RESEARCH OF REDUCING THE ENVIRONMENTAL IMPACT OF COPPER PROCESSING PLANT WASTE BASED ON COMPOSITE COMPOUNDS

ABSTRACT

The article examines the impact of mining waste on the environment, in particular based on waste from a copper processing plant. The amount of annual and accumulated waste from the plant is given. The chemical and granulometric composition of waste has been studied and determined in laboratory conditions. In connection with the impact of copper enrichment production waste on the environment in the form of dust, it was determined which dust group they belong to, the weather indicators of the area where the research complex is located were monitored, and compared with WHO standards. As a result of the comparison, it was found that the current air quality index exceeds the standards of PM 10 and PM 2.5. In order to reduce the impact of waste on the environment, a composite compound was prepared from organic substances - gossypol resin, carboxymethylcellulose, alkanolamines, and modification of the waste into a slurry state was proposed.

АННОТАЦИЯ

В статье рассматривается влияние отходов горнодобывающей промышленности на окружающую среду, в частности на основе отходов медеобогатительного комбината. Приведено количество годовых и накопленных отходов завода. Химический и гранулометрический состав отходов изучен и определен в лабораторных условиях. В связи с воздействием отходов меднообогащающего производства на окружающую среду в виде пыли определено, к какой группе пыли они относятся, проведен мониторинг погодных показателей района, где расположен научно-исследовательский комплекс, и сопоставлены со стандартами ВОЗ. В результате сравнения было установлено, что текущий индекс качества воздуха превышает нормативы РМ 10 и РМ 2,5. С целью снижения воздействия отходов на окружающую среду приготовлено композиционное соединение из органических веществ - госсиполовой смолы, карбоксиметилцеллюлозы, алканоламинов, предложена модификация отходов в в состоянии гидросмеси.

Ключевые слова: экология, руда, композиционное соединение, пыль, модификация.

Keywords: ecology, ore, composite compound, dust, modification.

Introduction. The mining industry is one of the most important sectors that improve the economic indicators of our country. The copper beneficiation industry is of particular importance in the mining industry. Today, more than 35 million tons of ores are processed and beneficiated into copper concentrate at copper beneficiation plants. It is known that industrial waste is generated in the process of obtaining this product and transported to the industrial waste storage basin through hydrotransport systems [1]. Over the years, more than 960.5 million tons of flotation ore waste and 13 million tons of flotation slag waste have accumulated in AMMK landfills as a result of copper ore processing. About 400,000 tons of waste slag with an iron content of 35-40% is stored due to the discharge of slag during the smelting of copper-containing raw materials [2]. The dust generated from the waste of the copper concentrator has negative consequences for the environment, which may cause environmental problems in the future. Taking into account the urgency of ecological problems, attention to ecology is being implemented at the state level in our country. The impact of man-made waste on the environment is observed mainly through the dust rising from the waste storage basins and the greening of plants. We recommend the use of composite compounds made on the basis of local raw materials to reduce rising dust and promote plant life. Composite compounds are added during the hydrotransport process in the state of hydromixing of waste. As a result of the use of this composite compound, the possibilities of achieving both economic and environmental efficiency were studied in the research process. Extensive studies have been conducted by scientists of our country and the world to study the impact of mining wastes on the environment, and these issues remain relevant even today [3, 4].

Research object and method. In the course of the research work, studies of the impact of man-made wastes on the environment of 2-MBF "Almalik Mining Metallurgical Combine" JSC, where an average of 4,5 million tons of beneficiation industry wastes are released every year, were carried out.

To study the impact of man-made waste on the environment, it is important to determine the composition of the waste. Therefore, during the research, the industrial methods recommended in GOST 15934-15934.17, GOST 2803-89, GOST 30609-98, GOST R 51947-202, TU 1733-368 004-2012 were used to determine the composition of the waste coming out of the factory. When studying the distribution of waste, their granulometric composition is determined, the granulometric composition was determined according to the recommendations specified in GOST 14180-80, GOST 10141-91, GOST R ISO 5223-99. The dust level of the waste was determined based on the air pollution standards of the World Health Organization (PM10, PM2.5). The impact of waste on the environment is mainly caused by the rise of dust. Dust refers to gas systems that contain small particles of solid matter, dust is usually formed during mechanical crushing, grinding and transfer of solid matter from one place to another. The size of industrial dust ranges from 0.001 to 0.1 mm. In the departments of enrichment factories, mainly during the preparation process, technological dusts appear, which are considered to be very small particles of fossil resources and move suspended in the air [3, 5]. In order to reduce the impact of these dusts on the environment, the method of modification of the waste in the state of hydromixing with composite compounds was used. In the process of modification, studies were conducted to increase the speed of dust particles falling to the ground and the interconnection of dusts, to increase productivity based on minerals in the waste. Organic substances prepared on the basis of secondary local raw materials - gossypol tar, carboxymethylcellulose, alkanolamines - made a composite compound and used it as a modifier [6, 7].

Research results and discussion. In order to study the environmental impact of enrichment factory waste, we determined the composition of the waste (table 1), the result showed that the substances in the waste, as well as salts dissolved in water formed during the enrichment process, flotation reagents in the form of emulsion, and products formed as a result of the interaction of reagents and minerals in the waste storage basin is collected.

Table 1.

The chemical composition of the wastes resulting from the enrichment of the MBF-2

The chemical composition of copper smelter waste was determined by fundamental parameter methods (Scatter FP) on a Rigaku Technologies (USA) NEXCG analyzer.

Figure 1. Chemical composition determined at the NEXCG laboratory facility of the copper concentrator

Due to the fact that the waste with the specified chemical composition produces dust, the granulometric composition was studied on the basis of the experimental test (Table 2) and the average diameter of the dust particles was determined. Dusts are divided into coarse, fine, fine and very fine dusts according to their granulometric composition.

1. Large dusts: 100-500 µm in size

2. Small dust: size 10-100 microns.

3. Fine dust: size 0.1-10 microns.

4. Superfine dusts: size <0.1 microns.

Table 2.

Granulometric composition of wastes of copper concentrator

Based on the results obtained in the laboratory, 97% of the slag consisted of particles smaller than 0.063 mm. Taking into account that the average diameter in our research facility is 0.071 mm or 71 μm, based on the determination of the granulometric composition of the particles, we determined that dust particles belong to the group of fine dust. Recommendations have been made by the WHO on the dispersion of these dusts in the air, and this is limited to certain standards [3].

Table 3.

WHO standards for PM10 and RM2.5 concentrations of dust particles in the air

Based on these criteria, we determined the annual average state of air quality in the area where our research object is located.

Figure 2. One-year air quality monitoring of Almalyk region

According to the obtained results, it was found that the air is moderately polluted and is greater than the maximum limit set by WHO for one year. Long-term exposure to this quality of weather poses a health risk.

On the basis of the determined results, the following features were created by combining the general properties of the organic substances in the composition of the composite compound - Gossypol resin (GS), Carboxymethylcellulose (KMTs), Alkonalamine (AL) substances:

1. Suppression of war. When the solid dispersion systems in the state of hydromixing are collected in the waste storage basin, the liquid phase leaves through the collection pipes, and the dispersion systems remain in the state of a dam. Composite compounds form a crust on the surfaces of dispersed systems and acquire the property of mutual viscosity, hold loose dispersed systems and ensure adhesion of small dust particles to the surfaces, as a result, the dust is suppressed without rising.
2. Bonding properties. binds dust particles together and acts as a binder, causing a thick layer to form.
3. Effect on soil fertility. AL in the composition of the composite compound normalizes the alkalinity of the soil, increases the fertility of the soil, creates conditions for the growth of plants, which helps the flora to grow.

When adding a composite compound to wastes in the form of a hydromix, the mass fraction of the solid phase in the hydromix is taken and 80 g/t is added as a solution. We proposed to calculate the average efficiency of dust suppression as a result of the addition of the composite compound using the following formula:

                                                                    (1)

Here С₀ – the previous concentration without dust suppression, mgm^-3;
С₁ – the concentration of dust after using the composite compound, mgm^-3, n – the number of concentration measurements (n=60, for each experiment, concentration measurements are made every minute for one hour) [8-10].

Here S0 is the previous concentration without dust suppression, mgm-3; S1 is the concentration of dust after using the composite compound, mgm-3, n is the number of concentration measurements (n=60, for each experiment, concentration measurements are made every minute for one hour) [8-10].

Figure 3. Comparing the effectiveness of suppression

From an ecological point of view, the importance of composite compounds in reducing the environmental impact of copper smelter waste is very high, as the proposed compound is made from local raw materials and is also economically efficient.

Conclusion. During the study, the environmental impact of waste from the copper beneficiation factory was studied. The amount of annual and accumulated waste from the factory was given. The chemical and granulometric composition of waste was studied and determined in laboratory conditions. Due to the impact of copper beneficiation industry waste on the environment in the form of dust, it was determined which dust group it belongs to, the weather quality indicators of the area where the research facility is located were monitored and compared with WHO standards. As a result of the comparison, it was found that the current air quality indicator is in high pollution. In order to reduce the impact of waste on the environment, a composite compound was prepared from organic substances - gossypol tar, carboxymethylcellulose, alkanolamines, modification of waste in a hydro-mixed state was proposed.

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