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In recent years, zero-valent iron (ZVI) has been extensively employed for the elimination of organic and inorganic contaminants. However, the performance of ZVI was restrained due to the inherent properties in the process of pollutants sequestration like agglomeration, surface passivation, and sensitivity to the pH and dissolved oxygen (DO) in the environment. To combat these issues, ZVI-based materials were utilized to attenuate the drawbacks of ZVI. Therefore, in this review, the representative hazardous hexavalent chromium (Cr(VI)) was chosen as the target pollutant to discuss the performance, limitations, and future of ZVI-based materials. The prevailing preparation methods of ZVI-based materials could be classified into aqueous reduction and mechanical procedures. Further, the conventional ZVI-based materials were mainly encompassed carbon-ZVI, sulfur-ZVI, bimetallic materials of ZVI, and magnetite-ZVI composites. A new insight into the co-effect of pH and DO on Cr(VI) removal by ZVI through five pathways was also proposed. The mechanism of Cr(VI) elimination by ZVI-based materials was dominant through the combination of reduction, adsorption, and co-precipitation, wherein the enhanced reduction capability of ZVI-based materials compared to their monometallic counterpart was critically scrutinized. Besides, some field applications of ZVI-based materials such as ZVI incorporation into the permeable reactive barrier (PRB) to remediate groundwater have also been examined. Finally, barriers in market penetration of ZVI-based materials in removing Cr(VI) have been highlighted which would open a new window for the researcher to accomplish the research gaps for shifting applications of ZVI-based materials from lab-scale to real or commercial implementations.
Yi Fang; Xiange Wu; Min Dai; A. Lopez-Valdivieso; Saleem Raza; Imran Ali; Changsheng Peng; Juying Li; Iffat Naz. The sequestration of aqueous Cr(VI) by zero valent iron-based materials: From synthesis to practical application. Journal of Cleaner Production 2021, 312, 127678 .
AMA StyleYi Fang, Xiange Wu, Min Dai, A. Lopez-Valdivieso, Saleem Raza, Imran Ali, Changsheng Peng, Juying Li, Iffat Naz. The sequestration of aqueous Cr(VI) by zero valent iron-based materials: From synthesis to practical application. Journal of Cleaner Production. 2021; 312 ():127678.
Chicago/Turabian StyleYi Fang; Xiange Wu; Min Dai; A. Lopez-Valdivieso; Saleem Raza; Imran Ali; Changsheng Peng; Juying Li; Iffat Naz. 2021. "The sequestration of aqueous Cr(VI) by zero valent iron-based materials: From synthesis to practical application." Journal of Cleaner Production 312, no. : 127678.
To enhance the inferior removal capability of aqueous Cr(VI) by commercial activated carbon under neutral conditions. The emerging ball milling technology was employed and the removal efficiency of Cr(VI) by ball-milled highly activated carbon (HAC) increased from 68.3% to 99.0% under pH 6 and from 42.7% to 77.8% under pH 7 compared to pristine activated carbon (AC), respectively. Raman spectra and Boehm's titration results signified that the enhanced Cr(VI) removal performance of HAC under neutral conditions was associated with the enriched surface acid functional groups, in which the content of COOH groups increased from 0.31 mmol/g to 0.97 mmol/g. Two Cr(VI) removal mechanisms were proposed established on the acid and alkalic solution washed chromium-loaded HAC, involving the reduction of Cr(VI) to Cr(III) subsequently accompany with the formation of chromium hydroxides on the surface and inside the pores of HAC, and the bonding of CrO42− on the surface COOH groups, as confirmed by SEM-EDX element mapping and specific surface area and porosity measurements. The Pseudo-second order model and Freundlich model fitted the adsorption kinetic and isotherm of AC and HAC well severally, suggesting that the specific interaction of Cr(VI) with the HAC surface and the Cr(VI) removal was multi-layer adsorption. Thermodynamic study exhibited the spontaneity of Cr(VI) removal on ball-milled HAC was increased. Reusability and regeneration studies of HAC denoted the potential application on Cr(VI) uptake under neutral conditions.
Yi Fang; Ke Yang; Yipeng Zhang; Changsheng Peng; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling. Environmental Research 2021, 197, 111151 .
AMA StyleYi Fang, Ke Yang, Yipeng Zhang, Changsheng Peng, Aurora Robledo-Cabrera, Alejandro López-Valdivieso. Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling. Environmental Research. 2021; 197 ():111151.
Chicago/Turabian StyleYi Fang; Ke Yang; Yipeng Zhang; Changsheng Peng; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. 2021. "Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling." Environmental Research 197, no. : 111151.
Yi Fang; Ke Yang; Yipeng Zhang; Changsheng Peng; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling. 2021, 111151 .
AMA StyleYi Fang, Ke Yang, Yipeng Zhang, Changsheng Peng, Aurora Robledo-Cabrera, Alejandro López-Valdivieso. Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling. . 2021; ():111151.
Chicago/Turabian StyleYi Fang; Ke Yang; Yipeng Zhang; Changsheng Peng; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. 2021. "Highly surface activated carbon to remove Cr(VI) from aqueous solution with adsorbent recycling." , no. : 111151.
This paper proposes a fuzzy comprehensive evaluation of ultrafine powders, namely, yield and quality value-based feature selection. Three indicators reflecting product yield and quality were selected to construct a simple and practical fuzzy comprehensive evaluation protocol. The weight set of the indices and the fuzzy evaluation set were calculated based on the analytic hierarchy process (AHP) method. The fuzzy comprehensive evaluation value was worked out as the only comprehensive index for the evaluation of product. The best ultrafine comminution condition will be established through the comparison of the fuzzy comprehensive evaluation values. Single-factor experiments and orthogonal experiments of the main influencing factors of ultrafine comminution were conducted. It was concluded that the importance of each factor is sequentially the concentration, specific surface area (SSA) of the media, and percentage of critical speed (PCS). Moreover, the concentration and SSA of the media were equally important. Ultrafine comminution by ball mill had the best overall performance under the PCS of 85%, the SSA of the media of 0.24 m2/kg, and the concentration of 75%.
Zaisheng Zhu; Jinbo Zhu; Yin Liu; Huaizhi Shao; Hongzheng Zhu; Chuanzhen Wang; Jingyu Wang; Yang Fan. Parameter Optimization of Ultrafine Comminution Based on Analytic Hierarchy Process: Fuzzy Comprehensive Evaluation. Journal of Control Science and Engineering 2021, 2021, 1 -7.
AMA StyleZaisheng Zhu, Jinbo Zhu, Yin Liu, Huaizhi Shao, Hongzheng Zhu, Chuanzhen Wang, Jingyu Wang, Yang Fan. Parameter Optimization of Ultrafine Comminution Based on Analytic Hierarchy Process: Fuzzy Comprehensive Evaluation. Journal of Control Science and Engineering. 2021; 2021 ():1-7.
Chicago/Turabian StyleZaisheng Zhu; Jinbo Zhu; Yin Liu; Huaizhi Shao; Hongzheng Zhu; Chuanzhen Wang; Jingyu Wang; Yang Fan. 2021. "Parameter Optimization of Ultrafine Comminution Based on Analytic Hierarchy Process: Fuzzy Comprehensive Evaluation." Journal of Control Science and Engineering 2021, no. : 1-7.
Pyrite concentrates with refractory gold and silver were roasted at different temperatures to improve the recovery of the metals by cyanide leaching. Scanning Electron Microscope characterization of the calcine revealed that the gold occluded in the pyrite less than one micron, and roasting produced channels in the concentrate, exposing the gold particles to the leaching solution. Gold and silver recoveries were maximum in the temperature range of 500-600?C due to the calcine high surface area and porosity. The Au and Ag recovery improved from 25 to 86% and 50 to 73%, respectively. The Au secondary encapsulation due to the sintering, the formation of the Ag-Fe-S species (Fe1?xS + Ag2S + Ag) and Ag ferrite in higher roasting temperatures hence Au and Ag recoveries decreased.
Y.-P. Zhang; K. Yang; Y. Fang; A. Robledo-Cabrera; C.-S. Peng; A. Lopez-Valdivieso. Roasting temperature effect on the recovery of refractory gold and silver in pyrite concentrates. Journal of Mining and Metallurgy, Section B: Metallurgy 2021, 19 -19.
AMA StyleY.-P. Zhang, K. Yang, Y. Fang, A. Robledo-Cabrera, C.-S. Peng, A. Lopez-Valdivieso. Roasting temperature effect on the recovery of refractory gold and silver in pyrite concentrates. Journal of Mining and Metallurgy, Section B: Metallurgy. 2021; (0):19-19.
Chicago/Turabian StyleY.-P. Zhang; K. Yang; Y. Fang; A. Robledo-Cabrera; C.-S. Peng; A. Lopez-Valdivieso. 2021. "Roasting temperature effect on the recovery of refractory gold and silver in pyrite concentrates." Journal of Mining and Metallurgy, Section B: Metallurgy , no. 0: 19-19.
This study demonstrates the effects of a potassium propyl xanthate (PPX) collector and sodium sulfite (Na2SO3) depressant on pure chalcopyrite in synthetic seawater (SSW) and potassium chloride (KCl) solutions. SSW solutions with 35 g/L of salt and 0.01-M KCl were used for microflotation and zeta potential tests. Particles sized between 200# and 100# (75–150 µm) were used, and the pH was between 8.0 and 8.5. The surface of the mineral and its interaction with the collector were characterized using Raman spectrometry. The zeta potential of the chalcopyrite was measured in KCl solution at a pH range of 3–12 using the collector and depressant at a monodispersed particle size of 635# (20 µm). The results indicate that the floatability of chalcopyrite is not affected by the presence of PPX collectors in SSW solutions. SSW provides better recoveries than KCl solutions with values of 91.42% and 88.15%, respectively. The Na2SO3 depressant does not hinder the mineral floatability throughout the entire concentration range used; however, special care must be taken when adjusting the pH range to avoid increasing the zeta potential.
María Arancibia-Bravo; Alejandro López-Valdivieso; Luís Flores; Luís Cisternas. Effects of Potassium Propyl Xanthate Collector and Sodium Sulfite Depressant on the Floatability of Chalcopyrite in Seawater and KCl Solutions. Minerals 2020, 10, 991 .
AMA StyleMaría Arancibia-Bravo, Alejandro López-Valdivieso, Luís Flores, Luís Cisternas. Effects of Potassium Propyl Xanthate Collector and Sodium Sulfite Depressant on the Floatability of Chalcopyrite in Seawater and KCl Solutions. Minerals. 2020; 10 (11):991.
Chicago/Turabian StyleMaría Arancibia-Bravo; Alejandro López-Valdivieso; Luís Flores; Luís Cisternas. 2020. "Effects of Potassium Propyl Xanthate Collector and Sodium Sulfite Depressant on the Floatability of Chalcopyrite in Seawater and KCl Solutions." Minerals 10, no. 11: 991.
Adsorption of Cr(VI) on highly porous granular activated carbon (GAC) was studied through batch adsorption tests at a very long time, various temperatures and pH 3.5, in order to delineate the adsorption mechanisms, model the adsorption process and assess the applicability of GAC in water treatment. Adsorption of Cr(VI) occurred through a redox reaction with the formation of Cr2O3(s) (Cruz-Espinoza et al., 2012). It is reported for the first time that Cr(VI) adsorption proceeded in two steps. Furthermore, adsorption increased with temperature and reached equilibrium after several hours. In the first step, very fast adsorption occurred with the formation of a nano-size continuous layer of Cr2O3(s) coating on the GAC surface, as revealed by SEM analysis. In the second stage, adsorption occurred at a very slow rate due to the slow diffusion rate through the continuous Cr2O3(s) layer on the GAC surface. The two adsorption steps were successfully described by the surface diffusion model and pore volume diffusion model. The first step is controlled by surface diffusion while the second step by both pore volume diffusion and surface diffusion. A pseudo-activation energy was determined for each adsorption step and found that more adsorption energy is required in the first step than the second step. The adsorption isotherms for various temperatures were fitted well by the Langmuir model. The Cr2O3 layer on the GAC is responsible for its low Cr(VI) adsorption capacity, so a large amount of GAC would be required to treat water with Cr(VI).
YongMei Wang; Changsheng Peng; Erika Padilla-Ortega; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. Cr(VI) adsorption on activated carbon: Mechanisms, modeling and limitations in water treatment. Journal of Environmental Chemical Engineering 2020, 8, 104031 .
AMA StyleYongMei Wang, Changsheng Peng, Erika Padilla-Ortega, Aurora Robledo-Cabrera, Alejandro López-Valdivieso. Cr(VI) adsorption on activated carbon: Mechanisms, modeling and limitations in water treatment. Journal of Environmental Chemical Engineering. 2020; 8 (4):104031.
Chicago/Turabian StyleYongMei Wang; Changsheng Peng; Erika Padilla-Ortega; Aurora Robledo-Cabrera; Alejandro López-Valdivieso. 2020. "Cr(VI) adsorption on activated carbon: Mechanisms, modeling and limitations in water treatment." Journal of Environmental Chemical Engineering 8, no. 4: 104031.
The traditional addition mode of frother as liquid and a novel mode as vapor were comparatively studied in presences of methyl isobutyl carbinol (MIBC) and sec-Octyl alcohol (2-octanol). Aeration rate and coal flotation were investigated in a downflow flotation column while bubble rising velocity was measured in a glass tank, wherein the aeration rate and bubble rising velocity were studied in a gas–liquid system. The comparison between these two frother addition modes shows that the vapor mode presented a faster bubble rising velocity, a larger aeration rate, a higher concentrate yield and a higher combustible matter recovery independently of frother sort. In addition, under the liquid mode MIBC presented a smaller aeration rate, a faster bubble rising velocity, a lower concentrate yield and a lower combustible matter recovery as compared with 2-octanol, while MIBC gave a smaller aeration rate, a roughly equal bubble rising velocity, a lower concentrate yield and a lower combustible matter recovery under the vapor mode. The aeration rate sharply decreased as the bubble rising velocity increased up to a critical point above which the aeration rate became almost constant, independent of frother addition mode. Furthermore, the concentrate yield sharply increased as the aeration rate increased up to a critical point above which the concentrate yield became gradual, independent of frother sort and addition mode. The MIBC and 2-octanol consumption was significantly reduced when the frother was added as vapor rather than liquid, and 2-octanol vapor presented the lowest concentration for achieving the concentrate yield of 60%.
Hongzheng Zhu; Jinbo Zhu; Alejandro López Valdivieso; Fanfei Min; Shaoxian Song; Hainan Wang. Effect of frother addition mode on gas dispersion and coal flotation in a downflow flotation column. Fuel 2020, 273, 117715 .
AMA StyleHongzheng Zhu, Jinbo Zhu, Alejandro López Valdivieso, Fanfei Min, Shaoxian Song, Hainan Wang. Effect of frother addition mode on gas dispersion and coal flotation in a downflow flotation column. Fuel. 2020; 273 ():117715.
Chicago/Turabian StyleHongzheng Zhu; Jinbo Zhu; Alejandro López Valdivieso; Fanfei Min; Shaoxian Song; Hainan Wang. 2020. "Effect of frother addition mode on gas dispersion and coal flotation in a downflow flotation column." Fuel 273, no. : 117715.
Emmanuel E Vázquez-Sánchez; Aurora Robledo-Cabrera; Xiong Tong; Alejandro López-Valdivieso. Raman spectroscopy characterization of some Cu, Fe and Zn sulfides and their relevant surface chemical species for flotation. Physicochemical Problems of Mineral Processing 2020, 56, 483 -492.
AMA StyleEmmanuel E Vázquez-Sánchez, Aurora Robledo-Cabrera, Xiong Tong, Alejandro López-Valdivieso. Raman spectroscopy characterization of some Cu, Fe and Zn sulfides and their relevant surface chemical species for flotation. Physicochemical Problems of Mineral Processing. 2020; 56 (3):483-492.
Chicago/Turabian StyleEmmanuel E Vázquez-Sánchez; Aurora Robledo-Cabrera; Xiong Tong; Alejandro López-Valdivieso. 2020. "Raman spectroscopy characterization of some Cu, Fe and Zn sulfides and their relevant surface chemical species for flotation." Physicochemical Problems of Mineral Processing 56, no. 3: 483-492.
The application of guar gum for pyrite depression in seawater flotation was assessed through microflotation tests, Focused Beam Reflectance Measurements (FBRM), and Particle Vision Measurements (PVM). Potassium amyl xanthate (PAX) and methyl isobutyl carbinol (MIBC) were used as collector and frother, respectively. Chemical species on the pyrite surface were characterized by Fourier-transform infrared spectroscopy (FTIR) spectroscopy. The microflotation tests were performed at pH 8, which is the pH at the copper sulfide processing plants that operate with seawater. Pyrite flotation recovery was correlated with FBRM and PVM characterization to delineate the pyrite depression mechanisms by the guar gum. The high flotation recovery of pyrite with PAX was significantly lowered by guar gum, indicating that this polysaccharide could be used as an effective depressant in flotation with sea water. FTIR analysis showed that PAX and guar gum co-adsorbed on the pyrite surface, but the highly hydrophilic nature of the guar gum embedded the hydrophobicity due to the PAX. FBRM and PVM revealed that the guar gum promoted the formation of flocs whose size depended on the addition of guar gum and PAX. It is proposed that the highest pyrite depression occurred not only because of the hydrophilicity induced by the guar gum, but also due to the formation of large flocs, which could not be transported by the bubbles to the froth phase. Furthermore, it is shown that an overdose of guar gum hindered the depression effect due to redispersion of the flocs.
César I. Castellón; Eder C. Piceros; Norman Toro; Pedro Robles; Alejandro López-Valdivieso; Ricardo I. Jeldres. Depression of Pyrite in Seawater Flotation by Guar Gum. Metals 2020, 10, 239 .
AMA StyleCésar I. Castellón, Eder C. Piceros, Norman Toro, Pedro Robles, Alejandro López-Valdivieso, Ricardo I. Jeldres. Depression of Pyrite in Seawater Flotation by Guar Gum. Metals. 2020; 10 (2):239.
Chicago/Turabian StyleCésar I. Castellón; Eder C. Piceros; Norman Toro; Pedro Robles; Alejandro López-Valdivieso; Ricardo I. Jeldres. 2020. "Depression of Pyrite in Seawater Flotation by Guar Gum." Metals 10, no. 2: 239.
In this study, the effects of calcium ions on the flotation of malachite with octyl hydroxamate collector has been investigated using micro-flotation, zeta potential, contact angle, adsorption, and particle size measurements. Although the adsorption amount of collector and the hydrophobicity of malachite surface were not influenced by the addition of 1 × 10−2 mol/L CaCl2 at the optimized flotation pH 9, it was found that the malachite flotation recovery was enhanced by the addition of CaCl2 in the pH range of 6–11. In the presence of CaCl2, energy barrier between the malachite particles and the bubbles were lower, leading to the aggregation of malachite particles, and the enhanced malachite recovery. However, at pH > 11, the formation of Ca(OH)+ and Ca(OH)2 species on malachite surface inhibited its flotation.
Zhili Li; Feng Rao; Bao Guo; Weiran Zuo; Shaoxian Song; Alejandro López-Valdivieso. Effects of calcium ions on malachite flotation with octyl hydroxamate. Minerals Engineering 2019, 141, 105854 .
AMA StyleZhili Li, Feng Rao, Bao Guo, Weiran Zuo, Shaoxian Song, Alejandro López-Valdivieso. Effects of calcium ions on malachite flotation with octyl hydroxamate. Minerals Engineering. 2019; 141 ():105854.
Chicago/Turabian StyleZhili Li; Feng Rao; Bao Guo; Weiran Zuo; Shaoxian Song; Alejandro López-Valdivieso. 2019. "Effects of calcium ions on malachite flotation with octyl hydroxamate." Minerals Engineering 141, no. : 105854.
Effects of common ions, namely hydroxyl ions and carbonate, on the adsorption and flotation of malachite with salicylaldoxime as a collector was investigated, making use of solubility, micro-flotation, zeta potential, contact angle, FTIR, and XPS measurements. The results suggested that hydroxyl and carbonate ions affect malachite recovery through altering solubility of this mineral. Under conditions of lower solubility, more stable copper atoms acted as adsorption sites for retaining salicylaldoxime on the malachite surface, and the collector consumed by copper species in slurry was reduced. This allowed more collectors to get adsorbed onto malachite surface, resulting in improved malachite recovery. Zeta potential, FTIR, and XPS measurements indicated that salicylaldoxime chemically adsorbs onto malachite by forming copper salicylaldoxime chelates, in which two salicylaldoxime molecules react with one copper atom by N atom and the O atom combined with benzene ring.
Zhili Li; Feng Rao; Shaoxian Song; Alejandro Uribe-Salas; Alejandro López-Valdivieso. Effects of common ions on adsorption and flotation of malachite with salicylaldoxime. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2019, 577, 421 -428.
AMA StyleZhili Li, Feng Rao, Shaoxian Song, Alejandro Uribe-Salas, Alejandro López-Valdivieso. Effects of common ions on adsorption and flotation of malachite with salicylaldoxime. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019; 577 ():421-428.
Chicago/Turabian StyleZhili Li; Feng Rao; Shaoxian Song; Alejandro Uribe-Salas; Alejandro López-Valdivieso. 2019. "Effects of common ions on adsorption and flotation of malachite with salicylaldoxime." Colloids and Surfaces A: Physicochemical and Engineering Aspects 577, no. : 421-428.
Malachite fines are easily produced in the grinding process, leading to low malachite flotation recovery. Floc-flotation of malachite fines with an octyl hydroxamate and kerosene mixture was studied to improve the flotation recovery, using microflotation, microscopy image observations, contact angle measurements, and Extended Derjguin–Landau–Verwey–Overbeek (EDLVO) analysis. The results showed that the addition of octyl hydroxamate as an emulsifier of kerosene enhanced the aggregation of malachite fines and improved malachite flotation recovery. In addition, when kerosene droplets were smaller and of uniform size distribution, the spreading of kerosene droplets on the malachite surface improved. The enhanced spreading of kerosene droplets led to higher coverage of kerosene on the malachite surface, resulting in improved hydrophobic aggregation and flotation recovery.
Zhili Li; Feng Rao; XiaoMing Lou; Shaoxian Song; Alejandro López-Valdivieso. Floc-Flotation of Malachite Fines with an Octyl Hydroxamate and Kerosene Mixture. Minerals 2019, 9, 301 .
AMA StyleZhili Li, Feng Rao, XiaoMing Lou, Shaoxian Song, Alejandro López-Valdivieso. Floc-Flotation of Malachite Fines with an Octyl Hydroxamate and Kerosene Mixture. Minerals. 2019; 9 (5):301.
Chicago/Turabian StyleZhili Li; Feng Rao; XiaoMing Lou; Shaoxian Song; Alejandro López-Valdivieso. 2019. "Floc-Flotation of Malachite Fines with an Octyl Hydroxamate and Kerosene Mixture." Minerals 9, no. 5: 301.
Magnetite (Fe3O4) ore is concentrated by low-magnetic-field drums to recover a magnetite concentrate that is low in silica (SiO2). The presence of SiO2 in the magnetite concentrate for steel production increases the steel processing costs, so a major challenge in magnetic concentration is to lower the SiO2 grade in the Fe concentrate. This work presents studies that were carried out on the removal of SiO2 from the magnetite concentration at the plant scale. Studies were performed with a three 36 × 96″ drum unit processing 46 ton/h of rougher magnetite concentrate. These studies showed that silica appears in the magnetite concentrate by three mechanisms, namely SiO2 entrainment in Fe3O4 chains, heterocoagulation between Fe3O4 and SiO2 particles, and mineral locking of SiO2 to Fe3O4. The SiO2 entrainment mechanism had the highest contribution (75%) to the SiO2 recovered in the Fe concentrate. Electrokinetic studies on Fe3O4 and SiO2 showed that heterocoagulation occurs because of the low negative zeta potential of the minerals at the pH of the plant slurry. This study also showed that a high percentage of ultrafine size SiO2 particles trapped in Fe3O4 agglomerates was not removed by the dilution water for the slurry fed to the drum. To lower the SiO2 recovery in the drum magnetic concentration process, work should be directed towards the removal of trapped SiO2 in Fe3O4 agglomerates.
M. Llamas-Bueno; A. López-Valdivieso; Mario Alberto Corona Arroyo. On the Mechanisms of Silica (SiO2) Recovery in Magnetite Ore Low-Magnetic-Drum Concentration. Mining, Metallurgy & Exploration 2018, 36, 131 -138.
AMA StyleM. Llamas-Bueno, A. López-Valdivieso, Mario Alberto Corona Arroyo. On the Mechanisms of Silica (SiO2) Recovery in Magnetite Ore Low-Magnetic-Drum Concentration. Mining, Metallurgy & Exploration. 2018; 36 (1):131-138.
Chicago/Turabian StyleM. Llamas-Bueno; A. López-Valdivieso; Mario Alberto Corona Arroyo. 2018. "On the Mechanisms of Silica (SiO2) Recovery in Magnetite Ore Low-Magnetic-Drum Concentration." Mining, Metallurgy & Exploration 36, no. 1: 131-138.
The Sauter mean diameter (d32) of bubbles was characterized for a gas-liquid system in a laboratory Jameson-type flotation cell with focus on the size variation in the uprising path of the bubbles in the riser of the flotation cell. Methyl isobutyl carbinol (MIBC) was used as frother for bubble stability. The effect of MIBC concentration, sampling height in the riser, gas flow rate (Jg) and liquid flow rate (Jl) in the downcomer on d32 was investigated. The d32 significantly decreased with increasing MIBC concentration until the Critical Coalescence Concentration (CCC), above which the d32 was almost constant at 0.645 mm. CCC95, CCC90 and CCC85 were calculated to be 0.059, 0.046 and 0.038 mmol/L, respectively for a Jg of 1.32 cm/s and Jl of 11 cm/s. Four frother concentrations covering these three values were selected for detailed studies. The size variation of bubbles was related to the Reynolds number (Re) in the downcomer, where the Re was influenced by Jl and Jg. Bubble size increased with the sampling height in the riser at MIBC concentrations below CCC95. This bubble size decreased with the Re and, for all the MIBC concentrations used in this investigation, it reached a critical value, even at MIBC concentrations below the CCC85.
Hongzheng Zhu; Alejandro López Valdivieso; Jinbo Zhu; Shaoxian Song; Fanfei Min; Mario Alberto Corona Arroyo. A study of bubble size evolution in Jameson flotation cell. Chemical Engineering Research and Design 2018, 137, 461 -466.
AMA StyleHongzheng Zhu, Alejandro López Valdivieso, Jinbo Zhu, Shaoxian Song, Fanfei Min, Mario Alberto Corona Arroyo. A study of bubble size evolution in Jameson flotation cell. Chemical Engineering Research and Design. 2018; 137 ():461-466.
Chicago/Turabian StyleHongzheng Zhu; Alejandro López Valdivieso; Jinbo Zhu; Shaoxian Song; Fanfei Min; Mario Alberto Corona Arroyo. 2018. "A study of bubble size evolution in Jameson flotation cell." Chemical Engineering Research and Design 137, no. : 461-466.
Bubble aspect ratios and rising velocities of dodecylamine (DDA), methyl isobutyl carbinol (MIBC), sec-octyl alcohol (2-octanol), DDA-MIBC blend, and DDA-2-octanol blend were investigated for different concentrations. The bubble aspect ratio of these individual reagents was found to follow the same order as molecular weight: DDA>2-octanol>MIBC. DDA addition further increased the aspect ratio of the bubbles in the individual MIBC and 2-octanol solutions, and the aspect ratio of the DDA-MIBC blend was found to be smaller than that of the DDA-2-octanol blend for a random but identical reagent concentration. The bubble rising velocity of these individual reagents followed the order MIBC>2-octanol>DDA. DDA addition had a significant effect in terms of decreasing the rising velocity of the bubbles in the individual MIBC and 2-octanol solutions; meanwhile, the bubble rising velocity of the DDA-MIBC blend was larger than that of the DDA-2-octanol blend. Bubble rising velocity showed a negative linear correlation with aspect ratio that was independent of reagent type, concentration, and blend.
Hongzheng Zhu; Alejandro López Valdivieso; Jinbo Zhu; Fanfei Min; Shaoxian Song; Dianqiang Huang; Shanmin Shao. Effect of dodecylamine-frother blend on bubble rising characteristics. Powder Technology 2018, 338, 586 -590.
AMA StyleHongzheng Zhu, Alejandro López Valdivieso, Jinbo Zhu, Fanfei Min, Shaoxian Song, Dianqiang Huang, Shanmin Shao. Effect of dodecylamine-frother blend on bubble rising characteristics. Powder Technology. 2018; 338 ():586-590.
Chicago/Turabian StyleHongzheng Zhu; Alejandro López Valdivieso; Jinbo Zhu; Fanfei Min; Shaoxian Song; Dianqiang Huang; Shanmin Shao. 2018. "Effect of dodecylamine-frother blend on bubble rising characteristics." Powder Technology 338, no. : 586-590.
The depression of magnetite in cationic flotation has been investigated using external 3D uniform low magnetic flux densities up to 0.015 T, in a laboratory Jameson-type flotation cell and in the absence of chemical depressants. In addition, the magnetic susceptibility and agglomeration of pure magnetite particles have been evaluated. The motion, size and morphology of magnetite aggregates and bubbles-magnetite aggregates in the flotation cell have been monitored by video microscopy. The cationic collector dodecyl amine and an iron concentrate with 65.1% total Fe, mainly as magnetite, were used for the flotation studies. In the absence of a magnetic field, the magnetite particles were fully dispersed and the iron flotation recovery linearly increased with the amine concentration. The 3D uniform magnetic flux density led to aggregation of magnetite particles as chains and chain columns whose sizes increased as the magnetic flux density increased. These magnetite aggregates rapidly settled by the action of the gravitational force and were removed easily from the flotation cell as tailings. The high amine flotation recovery of iron was significantly impaired by the magnetic field. Magnetite depression was associated with the large mass of the magnetite aggregates, which could not be floated by attached air bubbles so that they passed out as tailings.
A. López-Valdivieso; M.A. Corona-Arroyo; A. Encinas-Oropesa; H.A. García-Martínez; C.E. Aquino-Rosalío; Y. Nahmad-Molinari. Inhibiting the amine flotation of magnetite through aggregation with uniform low magnetic fields and no chemical depressants. Minerals Engineering 2018, 119, 130 -136.
AMA StyleA. López-Valdivieso, M.A. Corona-Arroyo, A. Encinas-Oropesa, H.A. García-Martínez, C.E. Aquino-Rosalío, Y. Nahmad-Molinari. Inhibiting the amine flotation of magnetite through aggregation with uniform low magnetic fields and no chemical depressants. Minerals Engineering. 2018; 119 ():130-136.
Chicago/Turabian StyleA. López-Valdivieso; M.A. Corona-Arroyo; A. Encinas-Oropesa; H.A. García-Martínez; C.E. Aquino-Rosalío; Y. Nahmad-Molinari. 2018. "Inhibiting the amine flotation of magnetite through aggregation with uniform low magnetic fields and no chemical depressants." Minerals Engineering 119, no. : 130-136.
Aerial lime-mortars are widely used in the conservation interventions, in which polymers could improve their mechanical strength. In this work, the effects of carboxymethyl cellulose (CMC) on the crystallization of calcium carbonate (CaCO3) in lime mortar have been studied in order to explore the mechanism of the improvement. The experimental results have shown that CMC molecules played as templates to control the morphology and size of CaCO3 crystals. Without CMC, the crystals appeared in the form of cylinder, while CMC addition changed the crystalline shape to be fusiform at the low concentration and spherical at the high concentration. The crystal size increased with CMC addition to the maximum value then declined, leading the lime mortar structure to be more compact, thus improving the compressive strength of lime mortar. These results might be attributed to the restraint effect of CMC molecules to slow down the growth rate and crystallinity of CaCO3 crystals. It was also found that CMC did not affect the polymorph of CaCO3 crystals, which is beneficial to maintain the compressive strength of lime mortar.
Hui Liu; Yunliang Zhao; Changsheng Peng; Shaoxian Song; Alejandro López–Valdivieso. Lime mortars – The role of carboxymethyl cellulose on the crystallization of calcium carbonate. Construction and Building Materials 2018, 168, 169 -177.
AMA StyleHui Liu, Yunliang Zhao, Changsheng Peng, Shaoxian Song, Alejandro López–Valdivieso. Lime mortars – The role of carboxymethyl cellulose on the crystallization of calcium carbonate. Construction and Building Materials. 2018; 168 ():169-177.
Chicago/Turabian StyleHui Liu; Yunliang Zhao; Changsheng Peng; Shaoxian Song; Alejandro López–Valdivieso. 2018. "Lime mortars – The role of carboxymethyl cellulose on the crystallization of calcium carbonate." Construction and Building Materials 168, no. : 169-177.
Isoperibol (pseudo-adiabatic) titration microcalorimetry was used to study the adsorption of various xanthates [CH3(CH2)nOCS2−] at the PbSO4/aqueous solution interface. The effect of the xanthate alkyl chain length (1n–3n) on the adsorption heat was evaluated. Xanthate adsorption isotherms were also determined. Furthermore, the amount of SO4 into the aqueous solution was quantified to correlate it with the xanthate uptake by PbSO4. The adsorption isotherms and the adsorption heat of the xanthates showed two steps. The first step occurred within a sub-monolayer xanthate coverage and was attributed to chemisorption of the xanthates exchanging surface hydroxyls to form CH3(CH2)nOCS2Pb. Lead xanthate (CH3(CH2)nOCS2)2Pb multilayers formed in the second step, which was attributed to an ionic exchange chemical reaction between the xanthates and PbSO4(aq). In the chemisorption step, the heat was found to be independent of the xanthate alkyl chain length and to linearly decrease in magnitude with the xanthate adsorption. In the multilayer formation step, the magnitude of the integral heat increased with the chain length of the xanthate. Heat contributions due to both the alkyl chain length and the interaction between the xanthate polar group and PbSO4(aq) for the formation of lead xanthates are presented. Raman spectroscopy was used to characterize the lead xanthate multilayers on PbSO4.
A. Robledo-Cabrera; A. López-Valdivieso; J. E. Pérez-López; O. A. Orozco-Navarro. Adsorption study of xanthates on PbSO4 by titration microcalorimetry. Journal of thermal analysis 2018, 133, 991 -999.
AMA StyleA. Robledo-Cabrera, A. López-Valdivieso, J. E. Pérez-López, O. A. Orozco-Navarro. Adsorption study of xanthates on PbSO4 by titration microcalorimetry. Journal of thermal analysis. 2018; 133 (2):991-999.
Chicago/Turabian StyleA. Robledo-Cabrera; A. López-Valdivieso; J. E. Pérez-López; O. A. Orozco-Navarro. 2018. "Adsorption study of xanthates on PbSO4 by titration microcalorimetry." Journal of thermal analysis 133, no. 2: 991-999.
The contact angle of ultrafine size particles has been evaluated using 1 µm monosize SiO2 particles of various degrees of wettability. The contact angle was determined by film flotation and Zisman plots. Chlorotrimethylsilane (CTS) was used to methylate the SiO2 particle surface and establish the level of surface wettability. Also, the vacuum floatability of the methylated ultrafine SiO2 particles was assessed to correlate it to the contact angle. This vacuum floatability was very low below 40º and increased monotonically above this contact angle value because of favorable bubble nucleation and a greater stability of the bubbles on the hydrophobic surface. Free energy of bubble nucleation on the hydrophobic surfaces has been estimated and correlated to the vacuum floatability of the ultrafine particles.
Mario Alberto Corona Arroyo; A. López-Valdivieso; S. Song. Contact angle and vacuum floatability of ultrafine size particles. Separation Science and Technology 2017, 53, 999 -1005.
AMA StyleMario Alberto Corona Arroyo, A. López-Valdivieso, S. Song. Contact angle and vacuum floatability of ultrafine size particles. Separation Science and Technology. 2017; 53 (6):999-1005.
Chicago/Turabian StyleMario Alberto Corona Arroyo; A. López-Valdivieso; S. Song. 2017. "Contact angle and vacuum floatability of ultrafine size particles." Separation Science and Technology 53, no. 6: 999-1005.