Aurora López-Delgado

• Research Scientist
• Scientific Researcher at Spanish National Research Council. CSIC

Two types of zeolites, coming from the total conversion of hazardous aluminum waste, have been considered in this study: NaP-type zeolite and LTA-type zeolite. Both zeolites are proposed to be used in cementitious mortars by substituting cement content in 5, 10 and 15%. The microstructure of both zeolites was characterized and they have certain int...

The use of solid waste and raw materials such as ceramic sludge, klin rollers, magnesite, and limestone to produce low cost refractory ceramics after sintering at 1300 ◦C for 2 h was studied. Sample D30 with a composition of, 30 % diopside and 70 % mullite, was selected to be treated at 1200 ◦C for 2 h to investigate the effect of temperature on ph...

The possibility of reusing ceramic roller waste to produce cordierite and mullite refractories was investigated. Five batches were designed using wastes representing ceramic roller waste, magnesite, and silica sand, shaped and fired at 1300 °C/2 h, and one batch was selected at 1200 °C. The chemical composition and precipitated phases of the used r...

The possibility of reusing ceramic roller waste to produce cordierite and mullite refractories was investigated. Five batches were designed using wastes representing ceramic roller waste, magnesite, and silica sand, shaped and fired at 1300 °C/2 h, and one batch was selected at 1200 °C. The chemical composition and precipitated phases of the used r...

The use of solid waste such as ceramic sludge, ceramic rollers, and magnesite was studied to obtain cheap refractory ceramics at temperatures of 1300 °C based on XRF, XRD SEM, EDX, bending strength, and dielectric properties. The prepared samples were examined. The results showed that the significant crystalline phases formed were mullite, spinel,...

In recent years, the demand for natural and synthetic zeolites has surged due to their distinctive properties and myriad industrial applications. This research aims to synthesise crystalline zeolites by co-recycling two industrial wastes: salt slag (SS) and rice husk ash (RHA). Salt slag, a problematic by-product of secondary aluminium smelting, is...

In recent years, the demand for natural and synthetic zeolites has surged due to their distinctive properties and myriad industrial applications. This research aims to synthesise crystalline zeolites by co-recycling two industrial wastes: salt slag (SS) and rice husk ash (RHA). Salt slag, a problem-atic by-product of secondary aluminium smelting, i...

The industrial alkaline battery recycling process produces an organic fraction (OF) consisting of waste paper, plastic and cardboard. Currently, this OF is used for energy recovery, given the absence of a successful alternative recycling approach, attributed to its contamination and limited economic value. This study explored the valorisation of th...

The growing demand of zeolites for many industrial applications has led to a search for ecofriendly alternatives for their production, in an attempt to reduce costs, save natural resources and alleviate the associated environmental impacts. In the present study, hazardous aluminum salt slag (aluminum source) and rice husk ash (silicon source) were...

The global issue of water resource pollution due to wastewater containing dyes is a significant environmental concern. The proper treatment of these harmful wastewaters is a great challenge due to their characteristic structural complexity and low biodegradability. The present work reports the application of a Linde Type-A (LTA) zeolite synthesized...

In this study, different lightweight expanded glass aggregates (LEGAs) were produced from glass cullet and various carbonated wastes, through a thermal impact process. The effects of LEGA microstructure and morphology on both the adherence to the cement paste and the mechanical properties of mortars after 28 days of curing were studied. The propert...

Aiming to solve the difficulties inherent in the separation of adsorbents in powder form loaded with contaminant ions from treated solutions, this study presents the Linde Type A (LTA) zeolite immobilized in agarose (AG) as a new alternative outstanding adsorbent material (AG-LTA) for cation removal from mine-impacted water (MIW). Synthetic MIW con...

A new adsorbent based on an immobilized waste-derived LTA zeolite in agarose (AG) has proven to be an innovative and efficient alternative for removing metallic contaminants from water impacted by acid mine drainage (AMD) because the immobilization prevents the solubilization of the zeolite in acidic media and eases its separation from the adsorbed...

The possibility of transforming a diatomite-rich waste from the brewing industry into synthetic zeolites has been investigated. After precalcination at 550 °C to eliminate the retained organic matter, the clean diatomite (Dt; with a Si/Al molar ratio of 17.4), was hydrothermally treated for 24 h with continuous stirring in a 3M NaOH solution at 80...

The management of salt slag, a waste from the secondary aluminum industry, is associated with huge environmental concerns due to the risk of atmospheric pollution (emission of toxic gases), groundwater contamination (high salt content that can percolate and cause an increase in salinity) and soil unavailability (large extensions required for dispos...

Lightweight aggregates are extensively used in construction and other industrial applications due to their technological characteristics. The extraction of natural aggregates results in serious environmental effects. Thus, within the circular economy concept, the valorization of waste through the optimization of materials and product design is enco...

The kinetics and mechanism of the development of nepheline (NaAlSiO4) through thermal transformation of sodalite (Na4Al3Si3O12Cl) was studied by means of differential thermal analysis at different heating rates (10°C min⁻¹ to 50°C min⁻¹) to control the evolution of the crystallization fraction. The conversion of sodalite (cubic crystal) to pure nep...

Sustainable glasses were prepared by green technology including the use of different wastes as raw materials and concentrated solar power (CSP) as renewable energy. The raw materials used to formulate the glasses were animal bone flour ash, which presents high contents of CaO, P2O5 and alkaline oxides; glassy sand from the waste of packaging glass...

Solar energy and especially concentrated solar power systems (CSP) need materials that can tolerate the demanding working conditions. In this sense, the receivers are exposed to large fluxes of solar radiation that produce very high temperatures. In addition, due to the operational conditions of receivers large temperature variations occur during d...

In this work, concentrated solar energy (CSE) was applied to an energy-intensive process such as the vitrification of waste with the aim of manufacturing glasses. Different types of waste were used as raw materials: a hazardous waste from the aluminum industry as aluminum source; two residues from the food industry (eggshell and mussel shell) and d...

Mullite (3Al2O3·2SiO2) is an aluminosilicate characterized by excellent physical properties, which makes it an important ceramic material. In this way, ceramics based on mullite find applications in different technological fields as refractory material (metallurgy, glass, ceramics, etc.), matrix in composite materials for high temperature applicati...

The potential application of silicon oxycarbonitride (SiOCN), silicon oxycarbide (SiOC) and silicon oxycarbide–SiC (SiOC–SiC) for photothermal devices such as volumetric solar absorbers has been studied evaluating the response to thermal shock from a Fresnel lens. The accelerated ageing test comprises fast heating (32 °C min⁻¹) and cooling rates (2...

Coal acid mine drainage (AMD) contaminates natural water to form mine-impacted water (MIW), which is characterized by high levels of acidity, sulfate, and metallic ions. This study investigates the use of a Linde Type-A (LTA) zeolite obtained from a hazardous industrial waste for Al3+, Fe2+, and Mn2+ removal from synthetic aqueous solutions. The ai...

This work reports the results of an investigation aimed at the development of sintered glass‐ceramic tiles by the sinter‐crystallization of mixtures composed of aluminum slag and reclaimed packaging glass. The thermal behaviors of mixtures incorporating 50 and 60 wt% Al slag were established by differential thermal analysis (DTA). Green compacts we...

A potential route to minimize the environmental impact of industrial activities is, among other approaches, the use of hazardous wastes as less-common raw materials for the preparation of other materials. Realistic technologies for waste management should include simple and low-cost processes as well as the nonproduction of new wastes. Thus, the to...

The reduction of copper (II) oxide was carried out under concentrated solar radiation in a stream of gaseous mixture 5/95 v/v H2/N2 in a 1.5 kW thermal power vertical axis parabolic concentrator at the PROMES-CNRS solar facility (Odeillo-Font Romeu, France). Experiments were performed using a commercial oxide in two different forms, powdered and co...

The removal of Pb2+, Cd2+, and Hg2+, which act as endocrine disruptors, from aqueous solutions was performed using a NaP1-type zeolite synthesized from a hazardous aluminum waste. The effects of parameters like pH, contact time, adsorbent dose, initial cation concentration, and coexisting-cations on the adsorption efficiency and capacity of the ads...

Materials used as solar receivers in concentrated solar power technology must withstand severe operational conditions caused by concentrated solar radiation. For this solar technology several ceramic material candidates (silicon carbide, porous and dense silicon oxycarbide) have been subjected to thermal shock resistance test by using Fresnel lens,...

This research aims to study the feasibility of applying real concentrated solar radiation to achieve the energy needed for melting glass frits. For this purpose, five glass compositions corresponding to different types of commercial frits were prepared. For comparison, the batches were melted by both in a solar furnace using concentrated solar ener...

This work evaluates the use of a synthetic NaP1 zeolite obtained from a hazardous Al-containing waste for the removal of ammonium (NH 4⁺ ) from aqueous solutions by batch experiments. Experimental parameters, such as pH (6–8), contact time (1–360 min), adsorbent dose (1–15 g/L), and initial NH 4⁺ concentration (10–1500 mg/L), were evaluated. Adsorp...

Procedimiento de revalorización de un residuo procedente de la molienda de escorias de aluminio. El objeto de la invención es un procedimiento de revalorización de residuos peligrosos procedentes de la molienda de escorias de aluminio mediante su transformación en zeolitas. Se contempla la utilización como materia prima de los finos de granulometrí...

The feasibility of developing an eco-friendly bench-scale zeolitization process of NaP1 from an Al-containing waste and under recycling of effluents was evaluated. Prior lab-scale tests were performed to optimize the synthesis conditions. The mixture of effluents, i.e., mother liquors (ML) from the synthesis and rinse water (RW) from the cleaning s...

Silicon oxycarbide glasses were synthesized from preceramic precursors and shaped onto porous and dense monoliths. The materials presented excellent resistance against oxidation up to 1400 0C and the determined values of reflectance (below 5%) and mechanical properties (E≈65 GPa) make of these materials suitable candidates of being used in solar vo...

Two alumina polymorphs, the metaestable γ -Al 2 O 3 and the stable α -Al 2 O 3 , were obtained from thermal treatment of the precursor γ -AlOOH (boehmite). This precursor was prepared by a precipitation method employing different raw materials in order to study their effect on the synthesis process and several characteristics of the materials, such...

Hydrotalcite-like compounds were co-precipitated with diluted sodium hydroxide from an unconventional aluminium source: the aluminium waste generated by the tertiary aluminium industry, with the assistance of ammonia and triethanolamine at pH 10. These products were characterised by several techniques (XRD, FT-IR, UV–vis-NIR, SEM, DTA-TG and BET me...

The powdered solids trapped in filter sleeves in the aluminium tertiary industry are currently disposed of in secure landfills as a result of environmental considerations. Their classification as a hazardous waste is due to their high aluminium content as metallic aluminium or in compounds such as aluminium nitride. These compounds can react with a...

Solar thermal technology for the production on electricity is one of the current technological challenges. In concentrating solar power (CSP) plants, in order to achieve high power it is required to use a high operating temperature to reach high conversion efficiencies. The majority of today's commercial solar thermal power plants are based on the...

Aluminum recycling is an important activity that allows returning this metal to the market saving energy and resources. This activity generates slag and dross, both hazardous materials, which are recovered by other industries (tertiary sector). In that process, new wastes are produced, but most of them are disposed in security storage facilities be...

Concentrated solar power systems are receiving increasing attention as electricity generating systems, whereby the sun’s heat is focused onto a receiver heated to high temperatures. Systems operating today are generally limited to temperatures below about 600 °C, but there is considerable interest in increasing operating temperatures, with heat rec...

The dehydration process of gypsum rock was studied under concentrated solar energy by using a Fresnel lens with power density of 260 Wcm�2. Temperatures higher than 700�C were attained for 1 min of solar exposure. The effect of grain size of sample and radiation exposure time on the formation of bassanite and anhydrite was studied by XRD. The compl...

Boehmite synthesized through a sol-gel route from a nonconventional raw material, as an aluminum waste, was calcined at temperatures between 500 and 1500°C. Quantification of crystalline phases was performed by the Rietveld refinement of the XRD patterns. γ-Al2O3 is formed at 500°C, and up to 1000°C, is the dominant phase. At temperatures ranging f...

In Spain, the secondary aluminum industry is a mature activity which produces 35% of the total aluminum production. This industry generates slag (black dross) with a valuable content of aluminum which is recovered by dry milling processes in the aluminum tertiary industry. The powdered fine solid is trapped in the sleeve filter suction system of th...

The aim of this paper is to evaluate the feasibility of obtaining alumina from boehmite using a free, clean, and unlimited power source as the solar energy. Boehmite was obtained by hydrothermal treatment of a hazardous waste coming from aluminum slag milling. The waste is considered as a hazardous substance because of it releasing toxic gases (hyd...

The dehydration process of gypsum rock was studied under concentrated solar energy by using a Fresnel lens with power density of 260 Wcm 2. Temperatures higher than 700C were attained for 1 min of solar exposure. The effect of grain size of sample and radiation exposure time on the formation of bassanite and anhydrite was studied by XRD. The comple...

The invention relates to a method for stabilizing liquid mercury using sulfur polymer cement, via mercury sulfide. The method for stabilizing liquid mercury by the production of sulfur polymer cement comprises (a) transformation of the liquid mercury into mercury sulfide (metacinnabar) by a chemical reaction, under stoichiometric conditions, betwee...

This paper analyzes the chemical, physical, morphological, mineralogical and pozzolanic characteristics of several reservoir sludges and assesses their potential for use as 20% additions in blended cement manufacture. The studied sludges exhibit good pozzolanic properties, especially sample 5 which has high SiO2, Al2O3 and Fe2O3 contents. Blended c...

Mercury is considered a priority hazardous substance due to its adverse effects on human health and the environment. A world-wide common effort is underway to reduce both the supply and demand of mercury. In order to solve the environmental concern of mercury, a number of technologies have been developed to reduce its mobility towards the environme...

A nanostructured α-Al2O3 with particle size lower than 100 nm was obtained from a hazardous waste generated in slag milling process by the aluminium industry. The route developed to synthesize alumina consisted of two steps: in the first one, a precursor of alumina, boehmite, γ-AlOOH was obtained by a sol-gel method. In the second step, the alumina...

Due to the adverse effects of mercury on human health and the environment, restrictive legislations and world-wide common efforts are now under way to reduce both the supply and demand of mercury. As a result, all excess Hg must be stored in safe conditions in secure places. This paper is an attempt to review the various treatment technologies type...

Dentro del Programa Europeo LIFE, se ha desarrollado un proceso de microencapsulación de mercurio liquido, utilizando la tecnología de estabilización/solidificación con azufre polimérico (SPSS). Como resultado se ha obtenido un material estable tipo concreto que permite la inmovilización de mercurio y su almacenamiento a largo plazo. La descripción...

Resumen Las Directivas Europeas consideran al mercurio una sustancia de peligrosidad prioritaria debido a sus efectos adversos sobre la salud humana y sobre el medio ambiente. En respuesta a estas preocupaciones ambientales, y dentro del Programa Europeo LIFE, se ha desarrollado un proceso de microencapsulación como una opción al almacenamiento a l...

The transport of Au(CN)2 between alkaline aqueous solutions and organic phases consisting of a mixture of the amine Primene JMT and the phosphine oxide Cyanex 923 in xylene was studied using the pseudo-emulsion based hollow-fiber strip dispersion (PEHFSD) technology. The feed phase was passed through the lumen side, and the pseudo-emulsions of the...

Nowadays, alternative uses of phosphogypsum (PG) in the building industry are being considered in several countries; however, the natural radioactivity level in the PG could be a restriction for those uses. United States Environmental Protection Agency (US-EPA) classified PG as Technologically Enhanced Naturally Occurring Radioactive Material (TENO...

The huge number of research studies carried out during recent decades focused on finding an effective solution for the waste treatment, have allowed some of these residues to become new raw materials for many industries. Achieving this ensures a reduction in energy and natural resources consumption, diminishing of the negative environmental impacts...

The facilitated transport of Co(II) from sulphate media through a flat-sheet supported liquid membrane is investigated, and whereas the mixture DP8R and Acorga M5640 extractants is used as ionophore, several experimental variables such as hydrodynamic conditions, concentration of cobalt (II) (0.01–0.16g/L) and pH variation (2.75–9.75) in the feed s...

This work reports the effect of pressure on the steam/oxygen gasification at 1000°C of the char derived from low temperature-pressure distillation of granulated scrap tyres (GST). The study was based on the analysis of gas production, carbon conversion, cold gas efficiency and the high heating value (HHV) of the product. For comparison, similar ana...

A solidification/stabilization process of different toxic and hazardous organic industrial wastes with sepiolite was studied. Wastes coming from, among other, paint, cosmetic, resin, liquid detergent industries were mixed with the clay. The process yielded granulated solids with low moistness and ignition point close to 100ºC. The materials so obta...

The recent European Directive on waste, 2008/98/EC seeks to reduce the exploitation of natural resources through the use of secondary resource management. Thus the main objective of this study was to explore how a waste could cease to be considered as waste and could be utilized for a specific purpose. In this way, a hazardous waste from the tertia...

The new phosphogypsum (PG) waste management policy allowed to reduce the negative environmental impact of this residue by finding better alternatives uses with an extremely limited radiological impact. Building material could be one of these alternatives that could lead to the production of final products with good mechanical properties and very li...

A hazardous waste generated in slag milling process by the aluminium industry was used as a raw material for the synthesis of alumina, α-Al 2 O 3. This waste is considered as hazardous material in the European legislation due to the release of toxic gases (hydrogen, ammonia, methane and hydrogen sulphide) in the presence of water. The process devel...

Nowadays, alternative uses of phosphogypsum (PG) in the building industry are being considered in several countries; however, the natural radioactivity level in the PG could be a restriction for those uses. United States Environmental Protection Agency (US-EPA) classified PG as Technologically Enhanced Naturally Occurring Radioactive Material (TENO...

The transport of chromium(VI) from hydrochloric acid medium by pseudoemulsion membrane strip dispersion (PEMSD), using CYPHOS IL101 (phosphonium salt) as ionophore, is investigated under various experimental variables in the feed phase [hydrodynamic conditions, concentration of Cr(VI) (0.01-1 g/L), concentration of HCl (0.01-1M)], in the organic ph...

In this paper we present the results of the formation of black HgS (metacinnabar) from liquid mercury and elemental sulfur using the mechanical energy provided by a ball mill in different conditions. Metacinnabar formation was observed even after short milling times (15 min) and unreacted liquid mercury was no longer detected after 60 min of millin...

The transport of iron(III) from acidic media using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technology is investigated. As a carrier, (PJMTH+)2(SO42−) ionic liquid, generated by direct reaction of the commercially available primary amine Primene JMT and sulphuric acid, is used. Several hydrodynamic conditions were investigated:...

A Spanish hazardous waste from tertiary aluminium industry was used as a raw material for the synthesis of calcium aluminate. An amorphous precursor was obtained by a hydrothermal method at different values of pH. The transformation of the precursor in a crystalline aluminate was followed by TG/DTA up to 1300 ºC. At temperatures between 719 and 744...

The removal of copper (II) from acidic liquid effluents had been investigated using non-dispersive solvent extraction with strip dispersion (NDSXSD) membrane technology and oxime derivative Acorga M5640 as ionophore. Several variables which influenced the transport of the metal had been studied.

The process developed to stabilize Hg-contaminated soil consisted of the incorporation of the soil in a mixture of gravel, sulfur and sulfur modified polymer. The mass percentage of soil stabilized is nearly 60%. This means the stabilization of a very high amount of Hg-contaminated soil per mass of sample. Due to the physical characteristic of the...

With the aim of looking for solution for the environmental concerns of mercury a process of stabilization /encapsulation was developed under the European LIFE Program. The process consists of the obtainment of stable sulfur-concrete matrix which allows the immobilization of mercury. The final product containing up to 30% of Hg exhibits excellent me...

Boehmite was synthesized by a low temperature hydrothermal procedure, via sol-gel, from an aluminium hazardous waste (AHW). The method consisted of a first stage of acid digestion to solubilize the metal content, and a second stage of gel precipitation in alkaline medium. Several experiments were performed to study the effect of concentration, time...

The alternative uses of waste-phophogypsum in the building industry are being considered nowadays in several countries, as its long-term storage and maintenance presents economic as well as potential environmental concerns. Advantages and disavantages of using both, natural gypsum and phosphogypsum, are discussed in this work over a radiological po...

The use of dispersión-free solvent extraction, through microporous hydrophobic membrane has been investigated. The hollow fiber contactor, with surface area of 1.4 m2 was used to extract Cr(VI) (0.005-0.12 g/L from aqueous sulphuric acidic media (pH 2.5-4.2 +/- 0.05). Several parameters such as extractant concentration, feed acidity and metal conce...

The production of phosphoric acid from natural phosphate rock by the wet process gives rise to an industrial by-product called phosphogypsum (PG). About 5 tons of PG are generated per ton of phosphoric acid production, and worldwide PG generation is estimated to be around 100-280 Mt per year. This by-product is mostly disposed of without any treatm...

The permeation of chromium (III) using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) technology and the quaternary ammonium salt trioctyl methylammonium chloride (TOMACl) dissolved in n-decane as mobile carrier has been investigated. Factors affecting chromium permeability, such as hydrodynamic conditions, carrier concentration in th...

A solid waste coming from the secondary aluminium industry was successfully vitrified in the ternary CaO-Al(2)O(3)-SiO(2) system at 1500 degrees C. This waste is a complex material which is considered hazardous because of its behaviour in the presence of water or moisture. In these conditions, the dust can generate gases such as H(2), NH(3), CH(4),...

This study presents an evaluation of the decomposition kinetic of low-grade nickeliferous laterite by thermogravimetric analysis. Kinetic parameters were calculated using the Ozawa and the iso-conversional Friedman methods. Simplified kinetics models like those based on the reaction order were also applied for the simulations. Two-dimensional shrin...

The transport of chromium by the emulsion pertraction technology (EPERT) using Hostarex A327 (tertiary amine) as a carrier has been investigated. The permeation of the metal is studied as a function of various experimental variables: hydrodynamic conditions, concentration of Cr(VI) and HCl in the source phase, carrier concentration and diluent in t...

The facilitated transport of cadmium (II) from HCl medium by Emulsion Pertraction Technique (EPERT), using Cyanex 923 (phosphine oxides mixture) as ionophore, is investigated as a function of various experimental variables: hydrodynamic conditions, concentration of cadmium (II) (5–100 mg L) and HCl (0.2–5 M) in the source phase, carrier concentrati...

The coordination of Fe3+ with chitosan was studied, considering the type of acid for dissolving the ligand, the pH for the medium, and the metal-biopolymer ratio. Potentiometric and ultraviolet–visible titrations, infrared spectroscopy, thermal analysis and X-ray diffraction were employed. The polymer coordinates with the metal cation through the a...

The production of phosphoric acid from natural phosphate rock, by means of the wet process gives rise to a large industrial by-product named phosphogypsum (PG). The worldwide generation of PG is estimated to be around 100-280 million tonnes/year. The Tunisian Ministry of the Environment indicates that approximately 12000 tonnes/day of dry PG are ge...

The thermal behaviour of chitosan was studied by means of thermogravimetry, mass spectrometry and infrared spectrometry. Kinetic parameters were obtained by advanced kinetic evaluation (differential isoconversional analysis) from DSC curves, in non-isothermal conditions, at several heating rates, between 5 and 30°C min−1. The results showed that th...

This study presents an evaluation of the decomposition kinetic of low-grade nickeliferous laterite by thermogravimetric analysis. Kinetic parameters were calculated using the Ozawa and the iso-conversional Friedman methods. Simplified kinetics models like those based on the reaction order were also applied for the simulations. Two-dimensional shrin...

The formation of HgS (metacinnabar) from elemental mercury and pure sulphur, in non stoichiometric conditions, by means of the mechanical energy provided by a ball mill was studied. The effect of milling time in the completeness of the reaction was also studied. The formation of metacinnabar (HgS black) was observed even at short milling time (15 m...