Sulfate Leach Liquor Research Articles

Extraction of uranium(VI) from sulfate leach liquor after iron removal using manganese oxide coated zeolite

The present work deals with purification of uranium(VI) solutions derived from leaching processes of as bearing silicate rocks at Gattar V (GV) area, eastern desert, Egypt. Manganese oxide coated zeolite (MOCZ) was used to minimize the iron content and most of impurities present in the leach liquor by adsorption process. In this concern, different parameters involving adsorption such as pH, MOCZ amount, iron concentration, stirring time and temperature were investigated. Uranium was extracted from treated sulfate leach liquor by solvent extraction using tributyl phosphate (TBP) at Org./Aq. (2:1) of 1.5M TBP in kerosene for 10min at room temperature. Under the optimum conditions 85.8% of uranium was extracted. The purified organic phase extract was then subjected to uranium stripping process using 7M sulfuric acid.

Selective recovery and separation of nickel and vanadium in sulfate media using mixtures of D2EHPA and Cyanex 272

In this research, selective recovery and separation of nickel and vanadium in sulfate media was investigated by solvent extraction using D2EHPA, Cyanex 272, and their mixtures in various proportions. For this purpose, synthetic sulfate solutions of nickel and vanadium were prepared in 2g/L of each metal. After dilution of the organic solvents in kerosene with the ratio of 1–4, experiments were carried out in the pH range of 1.0–7.0 in steps of 0.5 at ambient temperature. Solvent extraction of nickel and vanadium by sole D2EHPA was performed and the extraction percentages were determined to be 90% and 80% for nickel and vanadium, respectively. However, the co-extraction of nickel and vanadium by D2EHPA can be increased with increasing equilibrium pH and temperature. It was shown that using sole D2EHPA, pH50 (the pH at 50% metal extraction) values for nickel and vanadium were 3.5 and 2, respectively; which is not appropriate for the efficient simultaneous separation of nickel and vanadium. Adding Cyanex 272 to D2EHPA in the organic phase, leads to a right shifting of extraction isotherm of nickel and a slight left shifting of the extraction isotherm of vanadium; thus, improves the separation of nickel over vanadium. To optimize the recovery and separation process of nickel and vanadium from the sulfate leach liquor, the influence of different D2EHPA to Cyanex 272 ratios and various temperatures (25, 35, 45, and 55°C) were studied. As a result, optimum separation of vanadium over nickel was achieved with a Cyanex 272 to D2EHPA ratio of 0.35M: 0.25M. Based on the optimum results, pH50 values for nickel and vanadium were shifted from 3.5 to 4.75 and from 2 to 1.75, respectively.

Ternary phase diagrams of CdSO4–NiSO4–H2O at 40 °C and 80 °C

The separation of cadmium and nickel from sulfate leach liquors of waste Ni–Cd batteries is investigated by using ternary phase diagrams. Experimental studies are carried out to obtain ternary phase diagrams of nickel sulfate, cadmium sulfate and water mixture at 40°C and 80°C. The eutectic point is determined to be composed of CdSO4.8/3H2O+NiSO4.6H2O and CdSO4.H2O+NiSO4.6H2O, for 40°C and 80°C, respectively, while two univariant curves and two crystallization regions are observed corresponding to CdSO4.8/3H2O and NiSO4.6H2O at 40°C, CdSO4.H2O and NiSO4.6H2O at 80°C. Both low (40°C) and high (80°C) temperature systems belong to a simple saturated type while no double salts or solid solutions exist.

Recovery of molybdenum from uranium bearing solution by solvent extraction with 5-Nonylsalicylaldoxime

5-Nonylsalicylaldoxime, LIX 622N was used to extract and recover Mo(VI) from sulfate leach liquor containing Mo(VI) and U(VI). The extraction parameters were optimized as 10%(v/v) LIX 622N diluted in kerosene at equilibrium pH1.0 and O/A phase ratio=1:1. Under these conditions, complete extraction of Mo(VI) was realized by a two-stage counter current extraction. The formed complex MoO2R2 is assessed by FTIR analysis. The molybdenum content in the organic phase was stripped using a mixture of 2M NH4OH+2M (NH4)2CO3. It was precipitated at pH value 2.0 as ammonium molybdate. After drying, thermal decomposition high purity (>99.9%) of MoO3 was produced. The effect of temperature on the Mo(VI) extraction process showed that, the extraction process is exothermic with enthalpy change −24.514kJmol−1.

Synergistic extraction of uranium from acidic sulfate leach liquor using D2EHPA mixed with TOPO

Uranium extraction from sulfate leach liquor acid by D2EHPA and TOPO mixture in kerosene was investigated. The effect of different factors affecting the extraction mechanism such as sulfate leach liquor acid, D2EHPA and TOPO concentrations and temperature have been studied. The mathematical treatment for the obtained date suggested that the composition of synergistic extraction species is (UO2(D)2T). The logarithm of the apparent equilibrium constant, log Kex, of synergistic extraction reaction has been evaluated, to be 3.35 ± 0.1. The effect of temperature on extraction process was investigated and the apparent values of the thermodynamics parameters (∆H, ∆G and ∆S) were 38.2 kJ/mol, −19.1 kJ/mol and 192.5 J/mol respectively.

Removal of uranium from sulfate leach liquor of salcrete deposits using tri-n-octyl amine

A uranyl sulfate leach liquor obtained by uranium leaching of a technological sample of salcrete deposits of Gabal Qatrani ore was subjected to uranium extraction using the liquid–liquid technique. Uranium was effectively extracted from sulfate leach liquor by [(10 %) tri-n-octylamine (TOA)] dissolved in xylene as a diluent. The extraction efficiency was markedly enhanced as the concentration of TOA increases from 1 to 10 %. The relevant factors controlling the extraction process of uranium using tri-n-octylamine were studied. These factors include the effect of diluents used, TOA concentration, contact time, settling time and phase ratio (O/A) v/v. The optimum extraction conditions were chosen. Stripping of uranium from the loaded TOA has been carried out using 5 % Na2CO3 as an effective stripping agent. More than 97 % of uranium was extracted by 10 % TOA, at contact time 10 min, settling time 5 min, phase ratio (VO/VA) 1/1 and at room temperature. The feasibility of using the TOA for preconcentration-separation of uranium was assessed by stripping studies. The loaded uranium onto TOA has been stripped by 100 % when using 5 % Na2CO3 as an efficient eluting agent at 15 min contact time, 5 min settling time and phase ratio (O/A) 2/1.

Manganese precipitation kinetics and cobalt adsorption on MnO2 from the ammoniacal ammonium sulfate leach liquor of Indian Ocean manganese nodule

Precipitation of manganese from the SO2-roast leach ammoniacal ammonium sulfate solution bearing both high and low concentrations of manganese in the presence of copper, cobalt and nickel ions was carried out in a stainless steel reactor fitted with a turbo grid. Air/O2 was used to precipitate Mn as MnO2 from the solution. There was adsorption loss of cobalt from the solution. Precipitation of manganese from the solution was 57.2–99.9%. The maximum adsorption loss of Co was 22.1%. The precipitation of Mn and adsorption loss of cobalt from the solution followed the first order kinetics. The rate constants for the precipitation of manganese and loss of cobalt were evaluated and the experimental data were fitted to Freundlich and Langmuir adsorption isotherms.

Separation and Recovery of Cadmium from Acidic Leach Liquors of Spent Ni-Cd Batteries using Molten Paraffin Wax Solvent Extraction

Separation and recovery of cadmium from sulphate leach liquors of spent Ni-Cd batteries using TBP, HDEHP (D2EHPA), EHEHPA (PC 88A or Ionquest 801 or P507) have been investigated in a laboratory scale. Cadmium can be extracted into paraffin waxes from acidic solutions in the temperature range of 55–75°C using different extractants. The influence of various parameters on extraction and stripping were studied in detail. The feasibility of separation of cadmium from nickel using these extractants and their combination was studied. The mixture extractant of EHEHPA and TBP was found to be the best for the separation of Cd and Ni. A three-stage counter-current extraction simulation test for cadmium extraction was carried out at an A/O phase ratio of 4:1 and pH 2.5. More than 99.97% Cd2+ was extracted with the organic phase containing 0.7 mol L−1 EHEHPA and 0.5 mol L−1 TBP, while more than 99.97% nickel was left in the raffinate. The cadmium loaded organic phase was stripped with 2 mol L−1 hydrochloric acid in the stripping stage. The present method can be applied to the separation and recovery of cadmium from acidic leach liquor of spent Ni-Cd batteries or related waste liquor.

Purification of Sulphate Leach Liquor of Spent Raneynickel Catalyst Containing Al and Ni by Solvent Extraction with Organophosphorus-Based Extractants

Solvent extraction (SX) separation of Al from Ni sulphate leach liquor (LL) of spent Raneynickel catalyst containing 0.12 M Al and 1.448 M Ni using organophosphorus extractants has been investigated. Optimization of process conditions includes aqueous pH, extractant concentration, phase ratio, and stripping. Comparison of Al extraction efficiency with 0.45 M extractant concentration for TOPS 99, PC 88 A, and Cyanex 272 at an equilibrium pH of 2.23 was 81.8%, 98.6%, and 75%, respectively. The corresponding coextraction of Ni was 0.65, 0.6, and 0.9. Among the three extractants screened, PC 88A showed better extraction efficiency for Al at lower pH values than the others. Using 0.45 M PC 88 A, extraction isotherm was obtained at an aqueous-to-organic (A : O) phase ratio of 1 : 1–3 and O : A ratio of 1 : 1–5, which predicted possible separation of Al in 2 stages at A/O ratio of 2. Quantitative stripping was achieved by H2SO4.

Solvent extraction of uranium from lean grade acidic sulfate leach liquor with alamine 336 reagent

This paper describes the solvent extraction studies carried out on an acidic low assay uranium bearing leach liquor generated during sulfuric acid leaching of a refractory uranium ore using alamine 336–isodecenol–kerosene reagent combine. The leach liquor has a U3O8 content of about 270 mg/L, free acidity 2.4 N H2SO4 and total dissolved solids concentration of 260 g/L. Process parameteric variation studies indicated strong influence of free acidity of the leach liquor, alamine 336 concentration and aqueous to organic phase ratio on the extraction efficiency of uranium. An extraction efficiency of about 95% was achieved when the free acidity of leach liquor was 1 N H2SO4 or lower, using 2% (v/v) alamine 336 at ambient temperature with an aqueous to organic phase ratio of 1:1. The loading capacity under these conditions was 1.2 g/L of U3O8. About 98% of the uranium values could be stripped from the loaded organic using 1 N NaCl in 0.2 N H2SO4. The solvent extraction studies aided in developing a suitable process flowsheet for treating refractory uranium ores which need high acidity during leaching and relatively lower acidity for purification by solvent extraction.

Synthesis of TiO 2 nano-powders prepared from purified sulphate leach liquor of red mud

The research work presented in this paper is focused on the development of a purification process of red mud sulphate leach liquor for the recovery of titanium oxide (TiO 2) nano-powders in the form of anatase. Initially, titanium was extracted over iron and aluminium from the leach liquor by solvent extraction using Cyanex 272 in toluene, at pH: 0.3 and T: 25 °C, with 40% extractant concentration. Stripping of the loaded, with titanium, organic phase was carried out by diluted HCl (3 mol/L) at ambient temperature. Finally, the recovery of titanium nano-powder, in the form of anatase, was performed by chemical precipitation at pH: 6 and T: 95 °C, using 10 wt% MgO pulp as neutralizing agent. The produced precipitates were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric/differential thermal analysis (TGA/DTA). Their morphological characteristics and microstructure were studied by scanning electron microscopy (SEM). High grade titanium white precipitate, in the form of anatase, was obtained. Iron concentration in the precipitate did not exceed 0.3%, whereas no aluminium was detected.

Successive uranium and thorium adsorption from Egyptian monazite by solvent impregnated foam

The present work deals with uranium and thorium recovery from the Egyptian monazite sulfate leach liquor using the extraction chromatography technique (solvent impregnated material), where tributylamine (TBA) and di-n-octylamine (DOA) solvents were impregnated onto foam uranium and thorium separate recovery. The calculated theoretical capacities of the latter solvents were about 1.4 gU/g foam and 1.6 gTh/g foam, respectively. The attained uranium and thorium adsorption efficiencies (using ion-exchange columnar technique) were about 75 and 70% of its theoretical capacities, respectively. Using 1 M NaCl–0.1 M H2SO4 and 2 M H2SO4 as eluent solutions for uranium and thorium from the loaded solvents impregnated foam gave 95.8 and 98.7% elution efficiencies, respectively.

Liquid–liquid extraction of tantalum and niobium by octanol from sulfate leach liquor

Extraction of tantalum and niobium from sulfate leach liquor of south Gabal El-A’urf polymineralized ore material was carried out by using octanol. The latter was contacted with the sulfate leach liquor prepared after fusing the highly mineralized ore sample with potassium bisulphate in a weight ratio of 1/3 at 650°C for 3h. From the McCabe–Thiele diagram, it is proposed that three extraction stages are sufficient to extract most of the Ta and Nb contents efficiently at the optimum extraction conditions of 100% octanol, and A/O ratio of 1/1.A highly pure product of Ta was achieved by keeping the pH of the leach liquor at 2.0 with contact time of 15min. With respect to Nb, pH of 0.7 and contact time of 5min were sufficient to extract most of the Nb contents efficiently. Finally, a technical flowsheet was constructed.

Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching

The research work presented in this paper focused on the recovery of cobalt from mixed Co–Mn hydroxide precipitates (obtained from sulphate leach liquors of nickel oxide ore), using ammonia–ammonium carbonate leaching. The characterization of the initial mixed hydroxide precipitates, as well as the corresponding leached residue was carried out by X-ray Diffraction, TG–DTA and Scanning Electron Microscopy. Cobalt and manganese precipitation was based on the statistical design and analysis of experiments, in order to determine the main effects and interactions of the precipitation factors, which were the equilibrium pH and the temperature. Co and Mn were precipitated as hydroxides at pH = 10.5 and T = 25 °C, using 5 M NaOH as a neutralizing agent, by 99.9% and 99.5%, respectively. The main mineralogical phases were, Mn 3O 4 (Hausmannite), γ-Mn 3O 4 and CoMn 2O 4, while Co(OH) 2 and Mn(OH) 2 (Pyrochroite) were also present as minor constituents. Cobalt and manganese separation was based on selective cobalt recovery by ammonia–ammonium carbonate leaching of the produced mixed hydroxide precipitate. The factors studied were the ammonia–ammonium carbonate concentration and the solid to liquid ratio. The cobalt recovery efficiency reached 93%. Mn 3O 4 (Hausmannite) was the main mineralogical phase of the leached residue, while MnCO 3 (Rhodochrosite) and Mn 2O 3 were also present. Small quantities of cobalt were also observed in the residue as CoMn 2O 4.

Processing of manganese nodule leach liquor for the separation of cobalt and nickel using PC 88A

The SO2-ammoniacal ammonium sulfate leach liquor generated by leaching of manganese nodules, after removal of minor quantities of iron and manganese, contained copper, nickel, cobalt, zinc and (NH4)2SO4. After extraction of copper from the leach liquor with LIX 84I, stripping of ammonia from the Cu-barren raffinate was carried out followed by precipitation of metal ions from the ammonia-stripped solution as sulfides. Leaching of the sulfide precipitate was carried out with H2SO4 to obtain a leach liquor containing 0.58 kg/m3 Cu, 2.67 kg/m3 Zn, 2.00 kg/m3 Co, 24.68 kg/m3 Ni and 10.0 kg/m3 (NH4)2SO4. After extraction of copper and zinc from the sulfate leach liquor with LIX 84I and D2EHPA, respectively, the solution was left with Co and Ni. Extraction of cobalt from the Cu- and Zn-free solution was carried out with 0.1 M PC88A and stripping of the cobalt-loaded organic was carried out with the cobalt-spent electrolyte (pH 1.4). Extraction of nickel from the cobalt-free solution was carried out with 90% neutral 1M NaPC88A followed by stripping of the nickel-loaded organic with 120 kg/m3 H2SO4 solution. Extraction of metal ions increased with increasing equilibrium pH and extractant concentration. The maximum separation factors, with respect to the pH and extractant concentration variation studies, were 3796.7 and 15350.0, respectively. The extracted species for the metal ions were CoA2⊙3HA and NiA2⊙5HA.

Extraction of niobium from sulfate leach liquor of Egyptian ore sample by triazoloquinazolinone

The refractory niobium bearing minerals, Samarskite, Fergusonite, Betafite and Pyrochlore of the ore sample obtained from Kadabora, Egypt, was subjected to sulfuric acid leaching using acid concentrations varied from 17.6 to 4.5 mol/L. The extraction of niobium from the sulfate leach liquors was done using the synthesized 8,9-dihydro[1,2,4]triazolo[1,5-a]quinazolin-6(7H)-one dissolved in methylene chloride. It has been found that extraction efficiency of 84% was achieved by contacting equal volumes of 0.32% extractant with 4.5 mol/L sulfate solution for 15 min. The stripping was performed by 0.5 mol/L HF with efficiency of 86.7%.

Separation of rare earth elements from sulfate leach liquor by heterocyclic nitrogen compound

Separation of rare earth elements by solvent extraction has actually been widely used in various fields from analytical chemistry to hydrometallurgy. A representative ore sample obtained from Kadabora Batholiths-Eastern Desert of Egypt, containing the multiple oxides rare earth minerals: Samarskite, Fergusonite, Betafite, and Pyrochlore, was subjected to sulfuric acid leaching. Different sets of equilibrium loading experiments were carried out on a bench scale for the extraction of rare earths (cerium and yttrium) from the sulfate leach liquor using 8,9-dihydro[1,2,4]triazolo[1,5-a]quinazolin-6(7H)-one {TQ} dissolved in methylene chloride. Stripping was carried out by 20% sodium hydroxide. A rare earth cake was produced by oxalic acid precipitation. Its purity reached 87.3%.

Development of process flow sheet for recovery of high pure cobalt from sulfate leach liquor of LIB industry waste: A mathematical model correlation to predict optimum operational conditions

The paper contains a new hydrometallurgical process flow sheet for the recovery of high pure cobalt sulfate solution/salt from waste LiCoO 2 cathodic active material generated from lithium ion battery (LIB) industry waste. Cobalt was recovered as cobalt sulfate from sulfate leach liquor by solvent extraction process using Cyanex 272 as an extractant. For quantitative extraction of pure cobalt from waste LiCoO 2 different process parameters such as concentration of Cyanex 272, O/A volume ratio, McCabe–Thiele extraction isotherm, scrubbing isotherm required were optimized. A mathematical model was developed to correlate metal extractability and Cyanex 272 concentrations and volume content. Optimum conditions required for quantitative extraction of pure cobalt sulfate/salt using Cyanex 272 were estimated by a proposed model. From predicted model, the mechanism for extraction and McCabe–Thiele isotherm for extraction were derived and compared with obtained results. A good agreement between proposed model and observed results was indicated. The cobalt loaded Cyanex 272 was stripped with sulfuric acid and 99.99% pure cobalt sulfate was obtained.

Bulk precipitation of nickel and cobalt from sulphate leach liquor by CaO pulp

The research work in the present paper determined the conditions at which nickel and cobalt can be recovered, as easily filterable precipitates, from leach liquors, which are produced by sulphuric acid leaching of nickel oxide ores at atmospheric pressure. Nickel and cobalt were precipitated as hydroxides at pH = 8·7, using CaO pulp as a neutralising agent, by 99·9 and 99·8% respectively. At this pH value manganese and magnesium, which were contained in the leach liquor, were precipitated, having a concentration of about 2·6 and 4·7% respectively in the final mixed precipitate. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the precipitation factors, which were the pH value at equilibrium and temperature. The characterisation of the produced mixed precipitate was carried out by X-ray diffraction, thermogravimetric/differential thermal analysis (TG/DTA), scanning electron microscopy and particle size distribution analyser. The main mineralogical phases of the precipitate after drying at 110°C were nickel hydroxide and bassanite (CaSO4.0·5H2O).

Separation of cobalt and nickel from ammoniacal sulphate solution using Cyanex 272

The SO 2-ammoniacal ammonium sulphate leach liquor of manganese nodule bearing iron, manganese, copper, nickel, cobalt and zinc was subjected to aeration/oxygenation to precipitate out the minor quantities of iron and manganese leaving the other metal values in tact. After extraction of copper from the Fe- and Mn-free leach liquor with LIX 84I, stripping of ammonia from the Cu-barren raffinate, precipitation of metal sulphides from the solution and leaching of the sulphide precipitates with H 2SO 4, the leach liquor bearing 0.58 kg/m 3 Cu, 2.67 kg/m 3 Zn, 2.012 kg/m 3 Co, 23.747 kg/m 3 Ni and 10.0 kg/m 3 (NH 4) 2SO 4 was obtained. After extraction of the remaining copper with LIX84I and zinc with D2EHPA from the leach liquor, it was left with Co, Ni and (NH 4) 2SO 4. Extraction of cobalt from the Cu–Zn-free solution was carried out using Cyanex 272 in kerosene followed by extraction of nickel from the cobalt-free solution with NaCyanex 272 in kerosene. Extraction of both cobalt and nickel increased with increasing equilibrium pH and extractant concentration. The species extracted into the organic phase were CoA 2 and NiA 2·HA. The highest separation factor for cobalt and nickel was obtained with 0.1 M Cyanex 272 at pH 5.46.