Temat: alkaline leaching - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Basic theory and optimization of gold containing antimony concentrate leaching by alkaline sulfide
Autorzy:: Wu, Hao
Feng, Yali
Li, Haoran
Liao, Shengde
Wang, Hongjun
Tematy:: antimony concentrate
leaching process
alkaline leaching
kinetics; Pokaż więcej
Data publikacji:: 2019
Powiązania:: https://bibliotekanauki.pl/articles/109524.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2019, 55, 1; 248-257
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: As sodium sulfide is easily oxidized to polysulfide and thiosulfate which have a gold leaching effect, gold would dissolve in leaching solution when extracting stibium from gold containing antimony concentrate by alkaline sulfide. Through leaching test and kinetics analysis, the decomposition regularity of sodium sulfide and leaching rate were studied under different leaching conditions. The results indicated that the gold content in antimony concentrate was 28.41g/Mg, and the content of antimony and sulfur was 36.01% and 14.04%, respectively. The main metallic minerals were native gold, arsenopyrite, stibnite, and the gangue minerals were mainly quartz. Anodic polarization curve shows reduced iron powder can increase the peak potential of the oxidation of the leaching solution and it can effectively prevent the decomposition of sodium sulfide and the dissolution of gold. Optimized stibium-extraction efficiency was achieved under the following conditions: a concentration of sodium sulfide and sodium hydroxide at 110g/dm³ and 20g/dm³, respectively; a ratio of iron powder to concentrate of 1:30; a ratio of liquid to solid of 5:1; agitation speed of 600rad/min; reaction temperature of 353.15K; and a reaction time of 3 h. Under the optimized conditions, high antimony recovery (97.35%) and low gold dissolution (1.32%) were achieved.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Production of zinc powder from Co-Zn plant residue using selective alkaline leaching followed by electrowinning
Autorzy:: Kamran Haghighi, H.
Moradkhani, D.
Sardari, M. H.
Sedaghat, B.
Tematy:: zinc powder
HFC
alkaline leaching
sodium hydroxide
alkaline electrowinning; Pokaż więcej
Data publikacji:: 2015
Powiązania:: https://bibliotekanauki.pl/articles/951816.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2015, 51, 2; 411-425
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: Annually, gigagrams of cobalt residues, called hot filter cake (HFC), are produced from the Co neutralization step at Iranian zinc plants. With respect to the composition of HFC )i.e., 15-25% Zn, 0.5–1.5% Co, 3–8% Mn(, it can be used as a secondary source of zinc, cobalt and manganese. In the present study, for the first time, treatment of HFC for separation and recovery of zinc has been studied. The residue was treated by employing selective alkaline leaching, in order to recover the maximum amount of zinc, followed by zinc electrowinning process. As a results, a solution was obtained from alkaline leaching under the optimum condition of 75 °C, sodium hydroxide of 8 M, solid-to-liquid ratio dm3 of 1:10, and stirring speed of 600 rpm, having zinc recovery of 88.5 %. In the following step, the electrowinning process, under the optimum working conditions being current density 350 A/m2 and time 10 hours, was carried out to produce a zinc powder with high purity of 99 percent. Finally, a simple and effective conceptual flow diagram was proposed for the process.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Alkaline Leaching of Low Zinc Content Iron-Bearing Sludges
Autorzy:: Gargul, K.
Jarosz, P.
Małecki, S.
Tematy:: sludge
dust
alkaline leaching
Zn recovery
recycling; Pokaż więcej
Data publikacji:: 2016
Powiązania:: https://bibliotekanauki.pl/articles/355782.pdf Link otwiera się w nowym oknie
Źródło:: Archives of Metallurgy and Materials; 2016, 61, 1; 43-50
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Opis:: Various types of waste materials containing zinc (e.g. dusts and sludges from gas dedusting process) are obtained in steel industry. The contents of Zn in these materials may vary considerably. Even a low concentration of zinc in recirculated products precludes their recycling in ferrous metallurgy aggregates. Long storage of this type of material can lead to contamination of soil and water by zinc compounds which can be leached out by acid rain, for example. This paper focuses on research involving alkaline leaching tests of low zinc content iron-bearing materials. These tests were preceded by the analysis of the elemental, phase and grain size composition, and analysis of the thermodynamic conditions of the leaching process. The main aim of research was to decrease the content of the zinc in the sludge to the level where it is suitable as an iron-bearing material for iron production (~1% Zn). Leaching at elevated temperatures (368 K, 60 min) has led to a decrease in the zinc content in the sludge of about 66%. The research revealed that long hour leaching (298 K, 100 hours) carried out at ambient temperatures caused a reduction in zinc content by 60% to the value of 1.15-1.2% Zn.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Parametric optimization of coal desulfurization through Alkaline leaching
Autorzy:: Rehman, F.
Ahmad, S. W.
Zafar, M. S.
Ahmad, S.
Zia-Ul-Haq, M.
Tematy:: Desulfurization
Alkaline leaching
Response surface methodology
ANOVA
Central Composite design; Pokaż więcej
Data publikacji:: 2018
Powiązania:: https://bibliotekanauki.pl/articles/779964.pdf Link otwiera się w nowym oknie
Źródło:: Polish Journal of Chemical Technology; 2018, 20, 3; 103-109
1509-8117
1899-4741
Pojawia się w:: Polish Journal of Chemical Technology
Opis:: Desulfurization of Pakistani coal has been carried out through alkaline leaching. During present experimental investigation, the effect of operating parameters like alkali concentration, time, temperature and particle size has also been analyzed, graphically represented and critically discussed. Parametric optimization of leaching process has been carried out by using response surface methodology (RSM) based on central composite design (CCD). The analysis of variance (ANOVA) was performed in order to assess the highest level interactions of variables and three way interactions were observed significant. Further, the optimum value of total sulfur removal was observed as 53% when the operatic conditions fixed at 10% W/V, 60 min, 80°C and 140 mesh for alkaline concentration, leaching time, temperature and particle size, respectively.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Leaching behaviour of zinc from a smithsonite ore in sodium hydroxide solutions
Autorzy:: Ehsani, Ilhan
Ucyildiz, Ayse
Obut, Abdullah
Tematy:: alkaline leaching
calcium zincate
nonsulfide zinc ore
smithsonite
zinc carbonate; Pokaż więcej
Data publikacji:: 2019
Powiązania:: https://bibliotekanauki.pl/articles/110552.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2019, 55, 2; 407-416
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: In this study, the leaching behaviour of zinc from a smithsonite ore sample (23.43% Zn) having goethite and calcite as main gangue minerals was investigated in sodium hydroxide solutions using Xray diffraction and chemical analyses. Within the studied NaOH concentration range (1-4 mole/dm3), higher leaching ratio values for Zn were obtained by leaching at 298 K because of the decreased stability of soluble zincate species in solution at higher temperatures. When the concentration of NaOH solution was increased from 1 to 3 mole/dm3 at 298 K, leaching ratio value of Zn increased from 3.8 to 70.1%. At 4 mole/dm3 NaOH concentration, Zn leaching ratio value (70.9%) levelled off due to the formation of solid hydrated calcium zincate phase in leaching solution. On the other hand, very low leaching ratio values of Zn were obtained by leaching in 1 mole/dm3 NaOH solution at 298 K (3.8%) and 363 K (1.4%) due to the formation of solid zinc hydroxide and solid zinc oxide phases, respectively. It was observed that increasing leaching time from 1800 to 14400 s at 3 mole/dm3 NaOH concentration, favoured the formation of hydrated calcium zincate phase and so decreased the leaching ratio of Zn to a lower value (60.6%). The effect of solid/liquid ratio was also investigated and it was found that when solid/liquid ratio was decreased, Zn leaching ratio values decreased at constant OH/Zn mole ratio and increased at constant NaOH concentration conditions. Besides, for some of the experiments, leaching ratio values of lead were also given.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Leaching of High Arsenic Content Dust and a New Process for the Preparation of Copper Arsenate
Autorzy:: Sheng, W.
Shen, Y.-Y.
Sheng-Quan, Z.
Tematy:: high-arsenic dust
acidic leaching
alkaline leaching
copper arsenate
comprehensive utilisation of esources; Pokaż więcej
Data publikacji:: 2018
Powiązania:: https://bibliotekanauki.pl/articles/355005.pdf Link otwiera się w nowym oknie
Źródło:: Archives of Metallurgy and Materials; 2018, 63, 3; 1167-1172
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Opis:: In this research, the high arsenic content dust of copper smelting, as a raw material, the extraction of copper and arsenic from the high arsenic content dust in the leaching system containing acidic and alkaline compounds was investigated. Meanwhile, the effects of acid/alkaline initial concentration, liquid to solid ratio, leaching temperature, leaching time on the leaching rate of copper and arsenic were studied. The optimum conditions for the leaching of high arsenic content dust and preparation of copper arsenate were determined. The results showed that acidic/alkaline leaching of high arsenic content dust was particularly effective. 93.2% of the copper, and 91.6% of the arsenic were leached in an acidic leaching process and 95% of the arsenic, while less than 3% of the copper, less than 5% of the antimony, less than 2% of the bismuth was also leached in an alkaline leaching process. A new method (the parallel flow drop precipitate method) was developed in the synthesis of copper arsenate process. The parallel flow drop method was employed to adjust the molar ratio (copper to arsenic) of the mixed solution of the acid-leaching solution and the alkali-leaching solution by taking the drop acceleration of an acidic leaching solution and an alkaline leaching solution at 10 mL/min and 12 mL/min, at a temperature of 60°C and a reaction time of 1h. Copper arsenate was prepared by mixing an acidic leaching solution and an alkaline leaching solution. The main phases of copper arsenate were CuHAsO4·1.5H2O and Cu5As4O15·9H2O. Copper arsenate contained 30.13% copper and 31.10% arsenic.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A novel method to extract vanadium from high-grade vanadium slag: non-salt roasting and alkaline leaching
Autorzy:: Liu, B.
Meng, L.
Zheng, S.
Li, M.
Wang, S.
Tematy:: high-grade vanadium slag
cleaner production
non-salt roasting
alkaline leaching
mechanisms; Pokaż więcej
Data publikacji:: 2018
Powiązania:: https://bibliotekanauki.pl/articles/110480.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2018, 54, 3; 657-667
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: A new method using non-salt roasting-alkaline leaching to treat vanadium slag was proposed in this study. The V(III) in vanadium slag is oxidized to V(V) by roasting and the latter can be effectively leached out as vanadate by alkaline leaching. This method possesses distinct advantage of being able to treat high-grade vanadium slag. For the South Africa high-grade vanadium slag, the maximum vanadium recovery of 98% was achieved when the reaction conditions were roasting temperature of 850 °C, roasting time of 2 h, alkali concentration of 30 wt.%, leaching temperature of 210 °C, and leaching time of 2 h. The roasting and leaching mechanisms have been well elucidated based on the XRD and SEM analysis results. The phases transitions of vanadium slag were clearly presented. This work has laid the foundation for the industrial application of non-salt roasting-alkaline leaching and provided new insights into effective extraction of high-grade vanadium slag.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Recovery of vanadium and tungsten from spent selective catalytic reduction catalyst by alkaline pressure leaching
Autorzy:: Liu, Nana
Xu, Xinyang
Liu, Yuan
Tematy:: spent SCR catalyst
alkaline pressure leaching
response surface method
Box-Behnken design; Pokaż więcej
Data publikacji:: 2020
Powiązania:: https://bibliotekanauki.pl/articles/110694.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2020, 56, 3; 407-420
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: Improving the efficiency of precious metal recovery from spent Selective Catalytic Reduction (SCR) catalyst provides economic benefits and promises sustainable use of resources. Here we demonstrate highly efficient alkaline pressure leaching method for the extraction of vanadium (V) and tungsten (W) from spent SCR catalyst. We analyzed the effects of experimental parameters such as the stirring speed, leaching agent concentration, leaching temperature, liquid-to-solid ratio, and leaching time. The Box-Behnken design of experiments and the response surface methodology have been employed to understand the impact of the leaching parameters and the impact of their interactions on the leaching rate of V and W. The results showed that the leaching agent concentration significantly promoted the recovery of V and W; the influence of the reaction temperature and leaching time moderately increased the leaching rate of the metals. Moreover, the efficiency of the alkaline pressure leaching technique was determined by the interactions between leaching time and reaction temperature, and the relationships between reaction temperature and leaching agent concentration. By using the response surface methodology, the optimal leaching conditions were found that the leaching agent concentration was 4.75 molL-1, the leaching temperature was 190 °C, and the reaction time was 44.5 min, and the predicted values of V and W leaching rates were 95.76% and 98.36%, respectively. Based on the excellent fitting between modeling and experimental results demonstrated in this work, we conclude that our study can shed light on the development of highly efficient and sustainable metal recovery strategies for practical applications.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Dissolution of alkaline batteries in reductive acidic media
Autorzy:: Zeytuncu, B.
Tematy:: alkaline battery
manganese
zinc
reductive leaching
sulfur; Pokaż więcej
Data publikacji:: 2016
Powiązania:: https://bibliotekanauki.pl/articles/110179.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2016, 52, 1; 437-450
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: In this paper, recovery of manganese and zinc from alkaline battery paste by leaching under atmospheric condition using elemental sulfur as a reductive agent and sulfuric acid was investigated. Different dissolution parameters, acid concentrations, liquid-to-solid ratios, reaction temperatures, leaching times and amounts of elemental sulfur were studied in detail. According to results, the Mn dissolution in reductive acidic media was an intermediate-controlled process with activation energy of 10.21±2.60 kJ/mol. After the leaching step, Mn and Zn were selectively precipitated from the leaching solution using sodium hydroxide. After solid/liquid separation, manganese(II,III) oxide (Mn3O4) was obtained by drying at 105 °C in air. Next, Mn3O4 was converted to manganese(IV) oxide (MnO2) by heating at 800 °C in air. After that the solution containing Zn(OH)42- was treated with sulfuric acid to form zinc hydroxide, separated and next converted to zinc oxide by heating at 600 °C in air. The final products were characterized by XRD. The results showed that the proposed process can be effectively used for recovery of Mn and Zn from alkaline batteries.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Identification of tin species released in solution during water leaching of solids from the alkaline smelting (NaOH-KOH) of stanniferous ores
Autorzy:: Yuma, Phalaris M.
Kitungwa, Bertin K.
Mubiayi, Pierre Kalenga
Shengo, Michel L.
Moloto, Nosipho
Ngubeni, Grace
Mbayo, Marsi K.
Kyona, Crépin W.
Tematy:: tin ore
alkaline smelting
solids leaching
characterisation
tin species identification; Pokaż więcej
Data publikacji:: 2024
Powiązania:: https://bibliotekanauki.pl/articles/58971094.pdf Link otwiera się w nowym oknie
Źródło:: Physicochemical Problems of Mineral Processing; 2024, 60, 3
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Opis:: Tin species were studied from Makundju ores in DRCongo. The identification of tin species released in aqueous solution during leaching of solids from the alkaline smelting (NaOH-KOH) was done to prepare added-value mining products on tin ores mined in the eastern DR Congo. Prior to alkaline fusion to have the smelting products (SP), the initial sample (IS) was processed for tests and characterization of tin species. Alkaline fusion in molten KOH-NaOH system was used and leached solution was considered for further analyses. Various physicochemical techniques including X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and FTIR spectroscopy were used to characterize the initial ore and the molten cake. Water leached cake solution at a solid/liquid ratio of 1:10 was used to identify and characterize tin species. ICP-OES analysis of the pH 11.9 solution revealed a content of 4506.3 ppm, which is equivalent to a 95.87% leaching yield. Such yield attests to the stable Sn(OH)2-6(aq) ion as confirmed by UV-Vis. Crystallizations of M2Sn(OH) 6(s) (M = Na and/or K) was studied using XRD, FTIR and TGA. As pH decreases below 9, Sn(OH) )2-6(aq) ion changes to other tin species such as Sn(OH)-5(aq), Sn(OH)4(S), Sn(OH)+3(aq), Sn(OH)2+2(aq), Sn(OH)3+(aq) and Sn4+(aq). The stability of each the tinspecies was determined at different pH values in aqueous solution. Hence, alkaline hexahydroxostannate nanoparticles, used in many electronic applications, can be produced from tin ores.
Dostawca treści:: Biblioteka Nauki

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