the environmental protection of the Great Lakes (Friedman, et al., 2015, pp. 171-179; Gronewold, & Stow, 2014, pp. 1084-1085; Schoen, 2016, pp. 1800-1813). The IJC is a nongovernmental organization that operates as a collegial agency in the interests of both countries.

One of the main pollutants in the region is waste from power companies (thermal power plants and thermal boilers) that work on low quality solid fuels, and coal mines that produce and supply solid fuel. These enterprises’ ‘products’ that pollute the environment are flue gases containing NOx nitrogen oxides, CO carbon, SO2 sulfur, etc., as well as soot and fine-dyspersated ashes particles. Another type of pollution from power plants are thermal power plants’ ash and slag waste as well as coal mines’ heaps (Buyantuev, & Sultimova, 2004, pp. 51-53; Chaus, Chistov, & Labzina, 1988; Popova, 1977, pp. 20-37). The problem is further exacerbated by the fact that Lake Baikal is an isolated ecosystem; despite the fact that the lake has 336 tributaries, most of them are insignificant (Batuev, et al., 2015, pp. 5-16). The lake has a single main inlet and a single main outlet for refilling its water (Evangelinos, et al., 2016, pp. 179-182; Kozhov, 2013, p. 11). At the inlet lies the polluted Selenga River (Rozhkova, et al., 2016, pp. 53-64), which flows from Northern Mongolia; at the outlet lies the Angara River.

This study aims to develop a technique for manmade waste processing.

2. Materials and Method

2.1 Research object

The object of research is ash and slag waste of thermal power plants and thermal boilers working on low-grade brown coal. There are large reserves of such coal in the region.

Table 1. Chemical composition of brown coal’s ash and slag of the Zabaikalskiyi region

2.2 Research methods

In each case of destroying, recycling and disposing of man-caused, domestic, and medical waste it is needed to know that what its made from, what harmful effects it may cause to the environment, and then choos ethe most effective method of destruction, recycling, and utilization with useful products production.

So, the study was carried out based on the following procedure:

• Chemical analysis of experimental waste samples
• The choice of innovative recycling method in order to insure efficient recycling with minimal power consumption and exclusion of harmful emissions into the atmosphere
• The study of physical and chemical properties of waste recycling products during its utilization with not full destruction
• Recommendations development and creation of new technology for the studied waste recycling
• Comparative analysis of the effectiveness of traditional and innovative recycling waste technologies.

3. Data, Analysis, and Results

3.1 Plant design and experimental research

Schematic diagram of the smelting unit is shown in Figure 1. Ash and slag feedstock is fed from above into the reaction chamber of the smelting unit where arc burns at the first stage between three core electrodes. Then by the time of the molten bath formation begins the second stage of Joule heating. At these stages, to ensure even melt heating throughout the whole reactor chamber conductive plasma and fluid rotate between three electrodes due to the magnetic field of coils. These coils are connected in series to each of the three electrodes. Upon reaching the required melt fluidity by the temperature of 1750-1800 0С central locking electrode opens, opens the taphole opening, and the melt stream flows further on the fiber forming unit (not shown on the Figure) by any of the known circuits.

Figure 1. Slit (A) and cross cut (B) of electromagnetic technological reactor.
1- reaction chamber, 2- water-cooled cover, 3- water-cooled bottom,
4- core electrode (3 pcs.), 5- locking core electrode, 6- polepiece,
7- series coil, 8- power source, 9- additional power source for stream heating,
10- device for melt removing (taphole), 11- lined chamber bottom,
12- nozzle into reaction chamber for raw material supply, 13- lining.

Design features of the reactor allowed receiving clean melt that is free from occluded gases and reduced metals. This melt enables production of higher quality products and low energy consumption in comparison to the known smelting units.

With the new type of smelting unit it was possible to arrange smelting into one single step consisting of the combined heating of raw materials:

- Arc plasma heating and melting of raw material happens at a start. Then, while melt occurs and melt’s conducting bowl is formed, raw material is being added and electric current flows through the molten silica-alumina mass. At the same time, this mass is being mixed and homogenized with a help of series-connected series electromagnets. That significantly reduces the time-to-operation and reduces power consumption. Defined in practice expended power that is required to produce melt with a weight up to 150 kg/h is 1.1-1.3 kW/kg (in comparison, expended power of the known induction furnaces is 6 kW/kg) (Buyantuev, et al., 2011).

Mineral fibers obtained by the electromagnetic technological reactor were examined to determine their physical and chemical properties.

Mineral fibers composition was determined by methods of chemical analysis.

Table 2 shows chemical composition of the fiber obtained from ash and slag.

Table 2. Chemical composition of fiber

The Table 2 shows that the content of silicon and aluminum oxides in the ash and slag fiber decreases slightly, with a slight decline of iron oxide. That is because during melting contained in it metal oxides are being restored into a compact metal which is simultaneously drained with melt pouring. These features of the smelting unit allowed to produce clean melt that is free from occluded gases and reduced metals. And that allows to produce the product of higher quality.

It is important to determine mean diameter of the fibers in order to assess suitability of mineral fibers as thermal insulation materials. Because the thinner fibers are, the lower thermal productivity it possesses. Microscopic method of sample analysis was used to determine the fibers mean diameter. The mean diameter was calculated by the following formula:

MD = g*P    (1)

where g- fiber mean diameter in ocular micrometer division; P- price of ocular micrometer’s dividing, µm.

It has been determined that ash and slag fibers have a mean diameter MD = 4-12 µm. Thus, fiber materials represent thin mineral fibers (Spirin, Ustenko, & Volodina, 1968, pp. 24-25).

4. Discussion

In aggressive environments fibers are exposed to corrosive action. There are two kinds of corrosive actions of aggressive environment on fibers: chemical (lixiviation) and dissolution in environment’s volume. Transition from lixiviation to direct dissolution is possible by interaction of fibers with acids and even water in case if fiber is strongly enriched by alkali and contains little silica (ultra low acidity module Ma).

The results of water-, acid-, and alkali resistance are shown in Table 3.

Table 3. Fibers chemical resistance

It is evident from the Table 3 that fibers have sufficiently high water resistance. By acid resistance, fibers may be divided in three groups: dissolving, lixiviating, and relatively persistent. From the presented samples of mineral fibers, more persistent are ash and slag fibers that content high level of silica and alumina oxide and low level of calcium and magnesium.

In order to explain the reasons for a high chemical resistance of ash and slag fibers its acidity module Ma was calculated by the following formula:

As follows from the calculation, acidity module of ash and slag fibers is Ma=9,96. Fibers chemical resistance highly increases with Ma increase, which is observed in ash and slag fibers.

The dependence of strength properties according to diameter was also determined. Fibers mechanical characteristics were determined by breaking experiment. Breaking stress (σ) of filament was calculated by the following formula:

where σ- breaking stress, MPa, P- breaking load, H, d- filament diameter, µm. Data on the dependence of fibers strength according to diameter is shown in Table 4.

Table 4. Dependence of strength properties according to diameter

As follows from the Table 4, fibers specific breaking stress depends on its diameter. The lager the diameter is, the lower is breaking stress (Bobrov, et al., 2003; Zyablitskii, 1979).

By mechanical properties (breaking) presented fibers are not inferior to the fibers obtained at well-known fields, as well as satisfy required state standards.

As we can see, obtained fibers are characterized by high performance and high acidity module. There is also a possibility to produce mineral wool from ash and slag waste. That shows prospects of this material not only in construction industry, but also in the production of fire and thermal insulation materials.

5. Conclusion

The discussed above research results lead to the following conclusions. By physical and chemical methods it was determined that during electromagnetic technological method of obtaining of mineral fibers certain processes occur that are different from processes that occur during conventional methods. Namely, at high processing temperature (1600-2500 K) there is deeper decomposition of raw material into elemental constituents in the form of respective oxides (SiO2, СаО, MgO, etc.). At the same time the reactor’s design features allowed to obtain clean melt occluded gases and reduced metals enabling production of high quality products. Based on this research it is possible to see the advantages of using the designed plant and technology for destruction and utilization of various solid domestic, medical, and other toxic waste to produce new types of composite materials. Because, first, these types of waste melting point and evaporation is lower than ash and slag. Second, it is possible to control (with a wide range) melting point on the designed plant. And third, there is possibility to decompose released harmful toxic gases into neutral components.

Acknowledgement

The research was partially funded by the state task GZN № 13.892.2014/K.

References

Batuev, A.R., Beshentsev, A.N., Bogdanov, V.N., Dorjgotov, D., Korytny, L.M., Plyusnin, V.M. (2015). Contents Ecological atlas of the Baikal basin: cartographic innovation. Geography, 1, 5-16.

Bobrov, U.L., Ovcharenko, E.G., Shoikhet, B.M., & Petukhova, E.U. (2003). Thermal insulation materials and constructions. Moscow.

Buyantuev, S.L., Malikh, A.V., Pashinskiyi, S.G., Ivanov, A.A., & Kitaev, V.V. (2011).  Patent of the Russian Federation No. 2432719 “Electromagnetic technological reactor”.

Buyantuev, S. L., & Sultimova, V. D. (2004). Production of thermal insulating materials from ash and slag waste of thermal power plant with the help of low temperature plasma. Construction Materials, 10, 51-53.

Bychkov, I.V., Maksimova, I.I., & Kuznetsova, A.N. (2015). Institutional support of the implementation of system approach to monitoring the unique system of Lake Baikal. Geography and Natural Resources, 36(4), 350-357.

Chaus, K.V., Chistov, U.D., & Labzina, U.V. (1988). Production technology of construction materials, products and structures. Moscow.

Evangelinos, D., Nelsom, C.H., Escuita, C., De Batist, M. (2016). Late Quaternary climatic control of Lake Baikal (Russia) turbidite systems: Implications for turbidite systems worldwide. Geology, 45: 179-182.

Friedman, K.B., Laurent, K.L., Krantzberg, G., Scavia, D., Creed, I.F. (2015). The Great Lakes Futures Project: principles and policy recommendations for making the lakes great. Journal of Great Lakes Research, 41, 171-179.

Gronewold, A. D., & Stow, C. A. (2014). Water loss from the Great Lakes. Science, 343(6175), 1084-1085.

Hosaka, Y., Saraswat, C., Moe A.Th., Ramanathan, A. (2016). Enhancing Resilience for Sustainable Development in Lake Baikal and Baikal Basin: Fresh Water Paradise. Journal of Climate Change, 2(1), 61-67.

Jakob, L., Axenov-Gribanov, D.V., Gurkov, A.N., Ginzburg, M., Bedulina, D.S., Timofeev, M.A., Luckenbach, T., Lucassen, M., Sartoris., F.J., Portner, H.O. (2016). Lake Baikal amphipods under climate change: thermal constraints and ecological consequences. Ecosphere, 7(3).

Kozhov, M. (2013). Lake Baikal and its life. Springer Science & Business Media, 11.

Nekhoroshkov, A. V. (2016). Moral Dimensions of Youth’s World View in Multi-Ethnic Environment. IEJME-Mathematics Education, 11(6), 1761-1771.

Popova, V. V. (1977). Materials for thermal insulation works. Moscow, 20-37.

Ravera, O. (2013). Biological Aspects of Freshwater Pollution: Proceedings of the Course Held at the Joint Research Centre of the Commission of the European Communities. Italy: Elsevier.

Rozhkova, N.A., Sinyukovich, V.N., Timoshkin, O.A., Bondarenko, N.A., Nepokryrykh, A.V., Matveyev, A.N.  (2016). Modern State of the Biota of the Selenga River Delta (Lake Baikal Basin) under Conditions of Unstable Hydrological Regime. Report II. Macrozoobenthos. Hydrobiological Journal, 52(3):53-64.

Schoen, L.S., Student, J.J., Hoffman, J.C., Sierszen, M.E., Uzarski, D.G. (2016). Reconstructing fish movements between coastal wetland and nearshore habitats of the Great Lakes. Limnology and Oceanography, 61(5), 1800-1813.

Spirin, U.P., Ustenko, A.A., & Volodina, M.N. (1968). Some operating characteristics of thermal insulation fiber. Construction Materials, 6, 24-25.

Zyablitskii, A. V. (1979). Theoretical basis of fiber formation. Moscow.

1. East Siberian State University of Technology and Management, Ulan-Ude, Russia; E-mail: buyantuevsl@mail.ru

2. East Siberian State University of Technology and Management, Ulan-Ude, Russia.