We had the opportunity to speak with Research Associate at the Materials Science and Technology Laboratory of the Institute of Chemistry and Chemical Technology at the Mongolian Academy of Sciences U.Bayarzul. She holds a doctorate in chemistry and has extensive expertise in the field of materials science. She graduated in 2006 from the School of Materials Technology at the Mongolian University of Science and Technology, earning a degree as a chemical technologist specializing in new materials. Two years later, in 2008, she completed her master of technical sciences degree, presenting a thesis on improving the dissolution of phosphorus fertilizers produced by mechanochemical methods and their activation using additives. In December, last year, U.Bayarzul defended her doctoral thesis, which focused on the chemical technology of producing glass-ceramic materials from waste raw materials. Her research explores the environmental and economic advantages of utilizing waste materials in the production of glass-ceramics.
What was the main goal and significance of the chemical technology research on producing glass-ceramic materials using waste raw materials?
The primary goal of my research is to establish a technological framework for the production of a new type of technical material: glass ceramics. This involves selecting appropriate raw materials, including feldspar and rare earth elements, or cerium oxide, which serve as additional liquid-phase generators and crystallizers. A key focus of my work is to thoroughly examine and characterize the properties, composition and technical parameters of these materials.
From a practical standpoint, the core advantage of using waste materials in the production of glass ceramics is their ability to conserve natural resources and reduce environmental impact. By repurposing waste, my research aims to contribute to the development of a durable, crystallized material that meets market demand. This innovative glass-ceramic material has significant potential for use in both construction and technical applications, offering a sustainable solution to material production while also supporting environmental protection.
Is it true that research into the chemical and physical properties of ash and its use as a primary raw material for the production of new materials has never been conducted in our country before?
Research into the use of fly ash as a minor additive to concrete dates back to the 1970s. However, comprehensive studies on the chemical and physical properties of fly ash and its potential as a primary raw material for the production of new materials have remained limited. Since 2010, the Materials Research and Technology Laboratory of the Institute of Chemistry and Chemical Technology at the Mongolian Academy of Sciences, under the leadership of Academician J.Temuujin, has focused on pioneering research in this area. Specifically, the laboratory has explored the production of zeolite and geopolymer-based building, road and glass-ceramic materials with excellent absorption properties for heavy and toxic elements, utilizing fly ash derived from Mongolian power plants.
This body of experimental and research work has led to the identification of viable methods for producing glass-ceramic materials. Three distinct production techniques have been explored, utilizing two types of waste - power plant ash and waste window glass - along with raw materials that contain feldspar and rare earth elements. Extensive studies have been conducted on the chemical, physical and mechanical properties of the resulting products. In addition, a mathematical model for the experimental process has been developed, enabling the identification of key factors influencing material properties and performance.
A preliminary economic analysis of producing exterior cladding panels for buildings using these glass-ceramic materials has also been carried out. This research not only highlights the potential of fly ash and waste glass as sustainable raw materials but also opens the door for the development of environmentally friendly building materials with enhanced performance characteristics.
What positive environmental impact could the use of this type of waste raw material have?
Greenhouse gas emissions from waste are a significant contributor to global warming, accounting for an estimated 15 to 20 percent of total greenhouse gases. The effects of global warming are far-reaching, disrupting ecosystems, increasing the frequency and severity of natural disasters, and threatening the availability of vital resources like water and food. In an era where natural resources are being depleted due to industrialization and rising consumption, it has become imperative to conserve these resources and use them more efficiently, minimizing waste wherever possible. In response to these challenges, there has been a growing emphasis on the extraction and use of raw materials from waste as substitutes for natural resources. The perception of waste has evolved; it is no longer seen merely as something to be discarded, but as a valuable resource that can be repurposed. One such material is ash from thermal power plants, which is considered the fifth largest waste resource globally. In Mongolia, a country that relies heavily on thermal power plants for its energy needs - 85 percent of its energy comes from these plants - this material represents a potentially crucial raw material for the future.
Ulaanbaatar, is home to nearly half of the country’s population, with over 1.7 million residents, a number that continues to grow annually. As the population of Ulaanbaatar expands, so too does energy consumption, which places additional strain on the country’s energy resources and exacerbates environmental concerns. The utilization of waste materials, such as fly ash, could play a pivotal role in addressing both the environmental challenges of waste disposal and the increasing demand for energy-efficient and sustainable materials. This presents a unique opportunity for Mongolia to reduce its dependence on natural resources, lower greenhouse gas emissions and create new, innovative materials that contribute to both economic and environmental sustainability.
In Mongolia, thermal power plants rely heavily on coal as their primary fuel source, which contains an average of 10 to 20 percent minerals. These minerals are discarded in the form of ash after the coal is burned. Each year, approximately 800,000 tons of ash are produced by the power plants. Specifically, the slag waste from Ulaanbaatar’s Thermal Power Plant No. 4 increases by an average of 300,000 tons annually, while Thermal Power Plant No. 3 generates about 100,000 tons per year. This large volume of waste not only contributes to environmental pollution but also occupies vast amounts of land. For instance, the plant No. 4 has had to build an ash storage tank with an investment of 5 billion to 6 billion MNT. However, this storage will reach its capacity in about five years, necessitating the construction of another tank at a new site. Additionally, the annual cost of storing this waste amounts to around 1 billion MNT. On average, the removal and storage of waste ash from the Thermal Power Plant No. 4 alone costs approximately 2 billion MNT annually.
The environmental burden of this accumulating ash is significant, contributing to soil contamination, air pollution and the loss of land. On a positive note, there is growing awareness about the potential to repurpose certain waste materials, including fly ash, instead of discarding them. As of 2021, glass and glass products accounted for 10.2 percent of all waste collected for reuse and processing in Mongolia. Repurposing waste materials like ash and glass, rather than simply discarding them, has a dual benefit: it reduces environmental pollution and minimizes the spatial footprint of waste storage. Moreover, it offers substantial economic efficiency by turning waste into a valuable resource, particularly when used in the production of sustainable building materials, such as glass-ceramics.
Could you please provide detailed information on the economic benefits of using this type of waste raw material?
The price of exterior glass-ceramic tiles for building facades is currently the lowest in the global market at approximately 11 USD per square meter. However, the cost of producing the same type of tiles locally in Mongolia currently stands at 30,292 MNT per square meter. Despite this higher cost, this price comparison highlights a significant opportunity: with the use of local waste resources such as fly ash and waste glass, it is indeed possible to replace imported building materials, reduce dependency on foreign imports and produce high-quality, sustainable tiles at a much lower cost in the future.
What raw materials are primarily used in the production of glass-ceramic materials?
When producing glass-ceramic materials, the preparation of the raw material mixture is the most important step. Glass-ceramics are materials with a structure dominated by crystals rather than the usual amorphous glass structure. This transformation involves controlling the crystallization of glass, turning it into a ceramic material. The process consists of two stages of heat treatment. The first stage, crystal nucleation, involves heating the material to a temperature that allows small crystal seeds to form within the glass. This is essential for setting up the foundation for crystallization. In the second stage, crystallization, the material is heated further to encourage the growth of the crystal seeds into larger, stable crystals. Adjusting the temperature and duration of these two stages is crucial to achieve the right balance between glass and crystalline structures. Proper control ensures the desired properties of the final glass-ceramic material, such as strength and durability.
Could you provide information on how you prepare and process the raw materials for producing glass-ceramic materials?
To produce glass-ceramic materials, coal filter ash from the Baganuur deposit of the Thermal Power Plant No. 4, broken waste glass from windows, feldspar from the Airag soum in Dornogovi Province, and 99 percent cerium oxide from China were selected as raw materials. The study of producing glass-ceramic materials was conducted using three different methods.
The first method followed the traditional approach, where the mixture for producing glass-ceramics was melted at high temperatures in a furnace and rapidly cooled to prepare amorphous raw materials for glass-ceramics. Afterward, the product was dried, passed through a 76-micron sieve, semi-dry pressed at a pressure of 20 MPa, and then crystallized at temperatures ranging from 700 to 1,000 degrees Celsius.
In the production of glass-ceramic materials, the most crucial step is the preparation of the raw material mixture. Glass-ceramics are materials that have a ceramic structure dominated by crystals rather than being amorphous. This means the process focuses on controlling the crystallization of glass and further transforming it into a ceramic material with a crystal-dominated structure. As such, a two-stage heat treatment process is applied: the nucleation stage followed by the crystallization stage. The temperature and duration of these two stages are of critical importance. Proper adjustment of both the nucleation and crystallization stages ensures that the desired crystalline structure is achieved, leading to the production of high-quality glass-ceramic materials. The careful control of these parameters determines the material’s final properties, including its strength, thermal stability and durability.
Does our country have sufficient equipment to prepare and process the raw materials for producing glass-ceramic materials?
The equipment available is sufficient for conducting experimental studies on the production of glass-ceramic materials under laboratory conditions. However, the tools and equipment necessary for studying the properties of the produced materials are inadequate. For instance, to analyze the morphology of the glass-ceramic materials we produced, we had to send samples to Germany for analysis. This highlights the need for more advanced, specialized equipment in our laboratory to fully assess the properties of the materials we are developing.
Can glass-ceramic materials made from waste materials be more durable in terms of their properties?
Made from waste raw materials, this glass-ceramic material exhibits strength comparable to other glass-ceramics of the same type. It possesses high mechanical properties, excellent chemical resistance and outstanding abrasion resistance. Additionally, it demonstrates unique heat and electrical resistance, making it suitable for various technical applications in the future. This material represents a new, advanced technical solution that can be widely used in industries such as medicine, paint, metallurgy and optics, offering a sustainable alternative to traditional materials while maintaining high performance.
What difficulties were encountered during the research?
One of the main challenges in conducting this research is the lack of sufficient funding. Additionally, there is a shortage of the necessary tools and equipment to fully support the research process. This study was conducted as part of our laboratory’s broader project on “Research on Technologies for Processing Various Ashes and Extracting New Materials”, with funding provided by the Science and Technology Foundation. Despite these limitations, the research has made significant progress in exploring the potential of waste materials for producing high-performance glass-ceramic materials.
Is it possible to develop glass-ceramic materials using waste raw materials in our country and further advance them into widely used products?
We have an abundant supply of waste ash, which serves as a primary raw material for producing glass ceramics. This makes it entirely feasible to produce glass ceramics for use in engineering and construction. Traditionally, natural raw materials such as granite, mica, kaolin, silica sand, limestone, dolomite, feldspar, zircon and quartz are used in the production of glass ceramics. However, in recent years, there has been a shift towards utilizing various industrial wastes as alternative raw materials. For example, waste ash from power plants, along with rice husk and sugar cane ash, have gained attention for their potential.
Ashes are rich in oxides of key elements such as silicon, aluminum, calcium and iron. These chemical compositions make ash a promising raw material for glass ceramics. Researchers believe that by harnessing these industrial by-products, we can create high-quality glass-ceramic materials, while simultaneously addressing waste disposal issues and promoting sustainability in material production.
