Recovery Of Molybdenum Research Articles

Analysis of the reasons for molybdenite losses and improvement of recirculating water conditioning regimes in the process of copper-molybdenum ore flotation

Copper-molybdenum ore flotation at closed water circulation system is accompanied by significant losses of molybdenum, recovery of which often does not exceed 50%. The losses are often caused by changing ion composition of the pulp aqueous phase, and primarily accumulation of copper and calcium ions, causing the change in the state of mineral surface. The probability of molybdenite activation by copper cations under conditions of copper-molybdenum ore milling was determined by thermodynamic calculations and confirmed by spectral studies. It was demonstrated that the activation of molybdenite by copper ions increases floatability in the bulk flotation circuit, but causes depression and increase in molybdenite losses in the selective flotation circuit, that leads to decreasing the recovery into commercial concentrates. Kinetic parameters of the interaction of molybdenite with copper cations under milling conditions were experimentally determined, and the boundary concentration of copper cations (0.175 mg/l) was determined. The reasons for molybdenite flotability decline at elevated concentrations of calcium ions and molybdate ions were determined: the formation of calcium molybdate on the mineral surface under conditions of bulk flotation, which is transformed to hydrophilic calcium carbonate at pH above 9.5. The flotation studies established the maximum permissible concentration of copper ions (0.6 mg/l) and calcium (350 mg/l) in recirculating water, exceeding of which leads to deterioration of the process performance. Regime of joint conditioning of filtrates saturated with copper and utility fluids was developed, at the medium pH maintained at 7.5–7.8 by lime adding, providing reducing concentration of dissolved copper and technical fatty acids in the purified recirculating water to 0.4 mg/l and 0.55 mg/l, respectively. The developed conditioning regime for heavily polluted effluents of Erdenet GOK industrial cluster made it possible to increase the recovery of copper and molybdenum by 0.35% and 0.5%, respectively, when the effluents are involved in the water circulation system.

Sustainable recovery of nickel, molybdenum, and vanadium from spent hydroprocessing catalysts by an integrated selective route

Abstract: In this work, nickel, molybdenum, and vanadium were selectively extracted from the spent hydroprocessing catalysts (Ni–Mo–V/Al2O3) by using an integrated ammoniacal leaching and selective separation process. After roasted at 400 °C, molybdenum and nickel were selectively extracted by ammoniacal liquors at pH 9 in the first step and the leaching efficiency of nickel and molybdenum was 88.74% and 97.92%, respectively. In the second leaching step, vanadium was selectively extracted from the residues by ammoniacal liquors containing 6% (v/v) H2O2 at pH 12 and the leaching efficiency of vanadium was above 97.13%. The selective separation of nickel in the leachate was achieved at pH of 6.86 by solvent extraction with 2 mol/L neo-decanoic acid (Versatic10) in sulfonated kerosene, where the extraction efficiency was about 96% and the complete stripping of Ni was achieved with 3 mol/L NaOH to directly obtain Ni(OH)2 precipitates. The molybdenum in extraction raffinate can be recovered by barium molybdate precipitate method. The vanadium-bearing leachate was further treated to obtain ammonium metavanadate precursor by adding HNO3 to adjust the solution pH to 7.5–9 and then flower-like V2O5 was obtained after calcination at 500 °C. Based on the above highly-selective treatment process, nickel, molybdenum, and vanadium in the spent hydroprocessing catalysts were recovered as the corresponding metal compounds, respectively.

Recovery of molybdenum from leach solution using polyelectrolyte extraction

In this research, extraction and purification of molybdenum from a leach solution of molybdenite dissolution was performed. Cationic polyelectrolytes were used for the first time in this study for selective recovery of molybdenum. For this purpose, some water-soluble coagulants of KlarAid PC products were employed and the experimental results in terms of recovery percentages, optimum value of needed polyelectrolyte and their performance were investigated. In order to evaluate the extraction and purification process, the precipitated molybdenum compounds were studied by ICP-OES, XRD, FTIR, and SEM. The results showed that about 88% of molybdenum could be recovered in one step with a final estimated purity of 100%. Afterward, a relatively pure MoO3 product with a layered-structure was successfully synthesized by a simple heat treatment. Finally, the results showed that the proposed novel method, polyelectrolyte extraction (PX), could be an efficient alternative to other processes (i.e. ion exchange resins and solvent extraction) for selective recovery of metals from acid solution.

Recovery of molybdenum by solvent extraction from simulated high level liquid waste

In this study, simple and a rapid solvent extraction method is investigated to recover Mo(VI) from simulated HLLW. The (NH4)6Mo7O24·4H2O dissolved in 3 M HNO3 was treated with ascorbic acid and KSCN to form orange red colored Mo(V)-SCN. Reduction of Mo(VI) was confirmed by cyclic voltammetry. The freshly formed complex was completely extracted to ethyl acetate layer. The organic solvent could be recovered using rotary evaporator. The Mo-complex disproportionated gradually to form a yellow solid, Mo(OH)2(SCN)3·6H2O, which forms MoO3 @ 400 °C. The solid product was characterized by XRD, FT-IR, EDX, TG–DSC and SQUID measurements.

Rapid simultaneous recovery and purification of calcium and molybdenum from calcium molybdate-based crystal waste

Molybdenum (Mo) has wide applications like as alloying elements in steel industries and in experimental laboratories as a catalyst for organic synthesis and as scintillating crystals in high-energy physics experiments. The primary mineral resources of Mo have been ceaselessly exploited and are insufficient to meet the demand in manufacturing industries and experimental researches. Separation, purification, recovery and reuse of Mo will, therefore, be of great importance for environmental conservation and sustainable development. The objective of this study was to recover Mo and calcium (Ca) from crystal wastes. Mo and Ca were recovered from CaMoO4 scintillating crystal wastes in the forms of MoO3 and CaCO3 by adopting nitric acid and hydrochloric acid leaching schemes. About 98% recovery yield efficiency for both elements was obtained through hydrochloric acid leaching. The concentrations of impurity elements like strontium, barium, lead, thorium and uranium in the final products were also reduced by several dozen times as compared to the initial wastes. The finding of this study showed that the hydrochloric acid leaching method could be applied for a rapid and efficient recovery of Mo and Ca from CaMoO4 wastes on a large scale.

Silica-coated magnetite nanoparticles functionalized with betaine and their use as an adsorbent for Mo(VI) and Re(VII) species from acidic aqueous solutions

The aim of this work is to produce a superparamagnetic core-shell adsorbent material composed of magnetite nanoparticles coated with a silica layer and functionalized with betaine for applications associated with the recovery of molybdenum and rhenium anions from highly acidic aqueous solutions. The resulting nanoparticles with a quaternary amine surface were predominantly spherical with average diameters of 14.3±1.7nm. Adsorption experiments at pH values of 1-2 confirmed that it was possible to uptake molybdate and perrhenate species using this adsorbent nanomaterial, achieving maximum loading capacities of 15mg/gMNP for Mo and 19mg/gMNP for Re.

Using Partial Desalination Treatment To Improve the Recovery of Copper and Molybdenum Minerals in the Chilean Mining Industry

Limited water resources and greenhouse gas emissions from fossil fuels used in electricity production are problems experienced in Chile. To address water shortages, many copper mining companies have started to use seawater or desalinated water in their operations. However, seawater exerts a negative impact on the mineral processing operation. It reduces the recovery of copper and molybdenum minerals in the flotation of copper–molybdenum sulfide ores due to the presence of calcium and magnesium ions. This study aims to propose a partial desalination treatment for calcium and magnesium species removal to improve the recovery of valuable minerals in the flotation of copper–molybdenum sulfide ores. The proposed method uses carbon dioxide gas and sodium hydroxide to promote the removal of calcium and magnesium ions from seawater. As a result, the partial desalination treatment can remove 60.5% of calcium and 98.3% of magnesium species. In addition, it helped in reaching a high recovery of molybdenum (81.1%) an...

Recovery and separation of rhenium and molybdenum from aqueous solutions that simulate mine waters using magnetite nanoparticles functionalized with amine-derivative groups

The recovery and separation of rhenium and molybdenum from acidic aqueous solutions that simulate mine waters is studied through an adsorption process using magnetite nanoparticles functionalized with tertiary (TA-MNP) and quaternary amine (QA-MNP) groups as adsorbents. The functionalized nanoparticles (FMNP) were efficiently synthetized and physical and chemically characterized. An average particle size in the range of 6–8 nm based on HR-TEM analysis was determined for the nanoparticles, which exhibited a high saturation magnetization varying between 53 and 60 emu/g. Several factors that affected the recovery of Re(VII) and Mo(VI) from aqueous solution using the synthesized FMNP were studied, such as the adsorbent dose, initial concentration of metal and pH of the aqueous feed solution. In all experiments, QA-MNP presented a slightly better adsorption of both metals compared to TA-MNP. At pH 3, maximum rhenium loading capacities of 30 and 38 mgRe(VII)/gadsorbent were measured using TA-MNP and QA-MNP, respectively. In turn, maximum loading capacities of 60 and 65 mgMo(VI)/gadsorbent were determined utilizing TA-MNP and QA-MNP, respectively. Re(VII) and Mo(VI) equilibrium and kinetics were established in adsorption experiments. A pseudo-second-order kinetic model provided a good fit to the experimental data for the two metals using both adsorbents. Freundlich and Langmuir adsorption isotherm explained the experimental results.

Microwave sodium roasting (MWSR) spent HDS catalysts for recovery Mo and in situ sulfur fixation

Abstract The heat pretreatment of the spent hydrodesulfurization (HDS) catalysts plays an important role in its comprehensive recycling. In this work, the microwave sodium roasting (MWSR) strategy was used for the heat treatment of the spent catalyst, with the aim of achieving effective separation of Mo and Al while achieving in-situ sulfur fixation. Specifically, the de-oiled, spent HDS catalyst was roasted with Na2CO3 by microwave heating in air, followed by hot water leaching. Based on the thermodynamic analysis, the effects of microwave heating temperature, holding time and Na2CO3 addition on the recovery of molybdenum have been thoroughly investigated. Owing to the special heating method of microwave, the spent catalyst after roasting has a microstructure suitable for leaching, and S is more in situ converted to Na2CO3. After following the strategy, the leaching degree of Mo can reach 99%, while the leaching degree of Al is less than 8%, which indicates that Mo and Al are effectively separated. More importantly, a sulfur fixation degree of 79.1% was obtained. This strategy provides a novel reference for the harmless treatment of spent HDS catalysts.

Recovery of molybdenum and rhenium in scrub liquors of fumes and dusts from roasting molybdenite concentrates

The present work addresses the recovery of rhenium from scrub liquor of molybdenite concentrate roasting fume and dust by solvent extraction method. According to the results, recovery of rhenium from the scrub liquor is not practical unless molybdenum is removed in advance. The extraction of molybdenum was carried out using a D2EHPA-TBP system which resulted in up to 99.8% Mo extraction in a two-stage solvent extraction at pH = 1 and O/A = 1. Up to 99.6% of Re was extracted subsequently using TOA in a single-stage extraction at pH = −0.3 and O/A = 1:20. The organic phase was stripped by ammonium hydroxide 32% and the resultant liquor was further subjected to evaporation as a result of which, an enriched purified solution was obtained. Ammonium perrhenate was precipitated from the enriched liquor by adjusting the pH to 6.5–7.

Uranium and molybdenum recovery from copper leaching solutions using ion exchange

This work shows the technical feasibility to recover uranium and molybdenum from industrial copper leaching solutions (PLS). Both were obtained as by-products from hydrometallurgical operations of the Chilean copper mining industry, using the ion exchange technique. This process recovered uranium and molybdenum, without disturbing or changing the normal operation of the overall copper production process. Uranium concentration was 17 mg/L, while molybdenum concentration was 50 mg/L. Four different anionic resins were tested, along with the influence of impurities over the breakthrough and saturation points achieved. In a first instance, two resins were chosen based on their Langmuir parameters, namely, maximum load capacity (Qmax) and separation factor (RL): L-MP62 and M43. The overall dynamic process consisted in a pre-conditioning step for the resin, using a weak hydrochloric acid solution. Next, the copper PLS solution feeds the fixed bed of the ion exchange column. Once the PLS solution saturates the anionic resin, a hydrochloric solution extracts uranium, and a sodium hydroxide solution extracts molybdenum. The final products were purified elution solutions with 500 mg/L uranium and 800 mg/L molybdenum, respectively.

Effects of Collectors and Frothers on Copper and Molybdenum Coarse Particle Recoveries—A Statistical Approach

Typically, coarse dense mineral particles greater than 150 μm are difficult to float, and the recovery decreases progressively. Various physical parameters can be manipulated in an attempt to increase the recovery. These physical parameters are the following: liberation, turbulence in the flotation cell, pH, collector, frother type and dosage. The testwork discussed in this paper was performed for a copper-molybdenum operation that is experiencing coarse particle (>150 μm) losses in the tails. This operation uses Diesel No. 2 fuel and sodium ethyl xanthate for molybdenum and copper flotation, respectively and X-133 frother. In an attempt to increase coarse particle recovery, stronger collectors (potassium amyl xanthate, Aero 249 and Aero 3501) and frothers (FrothPro 618, FrothPro 630 and FrothPro 706) were used. The analysis was performed using the Analysis of Variance (ANOVA) approach. The conditions required by the ANOVA method were met. The results showed that the collector potassium amyl xanthate (PAX) with frothers X-133 and FrothPro 630 resulted in approximately 3% increase in copper rougher recovery relative to the baseline (sodium ethyl xanthate and X-133). The collectors and frothers did not have a significant effect on molybdenum recovery within the dosage limits investigated.

Recovery of vanadium and molybdenum from spent petrochemical catalyst by microwave-assisted leaching

The study of the leaching of vanadium (V) and molybdenum (Mo) from spent petrochemical catalysts in sodium hydroxide (NaOH) medium was performed using two approaches, namely, conventional leaching and microwave-assisted leaching methods. The influence of microwave power, leaching time, leaching temperature, and NaOH concentration on the leaching efficiency of spent petrochemical catalyst was investigated. Under microwave-assisted conditions (600 W, 10 min, 90°C, 2.0 mol·L−1 NaOH, and 0.20 g·mL−1 solid-liquid ratio), the leaching efficiencies of V and Mo reached 94.35% and 96.23%, respectively. It has been confirmed that microwave energy has considerable potential to enhance the efficiency of the leaching process and reduce the leaching time. It is suggested that the enhancement of the leaching efficiencies of V and Mo can be attributed to the existence of a thermal gradient between solid and liquid and the generation of cracks on the mineral surface.

Pyrogallic acid: A novel depressant for bismuthinite in Mo–Bi sulfide ore flotation

Molybdenum ore flotation techniques are constantly challenged by the emergence of complex sulfide minerals, such as bismuthinite, in the mineral processing industry. Conventional flotation depressants, such as sodium sulfide, used in Mo–Bi-containing ore flotation require high dosages, which leads to high cost and low selectivity. Therefore, in this study, pyrogallic acid (PA), a widely distributed organic source, is tested as an alternative depressant to selectively depress bismuthinite in Mo–Bi sulfide ores from Shizhuyuan. Results show that PA has a minimal effect on molybdenite recovery; by contrast, PA has a high depressing effect on bismuthinite amelioration. At 500 g/t PA, molybdenum recovery slightly decreases by 2 percentage points, and bismuth content in molybdenum concentrate sharply declines by 34 percentage points, with respect to samples floated without PA. Batch flotation tests demonstrate that PA addition affects froth stability, as indicated by the variations of solid and water recoveries. The superior selectivity of molybdenite over bismuthinite is promoted by increasing the PA dosage. On the basis of these findings, PA is a feasible option and thus can be used as a depressant for bismuthinite in the flotation of sulfide minerals.

Utilization of petrochemical by-products as a new frother in flotation separation of molybdenum

Recycling of petrochemical by-products is important for environmental protection and sustainable utilization of resources. In this study, petrochemical by-product was analyzed and used for the first time as a cost effective frother in flotation separation of molybdenum to replace terpineol. A significant improvement in molybdenum recovery was achieved by replacing terpineol with petrochemical by-products as frother. Properties of the petrochemical by-product and terpineol solutions, such as foaming, bulk rheology, and foam stability, were investigated through surface tension and rheological measurements. The properties of the petrochemical by-product solution are generally better than that of terpineol. In addition, results obtained in bench-scale flotation showed that the recovery of molybdenum substantially improved by 2.5% in the locked-cycle tests when the concentration of the petrochemical by-product was 100 g/t. Industrial tests showed that the molybdenum recovery obtained by using petrochemical by-products increased by 2.55% which can lead to about 6918192 RMB (1001113 USD) net profit per year. Therefore, these encouraging results suggest that petrochemical by-products can effectively be utilized in mineral processing plants as frothers, and interestingly, Jinduicheng Molybdenum Industry Co., Ltd, China is one that started to use it in industrial production by replacing terpineol.

Recovery of molybdenum from alkaline leach solution of spent hydrotreating catalyst by solvent extraction using methyl tricaprylammonium hydroxide

Detailed extraction of molybdenum(VI) from alkaline sodium hydroxide solution by quaternary ammonium salt (Aliquat 336, R3CH3NOH) mixed with kerosene was investigated. The different factors affecting the extraction system such as time of shaking, alkali, extractant, metal ion concentrations, temperature and the organic to aqueous volume phase ratio were studied in order to obtain the best conditions for separating molybdenum(VI). Based on the slope analysis method, the extracted molybdenum(VI) species was suggested to be [(R3CH3N)2MoO4]. Increasing the temperature was found to slightly increase the extraction affinity indicating the endothermic character of the process. Stripping was successfully accomplished by 2.0 M NaOH solution. The extraction procedures were applied to recover molybdenum(VI) from a sample of spent hydrotreating catalyst containing a significant amount of Al(III), Cu(II) and Ni(II). The recovery yield was found to be 96% and a hydrometallurgical flowsheet was also proposed.

New approach to the utilization of microwave thermal energy: Desulfurization and decarburization of spent catalyst via microwave treatment

Desulfurization and decarburization processes are key issues in the recovery of valuable metals from spent industrial catalysts because the carbon and sulfide on the surface of the spent catalyst are not conducive to metal leaching. This manuscript addresses the development of a process of roasting spent catalyst with microwave heating. In the present investigation, desulfurization and decarburization of the spent catalyst were studied by treating with microwave heating for the recovery of molybdenum. We also studied the effect of various reaction conditions (temperature, holding time, microwave power, and granularity of the spent catalyst) on desulfurization and decarburization, and the leaching of molybdenum. The maximum desulfurization (96.7%) and decarburization (99.7%) were achieved when the spent catalyst (200 mesh) was treated using microwave power (960 W) at a temperature of 650 °C for 45 min. The results show that no complex metal oxides such as CoMoO4 were found in the XPS and XRD spectra of the samples after desulfurization and decarburization and that >96% of molybdenum is leached with a sodium carbonate solution. This method not only promotes rapid desulfurization and decarburization but also does not produce any complex metal oxides, thereby promoting the recovery of valuable metals in spent catalysts.

Co-extraction of tungsten and molybdenum from refractory scheelite–powellite blend concentrates by roasting with Na2CO3 and SiO2 and leaching with water

ABSTRACTStudies on the recovery of tungsten and molybdenum from refractory scheelite–powellite blend concentrates – mainly composed of scheelite, powellite, and fluorite – were performed using soda-silicon roasting and water leaching processes. However, significant amounts of scheelite and powellite ore are present in an intergrowth state and the application of mineral dressing is not suitable for the separation and extraction of tungsten and molybdenum from this refractory ore. The effects of roasting parameters including sodium carbonate addition, roasting temperature, roasting time, and mass ratio of SiO2/concentrate (wSiO2/wconc.) and the effects of leaching parameters including leaching temperature, leaching time, and liquid-to-solid ratio on the leaching efficiency of tungsten and molybdenum were investigated. The results demonstrated the efficiency of this process for the extraction of tungsten and molybdenum from the ore. Under the optimum experimental conditions where soda-silicon roasting is performed for 2 h at 850°C with three times, the stoichiometric ratio of Na2CO3 (Na2CO3:WO3 and Na2CO3:MoO3) and wSiO2/wconc of 12%, and water leaching is subsequently performed for 1 h at 70°C with a liquid-to-solid ratio of 3:1, the leaching ratios of W and Mo are 98.89% and 99.41%, respectively.

An effective approach for improving flotation recovery of molybdenite fines from a finely-disseminated molybdenum ore

An effective flotation approach is proposed for improving the recovery of molybdenite fines from a finely-disseminated molybdenum ore. To maximize the flotation recovery of molybdenum, process mineralogy of raw ore, contrast tests, optimization of operation conditions and particle size analysis were systematically investigated. Process mineralogy suggests that in the raw ore, 61.63% of molybdenite particles distribute in the <20 μm size fraction, and intergrow with muscovite and pyrite as the contained and disseminated type. Contrast tests indicate that conventional flotation responds to poor collection efficiency for particles less than 25 μm. Oil agglomerate flotation (OAF) process demonstrates an obvious superiority in improving the flotation recovery of molybdenite fines. Furthermore, the flotation results of OAF process reveal that the dosage of transformer oil plays a critical role on the average size of collected mineral particles (d 50 p ), agglomerates (d 50 a ) and the molybdenum recovery. In addition, industrial tests illustrate that compared with the Mo-S bulk flotation approach, OAF process not only increases Mo recovery and grade of molybdenum concentrate by 22.75% and 17.47% respectively, but also achieves a sulfur concentrate with a superior grade of 38.92%.

Metal leaching from refinery waste hydroprocessing catalyst

ABSTRACTThe present study aims to develop an eco-friendly methodology for the recovery of nickel (Ni), molybdenum (Mo), and vanadium (V) from the refinery waste spent hydroprocessing catalyst. The proposed process has two stages: the first stage is to separate alumina, while the second stage involves the separation of metal compounds. The effectiveness of leaching agents, such as NH4OH, (NH4)2CO3, and (NH4)2S2O8, for the extraction of Mo, V, Ni, and Al from the refinery spent catalyst has been reported as a function of reagent concentration (0.5 to 2.0 molar), leaching time (1 to 6 h), and temperature (35 to 60°C). The optimal leaching conditions were achieved to obtain the maximum recovery of Mo, Ni, and V metals. The effect of the mixture of multi-ammonium salts on the metal extraction was also studied, which showed an adverse effect for Ni and V, while marginal improvement was observed for Mo leaching. The ammonium salts can form soluble metal complexes, in which stability or solubility depends on the nature of ammonium salt and the reaction conditions. The extracted metals and support can be reused to synthesize a fresh hydroprocessing catalyst. The process will reduce the refinery waste and recover the expensive metals. Therefore, the process is not only important from an environmental point of view but also vital from an economic perspective.