Liansheng Xiao

Leaching of nickel-molybdenum sulfide ore in membrane biological reactor

Abstract The bioleaching of molybdenum from its sulfide ore using a Mo-resistant thermophilic bacterium sulfolobus metallics combined with a membrane biological reactor (MBR) was studied. The experimental results showed that the concentration of Mo can be controlled by filter of the membrane in MBR and the toxicity of Mo to microorganism is decreased in the process of bioleaching. It was also evidenced that there were different leaching rates of Ni and Mo when the concentration of Mo was different. After leaching for 20 d in the MBR at Mo concentration of 395 mg/L, the leaching rates of Ni and Mo reached the maximum of 79.57% and 56.23% respectively under the conditions of 100 g/L of mineral density, 65 °C, pH=2 and 1.0 L/min of the aeration rate. While 75.59% Ni and 54.33% Mo were leached out in column without membrane under the same conditions.

Removal of Vanadium from Ammonium Molybdate Solution by Ion Exchange

The separation techniques of vanadium and molybdenum were summarized, and a new method of removal V (Ⅴ) from Mo (Ⅵ) by adsorption with chelate resin was presented. Nine kinds of chelate resins were used to investigate the adsorbent capability of V (Ⅴ) in ammonium molybdate solution with static method. The test results show that DDAS, CUW and CW-2 resins can easily adsorb V (Ⅴ) in ammonium molybdate solution, but hardly adsorb Mo (Ⅵ). The dynamic experimental results show more than 99.5% of V (Ⅴ) can be adsorbed, and the adsorption rate of Mo (Ⅵ) is less than 0.27% at 294-296 K for 60 min at pH 7.42-8.02. The mass ratio of V to Mo decreases to l/50000 in the effluent from 1/255 in the initial solution. The loaded resin can be desorbed by 5% NH3•H2O solution, and the vanadium desorption rate can reach 99.6%. The max concentration of vanadium in desorbed solution can reach 20g/L, while the concentration of molybdenum is less than 0.8 g/L.

Study on leaching of molybdenum and nickel from Ni-Mo ore using sodium chlorate

Abstract The leaching of molybdenum and nickel from a Ni–Mo ore was investigated by acidic oxidative leaching with sodium chlorate followed by caustic leaching of the acid leach residue. The results indicated that the sulphides of nickel and molybdenum in the Ni–Mo ore were oxidised and dissolved in the solution. The molybdenum remaining in the residue was further recovered by direct caustic leaching. The leaching of nickel and molybdenum reached 92 and 60% respectively, with sodium chlorate consumption of 60 g per 100 g ore and hydrochloric acid consumption of 0·52 mol per 100 g ore at a L/S ratio of 3∶1 and 90°C for 2 h. After caustic leaching of the acid leach residue with sodium hydroxide consumption of 45 g per 100 g dried residue at a L/S ratio of 3∶1 and 40°C for 15 min, the total leaching of molybdenum increased to 96%. A conceptual process flowsheet for the leaching of the Ni–Mo ore has been developed. On a examiné le lessivage du molybdène et du nickel à partir d’un minerai de Ni-Mo, par lessivage acide oxydant avec du chlorate de sodium suivi par lessivage caustique du résidu d’attaque acide. Les résultats indiquaient que les sulfures de nickel et de molybdène du minerai de Ni–Mo étaient oxydés et dissous dans la solution. Le molybdène du résidu était davantage récupéré par lessivage caustique direct. Le lessivage du nickel et du molybdène atteignait 92 et 60%, respectivement, avec une consommation de chlorate de sodium de 60 g par 100 g de minerai et une consommation d’acide chlorhydrique de 0·52 mol par 100 g de minerai avec un rapport de L/S de 3∶1 à 90°C pendant 2 h. Après le lessivage caustique du résidu d’attaque acide avec une consommation d’hydroxyde de sodium de 45 g par 100 g de résidu séché avec un rapport de L/S de 3∶1 à 40°C pendant 15 min, le lessivage total du molybdène augmentait à 96%. On a développé un schéma de procédé conceptuel pour le lessivage du minerai de Ni–Mo.

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

ABSTRACT The 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.

Direct Solvent Extraction of Nickel from Sulfuric Acid Leach Solutions of Low Grade and Complicated Nickel Resources Using a Novel Extractant of HBL110

A new process of direct solvent extraction of nickel from sulfuric acid leach solutions of low grade and complicated nickel resources using a novel extractant HBL110 was proposed. The basic performance of new organic system was investigated and the continuous pilot plant and the industrial test were conducted. The results indicated that the extractant of HBL110 can be used to directly extract nickel selectively over iron, aluminum, manganese, magnesium, calcium and chromium from sulfuric acid leach solutions. The loaded organic solution can be easily stripped using dilute H2SO4 solutions. Both kinetics of extraction and stripping of nickel were fast. The continuous pilot plant test with the sulfuric acid leach solution of laterite containing 6.22g/L Ni2+, 14.1g/L Fe3+, 0.73g/L Fe2+, 33.9g/L Mg2+, 1.58g/L Al3+, 0.495g/L Ca2+, 0.97g/L Mn2+ and 0.5g/L Cr3+ as feed in mixer-settlers showed that the process had run stably with 98% recovery of nickel. The concentration of nickel in strip liquors reached as high as 50 g/L while the removals of Fe3+, Fe2+, Mg2+, Al3+, Ca2+, Mn2+ and Cr3+ were 98.5%, 91.5%, 99.95%, 99.8%, 99.1%, 98.6% and 99.5%, respectively. The industrial test with the sulfuric acid leach solution of electroplating sludge containing 11.5g/L Ni2+, 2.68g/L Fe3+, 7.54g/L Cr3+, 0.61g/L Mg2+, 2.09g/L Al3+, 0.68g/L Ca2+, 0.022g/L Mn2+ and 0.154g/L SiO2 as feed in mixer-settlers also showed that the process had operated successfully with 99.5% recovery of nickel. The concentration of nickel in strip liquors reached 42.7 g/L while the removals of Fe3+, Cr3+, Mg2+, Al3+, Ca2+, Mn2+ and SiO2 were 99.2%, 99.77%, 99.73%, 99.56%, 99.57%, 98.51% and 98.75%, respectively. The new process exhibited big advantages of short flow sheet, high recovery of nickel, high removal of impurities, low chemical reagent consumption and low cost. Application of this process in industry is expected to make important impact on the extraction of nickel from sulfuric acid leach solutions and to deliver good environmental and economical benefits.

Study on removal of tungsten from molybdate solutions

The diagrams of Cx/Co-pH with W–H2O and Mo–H2O systems were established, separately, through thermodynamic analysis. Based on the different conditions to form polymeric anions of both metals, the optimum solution pH for the separation of tungsten from molybdenum was determined in the range of 7·5–8·0.A weak basic resin D363 was selected to selectively adsorb the polymerised species for the removal of tungsten from molybdate solutions, which has validated the thermodynamic analysis results.