Extraction Of Molybdenum Research Articles

Task-Specific Ionic Liquids as Extractants for the Solvent Extraction of Molybdenum(VI) from Aqueous Solution Using Different Commercial Ionic Liquids as Diluents

In this work, the recovery of molybdenum(VI) (Mo) from aqueous solutions was carried out by solvent extraction (SX) using ammonium and phosphonium-based task-specific ionic liquids (TSILs) as extractants diluted in kerosene and two other hydrophobic room-temperature ionic liquids (RTILs). Four different TSILs were used as extractants: trioctylmethylammonium bis(2-ethylhexyl) phosphate [TOMA][D2EHP]; trioctylmethylammonium benzoate [TOMA][BA]; trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate [P6,6,6,14][D2EHP]; and trihexyltetradecylphosphonium benzoate [P6,6,6,14][BA]. These TSILs were synthesized to assess the effect of the cation and anion on the SX of Mo(VI). Experimental results indicated that high extraction percentages of Mo(VI) were obtained with all the synthesized TSILs. Besides that, the best cation was [TOMA]+ for all the diluents and [BA]− was the best anion when kerosene and 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [omim][Tf2N], were the diluents. Furthermore, t...

Solvent Extraction of Molybdenum (VI) from Hydrochloric Acid Leach Solutions using P507. Part II: Stripping and Mechanism

ABSTRACTThermodynamic analysis of the Mo(VI)-H2A2-NH3-H2O system was conducted for the model establishment of molybdenum stripping from a loaded organic solution consisting of 30% (v/v) P507 in sulfonated kerosene. The results revealed that there were five ranges for the molybdenum stripping using ammonia, and the mole fraction of could be regarded as the saponification of the extractant. The molybdenum can be completely stripped at equilibrium pH higher than 5.0, and the consumption of ammonia for stripping 1 mol molybdenum can be expressed as: (mol), where P stands for the saturation of molybdenum in the loaded organic solution. The concentration of molybdenum in strip liquors reached as high as 228 g/L using a three-time reflux stripping with a loaded organic solution containing 35.9 g/L Mo and a stripping agent consisting of 1.2 mol/L NH3·H2O and 0.15 mol/L NH4NO3 at an A/O ratio of 1/2 and 30°C. The average stripping of molybdenum reached 96.4%, while the average molybdenum concentration in stripped organic solutions was only 1.30 g/L. The volume loss of strip liquor can be attributed to the formation of microemulsion during the stripping process.

Solvent extraction separation of molybdenum as thio-molybdate complex from alkaline tungsten leach liquor of spent HDS catalyst – A pilot study

Spent nickel-tungsten catalyst generated from hydrotreating petroleum industry always contains molybdenum about 0.1–2% as an impurity. Separation of Mo from spent Ni-W catalyst leach solutions is a critical step to produce high pure tungsten products like ammonium paratungstate (APT) and tungsten trioxide (WO3) for catalyst and tools applications. Though Mo and W have chemically similar properties but it is possible to exploit separation of Mo from W by modifying the aqueous phase species. In the present paper, alkaline leach liquor with a composition of 0.72g/L Mo and 18g/L W was taken. Selective separation of Mo as its thiocomplex from W was examined by Aliquat 336, a quaternary ammonium compound. Experimental parameters such as extraction pH, concentration of extractant and metal for extraction and selection of reagent and concentration for stripping were optimized to obtain maximum separation of Mo. Variation of extractant concentration indicated extracted Mo species as (R3CH3N)2MoS4. The McCabe-Thiele plots indicated that 2 and 3-counter-current stages are necessary at O:A ratio of 1:1 and 3:1 for quantitative extraction and stripping of molybdenum, respectively. A pilot run for 330h was operated with 3-stages of extraction, 1-stage of scrubbing, 3-stages of stripping and one stage of washing based on the equilibrium data to verify the performance of Mo separation from W from commercial point of view.

Rhenium(VII) extraction with Versatic hydrazides and N',N'-Dialkylhydrazides

Rhenium(VII) and molybdenum(VI) extraction with kerosene solutions of α-branched tertiary carboxylic Versatic acids derivatives containing hydrazide C(O)NHNH2 and C(O)NHNCH3)2 fragments instead of carboxyl group has been studied. Optimal extraction conditions have been determined depending on H2SO4, HCl, and extractant concentrations and composition of extracted complexes has been established. The mechanism of extraction and back extraction of perrhenate ion with ammonia solutions has been suggested.

Extraction of molybdenum from acidic leach solution of Ni–Mo ore by solvent extraction using tertiary amine N235

ABSTRACTTertiary amine N235 diluted with sulphonated kerosene containing sec-octyl alcohol as a phase modifier was used to directly extract molybdenum from the acidic leach solution of Ni–Mo ore. The results indicated that the extraction of molybdenum can reach more than 88% using a solvent extraction system consisting of 10 vol.-% N235 and 10 vol.-% sec-octyl alcohol in sulphonated kerosene with an O/A ratio of 1:2 at room temperature for 20 min. The extracted molybdenum species of Mo7O21(OH)33–, MoO2(SO4)22– and MoO2(HSO4)42– in loaded organic phase were identified, and the predominant species was Mo7O21(OH)33–. Molybdenum in the loaded organic phase can be stripped with ammonia solution, and the stripping of molybdenum can reach 95.8% at an O/A ratio of 7:1, phase contact time of 10 min, and the ammonia concentration of 6 mol L−1.

Solvent extraction of Cu, Mo, V, and U from leach solutions of copper ore and flotation tailings

Flotation tailings from copper production are deposits of copper and other valuable metals, such as Mo, V and U. New hydrometallurgical technologies are more economical and open up new possibilities for metal recovery. This work presents results of the study on the extraction of copper by mixed extractant consisting p-toluidine dissolved in toluene. The possibility of simultaneous liquid–liquid extraction of molybdenum and vanadium was examined. D2EHPA solutions was used as extractant, and recovery of individual elements compared for the representative samples of ore and copper flotation tailings. Radiometric methods were applied for process optimization.

Electrolytic Extraction of Copper, Molybdenum and Rhenium from Molten Sulfide Electrolyte

The validity of the electrochemical series for metal sulfides decomposition in their standard state has been tested experimentally at 1500K for La2S3, Cu2S, MoS2, and ReS2 in a molten electrolyte with the following molar composition: (BaS)54-(Cu2S)31-(La2S3)15 (electrolyte B). Voltammetry measurements indicated the presence of faradaic reactions in the investigated electrolyte with and without the addition of MoS2 and/or ReS2. Electrolysis experiments showed that the addition of La2S3 to BaS-Cu2S increases the faradaic efficiency for liquid copper production with respect to a previously studied (BaS)54-(Cu2S)46 electrolyte, and enabled isolation of elemental sulfur as the anodic product. Electrochemical measurements suggested the need to take into account the activity of dissolved Cu2S in order to explain the observed cell voltage during electrolysis. Electrolysis in the presence and absence of ReS2 and/or MoS2 confirmed their relative stability as predicted by assuming decomposition in their standard states. Analysis of the metal products electrowon from an electrolyte containing Cu2S, MoS2, and ReS2 indicated the simultaneous production of solid and liquid phases with nonequilibrium compositions.

Solvent Extraction of Molybdenum (VI) from Hydrochloric Acid Leach Solutions Using P507. Part I: Extraction and Mechanism

ABSTRACTThe extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) was used to selectively extract molybdenum (VI) from the hydrochloric acid leach solution of molybdenite after roasting with lime. The effects of solution acidity, organic composition, extractant concentration, impurity concentration, temperature and phase volume ratio on the separation of molybdenum (VI) over impurities of iron (III), aluminum, silicon and phosphorus were investigated. The increase in solution acidity resulted in the depolymerization of molybdenum heteropolyanions and , and the formation of molybdenum cations of . The saturated loading capacity of molybdenum (VI) with 30% (v/v) P507 in sulfonated kerosene reached 44.5 g/L. More than 99.8% of the molybdenum (VI) was extracted in a four-stage counter current extraction using an organic system consisting of 30% (v/v) P507 and 70% (v/v) sulfonated kerosene and a hydrochloric acid leach solution containing 14.8 g/L Mo(VI) and 1.73 mol/L H+ with an A/O ratio of 2.86/1 at room temperature for 7 min, while the extraction of iron(III) and phosphorus was only 1.02% and 2.96%, respectively. The separation factor of molybdenum and impurities was in the range of 104.31 ~ 105.89. The extracted molybdenum (VI) species of Mo2O5A2·2HA in the loaded organic solution was identified by the combination of the slope and saturation methods, and further proved by the FTIR spectral analysis.

Extraction of molybdenum and nickel from roasted Ni–Mo ore by hydrochloric acid leaching, sulphation roasting and water leaching

To extract molybdenum and nickel from the roasted Ni–Mo ore, a process of hydrochloric acid leaching, sulphation roasting and water leaching was investigated. The results showed that this process could get a high leaching rate of Mo and Ni. Under the optimum conditions of hydrochloric acid leaching (roasted Ni–Mo ore leached with 0.219 mL/g hydrochloric acid addition at 65 °C for 30 min with a L/S ratio of 3 mL/g), sulphation roasting (51.9% sulfuric acid addition, roasting temperature 240 °C for 1 h), followed by leaching with the first stage hydrochloric acid leaching solution at 95 °C for 2 h, the leaching rates of Mo and Ni reached 95.8% and 91.3%, respectively.

Solvent extraction of molybdenum (VI) from aqueous solution using ionic liquids as diluents

Abstract This work deals with the recovery of Molybdenum (VI) (Mo) from aqueous solutions carried out by solvent extraction (SX) using the bis(2-ethylhexyl) phosphoric acid (D2EHPA) diluted in kerosene and compared with two hydrophobic room temperature ionic liquids (RTILs) as potential replacements of the kerosene. These RTILs were 1-butyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide, [bmim][Tf2N], and 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [omim][Tf2N], because of its excellent properties such as negligible vapor pressure, high hydrophobicity and better extraction capacity than conventional organic diluents. Experimental results indicate that the extraction stoichiometry agrees with a cation exchange with formation of a neutral complex. The use of the selected RTILs as diluents involves higher extraction percentages for the whole measured range of extractant concentration and aqueous-organic ratios, reducing four times the required volume of diluent compared to the experiments carried out with kerosene. Furthermore, the proposed extraction medium offers excellent stripping capacity when a solution of ammonium carbonate is used as a stripping phase.

Selective extraction of molybdenum from copper concentrate by air oxidation in alkaline solution

Alkaline leaching of copper concentrate bearing molybdenite was investigated. Thermodynamic analysis of Mo-S-H2O and Cu-Fe-S-H2O indicates that alkaline leaching of copper concentrate is feasible for selective extraction of molybdenum. The oxidation mechanisms of sulfide ores in the copper concentrate were discussed based on the analysis results of X-ray diffraction (XRD) and scanning electron microscopy/energy-dipersive X-ray spectroscopy (SEM-EDS) of copper concentrate before and after leaching. The effects of leaching factors including sodium hydroxide concentration, temperature, leaching time and liquid to solid (L/S) ratio on the leaching rate were studied. The results show that molybdenite was oxidized and then dissolved selectively. The optimum parameters were as follows: temperature 80°C, L/S ratio 6/1mL/g, sodium hydroxide concentration 2mol/L, air with ventilation volume 0.6m3/h and leaching time 8h. About 97.5% of Mo was selectively extracted and only 1.84% of Cu was dissolved into the solution under the conditions.

Separation of Rhenium from Lead-Rich Molybdenite Concentrate via Hydrochloric Acid Leaching Followed by Oxidative Roasting

Lead-rich molybdenite is a typical rhenium-bearing molybdenum resource in China, which has not been efficiently utilized due to its high contents of lead and gangue minerals. In this study, hydrochloric acid was used for preliminarily removing lead and calcite from a lead-rich molybdenite concentrate. Oxidative roasting-ammonia leaching was then carried out for separation of rhenium and extraction of molybdenum. The hydrochloric acid leaching experiments revealed that 93.6% Pb and 97.4% Ca were removed when the leaching was performed at 95 °C for 10 min with HCl concentration of 8 wt. % and liquid-solid ratio of 5 (mL/g). The results of direct oxidative roasting indicated that 89.3% rhenium was volatilized from the raw concentrate after roasting at 600 °C for 120 min in air. In contrast, the rhenium volatilization was enhanced distinctly to 98.0% after the acid-leached concentrate (leaching residue) was roasted at 550 °C for 100 min. By the subsequent ammonia leaching, 91.5% molybdenum was leached out from the calcine produced from oxidative roasting of the acid-leached concentrate, while only 79.3% Mo was leached from the calcine produced by roasting molybdenite concentrate without pretreatment.

Sequential biological process for molybdenum extraction from hydrodesulphurization spent catalyst

Spent catalyst bioleaching with Acidithiobacillus ferrooxidans has been widely studied and low Mo leaching has often been reported. This work describes an enhanced extraction of Mo via a two stage sequential process for the bioleaching of hydrodesulphurization spent catalyst containing Molybdenum, Nickel and, Aluminium. In the first stage, two-step bioleaching was performed using Acidithiobacillus ferrooxidans, and achieved 89.4% Ni, 20.9% Mo and 12.7% Al extraction in 15 days. To increase Mo extraction, the bioleached catalyst was subjected to a second stage bioleaching using Escherichia coli, during which 99% of the remaining Mo was extracted in 25 days. This sequential bioleaching strategy selectively extracted Ni in the first stage and Mo in the second stage, and is a more environmentally friendly alternative to sequential chemical leaching with alkaline reagents for improved Mo extraction. Kinetic modelling to establish the rate determining step in both stages of bioleaching showed that in the first stage, Mo extraction was chemical reaction controlled whereas in the subsequent stage, product layer diffusion model provided the best fit.

A green method for extracting molybdenum (VI) from aqueous solution with aqueous two-phase system without any extractant

Abstract An aqueous two-phase system (ATPS) of TX-100 + (NH4)2SO4 + H2O without using any extractant was reported for the selective extraction and separation of molybdenum (VI) from aqueous media. The effects of aqueous pH, initial molybdenum concentration, phase-forming ammonium sulfate and TX-100 concentration, extracting temperature on the extraction of molybdenum were investigated. The experimental results indicate that the extraction rate and distribution coefficient of molybdenum have remarkable relationship with molybdenum species in aqueous phase and reach the maximum of 97% and 75 at pH = 3.00. The extraction rate of molybdenum decrease with increasing temperature within 298.15–343.15 K, and its distribution coefficient decrease with increasing temperature within 303.15–343.15 K, and the thermodynamic analysis of extracting process indicates that polymolybdate anion transferring from salt-rich phase to TX-100-rich micellar phase is a spontaneous and exothermic process. The high distribution coefficient and extraction rate of molybdenum are obtained in the broad initial molybdenum concentration range of 0.1–30 g L−1 in aqueous phase. The extraction mechanism reveals that there is no significant interaction between polymolybdate anion and ethylene oxide unit in TX-100 molecule by Fourier Transform Infrared Spectroscopy (FT-IR) and zeta potential of TX-100 micellar phase slightly changes from positive to negative after extracting polymolybdate anion, and from negative to positive again after adding charge modifier making for separation of molybdenum and metal cations by Dynamic Light Scattering (DLS), which can be deduced that polymolybdate anion is extracted into TX-100 micellar core depending on salting-out effect of phase-forming ammonium sulfate and relatively high hydrophobic nature of polymolybdate anion by micelle solubilization. The stripping rate of molybdenum can be easily achieved to 95% in single stage stripping. Some metal cations (Fe(III), Co(II), Ni(II), Cu(II), Zn(II)) are remained in salt-rich phase and separated from molybdenum under the suitable conditions by adding charge modifiers.

WAYS OF UTILIZATION OF SPENT PETROCHEMICAL MOLYBDENUM CATALYSTS

The article gives an overview of diff erent recycling technologies for exhaust catalysts. The quantitative indexes of extraction ratio of molybdenum are given. The reasons for the decline of molybdenum extraction rate from spent catalysts of pyrometallurgical and hydrometallurgical technologies are indicated. The advantages and disadvantages of technology of direct steel alloying by spent catalyst through the slag phase are described. The general scheme of tailings recycling of hydrometallurgical and pyrometallurgical refi ning of spent catalysts were proposed, implying their use as components of the solid slag mixtures. The optimal ways of complex catalysts processing and waste-free scheme for spent catalysts processing are described. The use of calcium molybdate was proposed as ligature at the stage of steel processing at ladle furnace.

Extraction of molybdenum(VI) from sulfate media by 3-pyridineketoxime and its quaternary salts

Hydrophobic complexing agents: 1-(3-pyridyl)undecan-1-one oxime and its quaternary salts (3-[1-(hydroxyimine)undecyl]-1-propylpyridinium bromide and 3-[1-(hydroxyimine)undecyl]-1-propylpyridinium chloride) were investigated as extractants of molybdenum(VI) ions from sulfate media. The extraction of Mo(VI) was studied as a function of several variables: equilibrium pH, acid, extractant and modifier concentrations, as well as phase ratio and contact time. The extraction of Mo(VI) was found near-quantitative for all studied compounds especially from solutions of pH 2.5, but 3-[1-(hydroxyimine)undecyl]-1-propylpyridinium chloride appeared to be the most efficient extractant of Mo(VI) from sulfate media. This salt was the most suitable extractant in terms of loading capacity and a fast stripping process with sodium nitrate and sodium or ammonium sulfate solutions. 1-(3-Pyridyl)undecan-1-one oxime was a slightly weaker extractant towards molybdenum(VI) ions, but in comparison to its quaternary salts this reagent formed more stable complexes and the re-extraction proceeded in 50%.

Concentration and determination of molybdenum(VI) in sea water

The sorption and complexing properties of styrene/maleic anhydride copolymer-based modified sorbent in relation to molybdenum(VI) have been studied and main quantitative characteristics of metal ion sorption have been defined. A sorbent containing p-phenylenediamine fragments has been proposed for selective extraction of molybdenum(VI) from solutions. Optimal sorption conditions are defined. The influence of various mineral acids (HClО4, H2SО4, HNО3, HCl) on molybdenum(VI) desorption from the sorbent has been studied. The experiment has revealed that maximum molybdenum(VI) desorption occurs in sulfuric acid. The molybdenum(VI) extraction rate in optimal conditions exceeds 95 %. Methods of sorption-photometric determination of molybdenum(VI) in sea water have been developed.

Bioleaching of a Molybdenite Concentrate by Thermophilic Microorganisms in a New RELVA-RBAL 1 AIR LIFT Bio-Reactor

In this paper bioleaching of molybdenite concentrate (MoS2) with extreme thermophilic microorganisms at constant temperature (65°C) was studied using a new RELVA-RBAL1 bioreactor, designed at the Faculty of Chemistry of the National Autonomous University of Mexico (UNAM). The equipment keeps homogeneous medium creating physical, chemical and biological conditions that lead to optimal growth of microorganisms, improving its resistance and tolerance to molybdenum significantly, thus achieving high extraction. The RELVA-ARBAL1 AIR LIFT bioreactor allows us the control of necessary conditions for a growth more efficient of the microorganisms. This will allow leach more rapidly the ore, increasing the molybdenum extraction kinetics. The results of extraction from bioleaching molybdenite in an orbital incubator were <1% Mo. The new RELVA-RBAL 1 AIR LIFT bioreactor showed a hight efficiency, 96.84% of molybdenum extracted, most reported, in the shortest time.

Electrochemical way of molybdenum extraction from the Bimetallic systems of Mo-W

Electrochemical dissolution of molybdenum and tungsten was investigated in water- dimethylsulfoxide (DMSO) media at different concentrations of lithium chloride and magnesium perchlorate. The terms of efficient extraction of molybdenum from bimetallic systems of Mo-W have been determined. The polarization curves of the electrooxidation of molybdenum in the solution of 0.25 M LiCl in the DMSO at the different rates of rotations and the scan rate equal to 50 mV/s were obtained. In the presence of the addition of water at the potential of 0.1-0.75 V the small area of polarizability occurs, then with increasing potentials above 1.5 V there is a sharp increase of the oxidation current. Comparison of the current values of anodic dissolution of molybdenum and tungsten showed that the rate of anodic dissolution of molybdenum significantly exceeds the rate of anodic dissolution of tungsten. In the case of molybdenum, the dissolution process is limited by diffusion, in the case of tungsten - by the passive film formation on the electrode surface.

Direct solvent extraction of molybdenum(VI) from sulfuric acid leach solutions using PC-88A

The extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) was used to directly extract molybdenum(VI) from high sulfuric acid leach solutions containing 3mol/L H+. The effects of extractant concentration, solution acidity and type of stripping reagent on the recovery of molybdenum(VI) were investigated. The saturated loading capacity of molybdenum(VI) with 40% PC-88A in sulfonated kerosene was 60g/L. More than 98.7% of the molybdenum(VI) was extracted in a four-stage counter current extraction using an organic system consisting of 40% PC-88A and 60% sulfonated kerosene and a feed containing 17.3g/L Mo(VI) and 157.3g/L H2SO4 with an A/O ratio of 3/1 at 20°C for 5min. The extracted molybdenum(VI) species of Mo2O5(HA2)2 in loaded organic solutions were identified by the combination of slope and saturation methods, and further proved by FTIR spectral analysis. The stripping of molybdenum(VI) was completed in a two-stage counter current stripping using 6mol/L of NH3 with an A/O ratio of 1/1.5 at 30°C for 5min. The concentration of molybdenum(VI) in the strip liquor reached as high as 146g/L.