29 research outputs found
DESARROLLO DE MEZCLAS BITUMINOSAS PARA CONSERVACIÓN DE CARRETERAS CON ESCORIAS DE ACERÍA
El sector de la construcción de infraestructuras viarias es uno de los sectores más demandantes de
materias primas que existen en la actualidad y, a su vez, uno de los más contaminantes. Para mitigar el
impacto ambiental, asociado por la extracción de materias primas consumidas en este sector, en la
presente tesis se contempla la utilización de escorias de horno de arco eléctrico y escorias de horno
cuchara como materiales sustitutivos de los tradicionales. Para la corroboración de esta hipótesis inicial
de investigación se realiza primeramente una caracterización completa de los subproductos
mencionados, así como el desarrollo de diversas mezclas bituminosas utilizadas habitualmente en el
ámbito de la conservación de carreteras. Los resultados reflejan una excelencia del comportamiento de
las mezclas bituminosas fabricadas con estos subproductos en comparación con las mezclas
tradicionales, confirmando de esta forma la idoneidad del empleo de escorias de acería en mezclas
bituminosas. The road infrastructure construction sector is one of the most demanding sectors in terms of raw
materials and, at the same time, one of the most polluting. In order to mitigate the environmental impact
associated with the extraction of raw materials consumed in this sector, this thesis considers the use of
electric arc furnace slag and ladle furnace slag as substitute materials for the traditional ones. In order to
corroborate this initial research hypothesis, a complete characterisation of the aforementioned by-
products is first carried out, as well as the development of various bituminous mixtures commonly used
in the field of road maintenance. The results reflect an excellence in the behaviour of the bituminous
mixtures manufactured with these by-products in comparison with traditional mixtures, thus confirming
the suitability of the use of steelworks slag in bituminous mixtures.Tesis Univ. Jaén. Departamento de Ingeniería Química, Ambiental y de los Materiale
Ceramics for Building Structures Made from Contaminated Soils: A Fuzzy Logic Intelligence Approach to Circular Mining
Soils contaminated by mining activities are a major environmental concern, and to avoid
this type of environmental impact, carrying out high-cost processes is necessary. For this reason, a
solution is proposed in this study in order to eliminate the soils contaminated by mining activities
and, in turn, prevent the soil’s contaminating elements from causing harm. All this is achieved
by using contaminated soils as raw materials for the production of ceramics for bricks. For this
purpose, the materials were initially characterized physically and chemically, and different ceramic
test pieces were manufactured with different percentages of clay and contaminated soil, subsequently
determining the physical properties and the leaching of toxic elements. In this way, it was possible to
evaluate, via innovative data mining and fuzzy logic techniques, the influence of the contaminated
soil's contribution on the properties of ceramics. Based on this, it was possible to affirm that the
contaminated soil incorporation negatively affects the physical properties of ceramics as well as
the leaching of polluting elements. The ceramic formed by contaminated soil and clay has a lower
compressive strength, and it is associated with lower linear shrinkage and lower density, as well
as higher porosity and cold-water absorption. However, the addition of different percentages of
contaminated soil (up to 70%) to clay created a ceramic that complied with regulation restrictions.
Therefore, it was possible to obtain a sustainable material that eliminates environmental problems at
a lower cost and that fits within the new circular mining concept thanks to fuzzy logic techniques
Retention of Pollutants Elements from Mine Tailings of Lead in Geopolymers for Construction
[EN] The construction sector is one of the most demanding sectors of raw materials in existence
today. As a consequence, the extraction of these materials has a significant impact on the environment.
At the same time, mining activities produce a series of wastes, in some cases with polluting elements,
which must be treated to avoid pollution. Therefore, the use of mining waste for the conformation
of new construction materials is an important environmental advantage, even more so when such
waste is prevented from producing polluting leachates. Therefore, in this research, geopolymers
are developed with mine tailings from the Linares lead mines, chemically activated with potassium
hydroxide. For this purpose, different percentages of the alkaline activator were tested and the
physical and mechanical properties of the conformed materials were evaluated. The analysis of
the different conformed geopolymers determined the optimum percentage of potassium hydroxide
for conforming the geopolymer with the best mechanical and physical properties. In addition, the
concentration in the leachate of potentially contaminating chemical elements in the mining waste
was estimated to be lower than those regulated by the regulations. Consequently, this research shows
the development of a sustainable material for construction with mining waste and reduction of the
environmental impact of traditional products.S
Corrosion Effect in Carbon Steel: Process Modeling Using Fuzzy Logic Tools
Acid mine drainage (AMD), resulting from mining activities, poses a significant environmental
concern. It adversely affects metallic materials, particularly carbon steel composites used in
mining machinery and structures. Highly acidic and oxidizing compounds like sulfuric acid and ferric
ions cause corrosion, iron oxide formation, and hydrogen gas release, which degrade carbon steel.
AMD also alters the solvent’s properties, dissolving heavy metals and contaminants, and intensifying
the environmental impact of mining. A 30-week experiment immersed metal plates in AMD to study
its effects. Weekly observations of the plates and solvent were made. The plate measurements and
physicochemical data were analyzed using graphical–statistical analysis and fuzzy logic techniques
to assess the data quality and identify errors. The results reveal consistent findings with prior studies,
such as material degradation with weight loss and alterations in acid drainage media, including
increased pH and total dissolved solids (TDS). These changes in the solvent characteristics stem from
the dissolution of metal ions from corroded surfaces, reacting with the acid solution. Overall, this
study discusses the effects of AMD (acid mine drainage) on metallic materials and emphasizes the
significance of monitoring and reducing the environmental consequences of mining activities.This research was funded by the Ministry of Science and Innovation (Spain), grant number
PID2021-123130OB-I00
Treatment of Soil Contaminated by Mining Activities to Prevent Contamination by Encapsulation in Ceramic Construction Materials
[EN] Mining is an essential activity for obtaining materials necessary for the well-being and development of society. However, this activity produces important environmental impacts that must be controlled. More specifically, there are different soils near new or abandoned mining productions that have been contaminated with potentially toxic elements, and currently represent an important environmental problem. In this research, a contaminated soil from the mining district of Linares was studied for its use as a raw material for the conforming of ceramic materials, bricks, dedicated to construction. Firstly, the contaminated soil was chemically and physically characterized in order to evaluate its suitability. Subsequently, different families of samples were conformed with different percentages of clay and contaminated soil. Finally, the conformed ceramics were physically and mechanically characterized to examine the variation produced in the ceramic material by the incorporation of the contaminated soil. In addition, in this research, leachate tests were performed according to the TCLP method determining whether encapsulation of potentially toxic elements in the soil occurs. The results showed that all families of ceramic materials have acceptable physical properties, with a soil percentage of less than 80% being acceptable to obtain adequate mechanical properties and a maximum of 70% of contaminated soil to obtain acceptable leachate according to EPA regulations. Therefore, the maximum percentage of contaminated soil that can be incorporated into the ceramic material is 70% in order to comply with all standards. Consequently, this research not only avoids the contamination that contaminated soil can produce, but also valorizes this element as a raw material for new materials, avoiding the extraction of clay and reducing the environmental impact.S
Reutilisation of Water Contaminated by Mining Waste for the Encapsulation of Potentially Toxic Elements
[EN] Mining activities are essential for a population’s development; however, they also produce
negative effects such as the production of waste, an impact on flora and water pollution. On the
other hand, construction is one of the sectors which is most demanding of raw materials, with one
of the main such materials being water. For this reason, this research evaluates the feasibility of
incorporating water contaminated by mining waste into ceramic materials for bricks. In this way,
the use of water is reduced and, on the other hand, the contaminating elements of the mining water
are encapsulated in the ceramic matrix. To achieve this, the clay used and the contaminated water
were first analysed, then different families of samples were conformed with different percentages of
contaminated water. These samples were tested to determine their physical and mechanical properties.
At the same time, leachate tests were carried out to determine that the ceramic material created did not
cause environmental problems. The test results showed that the physical and mechanical properties
of the ceramics were not influenced by the addition of contaminated water. On the other hand, the
leachate tests showed that encapsulation of most of the potentially toxic elements occurred. However,
the use of contaminated water as mixing water for ceramics could only be performed up to 60%,
as higher percentages would leach impermissible arsenic concentrations. Accordingly, a new way
of reusing water contaminated by mining activities is developed in this study, taking advantage of
resources, avoiding environmental pollution and creating economic and environmentally friendly
end products
Fiber-reinforcement and its effects on the mechanical properties of high-workability concretes manufactured with slag as aggregate and binder
The feasibility of manufacturing fiber-reinforced concretes of high workability through additions of high volumes of electric arc furnace steel slag is evaluated in this paper, using sustainable binders with ground granulated blast furnace slag and ladle furnace slag as a supplementary cementitious material. An extensive experimental plan is developed to test four (self-compacting and pumpable) concrete mixtures, some reinforced with 0.5% vol. of (metallic or synthetic) fibers, in both the fresh and the hardened state. Very specific mechanical aspects are examined, such as the evaluation of both longitudinal and transversal stress-strain compressive behavior, and the assessment of direct tensile strength through the “dog-bone” test. The results of testing this sustainable concrete design yielded suitable mechanical strengths, and good toughness, ductility and impact strength, among other properties. Good adhesion between the fibers and the cementitious matrix was also evident from the fiber pull-out test results. Finally, the overall results confirmed that the use of electric arc furnace steel slag can make a real contribution to construction-sector sustainability and that the mechanical behavior of these novel concretes meets the basic design requirements for use in real structures.Spanish Ministries MCI, AEI, EU and ERDF [RTI2018-097079-B-C31; 10.13039/501100011033; FPU17/03374]; the Junta de Castilla y León (Regional Government) and ERDF [UIC-231, BU119P17]; the Basque Government research group [IT1314-19]; Youth Employment Initiative (JCyL) and ESF [UBU05B_1274]; the University of Burgos [Y135.GI] and the University of the Basque Country [PPGA20/26]. Likewise, our thanks to CHRYSO and HORMOR for supplying the materials used in this research
Treatment of Soil Contaminated by Mining Activities to Prevent Contamination by Encapsulation in Ceramic Construction Materials
Mining is an essential activity for obtaining materials necessary for the well-being and development of society. However, this activity produces important environmental impacts that must be controlled. More specifically, there are different soils near new or abandoned mining productions that have been contaminated with potentially toxic elements, and currently represent an important environmental problem. In this research, a contaminated soil from the mining district of Linares was studied for its use as a raw material for the conforming of ceramic materials, bricks, dedicated to construction. Firstly, the contaminated soil was chemically and physically characterized in order to evaluate its suitability. Subsequently, different families of samples were conformed with different percentages of clay and contaminated soil. Finally, the conformed ceramics were physically and mechanically characterized to examine the variation produced in the ceramic material by the incorporation of the contaminated soil. In addition, in this research, leachate tests were performed according to the TCLP method determining whether encapsulation of potentially toxic elements in the soil occurs. The results showed that all families of ceramic materials have acceptable physical properties, with a soil percentage of less than 80% being acceptable to obtain adequate mechanical properties and a maximum of 70% of contaminated soil to obtain acceptable leachate according to EPA regulations. Therefore, the maximum percentage of contaminated soil that can be incorporated into the ceramic material is 70% in order to comply with all standards. Consequently, this research not only avoids the contamination that contaminated soil can produce, but also valorizes this element as a raw material for new materials, avoiding the extraction of clay and reducing the environmental impact
Evaluation of the Use of Electric Arc Furnace Slag and Ladle Furnace Slag in Stone Mastic Asphalt Mixes with Discarded Cellulose Fibers from the Papermaking Industry
The construction sector is one of the most demanding of raw materials that exist at present. In turn, the greenhouse gas emissions that it produces are important. Therefore, at present there are several lines of research in which industrial by-products are incorporated for the manufacture of bituminous mixtures and the reduction of CO2 emissions, framed inside the circular economy. On the base of the aforementioned, in this research, bituminous mixtures of the Stone Mastic Asphalt type were developed with electric arc furnace slag, ladle furnace slag and discarded cellulose fibers from the papermaking industry. To this end, the waste is first characterized physically and chemically, and its properties evaluated for use in bituminous mixtures. Later, different groups of samples are conformed with conventional materials and with the waste in order to be able to compare the physical and mechanical properties of the obtained bituminous mixtures. The physical tests carried out were bulk density, maximum density and void index, as well as the Marshall test for the evaluation of the strength and plastic deformations of all the bituminous mixtures manufactured. The study and evaluation of the results showed that the incorporation of slag makes it possible to absorb a greater percentage of bitumen and obtain better mechanical properties, while maintaining a similar deformation and void content. Therefore, it is feasible to use the mentioned slags to create sustainable, resistant and suitable pavements for important traffic
Leaching of Zinc for Subsequent Recovery by Hydrometallurgical Techniques from Electric Arc Furnace Dusts and Utilisation of the Leaching Process Residues for Ceramic Materials for Construction Purposes
Steel is one of the most widely used materials in the past and today. Various techniques are used to recycle this material, including the electric arc furnace. This process has several advantages, but it also has a major disadvantage, namely, the generation of waste such as electric arc furnace dusts. Electric arc furnace dusts are classified as hazardous waste due to their high percentage of heavy metals, including zinc. Consequently, in the present research, the leaching of zinc for recovery with sulfuric acid solutions at ambient temperature and atmospheric pressure is evaluated, as well as the reuse of the leaching process residue as a raw material for ceramic materials. The sulfuric acid solutions were 0.125, 0.25, 0.5, and 1 molar, using clay for ceramic conforming and percentages of the leaching residue from 0–50%. The results showed that the optimum solution was 1 molar sulfuric acid, recovering all the zinc in the sample in 36 h. Furthermore, it was found that the clay-conformed ceramics with less than 40% leaching residue showed acceptable physical and mechanical properties according to standards. Therefore, this research develops a new environmental hydrometallurgy in which metallic elements of interest are valorized and the production of waste is avoided, reducing the deposition of hazardous waste in landfills and the extraction of raw materials for the manufacture of construction materials