Processing of Waste from Enrichment with the Production of Cement Clinker and the Extraction of Zinc

This paper presents studies on the processing of enrichment tailings as a component of a raw mixture in order to obtain cement clinker, with simultaneous distillation of zinc. Thermodynamic studies were carried out in the temperature range of 600–1600 °C using the software application “HSC Chemistry 6” developed by the metallurgical company Outokumpu (Finland). As a result of the conducted studies, we found that zinc contributes to the intensification of mineral formation of cement clinker. In particular, it was found that the formation of belite is possible in the temperature range from 990.7 to 1500 °C with Gibbs energy values of −0.01 and −323.8 kJ (which is better than the standard process by −11.4 kJ), respectively; the formation of alite is possible in the temperature range from 982.9 to 1500 °C with Gibbs energy values of −0.05 and −402.1 kJ (better than the standard process by −11.4 kJ), respectively; the formation of tricalcium aluminate is thermodynamically possible in the temperature range from 600 °C at ΔGTo = −893.8 kJ to 1500 °C at ΔGTo = −1899.3 kJ (better than the standard process by −1570.1 kJ), respectively; and the formation of four calcium aluminoferrite is possible in the temperature range from 600 °C at ΔGTo = −898.9 kJ to 1500 °C at ΔGTo = −1959.3 kJ (better than the standard process by −1570.2 kJ), respectively, with simultaneous distillation of zinc into a gaseous state for its further capture.

Technologically Sustainable Route for Metals Valorization from Jarosite-PbAg Sludge

By-products from zinc hydrometallurgy are classified as hazardous waste with strong leaching toxicities. Even though numerous research papers are dedicated to valorizing valuable metals in it, the primary management route is still disposal or partial reuse, such as the Waelz process. Presented experimental research investigates possibilities of sulfidization and further processing as a technologically sustainable route for valuable metals valorization from non-standard jarosite-PbAg sludge. The comprehensive thermodynamic analysis was done by HSC Chemistry®, through optimizing process parameters, i.e., temperature, sulfur addition, and selection of possible additives. Technological possibility of magnetic separation, flotation, and smelting of sulfidized material was also investigated; the results were below the values that allow practical application, due to the obtained texture of sulfidized jarosite, which does not allow the liberation of minerals. Smelting tests were performed on sulfidized jarosite with sulfur and without and with carbon as additive. By smelting sulfidized jarosite-PbAg sludge with added carbon in sulfidization stage at 1375 °C, obtained products were matte, slag, raw lead, and dust in which base, critical, and slag forming components were valorized. Valuable metals were concentrated in smelting products so as to enable further processing, which also could be interesting in the case of treatment of complex, polymetallic, and refractory primary materials, which represent a significant contribution to the circular economy.

Solar Thermochemical Conversion of Carbon Dioxide into Fuel via MnFe2O4 based Two-Step Redox Cycle

Thermodynamic efficiency analysis of [[EQUATION]] based CO 2 splitting (CDS) cycle is reported. HSC Chemistry software is used for performing the calculations allied with the model developed. By maintaining the reduction nonstoichiometry equal to 0.1, variations in the thermal energy required to drive the cycle ( [[EQUATION]] ) and solar-to-fuel energy conversion efficiency ( [[EQUATION]] ) as a function of the ratio of the molar flow rate of inert sweep gas ( [[EQUATION]] ) to the molar flow rate [[EQUATION]] ( [[EQUATION]] ), i.e., [[EQUATION]] , reduction temperature ( [[EQUATION]] ), and gas-to-gas heat recovery effectiveness ( [[EQUATION]] ) are studied. The rise in [[EQUATION]] is responsible for the decrease in [[EQUATION]] . At [[EQUATION]] = 0.7, [[EQUATION]] increases from 176.0 kW to 271.7 kW when [[EQUATION]] escalates from 10 to 100. Conversely, [[EQUATION]] reduces from 14.9% to 9.9% due to the similar increment in [[EQUATION]] . The difference between [[EQUATION]] at [[EQUATION]] = 10 and 100 decreases from 363.3 kW to 19.2 kW as [[EQUATION]] rises from 0.0 to 0.9. As [[EQUATION]] and subsequently [[EQUATION]] reduces as a function of [[EQUATION]] , [[EQUATION]] increases noticeably. At [[EQUATION]] equal to 0.9 and [[EQUATION]] equal to 10 as well as 20, the maximum [[EQUATION]] equal to 17.5% is realized.

Modeling and Investigating the Production of Carbon Dioxide Gas Using HSC Software in the Tile Industry

Background: The study of the production and emission of greenhouse gases, including CO2 in the atmosphere, is one of the most important environmental issues and concerns of the international community. This study was conducted to investigate the effect of temperature and furnace fuel concentration changes on CO2 and CO production. Methods: In this study, using HSC Chemistry 6 software, the existing reactions for fuels used in the furnace, including CaCO3, MgCO3, Fe2O3, and Fe3O4, were simulated. The concentrations of carbon dioxide and carbon monoxide produced at different temperatures were investigated. Results: In the CaCO3 reaction, the temperature has a direct effect on carbon dioxide production but no effect on carbon monoxide production. In the MgCO3 reaction, the temperature has little effect on the production of both, and for the rest of the reactions, the effect of temperature depends on the molar composition and reaction conditions. Conclusion: In general, the results show that temperature affects the production of carbon dioxide and monoxide, so the emission of these gases to the environment can be reduced by adjusting the temperature of the furnace reactors.

Literature Review and Thermodynamic Modelling of Roasting Processes for Lithium Extraction from Spodumene

This review adds to the public domain literature on the extraction of lithium from mineral ores. The focus is on the pyrometallurgical pre-treatment of spodumene. Information on the phase transformation from α to β, the heat treatment methods as well as the behavior of various compounds in the roasting processes are evaluated. Insight into the chemical thermodynamics of the baking process is evaluated using HSC Chemistry software up to 1200 °C. It was observed that the alkaline, sulfation, chlorination (using Cl2 and CaCl2), carbonizing (to form Li2CO3) and fluorination processes were feasible either throughout or at a point within the temperature range considered. Chlorination using KCl and carbonizing to form Li2O are the processes found to be nonspontaneous throughout the temperatures considered.

A Study of Nickel and Iron Reduction Silicothermic Process by Thermodynamic Simulation

The results of studying the effect of silicon concentration of ferrosilicon: FeSi5 (5% Si), FeSi20 (20% Si), FeSi35 (35% Si), FeSi50 (50% Si), FeSi65 (65% Si) on the degree of nickel (ηNi) and iron (ηFe) reduction of the CaO-SiO2-MgO-Al2O3-FeO-NiO-P2O5 multicomponent oxide system at a temperature of 1500 °C by thermodynamic simulation are given2. The HSC Chemistry 6.12 software package developed by Outokumpu (Finland) was used for the simulation. The chemical compounds Ni3Si and Ni5Si2 with the corresponding thermodynamic characteristics are entered into the database. The calculations were performed by the “Equilibrium Compositions” subroutine at a gas pressure of 1 atm, containing 2.24 m3 N2, as a neutral additive. The obtained modeling results indicate the thermodynamic possibility of nickel and iron reduction from the CaO-SiO2-MgO-Al2O3-FeO-NiO-P2O5 oxide system by silicon of ferrosilicon. The degree of iron reduction increases from 88.8 to 91.4%, with an increase in the silicon concentration of ferrosilicon [Si]FeSi from 5 to 65%. The degree of nickel reduction with an increase in the silicon concentration of ferrosilicon remains almost unchanged and amounts to 99.8-99.7%. The degree of use of silicon is 92.1–94.5%. The chemical composition of the complex alloy – ferrosiliconickel is determined. The obtained simulation results can be used to develop the technology for producing ferrosiliconickel from nickel ore by silicothermic method.

Trace element emissions during the 2018 Kilauea Lower East Rift Zone eruption

<p>The 2018 eruption on the Lower East Rift Zone of Kilauea volcano, Hawai’i released unprecedented fluxes of gases (>200 kt/d SO<sub>2</sub>) and aerosol into the troposphere [1,2]. The eruption affected air quality across the island and lava flows reached the ocean, forming a halogen-rich plume as lava rapidly boiled and evaporated seawater.</p><p>We present the at-source composition – gas and size-segregated aerosol – of both the magmatic plume (emitted from ‘Fissure 8’, F8) and the lava-seawater interaction plume (ocean entry, OE), including major gas species, and major and trace elements in non-silicate aerosol. Trace metal and metalloid (TMM) emissions during the 2018 eruption were the highest recorded for Kilauea, and the magmatic ‘fingerprint’ of TMMs (X/SO<sub>2</sub> ratios) in the 2018 plume is consistent with measurements made at the summit lava lake in 2008 [3], and with other rift and hotspot volcanoes [4,5].</p><p>We show that the OE plume composition predominantly reflects seawater composition with a small contribution from plagioclase +/- ash. However, elevated concentrations of some TMMs (Bi, Cd, Cu, Zn, Ag) with affinity for Cl-speciation in the gas phase cannot be accounted for by the silicate correction and therefore may derive from degassing of lava in the presence of elevated Cl<sup>-</sup>. In the case of silver and copper, concentrations in the OE plume are elevated above both the F8 plume and seawater.</p><p>At-vent speciation of TMMs in the F8 plume during oxidation (following a correction for ash contributions) was assessed using a Gibbs Energy Minimization algorithm (HSC chemistry, Outotec Research). We also demonstrate the sensitivity of speciation in the plume to the concentration of common ligand-forming elements, chlorine and sulfur. These results could be used as initial conditions in atmospheric reaction models to investigate how plume composition evolves as low-temperature chemistry takes over.</p><p>References:</p><p>[1] Neal C et al. (2019) Science</p><p>[2] Kern C et al. (2019) AGU Fall meeting abstract V43C-0209</p><p>[3] Mather T et al. (2012) GCA 83:292-323</p><p>[4] Zelenzki et al. (2013) Chem Geol 357:95-116</p><p>[5] Gauthier P-J et al. (2016) J Geophys 121:1610-1630</p>

Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud

Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.

Thermodynamic simulation of the V-Al-N-C master alloy aluminothermic smelting

For microalloying of titanium with nitrogen and carbon, the V-Al-N-C complex master alloy is used. One of the main requirements presented by consumers of this ligature to its composition is oxygen content of less than 0.1 % mass. The use of elemental carbon (graphite) in the mixture for out-of-furnace aluminothermic smelting of the V-Al-N-C master alloy promotes the formation of aluminum oxonitrides in the melt, which, in the process of forming the metal and slag phases, can be stored in the alloy as separate inclusions. Since carbon in the master alloy is present in the form of V2Al0.96C1.1 carbide, it is advisable to replace graphite in the composition of the smelting mixture with an alternative precursor containing carbide of this composition. The paper presents the results of thermodynamic simulation of phase formation occurring in the process of V-Al-N-C master alloy smelting using various carbidizers. The equilibrium temperature dependences were obtained using the HSC Chemistry 6.12 software, the database of which was supplemented by the missing thermochemical characteristics of vanadium aluminides (VAl3, V5Al8, V3Al2) and V2AlC carbide borrowed from published sources. Thermodynamic models that take into account the formation of these intermetallic compounds adequately describe the processes that occur during the interaction of mixture components for the aluminothermic smelting of V-Al-N-C alloys. The predicted elemental and phase compositions of the V-Al-N-C model alloys are in a good agreement with the data of chemical, XRD and EMPA analyzes of samples of real alloys. Models that take into account the formation of V2AlC carbide and vanadium aluminides are applicable for calculating the compositions and thermality of mixtures, as well as for predicting the V-Al-N-C alloys smelting products. From the point of view of thermodynamics, replacing graphite in a mixture of the V-Al-N-C master alloy smelting with a precursor alloy V(70)-Al(23)-C(7), carbon in which is represented as V2AlC carbide and vanadium carbides V2C and VC, will not affect the carbon distribution over it phase component and will not adversely affect the technological performance of the smelting.