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In this research, an efficient method of lithium extraction from α-spodumene by thermal treatment with NH4HF2 was optimized. Temperature (T), α-spodumene:NH4HF2 molar ratio (m), and reaction time (t) were studied using a two-level univariate strategy. The results were modeled using least squares (LS) and artificial neural networks (ANN) and then compared to obtain a predictive model of the system. Both models showed good concordance with the experimental data (R² of 0.9881 and 0.9957, respectively) and with each other. The ANOVA of the cubic model indicated that T, m, t, and the interactions Tt, T², and T³ were significant. Finally, the system was optimized using response surface methodology to maximize Li extraction and minimize operational parameters. The desirability function predicted an extraction value of 95.48 ± 2.50% for T = 156.7 °C, m = 1:17.5, and t = 100.6 min. Experimental lithium extractions of 96.45 ± 3.68% were obtained at 157 °C using a molar ratio of 1:17.5 for 100 min. The products of the thermal treatment were LiF, (NH4)3SiF6·F, (NH4)3AlF6, NH3, and H2O. After a water leaching step, the silicon in the sample was separated, obtaining (NH4)3SiF6·F as a by-product. Finally, the solid products were leached with H2SO4 10% (v/v) to solubilize all lithium.
Alexander C. Resentera; Marcelo R. Esquivel; Mario H. Rodriguez. Low-temperature lithium extraction from α-spodumene with NH4HF2: Modeling and optimization by least squares and artificial neural networks. Chemical Engineering Research and Design 2021, 167, 73 -83.
AMA StyleAlexander C. Resentera, Marcelo R. Esquivel, Mario H. Rodriguez. Low-temperature lithium extraction from α-spodumene with NH4HF2: Modeling and optimization by least squares and artificial neural networks. Chemical Engineering Research and Design. 2021; 167 ():73-83.
Chicago/Turabian StyleAlexander C. Resentera; Marcelo R. Esquivel; Mario H. Rodriguez. 2021. "Low-temperature lithium extraction from α-spodumene with NH4HF2: Modeling and optimization by least squares and artificial neural networks." Chemical Engineering Research and Design 167, no. : 73-83.
In this article, we analyze the leaching kinetics with phosphoric acid of LiCoO2 samples from spent Li-ion batteries and commercial LiCoO2. The purpose was to study the mechanism by which the extraction reaction of cobalt and lithium is produced from the solid samples. The experimental results showed that raising the temperature and the reaction time contributed to improving both the extraction of Li and Co from the structure. The leaching rate of the metals from both samples in the phosphoric acid solution could be expressed as:ln1-X=-b1ln1+b2t-b2t1+b2t. The morphology of the solid revealed that the dissolution reaction of the samples develops from preferential growth of active sites, points susceptible to chemical interaction, occurring in one direction, giving rise to the start and progress of the reaction. The generation of these sites in the LCO-H3PO4 reaction system is of the "sequential" type. The apparent activation energy values for the leaching of Co and Li would indicate that the surface chemical reaction is the rate-controlling step during this dissolution process.
Eliana G. Pinna; D. Sebastián Drajlin; Norman Toro; Mario H. Rodriguez. Kinetic modeling of the leaching of LiCoO2 with phosphoric acid. Journal of Materials Research and Technology 2020, 9, 14017 -14028.
AMA StyleEliana G. Pinna, D. Sebastián Drajlin, Norman Toro, Mario H. Rodriguez. Kinetic modeling of the leaching of LiCoO2 with phosphoric acid. Journal of Materials Research and Technology. 2020; 9 (6):14017-14028.
Chicago/Turabian StyleEliana G. Pinna; D. Sebastián Drajlin; Norman Toro; Mario H. Rodriguez. 2020. "Kinetic modeling of the leaching of LiCoO2 with phosphoric acid." Journal of Materials Research and Technology 9, no. 6: 14017-14028.
In this work, the thermal and microstructural analysis of the reaction pathways of α-spodumene with NH4HF2 at low temperatures is presented. The thermal behavior of NH4HF2, mixtures α-LiAlSi2O6/NH4HF2 and by-products (NH4)3SiF6·F/(NH4)2SiF6, are analyzed by simultaneous thermogravimetry and differential thermal analysis (TG-DTA). The study of the crystallite size and lattice strain in the solids is carried out using X-ray diffraction (XRD). The obtained results indicate that the heating rate has a remarkable influence on the processes. At low heating rates, 1 K/min, the reaction between the mineral and NH4HF2 begins at about 351 K and is completed around 426 K, approximately. The obtained products are LiF, (NH4)3SiF6·F, (NH4)3AlF6, NH3 and H2O. In the 368–429 K temperature range, the unreacted NH4HF2 is removed and (NH4)3SiF6·F starts to decompose to generate (NH4)2SiF6. Finally, (NH4)2SiF6 and (NH4)3AlF6 sublimate and decompose at 433 and 493 K, respectively. The main final product is a LiF/AlF3 mixture at 533 K.
Alexander C. Resentera; Gustavo D. Rosales; Marcelo R. Esquivel; Mario H. Rodriguez. Thermal and structural analysis of the reaction pathways of α-spodumene with NH4HF2. Thermochimica Acta 2020, 689, 178609 .
AMA StyleAlexander C. Resentera, Gustavo D. Rosales, Marcelo R. Esquivel, Mario H. Rodriguez. Thermal and structural analysis of the reaction pathways of α-spodumene with NH4HF2. Thermochimica Acta. 2020; 689 ():178609.
Chicago/Turabian StyleAlexander C. Resentera; Gustavo D. Rosales; Marcelo R. Esquivel; Mario H. Rodriguez. 2020. "Thermal and structural analysis of the reaction pathways of α-spodumene with NH4HF2." Thermochimica Acta 689, no. : 178609.
The progressive depletion of primary sources to obtain metals has led to the search for alternative sources for their recovery. In the particular case of titanium, titaniferous sands are a viable option for obtaining this metal. This paper presents the results of the dissolution of titanium from titaniferous sands of Buenos Aires province (Argentina) in a laboratory autoclave (450 mL of capacity). The operating parameters studied were as follows: different acids (HF, H2SO4 and mixtures of these acids); leaching agent concentration, 5–20% v/v; temperature, 75–150 °C; time, 30–180 min; solid–liquid ratio, 0.9–3.6% w/v; stirring speed, 110–550 rpm. The obtained results indicate that the increase in the leaching agent(s) concentration, temperature and time of contact with the acid mixtures have a marked effect on the dissolution reaction of titanium. Optimal conditions to achieve 89% extraction of titanium were obtained by leaching at 123 °C, 330 rpm, 80 min and 1.8% w/v with a mixture of 15% HF (v/v) and 10% H2SO4 (v/v).
Mario H. Rodriguez; Gustavo D. Rosales; Eliana G. Pinna; Fernando M. Tunez; Norman Toro. Extraction of Titanium from Low-Grade Ore with Different Leaching Agents in Autoclave. Metals 2020, 10, 497 .
AMA StyleMario H. Rodriguez, Gustavo D. Rosales, Eliana G. Pinna, Fernando M. Tunez, Norman Toro. Extraction of Titanium from Low-Grade Ore with Different Leaching Agents in Autoclave. Metals. 2020; 10 (4):497.
Chicago/Turabian StyleMario H. Rodriguez; Gustavo D. Rosales; Eliana G. Pinna; Fernando M. Tunez; Norman Toro. 2020. "Extraction of Titanium from Low-Grade Ore with Different Leaching Agents in Autoclave." Metals 10, no. 4: 497.
Exotic type deposits include several species of minerals, such as atacamite, chrysocolla, copper pitch, and copper wad. Among these, copper pitch and copper wad have considerable concentrations of manganese. However, their non-crystalline and amorphous structure makes it challenging to recover the elements of interest (like Cu or Mn) by conventional hydrometallurgical methods. For this reason, black copper ores are generally not incorporated into the extraction circuits or left unprocessed, whether in stock, leach pads, or waste. Therefore, to dilute MnO2, the use of reducing agents is essential. In the present research, agitated leaching was performed to dissolve Mn of black copper in an acidic medium, comparing the use of ferrous ions and tailings as reducing agents. Two samples of black copper were studied, of high and low grade of Mn, respectively, the latter with a high content of clays. The effect on the reducing agent/black copper ratio and the concentration of sulfuric acid in the system were evaluated. Better results in removing Mn were achieved using the highest-grade black copper sample when working with ferrous ions at a ratio of Fe2+/black copper of 2/1 and 1 mol/L of sulfuric acid. Besides, the low-grade sample induced a significant consumption of H2SO4 due to the high presence of gangue and clays.
Kevin Pérez; Norman Toro; Eduardo Campos; Javier González; Ricardo I. Jeldres; Amin Nazer; Mario H. Rodriguez. Extraction of Mn from Black Copper Using Iron Oxides from Tailings and Fe2+ as Reducing Agents in Acid Medium. Metals 2019, 9, 1112 .
AMA StyleKevin Pérez, Norman Toro, Eduardo Campos, Javier González, Ricardo I. Jeldres, Amin Nazer, Mario H. Rodriguez. Extraction of Mn from Black Copper Using Iron Oxides from Tailings and Fe2+ as Reducing Agents in Acid Medium. Metals. 2019; 9 (10):1112.
Chicago/Turabian StyleKevin Pérez; Norman Toro; Eduardo Campos; Javier González; Ricardo I. Jeldres; Amin Nazer; Mario H. Rodriguez. 2019. "Extraction of Mn from Black Copper Using Iron Oxides from Tailings and Fe2+ as Reducing Agents in Acid Medium." Metals 9, no. 10: 1112.
Eliana G. Pinna; M E Si Mat; A.A. Martinez; F.M. Tunez; D.S. Drajlin; M.H. Rodriguez. ACID LEACHING OF LiCoO2 FROM LIBs: THERMODYNAMIC STUDY AND REDUCING AGENT EFFECT. Revista Mexicana de Ingeniería Química 2019, 18, 441 -449.
AMA StyleEliana G. Pinna, M E Si Mat, A.A. Martinez, F.M. Tunez, D.S. Drajlin, M.H. Rodriguez. ACID LEACHING OF LiCoO2 FROM LIBs: THERMODYNAMIC STUDY AND REDUCING AGENT EFFECT. Revista Mexicana de Ingeniería Química. 2019; 18 (2):441-449.
Chicago/Turabian StyleEliana G. Pinna; M E Si Mat; A.A. Martinez; F.M. Tunez; D.S. Drajlin; M.H. Rodriguez. 2019. "ACID LEACHING OF LiCoO2 FROM LIBs: THERMODYNAMIC STUDY AND REDUCING AGENT EFFECT." Revista Mexicana de Ingeniería Química 18, no. 2: 441-449.
Lithium (Li) is considered a strategic element whose use has significantly expanded. Its current high demand is due to its use in lithium ion batteries for portable electronic devices, whose manufacture and market are extensively growing every day. These days there is a great concern about the final disposal of these batteries. Therefore, the possibility of developing new methodologies to recycle their components is of great importance, both commercially and environmentally. This paper presents results regarding important operational variables for the dissolution of the lithium and cobalt mixed-oxide (LiCoO2) cathodes from spent lithium ion batteries (LIBs) with hydrofluoric acid. The recovery and synthesis of Co and Li compounds were also investigated. The dissolution parameters studied were: temperature, reaction time, solid-liquid ratio, stirring speed, and concentration of HF. The investigated recovery parameters included: pH, temperature, and time with and without stirring. The final precipitation of lithium fluoride was also examined. The results indicate that an increase in the HF concentration, temperature, and reaction time favors the leaching reaction of the LiCoO2. Dissolutions were close to 60%, at 75 °C and 120 min with a HF concentration of 25% (v/v). The recovery of Co and Li were 98% and 80%, respectively, with purities higher than 94%. Co and Li compounds, such as Co3O4 and LiF, were synthesized. Furthermore, it was possible to almost completely eliminate the F− ions as CaF2.
Daniela S. Suarez; Eliana G. Pinna; Gustavo D. Rosales; Mario H. Rodriguez. Synthesis of Lithium Fluoride from Spent Lithium Ion Batteries. Minerals 2017, 7, 81 .
AMA StyleDaniela S. Suarez, Eliana G. Pinna, Gustavo D. Rosales, Mario H. Rodriguez. Synthesis of Lithium Fluoride from Spent Lithium Ion Batteries. Minerals. 2017; 7 (5):81.
Chicago/Turabian StyleDaniela S. Suarez; Eliana G. Pinna; Gustavo D. Rosales; Mario H. Rodriguez. 2017. "Synthesis of Lithium Fluoride from Spent Lithium Ion Batteries." Minerals 7, no. 5: 81.
This work describes the development of a new process for the recovery of Li, Al and Si along with the proposal of a flow sheet for the precipitation of those metals. The developed process is comprised of lepidolite acid digestion with hydrofluoric acid, and the subsequent precipitation of the metals present in the leach liquor. The leaching operational parameters studied were: reaction time, temperature and HF concentration. The experimental results indicate that the optimal conditions to achieve a Li extraction higher than 90% were: solid-liquid ratio, 1.82% (w/v); temperature, 123 °C; HF concentration, 7% (v/v); stirring speed, 330 rpm; and reaction time, 120 min. Al and Si can be recovered as Na3AlF6 and K2SiF6. LiF was separated from the leach liquor during water evaporation, with recovery values of 92%.
Gustavo D. Rosales; Eliana G. Pinna; Daniela S. Suarez; Mario H. Rodriguez. Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF. Minerals 2017, 7, 36 .
AMA StyleGustavo D. Rosales, Eliana G. Pinna, Daniela S. Suarez, Mario H. Rodriguez. Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF. Minerals. 2017; 7 (3):36.
Chicago/Turabian StyleGustavo D. Rosales; Eliana G. Pinna; Daniela S. Suarez; Mario H. Rodriguez. 2017. "Recovery Process of Li, Al and Si from Lepidolite by Leaching with HF." Minerals 7, no. 3: 36.
Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 μm; HF concentration 4% v/v, and the solid–liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM) analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X) = −b1 [ln(1 + b2t) − b2t/(1 + b2t)]. This model is based on “nucleation and growth of nuclei” theory, and describes the style of attack physically observed by SEM on the residues.
Gustavo D. Rosales; María C. Ruiz; Mario H. Rodriguez. Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid. Minerals 2016, 6, 98 .
AMA StyleGustavo D. Rosales, María C. Ruiz, Mario H. Rodriguez. Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid. Minerals. 2016; 6 (4):98.
Chicago/Turabian StyleGustavo D. Rosales; María C. Ruiz; Mario H. Rodriguez. 2016. "Study of the Extraction Kinetics of Lithium by Leaching β-Spodumene with Hydrofluoric Acid." Minerals 6, no. 4: 98.
The effect of different leaching media on the dissolution of ferrocolumbite from the province of San Luis, Argentina, in an autoclave was investigated. The leaching agents used were aqueous solutions of HF–NaF or HF–Na2C2O4. The researched parameters were temperature and different types and concentrations of the leaching media. The obtained results show that the values of Nb and Ta extractions from ferrocolumbite with diluted HF are substantially modified when NaF or Na2C2O4 are added to the leaching medium, and separation of Ta from the other components present in the sample is successfully accomplished while working under certain conditions of temperature and reagent concentrations.
Mario H. Rodriguez; Gustavo D. Rosales; Eliana G. Pinna; Daniela S. Suarez. Effect of Na + ion on the dissolution of ferrocolumbite in autoclave. Hydrometallurgy 2016, 159, 60 -64.
AMA StyleMario H. Rodriguez, Gustavo D. Rosales, Eliana G. Pinna, Daniela S. Suarez. Effect of Na + ion on the dissolution of ferrocolumbite in autoclave. Hydrometallurgy. 2016; 159 ():60-64.
Chicago/Turabian StyleMario H. Rodriguez; Gustavo D. Rosales; Eliana G. Pinna; Daniela S. Suarez. 2016. "Effect of Na + ion on the dissolution of ferrocolumbite in autoclave." Hydrometallurgy 159, no. : 60-64.
Gustavo D. Rosales; María Del Carmen Ruiz; Mario H. Rodriguez. Novel process for the extraction of lithium from β-spodumene by leaching with HF. Hydrometallurgy 2014, 147-148, 1 -6.
AMA StyleGustavo D. Rosales, María Del Carmen Ruiz, Mario H. Rodriguez. Novel process for the extraction of lithium from β-spodumene by leaching with HF. Hydrometallurgy. 2014; 147-148 ():1-6.
Chicago/Turabian StyleGustavo D. Rosales; María Del Carmen Ruiz; Mario H. Rodriguez. 2014. "Novel process for the extraction of lithium from β-spodumene by leaching with HF." Hydrometallurgy 147-148, no. : 1-6.
This paper investigated the development of new techniques to recover fluorine as three valuable fluorides: cryolithionite (Li3Na3Al2F12), sodium hexafluorosilicate (Na2SiF6) and cryolite (Na3AlF6). The synthesis of these compounds was carried out through three routes: I) by precipitation “in situ” during the leaching process of β-spodumene at different temperatures and different HF concentrations, to produce Li3Na3Al2F12; II) by precipitation adding NaOH to the leach liquor of β-spodumene, to produce Na2SiF6 and Na3AlF6; and III) by co-precipitation from pure reagents, to separately produce Li3Na3Al2F12, Na2SiF6 and Na3AlF6. Reagents and products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), atomic absorption spectroscopy (AAS), scanning electronic microscopy (SEM) and electron probe microanalysis (EPMA). The experimental results indicate that the production of the fluorinated compounds was possible. Following route I), an enhancement of the crystal size was observed after increasing the concentrations of HF. It was also observed that a decrease in temperature favors precipitation of the solid. Furthermore, the presence of Na+ from albite (gangue) was essential for the formation of Li3Na3Al2F12. The compounds Na2SiF6 and Na3AlF6 were synthesized together using route II), with a recovery of 92%. Through route III) the three compounds were synthesized separately and these compounds were used as standards for XRD analysis.
Gustavo D. Rosales; María Del Carmen Ruiz; Mario H. Rodriguez. Alkaline metal fluoride synthesis as a subproduct of β-spodumene leaching. Hydrometallurgy 2013, 139, 73 -78.
AMA StyleGustavo D. Rosales, María Del Carmen Ruiz, Mario H. Rodriguez. Alkaline metal fluoride synthesis as a subproduct of β-spodumene leaching. Hydrometallurgy. 2013; 139 ():73-78.
Chicago/Turabian StyleGustavo D. Rosales; María Del Carmen Ruiz; Mario H. Rodriguez. 2013. "Alkaline metal fluoride synthesis as a subproduct of β-spodumene leaching." Hydrometallurgy 139, no. : 73-78.