Isabel Padilla - Profile on Academia.edu (original) (raw)

Papers by Isabel Padilla

The Directive 2008/98/EC encourages the study of innovative ways for the hazardous waste recovery... more The Directive 2008/98/EC encourages the study of innovative ways for the hazardous waste recovery instead of the traditional dilution to levels below the legal thresholds values. In this context, the slag milling process performed by the aluminium tertiary industries generates fine powders which are trapped through the suction systems in the filter sleeves. The European Waste Catalogue classifies these powders as a hazardous waste (number code 100321). Currently, the treatment of these wastes is based on the disposal into secure landfills. The characterisation of these powders indicates a remarkable presence of fine particle sizes as well as complex and heterogeneous blends of several components such as corundum, spinel, aluminium nitride (10-25% in weight), metallic aluminium, quartz, calcite, iron oxide, salts and other minor metallic oxides. As a consequence, the total amount of aluminium present in these phases is still significant and valuable. Relating to aluminium nitride in wastes, its high content can initiate the ammonia releasing as toxic by-product with the simple reaction between the waste and small amounts of water (including the moisture in air) (Krnel et al., 2004) when storage conditions are unsuitable. In the literature, the use of aluminium waste to obtain added-value materials has been explored especially in the case of white and black dross. Thus, alumina and hydrotalcite from aluminium dross have been prepared (David et al., 2012; Murayama et al., 2006). In particular, the use of fine powdery hazardous waste in the aluminium tertiary industry to obtain added-value materials has been analysed in few examples. For instance, concrete blocks were prepared by adding the hydrolysed waste to cement and sand (Shinzato et al., 2005). The synthesis of boehmite and corundum from aluminium waste as raw materials has been also studied (Gonzalo-Delgado et al., 2011; López-Delgado et al., 2012). In this context, the aim of this work was the evaluation of the feasibility for a full recovery alternative focused on the fine powders extracted from the filter sleeves in the aluminium tertiary industry, in order to propose an alternative to overtake the current barrier which avoids the recovery process. This alternative was based on the production of added-value materials such as Mg-Al hydrotalcites and inorganic glasses in the CaO-Al 2 O 3 -SiO 2 system. The methodology consisted in the dispersion of the hazardous waste (20 g of powder) in 200 ml of hydrochloric aqueous solution (10% v/v) for 3 hours at 80ºC which favoured the nitride decomposition, the metal hydrolysis as well as the solubility of other aluminium salts and transition metals. After that, the dispersion was filtered on a GTTP Millipore filter at 5 bars pressure. As a result, a rich Al 3+ solution and a more stable solid cake were produced (Gonzalo-Delgado et al., 2011). The solution was analysed by Atomic Absorption Spectroscopy (AAS) on a Varian SpectrAA 220 FS to determine the Mg 2+ and Al 3+ content. In the meantime, the solid cake was dried in air for 24 h at 110ºC.

Ecology and the Environment, May 12, 2014

In Spain, the secondary aluminum industry is a mature activity which produces 35% of the total al... more 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 the aluminum slag milling process. This solid is considered as a hazardous waste within the 10 03 21 group in the European Waste Catalogue (EWC), because of the very fine grain size (x 50 < 50 µm) and the presence of dangerous substances (metallic aluminum, AlN, heavy metals, etc.). The high aluminum nitride content, ranging between 2 and 24%, is remarkable and it releases ammonia gas in the presence of environmental humidity. The aim of this work was to evaluate the complete recovery of the fine powders coming from the sleeve filters in the aluminum tertiary industry, as a zeolite. Two types of zeolite, analcime and NaP were obtained by hydrothermal processes from the aluminum waste and silica as raw materials. Different compositions of wastes and parameters such as time and temperature were assayed to study their effects on the obtained zeolites. The materials were characterized by X-ray diffraction and scanning electron microscopy.

Journal of Analytical Atomic Spectrometry, Apr 2, 2002

The feasibility of using an anion-exchange resin for on-line separation of trace amounts of Fe, C... more The feasibility of using an anion-exchange resin for on-line separation of trace amounts of Fe, Cu, Mn, Mg, Cr, Ni, Zn, Co, Pb, and Cd from pure aluminium was investigated. A test portion of 50 mg of aluminium drillings was dissolved with 6 ml of a buffer solution, 2.64% m/v NaOH-0.91% m/v KCl (pH ~13.4 ¡ 0.1). An aliquot of 500 ml of the solution obtained was passed through a micro-column, included in a flow injection (FI) manifold, packed with a 2 1 1 mixture of Metalfix Chelamine and Hyphan Cellulose (the micro-column volume was about 150 ml). The retained trace elements were eluted in the back-direction with 200 ml of a 3 1 1 mixture of 1 mol l 21 HCl-1 mol l 21 HNO 3 and then determined using flow injection inductively coupled plasma mass spectrometry. The operating parameters and operational scheme of the manifold of the FI on-line ion-exchange assembly are given. The accuracy of the proposed method was tested by analysing a pure aluminium standard sample (Aluminium Pechiney, CODE 566). Recoveries from 50 mg test portions of a high-purity aluminium (99.999%) spiked with 2.5 and 25 ng each of the studied analytes were close to 100%, and the relative standard deviations ranged from 1 to 3%. Determination limits (10s) were in the ng g 21 range.

Revista De Metalurgia, Feb 28, 2012

Trabajo recibido el día 29 de julio de 2011 y aceptado en su forma final el día 20 de diciembre d... more Trabajo recibido el día 29 de julio de 2011 y aceptado en su forma final el día 20 de diciembre de 2011.

Twenty-Eighth International Conference on Solid Waste Technology and Management. Filadelfia, PA, USA

Determination for ICP-MS of phosphorus in steels using segmented-flow injection

Trabajo presentado en el European Winter Conference on Plasma Spectrochemistry, celebrado en Gant... more Trabajo presentado en el European Winter Conference on Plasma Spectrochemistry, celebrado en Gante (Bélgica), del 12 al 17 de enero de 199

International Conference on Sustainable Materials Science and Technology, Paris, Fr. Comunicacion... more International Conference on Sustainable Materials Science and Technology, Paris, Fr. Comunicacion Oral

Europace, 2006

Introduction The LA-ICP-MS technique has been evaluated with respect to applications relevant for... more Introduction The LA-ICP-MS technique has been evaluated with respect to applications relevant for the steel industry, with special emphasis on spatially resolved analysis. Three different commercially available laser ablation units have been used, CETAC LSX 100, CETAC LSX 200 and New Wave Research UP 213. These are all based on NdYAG lasers combined with frequency doubling and frequency mixing crystals in order to obtain UV laser output. The CETAC systems operate at 266 nm, the New Wave system at 213 nm. In addition, some investigations have been carried out using specially designed systems with excimer lasers. The different laser ablation units are coupled to ICP-MS systems with mass analysers of different types, a quadropole, a time-of-flight (TOF) and a magnetic sector system. Samples and sample preparation A number of samples were selected and prepared for different parts of the investigations. For the lateral resolution studies, special welded samples of different steel alloys ...

Journal of Cleaner Production, 2020

A potential route to minimize the environmental impact of industrial activities is, among other a... more 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 lowcost processes as well as the nonproduction of new wastes. Thus, the total conversion of a type of hazardous aluminum waste into zeolite was achieved at the pilot-scale (200 l autoclave reactor) under mild hydrothermal operating conditions. In a one-step process, 3.2 tons of zeolite, 76.4 Nm 3 of ammonia and 105.9 Nm 3 of hydrogen can be produced per ton of aluminum waste. The process does not generate other wastes. The recycling of process effluents (mother liquor and rinse water), along with the process gases capture and its subsequent commercialization, would increase the environmental impact and the economic yield. The obtained Linde type-A zeolite, exhibited structural, textural and morphological characteristics similar to those of zeolites prepared from commercial reagents. A conceptual design for zero-waste process is proposed. The sustainable process developed can contribute to reduce the high environmental impact of aluminum industry waste, and contribute to the circular economy by converting a hazardous waste into a raw material.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2000

Ž. A commercial atomic absorption graphite furnace AAGF , with a self-made adapter and valve syst... more Ž. A commercial atomic absorption graphite furnace AAGF , with a self-made adapter and valve system, was used as Ž. a slurry sampling cell for electrothermal vaporization inductively coupled plasma mass spectrometry ETV-ICP-MS. The system was applied to the determination of As, Sn, Sb, Se, Te, Bi, Cd, V, Ti and Mo in steelmaking flue dusts. Experimental conditions with respect to ETV and ICP-MS operating parameters were optimized. Compared to aqueous solutions, slurry samples were found to present better analyte transport. Microgram amounts of Rh were used to reduce the difference in analyte response in sensitivity for aqueous solutions of the tested analytes. No such increasing effect was observed for slurry samples and aqueous standards. An added quantity of Rh acting as modifierrcarrier resulted in an increase for the same analytes in matrix-slurry solutions, even the addition of an Ž. extra Rh quantity has resulted in a decrease in the signals. The effect of Triton X-100 used as a dispersant agent on analyte intensity and precision was also studied. External calibration from aqueous standards spiked with 100 g ml y1 Rh was performed to quantified 0.010 gr100 ml slurry samples. Results are presented for a certified reference Ž. Ž. electrical arc furnace flue dust EAF : CRM-876-1 Bureau of Analysis Samples Ltd., Cleveland, UK , a reference Ž. sample of coke ashes X-3705 from AG der Dillinger Huttenwerke, Germany , and a representative sample of EAF Ž. flue dust from a Spanish steelmaking company CENIM-1. For the two reference materials an acceptable agreement with certificate values was achieved, and the results for the CENIM sample matched with those obtained from conventional nebulization solution.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2005

An extended study of different sampling introduction approaches using inductively coupled plasma ... more An extended study of different sampling introduction approaches using inductively coupled plasma mass spectrometry (ICP-MS) is presented for the determination of boron in steel samples. The following systems for sample introduction were applied: direct sample solution nebulization by continuous nebulization (CN) using a cross-flow nebulizer and with flow injection (FI), applied to 0.1% (m/v) and 0.5% (m/v) sample solutions, respectively; FI after iron matrix extraction, using acetylacetone-chloroform, and isotopic dilution (ID) analysis as the calibration method; FI with on-line electrolytic matrix separation; and spark ablation (SA) and laser ablation (LA) as solid sampling techniques. External calibration with matrix-matching samples was used with CN, SA, and LA, and only acid solutions (without matrix matching) with FI methods. When FI was directly applied to a sample solution, the detection limit was of 0.15 Ag g À1 , improving by a factor of 4 that was obtained from the CN measurements. Isotopic dilution analysis, after matrix removal by solvent extraction, made it possible to analyse boron with a detection limit of 0.02 Ag g À1 and, with the on-line electrolytic process, the detection limit was of 0.05 Ag g À1. The precision for concentrations above 10 times the detection limit was better than 2% for CN, as well as for FI methods. Spark and laser ablation sampling systems, avoiding digestion and sample preparation procedures, provided detection limits at the Ag g À1 levels, with RSD values better than 6% in both cases. Certified Reference Materials with B contents in the range 0.5-118 Ag g À1 were used for validation, finding a good agreement between certified and calculated values.

Revista de Materiales Compuestos

Estudio del envejecimiento acelerado bajo radiación solar concentrada de vidrios de oxicarburo co... more Estudio del envejecimiento acelerado bajo radiación solar concentrada de vidrios de oxicarburo como receptores de alta temperatura Historia del artículo:

E3D 2012, Eau, Dechets et Developpment Durable Congres. Agadir, MarruecosThis paper reports the s... more E3D 2012, Eau, Dechets et Developpment Durable Congres. Agadir, MarruecosThis paper reports the study of the pozzolanic properties of sludges from different hydraulic dams from Algeria compared with normalized pozzolans, such as silica fume and fly ash. The study of the pozzolanic activity was carried out by an accelerated method of saturated lime solution, based on the Frattini method for pozzolanic cements. The results showed that one of the studied sludge (SLD5) is more active than silica fume (a very reactive pozzolan) at 28 days of reaction. The rest of sludges (SLD1-SLD4) show also high pozzolanic activity and consumed about 61-78% of the available lime at 28 days of pozzolanic reaction. The blended cements made with 20% of this waste showed compressive strength lower than the obtained by reference ordinary Portland cement (OPC) due to the dilution effect provokes by pozzolans, but SLD5 obtain a higher value of compressive strength at long ages of curing (90 days).N

Materials

In this study, different lightweight expanded glass aggregates (LEGAs) were produced from glass c... more 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 properties of lightweight mortars made of either LEGAs or expanded clay aggregates were compared. The results demonstrated the feasibility of using LEGAs to produce glass lightweight aggregate mortar, with flexural and compressive strength values ranging from 5.5 to 8.2 MPa and from 28.1 to 47.6 MPa, respectively. The differences in mechanical properties were explained according to the microstructures of the fracture surfaces. Thus, arlite-type ceramic aggregates presented surface porosities that allowed mortar intrusion and the formation of an interconnected interface; although the surfaces of the vitreous aggregates were free from porosity due ...

Kinetic study of the transformation of sodalite to nepheline

Journal of the American Ceramic Society, 2022

The Directive 2008/98/EC encourages the study of innovative ways for the hazardous waste recovery... more The Directive 2008/98/EC encourages the study of innovative ways for the hazardous waste recovery instead of the traditional dilution to levels below the legal thresholds values. In this context, the slag milling process performed by the aluminium tertiary industries generates fine powders which are trapped through the suction systems in the filter sleeves. The European Waste Catalogue classifies these powders as a hazardous waste (number code 100321). Currently, the treatment of these wastes is based on the disposal into secure landfills. The characterisation of these powders indicates a remarkable presence of fine particle sizes as well as complex and heterogeneous blends of several components such as corundum, spinel, aluminium nitride (10-25% in weight), metallic aluminium, quartz, calcite, iron oxide, salts and other minor metallic oxides. As a consequence, the total amount of aluminium present in these phases is still significant and valuable. Relating to aluminium nitride in wastes, its high content can initiate the ammonia releasing as toxic by-product with the simple reaction between the waste and small amounts of water (including the moisture in air) (Krnel et al., 2004) when storage conditions are unsuitable. In the literature, the use of aluminium waste to obtain added-value materials has been explored especially in the case of white and black dross. Thus, alumina and hydrotalcite from aluminium dross have been prepared (David et al., 2012; Murayama et al., 2006). In particular, the use of fine powdery hazardous waste in the aluminium tertiary industry to obtain added-value materials has been analysed in few examples. For instance, concrete blocks were prepared by adding the hydrolysed waste to cement and sand (Shinzato et al., 2005). The synthesis of boehmite and corundum from aluminium waste as raw materials has been also studied (Gonzalo-Delgado et al., 2011; López-Delgado et al., 2012). In this context, the aim of this work was the evaluation of the feasibility for a full recovery alternative focused on the fine powders extracted from the filter sleeves in the aluminium tertiary industry, in order to propose an alternative to overtake the current barrier which avoids the recovery process. This alternative was based on the production of added-value materials such as Mg-Al hydrotalcites and inorganic glasses in the CaO-Al 2 O 3 -SiO 2 system. The methodology consisted in the dispersion of the hazardous waste (20 g of powder) in 200 ml of hydrochloric aqueous solution (10% v/v) for 3 hours at 80ºC which favoured the nitride decomposition, the metal hydrolysis as well as the solubility of other aluminium salts and transition metals. After that, the dispersion was filtered on a GTTP Millipore filter at 5 bars pressure. As a result, a rich Al 3+ solution and a more stable solid cake were produced (Gonzalo-Delgado et al., 2011). The solution was analysed by Atomic Absorption Spectroscopy (AAS) on a Varian SpectrAA 220 FS to determine the Mg 2+ and Al 3+ content. In the meantime, the solid cake was dried in air for 24 h at 110ºC.

Ecology and the Environment, May 12, 2014

In Spain, the secondary aluminum industry is a mature activity which produces 35% of the total al... more 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 the aluminum slag milling process. This solid is considered as a hazardous waste within the 10 03 21 group in the European Waste Catalogue (EWC), because of the very fine grain size (x 50 < 50 µm) and the presence of dangerous substances (metallic aluminum, AlN, heavy metals, etc.). The high aluminum nitride content, ranging between 2 and 24%, is remarkable and it releases ammonia gas in the presence of environmental humidity. The aim of this work was to evaluate the complete recovery of the fine powders coming from the sleeve filters in the aluminum tertiary industry, as a zeolite. Two types of zeolite, analcime and NaP were obtained by hydrothermal processes from the aluminum waste and silica as raw materials. Different compositions of wastes and parameters such as time and temperature were assayed to study their effects on the obtained zeolites. The materials were characterized by X-ray diffraction and scanning electron microscopy.

Journal of Analytical Atomic Spectrometry, Apr 2, 2002

The feasibility of using an anion-exchange resin for on-line separation of trace amounts of Fe, C... more The feasibility of using an anion-exchange resin for on-line separation of trace amounts of Fe, Cu, Mn, Mg, Cr, Ni, Zn, Co, Pb, and Cd from pure aluminium was investigated. A test portion of 50 mg of aluminium drillings was dissolved with 6 ml of a buffer solution, 2.64% m/v NaOH-0.91% m/v KCl (pH ~13.4 ¡ 0.1). An aliquot of 500 ml of the solution obtained was passed through a micro-column, included in a flow injection (FI) manifold, packed with a 2 1 1 mixture of Metalfix Chelamine and Hyphan Cellulose (the micro-column volume was about 150 ml). The retained trace elements were eluted in the back-direction with 200 ml of a 3 1 1 mixture of 1 mol l 21 HCl-1 mol l 21 HNO 3 and then determined using flow injection inductively coupled plasma mass spectrometry. The operating parameters and operational scheme of the manifold of the FI on-line ion-exchange assembly are given. The accuracy of the proposed method was tested by analysing a pure aluminium standard sample (Aluminium Pechiney, CODE 566). Recoveries from 50 mg test portions of a high-purity aluminium (99.999%) spiked with 2.5 and 25 ng each of the studied analytes were close to 100%, and the relative standard deviations ranged from 1 to 3%. Determination limits (10s) were in the ng g 21 range.

Revista De Metalurgia, Feb 28, 2012

Trabajo recibido el día 29 de julio de 2011 y aceptado en su forma final el día 20 de diciembre d... more Trabajo recibido el día 29 de julio de 2011 y aceptado en su forma final el día 20 de diciembre de 2011.

Twenty-Eighth International Conference on Solid Waste Technology and Management. Filadelfia, PA, USA

Determination for ICP-MS of phosphorus in steels using segmented-flow injection

Trabajo presentado en el European Winter Conference on Plasma Spectrochemistry, celebrado en Gant... more Trabajo presentado en el European Winter Conference on Plasma Spectrochemistry, celebrado en Gante (Bélgica), del 12 al 17 de enero de 199

International Conference on Sustainable Materials Science and Technology, Paris, Fr. Comunicacion... more International Conference on Sustainable Materials Science and Technology, Paris, Fr. Comunicacion Oral

Europace, 2006

Introduction The LA-ICP-MS technique has been evaluated with respect to applications relevant for... more Introduction The LA-ICP-MS technique has been evaluated with respect to applications relevant for the steel industry, with special emphasis on spatially resolved analysis. Three different commercially available laser ablation units have been used, CETAC LSX 100, CETAC LSX 200 and New Wave Research UP 213. These are all based on NdYAG lasers combined with frequency doubling and frequency mixing crystals in order to obtain UV laser output. The CETAC systems operate at 266 nm, the New Wave system at 213 nm. In addition, some investigations have been carried out using specially designed systems with excimer lasers. The different laser ablation units are coupled to ICP-MS systems with mass analysers of different types, a quadropole, a time-of-flight (TOF) and a magnetic sector system. Samples and sample preparation A number of samples were selected and prepared for different parts of the investigations. For the lateral resolution studies, special welded samples of different steel alloys ...

Journal of Cleaner Production, 2020

A potential route to minimize the environmental impact of industrial activities is, among other a... more 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 lowcost processes as well as the nonproduction of new wastes. Thus, the total conversion of a type of hazardous aluminum waste into zeolite was achieved at the pilot-scale (200 l autoclave reactor) under mild hydrothermal operating conditions. In a one-step process, 3.2 tons of zeolite, 76.4 Nm 3 of ammonia and 105.9 Nm 3 of hydrogen can be produced per ton of aluminum waste. The process does not generate other wastes. The recycling of process effluents (mother liquor and rinse water), along with the process gases capture and its subsequent commercialization, would increase the environmental impact and the economic yield. The obtained Linde type-A zeolite, exhibited structural, textural and morphological characteristics similar to those of zeolites prepared from commercial reagents. A conceptual design for zero-waste process is proposed. The sustainable process developed can contribute to reduce the high environmental impact of aluminum industry waste, and contribute to the circular economy by converting a hazardous waste into a raw material.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2000

Ž. A commercial atomic absorption graphite furnace AAGF , with a self-made adapter and valve syst... more Ž. A commercial atomic absorption graphite furnace AAGF , with a self-made adapter and valve system, was used as Ž. a slurry sampling cell for electrothermal vaporization inductively coupled plasma mass spectrometry ETV-ICP-MS. The system was applied to the determination of As, Sn, Sb, Se, Te, Bi, Cd, V, Ti and Mo in steelmaking flue dusts. Experimental conditions with respect to ETV and ICP-MS operating parameters were optimized. Compared to aqueous solutions, slurry samples were found to present better analyte transport. Microgram amounts of Rh were used to reduce the difference in analyte response in sensitivity for aqueous solutions of the tested analytes. No such increasing effect was observed for slurry samples and aqueous standards. An added quantity of Rh acting as modifierrcarrier resulted in an increase for the same analytes in matrix-slurry solutions, even the addition of an Ž. extra Rh quantity has resulted in a decrease in the signals. The effect of Triton X-100 used as a dispersant agent on analyte intensity and precision was also studied. External calibration from aqueous standards spiked with 100 g ml y1 Rh was performed to quantified 0.010 gr100 ml slurry samples. Results are presented for a certified reference Ž. Ž. electrical arc furnace flue dust EAF : CRM-876-1 Bureau of Analysis Samples Ltd., Cleveland, UK , a reference Ž. sample of coke ashes X-3705 from AG der Dillinger Huttenwerke, Germany , and a representative sample of EAF Ž. flue dust from a Spanish steelmaking company CENIM-1. For the two reference materials an acceptable agreement with certificate values was achieved, and the results for the CENIM sample matched with those obtained from conventional nebulization solution.

Spectrochimica Acta Part B: Atomic Spectroscopy, 2005

An extended study of different sampling introduction approaches using inductively coupled plasma ... more An extended study of different sampling introduction approaches using inductively coupled plasma mass spectrometry (ICP-MS) is presented for the determination of boron in steel samples. The following systems for sample introduction were applied: direct sample solution nebulization by continuous nebulization (CN) using a cross-flow nebulizer and with flow injection (FI), applied to 0.1% (m/v) and 0.5% (m/v) sample solutions, respectively; FI after iron matrix extraction, using acetylacetone-chloroform, and isotopic dilution (ID) analysis as the calibration method; FI with on-line electrolytic matrix separation; and spark ablation (SA) and laser ablation (LA) as solid sampling techniques. External calibration with matrix-matching samples was used with CN, SA, and LA, and only acid solutions (without matrix matching) with FI methods. When FI was directly applied to a sample solution, the detection limit was of 0.15 Ag g À1 , improving by a factor of 4 that was obtained from the CN measurements. Isotopic dilution analysis, after matrix removal by solvent extraction, made it possible to analyse boron with a detection limit of 0.02 Ag g À1 and, with the on-line electrolytic process, the detection limit was of 0.05 Ag g À1. The precision for concentrations above 10 times the detection limit was better than 2% for CN, as well as for FI methods. Spark and laser ablation sampling systems, avoiding digestion and sample preparation procedures, provided detection limits at the Ag g À1 levels, with RSD values better than 6% in both cases. Certified Reference Materials with B contents in the range 0.5-118 Ag g À1 were used for validation, finding a good agreement between certified and calculated values.

Revista de Materiales Compuestos

Estudio del envejecimiento acelerado bajo radiación solar concentrada de vidrios de oxicarburo co... more Estudio del envejecimiento acelerado bajo radiación solar concentrada de vidrios de oxicarburo como receptores de alta temperatura Historia del artículo:

E3D 2012, Eau, Dechets et Developpment Durable Congres. Agadir, MarruecosThis paper reports the s... more E3D 2012, Eau, Dechets et Developpment Durable Congres. Agadir, MarruecosThis paper reports the study of the pozzolanic properties of sludges from different hydraulic dams from Algeria compared with normalized pozzolans, such as silica fume and fly ash. The study of the pozzolanic activity was carried out by an accelerated method of saturated lime solution, based on the Frattini method for pozzolanic cements. The results showed that one of the studied sludge (SLD5) is more active than silica fume (a very reactive pozzolan) at 28 days of reaction. The rest of sludges (SLD1-SLD4) show also high pozzolanic activity and consumed about 61-78% of the available lime at 28 days of pozzolanic reaction. The blended cements made with 20% of this waste showed compressive strength lower than the obtained by reference ordinary Portland cement (OPC) due to the dilution effect provokes by pozzolans, but SLD5 obtain a higher value of compressive strength at long ages of curing (90 days).N

Materials

In this study, different lightweight expanded glass aggregates (LEGAs) were produced from glass c... more 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 properties of lightweight mortars made of either LEGAs or expanded clay aggregates were compared. The results demonstrated the feasibility of using LEGAs to produce glass lightweight aggregate mortar, with flexural and compressive strength values ranging from 5.5 to 8.2 MPa and from 28.1 to 47.6 MPa, respectively. The differences in mechanical properties were explained according to the microstructures of the fracture surfaces. Thus, arlite-type ceramic aggregates presented surface porosities that allowed mortar intrusion and the formation of an interconnected interface; although the surfaces of the vitreous aggregates were free from porosity due ...

Kinetic study of the transformation of sodalite to nepheline

Journal of the American Ceramic Society, 2022