DETERMINING THE COMPOSITION OF SOLID WASTE FORMED AT THE BAKU STEELMAKING PLANT USING THE SPECTROMETER S8 TIGER

ABSTRACT

In our research, the composition of solid waste slag collected from this facility was analyzed using the modern X-ray fluorescence (XRF) S8 TIGER spectrometer. Bruker XRF spectrometers combine simple and fast sample preparation with the highest accuracy in elemental analysis, covering concentration ranges from 100% down to the ppm level. Until now, an in-depth analysis of the composition of slag waste generated at the Baku Steelmaking Plant has not been conducted. Based on the research findings, it is possible to substantiate the significant economic and environmental benefits of assessing the ecological impact of this slag waste and its potential reuse in secondary steelmaking.

АННОТАЦИЯ

В ходе наших исследований состав твердых отходов — шлака, собранных на этом предприятии, анализировался с помощью современного рентгенофлуорецентного (РФА) спектрометра S8 TIGER. Спектрометры XRF компании Bruker сочетают в себе простую и быструю подготовку образцов с высочайшей точностью элементного анализа, охватывая диапазоны концентраций от 100% до уровня ppm. До настоящего времени глубокий анализ состава шлаковых отходов, образующихся на Бакинском Сталеплавильном заводе, не проводился. На основании результатов исследования можно обосновать значительные экономические и экологические преимущества оценки воздействия этих шлаковых отходов на окружающую среду и их потенциального повторного использования при вторичном производстве стали.

Keywords: secondary steelmaking, slag waste, spectrometer, concentration, X-ray fluorescence.

Ключевые слова: вторичная выплавка стали, шлаковые отходы, спектрометр, концентрация, рентгенофлуорецент.

Introduction

As is well known, solid waste generated in various industrial sectors plays a significant role in soil and groundwater contamination over time, depending on its composition. Solid production waste-slag obtained in the Secondary Steelmaking Industry varies in composition and environmental impact. Therefore, determining the composition of solid waste generated at the Baku Steelmaking Plant is one of the most pressing environmental issues. To address this problem, the first step is to analyze the composition of this solid waste using modern equipment and conduct an environmental assessment, which is considered a crucial ecological study.

According to modern environmental requirements, environmental protection is one of today's most critical ecological demands. One of the leading causes of environmental pollution is the melting of old, unusable metal waste in the industry. Although the Secondary Steelmaking Industry has advantages over the Primary Steelmaking Industry, it is still considered one of the main sources of environmental pollution in various aspects. In many cases, the quality of metal alloys decreases during the overall melting process in the Secondary Steelmaking Industry. One of the factors contributing to this issue is the presence of mercury compounds in the alloys, which are toxic to the human body and can even lead to fatal consequences. Another factor is the presence of tungsten-containing metal waste, which requires extremely high temperatures and additional costs during the melting process. For this reason, such metal waste is considered unusable waste.

The in-depth study of slag composition, a solid industrial waste that plays a crucial role in the Secondary Steelmaking Industry and contributes to environmental pollution, is essential for identifying the causes of its ecological impact. Therefore, we collected samples of all types of solid waste slag stored near the production areas of this industry using established procedures. According to various technical sources, metal waste can cause numerous diseases, even at low concentrations. For this reason, after determining the composition of slag waste generated in the Secondary Steelmaking Industry, conducting continuous ecological analyses of the soil, water, and air in the open storage areas (landfills) and nearby locations is crucial. Conducting ecological research in this field is considered one of the most important aspects of modern environmental safety requirements for waste management.

Materials and methods

By the research objective, the study on determining the composition of slag waste samples collected from the Baku Steelmaking Plant was conducted using the X-ray fluorescence (XRF) S8 TIGER spectrometer. X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) are powerful analytical techniques used to determine the composition and structure of materials, including sand samples used as reference standards. These methods provide valuable information about samples' elemental and mineralogical composition and are widely used in various industrial and scientific applications. X-ray Fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. Its operating principle is based on the emission of high-energy X-rays.

Working Principle of XRF: X-ray Fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. The working principle is based on the interaction of high-energy X-rays with a sample, leading to the emission of characteristic secondary (fluorescent) X-rays.

1. X-ray Excitation: The sample is exposed to a primary X-ray beam generated by an X-ray tube or radioactive source.
2. Electron Ejection: The high-energy X-rays knock out inner-shell electrons (typically from the K or L shell) of atoms in the sample.
3. Fluorescence Emission: As outer-shell electrons fill the vacancies, characteristic X-rays are emitted, which are unique to each element.
4. Detection and Analysis: A detector captures the emitted X-rays, and a spectrometer analyzes the energy or wavelength of these X-rays to determine the elements present and their concentrations.

XRF analysis is widely used to determine the elemental composition of sand samples, including major and trace elements. This process primarily involves the following stages:

1. Sample Preparation: Sand samples can be analyzed as loose powder, compressed pellets, or fused glass beads.
2. Instrument Calibration: The XRF device is calibrated using standard samples to ensure accurate elemental identification.
3. Analysis: The sample is placed inside the device, exposed to X-rays, and the emitted radiation is measured to determine elements such as Si, Al, Fe, Ca, Ti, Mg, Na, K, and others.
4. Interpretation of Results: The identified elements help assess the sand's purity, chemical composition, and industrial suitability.

Table 1.

Comparison of XRF and XRD for Sand Analysis

XRF and XRD analysis methods are complementary important techniques in the analysis of sand samples, and their combined use is an ideal approach for a complete material characterization.

Results and discussion

The analysis results of the solid waste slag composition collected from the Baku Steelmaking Plant using the modern X-ray fluorescence (XRF) S8 TIGER spectrometer are shown in Tables 1 and 2 below.

Table 2.

The results of the analysis of the composition of solid waste slag

Table 3.

 The results of the analysis of the composition of solid waste slag

As shown in the tables above, the slag waste (Slag 1, Slag 2, Slag 3) contains a high amount of Fe₂O₃ and CaO, indicating that the problem of recycling these slags needs to be addressed. Furthermore, as indicated in the tables, the presence of more than 1% MgO and Al₂O₃ suggests that recycling slag waste containing these compounds would have significant economic and ecological importance.

It should be noted that some slags, as seen in the table, contain TiO₂, Cr₂O, and SrO, which, when used in secondary steel alloys, play a crucial role in improving the quality of steel, such as enhancing corrosion resistance, heat resistance, and the production of heat-resistant steels.

As is known from various sources, the storage of slag waste, which contains many heavy metals as shown in the table, in open landfills without proper utilization leads to soil contamination with heavy metals and groundwater pollution.

As mentioned in the referenced literature, these slags, like fine dust and aerosols, can travel long distances, negatively impacting the atmospheric air quality and the entire biosphere. As a result, this has a significant adverse effect on plant and animal life and, after some time, on human health.

We have also conducted scientific-ecological studies to determine the reasons for the formation and composition of slag waste in Secondary Steelmaking Plants. The ecological research was carried out based on explanations from scientific and technical literature. The main experimental part of the research involved determining the composition of the collected slag samples using various known methods and devices through modern equipment available in several institutions. Depending on the accuracy of the devices and the sensitivity of the analysis, the tests were repeated multiple times. During the study, the operation of the devices and the preparation of samples were carried out in collaboration with experts from these institutions.

Conclusions

The elemental compositions of slag waste samples formed at the Baku Steelmaking Plant were determined for the first time using modern analytical devices. It was found that in the Secondary Steelmaking Plant, the production of high-quality metal alloys results in the formation of slag waste with various compositions, depending on the composition of the metal waste, the reagents used, and the melting temperature. Due to the presence of many metal oxides in the slag, it is possible to scientifically explain the ecological impact of these wastes on the environment based on information from technical literature. As noted in the tables below, each type of oxide compound, after some time, can rise into the air as dust and aerosols, especially in windy conditions, leading to pollution in the surrounding area of the plant and areas beyond it.

Based on the results of the ecological-scientific research conducted by us, we present the following proposals, which hold significant ecological and economic importance:

1. It is advisable to use slag containing TiO₂ and other high-quality oxides as an additional material in secondary steelmaking. By using a certain percentage of TiO₂ in metal alloys, it is possible to obtain alloys that are resistant to high temperatures, fire, and corrosion, and this proposal can be considered scientifically grounded.

Therefore, after thoroughly determining the composition of other slags formed in the Secondary Steelmaking Plant, it can be scientifically justified that using these slags in secondary steelmaking holds significant ecological and economic benefits.

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