L. Piga - Academia.edu (original) (raw)

Papers by L. Piga

Waste Management, 1998

... of wastes containing heavy metals, though sight must not be lost of the possibilities offered... more ... of wastes containing heavy metals, though sight must not be lost of the possibilities offered by the emerging technology of vitrification ... 2. JH Tay and HK Cheong, Use of ash derived from refuse incineration as a partial replacement of cement ... Van Nostrand Reinhold, New York, pp ...

International Journal of Mineral Processing, 1999

Environmental Engineering Science, 1998

The incinerator ash, the fine residue resulting from the burning of municipal solid waste (MSW), ... more The incinerator ash, the fine residue resulting from the burning of municipal solid waste (MSW), has been characterized with a view to utilizing the material to replace part of the Portland cement normally used for making concrete. Characterization involved chemical and particle size analysis, observation under the scanning electron microscope (SEM), thermal analysis (TG/DTA) both in air and argon, and XRD analysis. Leaching tests in neutral and acid media were also run to assess whether this material is likely to release heavy metals into the environment. Blended cements were prepared by mixing a Portland cement with various amounts of ash. Mortars made of samples of Portland and blended cements were tested to ascertain compressive and flexural strength. It ensues from consideration of the chemical and physical characteristics of the ash, as well as the mechanical properties of the mortars produced, that after preliminary washing and/or grinding the material could, in fact, be used as partial replacement for Portland cement, although there is some slight reduction in the mechanical properties of the product.

American Journal of Applied Sciences, 2014

The aim of this study is the thermal recovery of manganese and zinc from a mixture of zinc-carbon... more The aim of this study is the thermal recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries containing 40.9% of Mn and 30.1% of Zn after a preliminary physical treatment. Separation of the metals is carried out on the basis of their different phase change temperatures, the boiling point of zinc being 906°C and 1564°C that of Mn 3 O 4 , the main Mn-bearing phase in the mixture. After wet comminution and sieving to remove the anodic collectors and most of the chlorides contained in the mixture, chemical and X-Ray Powder Diffraction (XRPD) analyses were performed. The mixture was heated in CO 2 atmosphere and the temperature raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture. Other tests were carried out by addition to the mixture of activated charcoal (95% C) or of the automotive shredder residue (fluff) containing 45% C.A zinc product was obtained suitable, after refining, for the production of new batteries. The treatment residue consisted of manganese and iron oxides that could be used to produce manganese-iron alloys. From these results, an integrated process for the recovery of the two metals was proposed.

Thermochimica Acta, 2011

The aim of this paper is to characterize spent zinc–carbon and alkaline batteries. Characterizati... more The aim of this paper is to characterize spent zinc–carbon and alkaline batteries. Characterization is essential to any process devoted to recovering the valuable materials contained in the batteries. In particular, the status of zinc and manganese has been established to permit treating only the zinc and manganese-bearing components in a recovery process, thus using smaller equipments and reducing both the material to treat and the energy consumption. At present, in fact, industrial processes treat the spent batteries as a bulk, only performing a preliminary separation with physical methods followed by a pyro- or hydrometallurgical process to recover zinc and manganese. Characterization has been carried out by chemical analysis, TGA/DTA analysis, XRPD and SEM analysis after having dismantled the batteries into the single components. Zinc and manganese are well separated in alkaline batteries while in zinc–carbon batteries the two metals are mixed, thus rendering difficult a preliminary separation by picking up the components containing the two metals separately.

International Journal of Mineral Processing, 1998

Physical separation methods were applied for upgrading the TiO contained in a fine waste 2 genera... more Physical separation methods were applied for upgrading the TiO contained in a fine waste 2 generated by the sulfuric acid process of a titanium pigment plant. The main components of this Ž. Ž. waste are TiO 42.0%-30% sulfuric-acid soluble TiO s and 12% insoluble TiO i-SiO 2 2 2 2 25%, and Al O 6%. Ninety percent of the material is finer than 45 mm. Gravity and magnetic 2 3 separation tests were carried out on the mud with the aim of recycling a TiO s enriched fraction. 2 Flotation tests were also carried out on the mud to obtain a TiO-enriched fraction to consider as 2 feed to a chlorination plant for the production of TiCl .

Recycling of Biomass …, 2011

100% relative humidity, these specimens were tested for heavy metal leachability through the use ... more 100% relative humidity, these specimens were tested for heavy metal leachability through the use of a sequential leaching protocol, at a constant pH of leachant (deionized water; pH 6.0). It was found that, except for the chloride content, the WBFA is able to meet the European ...

Asian Journal of Chemistry, 2013

Spent tea leaves (STL), a solid waste that is available in large amounts worldwide, was investiga... more Spent tea leaves (STL), a solid waste that is available in large amounts worldwide, was investigated as a potential low-cost adsorbent for the removal of two azo dyes, Reactive Green 19 (RG19) and Reactive Violet 5 (RV5), from contaminated waters. Preliminary experiments conducted on untreated STL showed that this material exhibited very low removal efficiencies (<10 %). By contrast, thermal activation of STL (200 to 400 °C for up to 2 h) resulted in a significant increase in dye adsorption. After thermal exposure of STL to 300 °C for 1 hour, removal efficiencies of 98.8 % and 72.8 % were observed, respectively, for RG19 and RV5. Characterization of the adsorbent by TG/DTA and FTIR measurements showed that structural and chemical changes occurred in the lignocellulosic material which were probably responsible for the enhancement in adsorption capacity. These results strongly support the use of activated STL as a low-cost alternative to conventional adsorbents.

CHEMICAL …, 2012

Drinking water contamination by fluoride is recognized as a major public health problem in many p... more Drinking water contamination by fluoride is recognized as a major public health problem in many parts of the world. In fact, although fluoride is an essential trace element for animals and humans, excessive fluoride intake may cause adverse health effects. In this study we investigated the potential of a natural, high alumina content, bauxite for the removal of fluoride from contaminated water. Both batch and continuous experiments were performed. In continuous-flow column experiments, the effects of inlet fluoride concentration (5-50 mg L-1) and flow rate (up to 2.5 mL min-1) on breakthrough time and adsorption capacity were studied. Batch equilibrium data were found to be well described by the Freundlich equation. Column studies showed that the dynamic adsorption capacity of the bed decreased as the inlet fluoride concentration and the flow rate increased. A maximum fluoride uptake capacity of 3.125 mg g-1 was determined. Overall, the results obtained indicate that this bauxite could be effectively used for defluoridation of drinking water.

Waste Management, 2012

The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alk... more The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn 2 O 3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30 min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

Waste Management, 2012

The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alk... more The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn 2 O 3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30 min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

The aim of this paper is to characterize spent zinc-carbon and alkaline batteries. Characterizati... more The aim of this paper is to characterize spent zinc-carbon and alkaline batteries. Characterization is essential to any process devoted to recovering the valuable materials contained in the batteries. In particular, the status of zinc and manganese has been established to permit treating only the zinc and manganesebearing components in a recovery process, thus using smaller equipments and reducing both the material to treat and the energy consumption. At present, in fact, industrial processes treat the spent batteries as a bulk, only performing a preliminary separation with physical methods followed by a pyro-or hydrometallurgical process to recover zinc and manganese. Characterization has been carried out by chemical analysis, TGA/DTA analysis, XRPD and SEM analysis after having dismantled the batteries into the single components. Zinc and manganese are well separated in alkaline batteries while in zinc-carbon batteries the two metals are mixed, thus rendering difficult a preliminary separation by picking up the components containing the two metals separately.

Waste Management, 1998

... of wastes containing heavy metals, though sight must not be lost of the possibilities offered... more ... of wastes containing heavy metals, though sight must not be lost of the possibilities offered by the emerging technology of vitrification ... 2. JH Tay and HK Cheong, Use of ash derived from refuse incineration as a partial replacement of cement ... Van Nostrand Reinhold, New York, pp ...

International Journal of Mineral Processing, 1999

Environmental Engineering Science, 1998

The incinerator ash, the fine residue resulting from the burning of municipal solid waste (MSW), ... more The incinerator ash, the fine residue resulting from the burning of municipal solid waste (MSW), has been characterized with a view to utilizing the material to replace part of the Portland cement normally used for making concrete. Characterization involved chemical and particle size analysis, observation under the scanning electron microscope (SEM), thermal analysis (TG/DTA) both in air and argon, and XRD analysis. Leaching tests in neutral and acid media were also run to assess whether this material is likely to release heavy metals into the environment. Blended cements were prepared by mixing a Portland cement with various amounts of ash. Mortars made of samples of Portland and blended cements were tested to ascertain compressive and flexural strength. It ensues from consideration of the chemical and physical characteristics of the ash, as well as the mechanical properties of the mortars produced, that after preliminary washing and/or grinding the material could, in fact, be used as partial replacement for Portland cement, although there is some slight reduction in the mechanical properties of the product.

American Journal of Applied Sciences, 2014

The aim of this study is the thermal recovery of manganese and zinc from a mixture of zinc-carbon... more The aim of this study is the thermal recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries containing 40.9% of Mn and 30.1% of Zn after a preliminary physical treatment. Separation of the metals is carried out on the basis of their different phase change temperatures, the boiling point of zinc being 906°C and 1564°C that of Mn 3 O 4 , the main Mn-bearing phase in the mixture. After wet comminution and sieving to remove the anodic collectors and most of the chlorides contained in the mixture, chemical and X-Ray Powder Diffraction (XRPD) analyses were performed. The mixture was heated in CO 2 atmosphere and the temperature raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture. Other tests were carried out by addition to the mixture of activated charcoal (95% C) or of the automotive shredder residue (fluff) containing 45% C.A zinc product was obtained suitable, after refining, for the production of new batteries. The treatment residue consisted of manganese and iron oxides that could be used to produce manganese-iron alloys. From these results, an integrated process for the recovery of the two metals was proposed.

Thermochimica Acta, 2011

The aim of this paper is to characterize spent zinc–carbon and alkaline batteries. Characterizati... more The aim of this paper is to characterize spent zinc–carbon and alkaline batteries. Characterization is essential to any process devoted to recovering the valuable materials contained in the batteries. In particular, the status of zinc and manganese has been established to permit treating only the zinc and manganese-bearing components in a recovery process, thus using smaller equipments and reducing both the material to treat and the energy consumption. At present, in fact, industrial processes treat the spent batteries as a bulk, only performing a preliminary separation with physical methods followed by a pyro- or hydrometallurgical process to recover zinc and manganese. Characterization has been carried out by chemical analysis, TGA/DTA analysis, XRPD and SEM analysis after having dismantled the batteries into the single components. Zinc and manganese are well separated in alkaline batteries while in zinc–carbon batteries the two metals are mixed, thus rendering difficult a preliminary separation by picking up the components containing the two metals separately.

International Journal of Mineral Processing, 1998

Physical separation methods were applied for upgrading the TiO contained in a fine waste 2 genera... more Physical separation methods were applied for upgrading the TiO contained in a fine waste 2 generated by the sulfuric acid process of a titanium pigment plant. The main components of this Ž. Ž. waste are TiO 42.0%-30% sulfuric-acid soluble TiO s and 12% insoluble TiO i-SiO 2 2 2 2 25%, and Al O 6%. Ninety percent of the material is finer than 45 mm. Gravity and magnetic 2 3 separation tests were carried out on the mud with the aim of recycling a TiO s enriched fraction. 2 Flotation tests were also carried out on the mud to obtain a TiO-enriched fraction to consider as 2 feed to a chlorination plant for the production of TiCl .

Recycling of Biomass …, 2011

100% relative humidity, these specimens were tested for heavy metal leachability through the use ... more 100% relative humidity, these specimens were tested for heavy metal leachability through the use of a sequential leaching protocol, at a constant pH of leachant (deionized water; pH 6.0). It was found that, except for the chloride content, the WBFA is able to meet the European ...

Asian Journal of Chemistry, 2013

Spent tea leaves (STL), a solid waste that is available in large amounts worldwide, was investiga... more Spent tea leaves (STL), a solid waste that is available in large amounts worldwide, was investigated as a potential low-cost adsorbent for the removal of two azo dyes, Reactive Green 19 (RG19) and Reactive Violet 5 (RV5), from contaminated waters. Preliminary experiments conducted on untreated STL showed that this material exhibited very low removal efficiencies (<10 %). By contrast, thermal activation of STL (200 to 400 °C for up to 2 h) resulted in a significant increase in dye adsorption. After thermal exposure of STL to 300 °C for 1 hour, removal efficiencies of 98.8 % and 72.8 % were observed, respectively, for RG19 and RV5. Characterization of the adsorbent by TG/DTA and FTIR measurements showed that structural and chemical changes occurred in the lignocellulosic material which were probably responsible for the enhancement in adsorption capacity. These results strongly support the use of activated STL as a low-cost alternative to conventional adsorbents.

CHEMICAL …, 2012

Drinking water contamination by fluoride is recognized as a major public health problem in many p... more Drinking water contamination by fluoride is recognized as a major public health problem in many parts of the world. In fact, although fluoride is an essential trace element for animals and humans, excessive fluoride intake may cause adverse health effects. In this study we investigated the potential of a natural, high alumina content, bauxite for the removal of fluoride from contaminated water. Both batch and continuous experiments were performed. In continuous-flow column experiments, the effects of inlet fluoride concentration (5-50 mg L-1) and flow rate (up to 2.5 mL min-1) on breakthrough time and adsorption capacity were studied. Batch equilibrium data were found to be well described by the Freundlich equation. Column studies showed that the dynamic adsorption capacity of the bed decreased as the inlet fluoride concentration and the flow rate increased. A maximum fluoride uptake capacity of 3.125 mg g-1 was determined. Overall, the results obtained indicate that this bauxite could be effectively used for defluoridation of drinking water.

Waste Management, 2012

The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alk... more The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn 2 O 3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30 min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

Waste Management, 2012

The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alk... more The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn 2 O 3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30 min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

The aim of this paper is to characterize spent zinc-carbon and alkaline batteries. Characterizati... more The aim of this paper is to characterize spent zinc-carbon and alkaline batteries. Characterization is essential to any process devoted to recovering the valuable materials contained in the batteries. In particular, the status of zinc and manganese has been established to permit treating only the zinc and manganesebearing components in a recovery process, thus using smaller equipments and reducing both the material to treat and the energy consumption. At present, in fact, industrial processes treat the spent batteries as a bulk, only performing a preliminary separation with physical methods followed by a pyro-or hydrometallurgical process to recover zinc and manganese. Characterization has been carried out by chemical analysis, TGA/DTA analysis, XRPD and SEM analysis after having dismantled the batteries into the single components. Zinc and manganese are well separated in alkaline batteries while in zinc-carbon batteries the two metals are mixed, thus rendering difficult a preliminary separation by picking up the components containing the two metals separately.