Lead Slag Research Articles

Sodium Hydroxide Leaching of Germanium from Lead Slag

Sodium Hydroxide Leaching of Germanium from Lead Slag

Recovery of Zinc and Copper from Lead Slag by the Combined Process of Beneficiation and Roasting

Recovery of Zinc and Copper from Lead Slag by the Combined Process of Beneficiation and Roasting

Volatilisation Behaviour and Mechanism of Lead-Containing Slag during Physical Property Tests.

According to physical property tests of lead-containing slag, the volatilisation behaviour of lead slag will have adverse impacts on test accuracy and further affect the control of chemical reactions, solidification and removal of inclusions during smelting. To analyse the volatilisation characteristics of lead slag, in this paper, four kinds of lead slags from lead direct reduction smelting with different PbO and ZnO content are taken. thermogravimetry, ISP-TOF were used. Additionally, the changes in volatiles and slag composition and phases were analysed with XRD and ICPS, and the volatilisation reaction mechanism was discussed. The results indicated that the volatilisation of lead slag can lead to a big weight loss of about to the slag with higher PbO content. The weight loss increases with the PbO content in slag increases. The volatile corresponding to the weight loss above 900 °C is mainly PbO and less ZnO. The higher the temperature is, the stronger the volatilisation is. With the increase in temperature and keeping time, most of the PbO can be evaporated and leaves little PbO in the residual slag. This will has great effect to physico-chemical property measurement of the slag with higher PbO content, especially to the property measurement that be kept at high temperature for a long time. Because the volatiles is trend to condense with the temperature decrease, mass spectrometer is limited by the condensation of volatiles, i.e., PbO, ZnO and so on, in the connection pipeline. The device should be modified for this use.

Efficiency of Portable X-ray Fluorescence for Distinguishing Lead Slag.

In the Minier Valley (France, Aveyron), an archaeological site excavation has led to the discovery of 25 kg of lead (Pb) slag, found in a secondary position. On a macroscopic level, these slags can be classified into two distinct categories, vitreous black and porous gray. This clear visual differentiation has been previously documented at other Pb-silver (Ag) metallurgy sites dating from the 12th century to the 14th century in Europe, and more particularly in the workshops of Mont Lozère, located approximately 80 km away from Le Minier. However, to date, scant evidence exists regarding the specific metallurgical process that produced this slag. This study presents the results of the analysis of 218 Pb slags (Supplemental Material) using portable X-ray fluorescence (pXRF). This method does not appear to be ideally suited for investigating this type of artifact, as it does not provide quantification of oxygen content. Nevertheless, it can be used to quickly identify trends and determine whether the two identified facies exhibit dissimilar chemical compositions. The results indicate that, based on the elemental compositions of the slags, no discernible distinction can be made to categorize them into two separate groups, both in bivariate and multivariate analyses. Consequently, it can be inferred that the gray and black slags originate from a single process executed within the same type of furnace. Scanning electron microscopy energy dispersive spectrometry analyses on selected samples demonstrate that variations in metal content are considerably exaggerated by pXRF, but that the trends observed are confirmed. The use of pXRF is therefore a relevant tool for determining whether or not Pb-Ag slag is the result of the same process. However, this initial approach needs to be refined by other analyses to confirm whether the smelted ores are of local origin and to be able to better define the details of the metallurgical process used.

Migration behavior of germanium and its related elements in zinc hydrometallurgy process

Lead-zinc sulfide ore is one of the raw materials for the recovery of strategic germanium resources. Due to the complexity of its mineralization and the diversity of elements, the occurrence and migration of germanium and its related elements in the process of zinc hydrometallurgy is still a mystery. This leads to the recovery efficiency of germanium is always in a disappointing state, which seriously reduces the economic benefits and resource recovery rate in the process of germanium recovery, and limits the development of some cutting-edge industries. Therefore, in view of the above problems, based on the properties of germanium compounds in lead–zinc sulfide minerals, this study analyzed the occurrence state and quantity of germanium in the products of each stage in the process of zinc hydrometallurgy by ICP, XRD, FT-IR, SEM, XPS, Raman spectrum and TG, so as to reveal the reaction behavior and migration law of germanium compounds in the process of zinc hydrometallurgy. The results indicate show that the two roasting will lead to the mutual transformation of GeO2 crystal form between soluble and insoluble, especially in the process of reduction and volatilization of zinc leaching residue. The phenomenon of soluble GeO2 to insoluble GeO2 is particularly significant, and the germanium-containing silicate cannot be reacted in the whole process. In addition, zinc blende, zinc ferrite, tin dioxide and other substances that exhibit isomorphism with germanium compounds will carry germanium into lead slag due to their low solubility. Finally, in view of the problems existing in the current germanium recovery process, positive solutions are proposed to introduce green additives in the two roasting stages to improve the phase of germanium, and to add oxidants or reducing agents in the leaching stage.

Effect of heavy-weight recycled materials on radiation shielding and properties of high-strength concrete with CEM III

This research aims to study the effect of replacing up to 100% of recycled coarse aggregates with heavyweight aggregates. In addition to the effect of adding heavyweight aggregate slag on the efficiency of shielding against radiation and on the mechanical physical properties and elevated temperature of heavyweight high-strength concrete (HWHSC). In this investigation, HWHSC mixtures incorporate lead slag (LS), copper slag (CS), and steel slag (SS) as coarse aggregate. Recycled heavyweight coarse aggregates are added to concrete mixtures at volume ratios of 0%, 25%, 50%, 75%, and 100%. Slump test, compressive strength, flexural strength, tensile strength, elastic modulus, and bulk density tests were carried out. Three different gamma-ray energies at 137Cs 662, 60Co 1173, and 60Co 1332 (keV) sources were used to evaluate the mass attenuation coefficient, linear attenuation coefficient, half and tenth-value layer, and mean free path. To evaluate the impact of elevated temperature on density, compressive strength, and radiation shielding properties, concrete mixtures were exposed to 22 °C, 300 °C, 500 °C, and 800 °C. Compared to basalt-based concrete, heavy-weight concrete (HWC) incorporating LS, CS, and SS coarse aggregate has a significantly higher density. The results show a good effect of recycled heavyweight coarse aggregates on fresh, mechanical, and radiation-shielding properties. The density of the developed high-strength concrete (HSC) mixes ranges between 2400 and 3370 kg/m3, and the increase in recycled heavyweight coarse aggregates replacement ratio up to 75% increased all mechanical characteristics of HWC mixtures. Using LS as a replacement of basalt by 75% resulted in the highest compressive strength, splitting tensile strength, flexural strength, and elastic modulus of 105.8 MPa, 14.2 MPa, 19.5 MPa, and 45.76 GPa, respectively. Compared to basalt, LS, CS, and SS eliminate the impact of elevated temperatures on HSHWC strength. The best radiation protection properties were achieved with the complete replacement of basalt by LS.

Chloride converts lead slag into a bifunctional material to remove heavy metals

Efficient and safe removal of arsenic and lead from industrial wastewater is essential for ecological protection. In this study, we developed a novel method using lead slag as a purifying agent and sodium chloride as a reinforcing agent to remove arsenic and lead from industrial wastewater. Through a combination of experiments and simulations, we elucidated the mechanisms involved in this reaction. The initial concentrations of As and Pb ions in the industrial wastewater were 4333 and 188 mg/L, respectively. After the reaction at 25 °C and a pH ranging from 9.7 to 10, the concentrations of arsenic and lead were reduced to 4.9 mg/L and 0.008 mg/L, respectively, achieving a removal rate of 99.9%. Our experimental results demonstrated that Pb2+ and AsO43− ions released from the lead slag and industrial wastewater reacted with Cl− ions to form Pb5(AsO4)3Cl precipitates, thus effectively eliminating a significant amount of As and Pb species. Simulation studies indicated that Pb5(AsO4)3Cl exhibited exceptional stability below 400 °C and could be directly stored. Additionally, the lead slag, which is rich in silica, played a crucial role in removing and stabilizing As and Pb ions. Under alkaline conditions, silica encapsulated the As and Pb species, adhering to the surface of the Pb–As co-precipitates and forming dense, irregular, small particles with internal and external structures that impeded the efflux of As and Pb ions. This phenomenon was confirmed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The kinetics of As and Pb ion removal was consistent with the pseudo-second-order kinetic model, indicating that the removal process was primarily governed by chemical interactions. Lead slag exhibits significant potential and advantages in the removal of As and Pb. This innovative method offers an effective approach to address heavy metal contamination in industrial wastewater, thus contributing to ecological protection.

Studies of Utilization of Technogenic Raw Materials in the Synthesis of Cement Clinker from It and Further Production of Portland Cement

Four series of experiments were carried out to study the possibility of replacing clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge for Portland cement. The experiments were carried out at atmospheric pressure and a temperature of 1350 °C. It was shown that the replacement of clay and an iron-containing component with tefritobasalt and lead slag as part of the initial charge in the cement industry will lead to a decrease in temperature by 100 °C in the technological scheme of production and a reduction in energy consumption, since the theoretical specific consumption of raw materials is 1.481 t/t of clinker, which is approximately 70 kg lower than in traditional mixtures. The content of non-traditional components in total was 24.69%. In addition, tefritobasalts improved clinker formation processes, contributed to a decrease in the firing temperature, and intensified the clinker firing process. A small amount of lead slag (5.06%) introduced into the mixture changed the structure of the clinker and improved the process of mineral formation while also improving roasting and reducing the anthropogenic impact on the environment through the disposal of man-made waste. The strength of the experimental composite cements was tested after 7 and 28 days on small samples measuring 2 × 2 × 2 cm. The physicomechanical characteristics and structure of composite cements were studied.

Preparation of magnesium potassium phosphate cement from municipal solid waste incineration fly ash and lead slag co-blended: Ca-induced crystal reconstruction process and Pb-Cl synergistic solidification mechanism

Higher chlorine (Cl) content than lead (Pb) content in municipal solid waste incineration fly ash (MSWIFA) impeded the practical application of Pb5(PO4)3Cl-derived magnesium potassium phosphate cement (MKPC) preparation strategy. Herein, Pb/Ca-rich lead slag (LS) was co-blended with MSWIFA to prepare MKPC for the synergistic treatment of both two solid wastes and the Pb-Cl solidification. The results showed that the resulting 15–15 (15 wt% MSWIFA and 15 wt% LS incorporation) sample achieved 25.44 MPa compressive strength, and Pb and Cl leaching toxicity was reduced by 99.18 % and 92.80 %, respectively. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses showed that Pb2+, Ca2+, phosphate and Cl- formed PbxCa5−x(PO4)3Cl in samples. The formation of PbxCa5−x(PO4)3Cl was also demonstrated by the high-angle annular dark field scanning transmission electron microscope (HAADF-STEM), while differences in the lattice characteristics of PbxCa5−x(PO4)3Cl and Pb5(PO4)3Cl were found. In-situ XRD indicated that Ca2+ accelerated the transformation of Pb2+ to Pb5(PO4)3Cl. After co-precipitating with Ca2+ to form PbxCa5−x(PO4)3Cl, Pb2+ continuously substituted Ca2+ to eventually transform to Pb5(PO4)3Cl. This work informs the synergistic treatment of MSWIFA and LS and offers new insights into the reaction mechanism between Pb2+, phosphate and Cl- under Ca2+ induction.

Preparation and characterization of glass ceramics synthesized from lead slag and lead-zinc tailings

Using lead slag and lead-zinc tailings to prepare high-value glass-ceramic can realize the comprehensive utilization of solid waste and reduce the environmental pollution caused by lead slag landfill. Firstly, lead-zinc tailings and borax are used to melt and temper lead slag to improve its sintering performance. At 1450 °C, the lead slag melted and tempered by adding 40% lead-zinc tailings and 4% borax has good fluidity in the molten state. In water quenching, crystallization is not easy, and the water quenching slag has good sintering performance. Then, the water-quenched slag obtained by melting and tempering lead slag with lead-zinc tailings and borax was ball-milled and mixed with 10% albite feldspar and sintered at 1050 °C for 90 min to prepare glass ceramics. The prepared glass-ceramics have excellent performance parameters such as bulk density of 2.79 g/cm3, water absorption of 0.05%, the flexural strength of 102.18 MPa, acid resistance of 0.15%, and alkali resistance of 0.032%. Simultaneously, the glass ceramics exhibited excellent resistance to the leaching of heavy metals where the leaching concentrations of Pb, Zn, As, and Cd were 0.125, 1.268, 0.324, and 0.029 mg/L, respectively. This research can provide a new idea for comprehensively utilizing solid waste.

Investigation of the Splashing Characteristics of Lead Slag in Side-Blown Bath Melting Process

Aiming at the melt splashing behavior in the smelting process of an oxygen-enriched side-blowing furnace, the volume of fluid model and the realizable k−ε turbulence model are coupled and simulated. The effects of different operating parameters (injection velocity, immersion depth, liquid level) on splash height are explored, and the simulation results are verified by water model experiments. The results show that the bubbles with residual kinetic energy escape to the slag surface and cause slag splashing. The slag splashing height gradually increases with the increase in injection velocity, and the time-averaged splashing height reaches 1.01 m when the injection speed is 160 m/s. Increasing the immersion depth of the lance, and the slag splashing height gradually decreases. When the immersion depth is 0.12 m, the time-averaged splashing height is 0.85 m. Increasing the liquid level is beneficial to reduce the splash height, when the liquid level is 2.7 m, the splash height reduces to 0.77 m. With the increase in the liquid level, the slag splashing height gradually decreases, and the time-averaged splashing height is 0.77 m when the initial liquid level is 2.7 m.

Mechanical, Durability, and Gamma Ray Shielding Characteristics of Heavyweight Concrete Containing Serpentine Aggregates and Lead Waste Slag

Heavyweight concrete is used to prevent harmful radiation for the construction of hospital, military, and nuclear power plants and also to increase the durability for the construction of marine concrete structures. In this research, using a combination of serpentine aggregates and lead slag, the mechanical, durability, impact resistance, and shielding properties of heavyweight concrete were examined. The variables included fine and coarse serpentine aggregates, which were replaced with normal fine and coarse aggregates in amounts of 0, 25, 50, and 100 percent, respectively. The lead slag in all samples was considered constant. Slump, compressive strength, flexural strength, water penetration depth, impact resistance (drop hammer), and gamma ray attenuation coefficient tests were conducted. The chemical composition of serpentine aggregates and lead slag were evaluated by X-ray powder diffraction. The results showed that the density and linear attenuation coefficient (LAC) increased with the increase of fine and coarse serpentine aggregates in heavyweight concrete containing lead slag. The highest density and LAC were obtained in a sample in which 100% fine serpentine aggregates and 100% coarse serpentine aggregates were used. Using 25% of serpentine fine aggregates and 25% of serpentine coarse aggregates in heavyweight concrete samples containing lead slag has achieved the highest compressive strength and flexural strength. But with the increase of fine and coarse serpentine aggregates to more than 25%, the upward trend of increasing compressive strength decreased. Silica constitutes a large part of the chemical structure of serpentine aggregates (about 42%). Increasing the amount of serpentine aggregates in concrete mixes leads to excessive release of calcium hydroxide in concrete. This issue can lead to the formation of a weak zone in concrete and decrease the compressive and impact resistance.

The Dawn of Metallurgy at Chalcolithic Arslantepe: Metal Finds and Other Metallurgical Remains from Level VII

This paper deals with archaeometallurgical remains from period VII (Late Chalcolithic 3-4, 3900-3400 BC) of the settlement of Arslantepe (Malatya, Turkey). It aims at compiling early metallurgy (metallurgical artefacts, slags) by means of interdisciplinary scientific analysis. In contrast to later periods, the metallurgy of the Late Chalcolithic has as yet only been investigated to a limited degree. Trace elements and lead isotope analysis of metal artefacts and slags allowed for a reconstruction of provenances of raw materials in order to deal with trade networks. Lead and copper slags were analysed for texture and phase content to reconstruct metallurgical operations. Late Chalcolithic activities from Arslantepe level VII are compared with the metallurgy of the previous level, VIII, as well as of later periods (levels VI A, VI B). Various metal groups could be identified at Arslantepe VII, most notably copper, arsenic copper and arsenic-nickel copper. The slag samples show the smelting and processing of copper and lead within the settlement, while the lead slags may also indicate the extraction of silver. The differing compositions indicate the use of differentraw material sources, which is also supported by the lead isotope analysis data.

Utilization of Lead Slag as In Situ Iron Source for Arsenic Removal by Forming Iron Arsenate.

In situ treatment of acidic arsenic-containing wastewater from the non-ferrous metal smelting industry has been a great challenge for cleaner production in smelters. Scorodite and iron arsenate have been proved to be good arsenic-fixing minerals; thus, we used lead slag as an iron source to remove arsenic from wastewater by forming iron arsenate and scorodite. As the main contaminant in wastewater, As(III) was oxidized to As(V) by H2O2, which was further mineralized to low-crystalline iron arsenate by Fe(III) and Fe(II) released by lead slag (in situ generated). The calcium ions released from the dissolved lead slag combined with sulfate to form well-crystallized gypsum, which co-precipitated with iron arsenate and provided attachment sites for iron arsenate. In addition, a silicate colloid was generated from dissolved silicate minerals wrapped around the As-bearing precipitate particles, which reduced the arsenic-leaching toxicity. A 99.95% removal efficiency of arsenic with initial concentration of 6500 mg/L was reached when the solid-liquid ratio was 1:10 and after 12 h of reaction at room temperature. Moreover, the leaching toxicity of As-bearing precipitate was 3.36 mg/L (As) and 2.93 mg/L (Pb), lower than the leaching threshold (5 mg/L). This work can promote the joint treatment of slag and wastewater in smelters, which is conducive to the long-term development of resource utilization and clean production.

Experimental weathering of historical slags exposed to rhizosphere-like organic acids and various pH conditions

The long-lasting mining and smelting activity that took place in southern Tuscany since the 1st millennium BCE has left several remains of metallurgical interest, along with metallurgical slags. Over the centuries, these materials were treated as wastes and dumped close to the industrial sites, with no specific disposal or confinement from the surrounding environment. We performed leaching experiments on slag samples from two selected sites, applying conditions to test the effects of various pH conditions, as well as their behavior following the addition of organic acids to simulate a rhizospheric environment. The samples, a crystalline Pb slag and a glass-rich Cu slag, showed a different leachability depending upon their physical and mineral-chemical characteristics, such as the size of the fragments used in the experiments, the mineralogical composition, and the bulk content of metals in the samples. The crystalline Pb slag showed a higher susceptibility to leaching (e.g., 31 % Cu and 65 % Zn) under acidic inorganic conditions, compared to the glass-rich Cu slag, which was prone to organic mediated dissolution (14 % Cu and 6 % Zn). The highest metal mobilization occurred during the pH-dependent leaching experiments at pH 1, reaching 92 % (of leached Pb) and 65 % (Zn) for lead slag and copper slag, respectively.

Historical Lead Smelting Slag Harmlessness and Valuable Metals Recovery: A Co-Treatment of Lead Slag and Zinc-Bearing Material in Rotary Kiln

The harmless treatment of historical lead smelting slag (LSS) is of significance to ecological and environmental protection, but it is still challenging in terms of the economic feasibility of alone processing due to the low content of valuable metals. Here, we performed an industrialized test with a co-treatment of LSS and zinc oxide ore in a rotary kiln to evaluate the economic feasibility and solidification effect of harmful elements. The results revealed that more than 70% of Zn and Pb were recovered from LSS in the form of dust, while the nonvolatile part of Pb, Zn, and Cd were solidified in gangue as complex silicate phases. The nonvolatile part of As came into being Fe-As intermetallic compound which was encapsulated by gangue particles or was solidified in silicate phases. The entirely enclosed structure of water-quenched slag plays an important role in the stability of slag. The TCLP and SNAL leaching tests demonstrated the high stability of water-quenched slag. A zinc oxide ore addition of 20% was recommended for energy consumption and processing capacity. Our findings highlight that the valuable metals not only can be effectively recovered but also harmful elements are solidified in gangue, providing an economical and feasible technical route for the treatment of historical LSS.

Accelerated carbonation of ferrous and non-ferrous slags to produce clinker-free carbonate-bonded blocks: Synergetic reduction in environmental leaching

• Clinker-free blocks by accelerated carbonation of ferrous and/or non-ferrous slags. • Decreased Cr-leaching in SSS used individually, disproportional decrease with NFMS. • Pb-slag vs P(CO 2 ): decreased Pb-leaching, Co/Zn/Mn leaching increase then decrease. • Synergetic reduction in leaching from mixes of ferrous/non-ferrous slags. • In addition to encapsulation, a chemical synergy between sulfide/Cr is discussed. Clinker-free, carbonate-bonded monoliths are prepared by accelerated carbonation for immobilization of hazardous elements present in: a stainless-steel slag, two copper slags, and one lead slag. In addition to the studies on individual slags, mixes of copper slags and lead slags with 33 % and 66 % replacements of stainless-steel slag are also studied. Combinations of two temperatures (30 and 60 °C) and three CO 2 -pressures (1, 5, and 10 barg) are studied. Among the non-ferrous slags carbonated individually, lead slag carbonated at 10 barg exhibited carbonate-cementation. The carbonate-bonded monoliths containing stainless-steel slag exhibited high compressive strengths, individually or as in its mixes with other slags. In stainless-steel slag, while its individual carbonation also showed a decrease in Cr-leaching, the Cr-leaching from its mixes with non-ferrous slags are disproportionately lower: possible chemical synergy of stainless-steel slag with sulfidic non-ferrous slags is discussed. For lead slag individually, carbonation significantly decreases Pb-leaching; while Co, Zn, and Mn leaching first increase and then decrease with an increase in CO 2 -pressure. In mixes of lead slag with stainless-steel slag, Pb, Co, Zn, and Mn leaching are significantly decreased. Temperature does not have a significant influence on the product properties. Copper slag remained relatively insensitive towards carbonation. Comparisons are made with the Flemish legislative limits.

From hazardous waste to fertilizer: Recovery of high-value metals from smelter slags

This work proposes a method to valorize lead slag for fertilizer purposes. The research concept was to selectively recover valuable microelements (Cu(II), Fe(II), Zn(II) in an amount of at least 0.2% m/v of each) by chemical leaching while retaining toxic elements in the slag (i.e. As and Pb). Among acids, hydroxides, salts and their mixtures tested for slag treatment, it was potassium hydrogen sulfate and ammonia liquor under strongly oxidizing conditions (in the presence of hydrogen peroxide) that proved to be the most effective leaching agents. Response Surface Methodology applied to optimize the slag leaching conditions set the most favorable process parameters (concentration of leaching agents, slag to reagent weight ratio, and temperature). As a result, the concentration of Cu(II) in the extract was 3751 mg/L (for ammonia liquor) and Fe(II) and Zn(II) concentrations in potassium hydrogen sulfate were 4738 mg/L and 6102 mg/L, respectively. To close the life cycle of the waste, immobilization in polyethylene and binding to cement were indicated as methods to manage the solid waste material after leaching. The mixed extracts rich in Cu(II), Fe(II) and Zn(II) ions were tested in germination tests on cucumber. No phytotoxic effect was observed, which raises the possibility of utilizing the solutions after chemical leaching of slag as an alternative source of micronutrients for the production of multicomponent fertilizers. The results are promising and fit in the assumptions of circular economy.

Insights into CO2-mineralization using non-ferrous metallurgy slags: CO2(g)-induced dissolution behavior of copper and lead slags

The possibility of utilizing non-ferrous slags for CO2-mineralization is explored in this study by investigating their dissolution behaviors in CO2-environments, since dissolution is usually considered as a major rate-limiting step during CO2-mineralization. Dissolution of two copper slags and a lead slag are studied at the liquid to solid ratio (w/w) of 1000 at combinations of two temperatures (30 and 60 °C) and two CO2-pressures (1 and 10 barg) with time (30, 60, 120, and 240 min). Among the systems in which the slags are dissolved in CO2-environments, the lead slag exhibits Fe-dissolution of up to 10%, and the copper slags up to 5–6% within four hours. The solution-pH were between 4 and 5 in almost all the observations. The dissolution rates of the slags are found to be in the range of 10−7-10−9 mol/m2/s which are comparable with the dissolution of natural fayalite in (in)organic acids. Following the dissolution during the initial 30–60 min, the systems at a higher temperature (at constant CO2-pressure) and higher CO2-pressure (at constant temperature) exhibit higher (or comparable) [Ca], [Fe], [Si], and solution-pH. Moreover, even though the systems at higher temperature and CO2-pressure exhibit higher solution-pH following the initial 30–60 min of dissolution, they continue to exhibit higher dissolution rates throughout the study. Since the residues like non-ferrous copper and lead slags are readily available compared to the analogous natural minerals (like olivines) that usually need to be pre-processed before carbonation, they are proposed as promising sources for CO2-mineralization.

Assessment of Metallurgical Slags as Solar Heat Absorber Particles

The use of ceramic solid particle technology in TES-integrated CSP plants offers a high solar-to-electricity ratio and enhanced storage densities, thanks to their high operational temperatures and wide temperature ranges. Metallurgical slags with composition similar to that of the state-of-art bauxite particles can be used as a sustainable and economical secondary raw material to prepare solid particles. In this study, the as-received state and the high-temperature phase and microstructural changes of two fayalite slags from copper and lead production were elucidated by XRD and SEM/EDS methods in a comparative manner. Solid particles were prepared from slags by the oil dropping method, with subsequent heat treatment. Solar-thermal-application-related functional properties of slag particles, such as heat capacity, absorptance, and thermophysical properties, were evaluated by differential scanning calorimetry (DSC), spectrophotometer, heating microscope, and high-temperature compressive tests, respectively. Owing to the formation of more stable Fe-rich phase components and less amount of glassy phase, copper slag is found to be a more promising secondary resource than lead slag in terms of material and functional properties.