Extractable Mn Research Articles

Selective extraction and separation of Li, Co and Mn from leach liquor of discarded lithium ion batteries (LIBs)

Novel route has been developed to selectively extract lithium (Li), cobalt (Co) and manganese (Mn) from the leach liquor of discarded lithium ion batteries (LIBs) containing 1.4 g/L Cu, 1.1 g/L Ni, 11.9 g/L Co, 6.9 g/L Mn and 1.2 g/L Li. Initially, Cu and Ni were extracted by solvent extraction techniques using 10% LIX 84-IC at equilibrium (Eq.) pH 3 and 4.6, respectively. Subsequently, precipitation studies were carried out at different conditions such as pH, reaction time, precipitant concentration etc., to optimize the parameters for selective precipitation of Co from the leach liquor. Result showed that 99.2% Co was precipitated from the leach liquor (11.9 g/L Co, 6.9 g/L Mn and 1.2 g/L Li) after extraction of Cu and Ni in a range of pH 2.9 to 3.1 using un-diluted ammonium sulfide solution (10% v/v) as a precipitant at 30 °C, while only 0.89% Mn and 0.62% Li were co-precipitated. After Co precipitation, 98.9% Mn was extracted from the filtrate using 10% D2EHPA at equilibrium pH 4.5, and Li remained in raffinate. From the obtained purified solution, metals could be recovered either in a form of salt/metals by precipitation/ evaporation/ electrolysis method.

Promotion of manganese extraction and flue gas desulfurization with manganese ore by iron in the anodic solution of electrolytic manganese

In this work, Mn ore was mixed with the wastewater anode solution of electrolytic Mn (ASEM, instead of water) and utilized as the desulfurizer for simultaneous SO2 removal from flue gas and Mn extraction. The effects of Fe2+ and Fe3+ on Mn leaching and flue gas desulfurization were investigated. For MnO2 and Mn2O3 (mixed with ASEM), the introduction of Fe2+could simultaneously increase Mn extraction efficiency and flue gas desulfurization efficiency when MnO2 and Mn2O3 mixed with ASEM was used. Fe3+ addition could improve desulfurization efficiency obviously for MnCO3. Fe2+ could react with MnO2 and H+ to form Mn2+ and Fe3+. This reaction further improved Mn extraction and simultaneously decreased the acidity of ASEM, thus promoting SO2 removal. The introduced Fe3+ could react with SO2, when MnO2 was absent from the desulfurizer slurry. The resulting Fe2+ was then oxidized by O2 to form Fe3+, which underwent a Fe3+ ↔ Fe2+ cycle to promote flue gas desulfurization. Thus, the introduction of Fe ions, especially Fe2+, could promote simultaneous Mn leaching and flue gas desulfurization with Mn ore. This work provided not only a new way for effective SO2 removal from flue gas and Mn extraction but also for recycling ASEM.

Solvent Extraction of Zinc(II) and Manganese(II) with 5,10,15,20-Tetraphenyl -21H,23H-Porphine (TPP) through The Metal Exchange Reaction of LEAD(II)-TPP (Dept.M)

An investigation was carried out on the extraction of aqueous Zn(II) and Mn(π) with a hydrophobic porphyrin (5,10,15,20-tetraphenyl-21H,23H porphine, TPP) through a metal exchange reaction of Pb(π)-TPP. The distribution ratios (D) of these metals were found to be independent of the Pb(π) concentration in the aqueous phase. Pb(π) in the aqueous phase acted as a catalyst which promoted the metal-TPP complexation.

Selective extraction of valuable metals from spent EV power batteries using sulfation roasting and two stage leaching process

Selective extraction of valuable metals from spent electric vehicles (EVs) power batteries was undertaken by a sulfation roasting-water leaching-acidic leaching process. After sulfation roasting (acid-to-lithium molar ratio (nH2SO4:nLi) = 0.95, 550 °C and 3 h), the roasted products were subject to the 1st stage of water leaching. Under optimum conditions (30 °C, 2 h and liquid-to-solid (L/S) ratio of 4 mL/g), the extraction of Li and Mn reached 90% and 10%, whereas extractions of Co and Ni were negligible. The water leaching residues were then treated by the 2nd stage of acidic leaching (2 mol/L H2SO4 solution with L/S ratio of 5 mL/g at 60 °C for 2 h) which resulted in an additional 98% Ni, 97% Co and 90% Mn being leached from the residue. An investigation of the phase transformation mechanism indicated that the extraction behaviors of valuable metals might be induced by the different reduction pathways of the metals while controlling the roasting conditions. With roasting temperature <550 °C and roasting time <2 h, Li within the crystalline LiCoxNiyMn1-x-yO2 was de-intercalated and transformed to soluble Li2SO4, while Ni, Co and Mn in the LiCoxNiyMn1-x-yO2 decomposed to MnCo2O4 and Ni6MnO8 because of the co-existence of sulfuric acid and carbon reductant from the graphite anode material. When nH2SO4:nLi was higher than 1.2, Li was further converted to Li2Mn2(SO4)3. Under the conditions of roasting temperature > 550 °C and roasting time >2 h, MnCo2O4 and Ni6MnO8 were further reduced into low-valence states CoO and (NiO)0.75(MnO)0.25. These results provide a fundamental basis for the development of an efficient and selective extraction strategy for the recycling of valuable metals from spent EV power batteries.

Assessment of bioavailability and mobility of major and trace elements in agricultural soils collected in Port St Johns, Eastern Cape, South Africa using single extraction procedures and pseudo-total digestion.

The aim of this study was to evaluate the applicability of ultrasound assisted single extraction and pseudo-total digestion procedures to investigate the bioavailability and mobility of major and trace elements collected from agricultural soil collected in Mzimvubu farmstead area located in Port St Johns, Eastern Cape Province (South Africa). The potential metal availability was assessed using complexing agent (ethylenediaminetetraacetic acid (EDTA)), mild (cacium chloride (CaCl2) and ammonium nitrate (NH4NO3)), deionized water and acidic (CH3COOH) extractants with the assistance of ultrasound to evaluate mobility and bioavailability of metals. The ultrasound radiation was used to assist the single extraction of major and trace metals from agricultural soils as well shortening the extraction time. The pseudo-total metal content in agricultural soils was obtained using pseudo-total digestion employing aqua-regia. The results obtained using different solvents for single extraction procedures, revealed that higher extraction of Al (256-681mgkg-1), Fe (172-430mgkg-1) and Mn (35-136mgkg-1), was observed compared to other metals. Among the investigated solvents, deionized water, acetic acid and EDTA proved to be the most aggressive extractants. The geo-accumulation index (2-6) and contamination factor (3-6) demonstrated that Fe, Cr, Mn, Co, Cu, Ni, and Zn could pose significant environmental contamination risk. Based on the results obtained, it can be concluded that the high levels of some studied metals was due to anthropogenic activities. The online version contains supplementary material available at 10.1007/s40201-020-00581-x.

Patates (Solanum tuberosum L.) Yetiştirilen Toprakların Verimlilik Durumu ve Potansiyel Besin Maddesi Sorunlarının Belirlenmesi

In this research, it was aimed to determine the fertility status of potato (Solanum tuberosum L.) cultivated soils by soil analysis and to reveal potential plant nutrient problems. For this purpose, 109 soil samples were taken from agricultural land with potatoes in the provinces located in the Black Sea region of Turkey Ordu and Trabzon. Some physical (texture) and chemical soil reaction (pH), electrical conductivity (EC), lime, organic matter, total nitrogen (N), available phosphorus (P), extractable potassium (K), calcium (Ca), magnesium (Mg), boron (B), iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn) properties were determined in the samples. According to the results of the research; It has been determined that predominantly (95.42%) of the soils are loamy (medium textured) soils and do not pose a problem in terms of salinity, the ratio of soils in the ideal pH range for potatoes is approximately 42.2%. Most of potato soils are less calcareous; Organic matter at 51.37%, total N at 86.24%, obtainable P at 53.22% and extractable K at 56.88% are sufficient and / or high. In research soils where extractable Ca and Mg levels are mostly at good levels; 45.87% of extractable B, 35.78% of extractable Zn and 11.93% of extractable Mn is very low / low level. Extractable Fe and Cu contents of potato cultivation soils were found to be high/sufficient. In the areas where potato cultivation is carried out in Ordu and Trabzon provinces, fertilization programs should be arranged for soil analysis and fertilization recommendations should be made by taking into account the leaf analysis.

Комплексная электротермическая переработка пылей производства ферромарганца

This study investigates the feasibility of recovering ferroalloy from dust produced during the smelting of ferrosilicon manganese at the Taraz Metallurgical Plant LLP. Typically, the dust comprises (%wt.): MnO - 53.3; SiO 2 - 24.0; MgO - 5.4; CaO - 9.6; Al 2 O 3 - 3.8; Fe 2 O 3 - 1.5; ZnO - 1.8; PbO - 0.6. To determine the optimal process parameters, thermodynamic modelling was deployed using the HSC-5.1 software package to analyse results from a second-order rotatable experimental design (a Box-Hunter design). Dust was pelletised in a bowl granulator followed by electric smelting in combination with coke and steel chips in a single-electrode arc furnace with a power of up to 15 kV×A; the steel chips were added as a source of iron. The study shows that at equilibrium in the presence of iron, components of the dust reacted with carbon forming manganese silicides and FeSi at temperatures above 1300 º C and 1400 º C, respectively. By increasing the amount of carbon in the charge from 14 to 30% by weight of dust, the extraction of silicon and manganese into the alloy is increased to 44.7 and 92%, respectively, at a temperature of 1800 º C. The MnC22 and MnC25 grades of ferrosilicon manganese are obtained when the amount of carbon is equal to 20-30% by weight of dust, allowing 56.4-79.3% of Si and 67.7-84.3% of Mn to be extracted into the alloy over the temperature range of 1600-1800ºC. The time taken for electric smelting of the dust is reduced by 16-18% by increasing the amount of both carbon from 18 to 36% and steel chips from 2 to 6% which resulted in a corresponding increase in the extraction of Si and Mn into the alloy from 20.9 to 60% and 68.3-82.1%, respectively. Thermodynamic modelling of the system at equilibrium was deployed to determine the temperature effect on the distribution of silicon, manganese, zinc and lead in the "dust components - carbon - iron" system, the extraction efficiency of silicon, manganese and iron into ferroalloy, and the content of these metals in the alloy. The electric smelting produces grade MnC22 of ferrosilicon manganese from a combination of granular dust, 30% coke and 6% steel chips resulting in an alloy containing silicon and manganese at 20.5 and 65.8%, respectively.

Effectiveness of innovative organic amendments in acid soils depends on their ability to supply P and alleviate Al and Mn toxicity in plants

Soil acidity with high Al3+ and Mn2+ is one of the major constraints to global food production. Lime is effective to increase soil pH, but it is not always readily available and can be expensive. This study aimed to evaluate the effectiveness of organic amendments that may be viable for treating soil acidity. Thirteen organic amendments (including manures, composts, biochars and plant residues) were added (1% soil weight) to two acid soils differing in pH buffer capacity, and Al3+ and Mn2+concentrations. They included a Dermosol with a pHCaCl2 of 4.1 and a Sodosol with pHCaCl2 of 4.0. Four inorganic amendments (lime, dolomite, gypsum, and KH2PO4) were included for comparison. The Al-sensitive wheat ES8 was grown for 49 days. Organic amendments (manures, composts, biosolids and biochars) outperformed or matched the shoot biomass response to lime in both soils. The most effective treatments were poultry litter, poultry-litter-biochar and biosolids, which increased shoot biomass by 128%, 158% and 95% for the Dermosol and by 58%, 43% and 33% for the Sodosol, respectively, compared with the limed controls. Organic amendments increased soil pHCaCl2 by up to 0.32 and 0.62 units and Olsen-P concentration by 16.1 μg g−1 and 30.7 μg g−1 for the Dermosol and Sodosol, respectively. Shoot biomass correlated positively with Olsen-P (R2 = 0.85) but negatively with concentrations of extractable Mn (R2 = 0.62) and Al (R2 = 0.58). Organic amendments were effective ameliorants for soil acidity. Their effectiveness depends on their ability to supply nutrients, primarily phosphorus, and to overcome Al3+ and Mn2+ toxicities.

Heavy metals removal from sewage sludge with mixed chelators of N, N-bis(carboxymethyl) glutamic acid and citric acid

ABSTRACT The mixed chelators (MC) of N, N-bis(carboxymethyl) glutamic acid (GLDA) and citric acid (CA), which were biodegradable chelating ligand, were employed to remove heavy metals from sewage sludge. The extraction of Cd, Cu, Zn, Mn, and Cr from sludge was studied under different experimental conditions. Results showed that the removal efficiencies of heavy metals from both sludges were the highest with MC of GLDA and CA at the molar ratio of 1:5. For the sludge of plant A, the extraction efficiencies increased with increasing contact time, but only slowly increase was observed after 24 h. However, for the sludge of plant B, the removal efficiencies were significantly decreased after 16 h, and sharply decreased after 24 h. The removal efficiencies of heavy metals decreased with the increase of the solution pH, while they increased with the increase of the solution concentration. For the sludge of plant A, single washing with 200 mmol·L−1 MC might be favourable to remove heavy metals. However, for the sludge of plant B, duplicate washing with 100 mmol·L−1 MC could remove much more heavy metals. The concentration of Cu in sludge of plant B decreased from 695.79–139.16 mg·kg−1, which was conformed to the standard (GB 4284-2018). These results suggested that MC may be useful and environmentally friendly chelators in the removal of heavy metals from sewage sludge.

Applications of Gypsum and Ammonium Sulfate Change Soil Chemical Properties of a Salt-Affected Agricultural Soil

Irrigation water with high electrical conductivity (EC) compromises the sustainability of agricultural soils. Calcium sulfate (CS) or gypsum is commonly used on removal of soluble ions such as sodium (Na), however, large applications of CS can affect soil pH, EC, and nutrient availability to plants. The objective of this study was to investigate the effects of CS and ammonium sulfate (AS) rates on the soil pH, EC, and exchangeable cations in a salt-affected agricultural soil. Samples from the 0-20 cm soil depth layer were collected from an agricultural soil reported to have low potato yield due to high EC irrigation water. Soil was incubated with rates ranging from 0 to 4000 kg ha-1 of CS and 0 to 600 kg ha-1 of nitrogen (N) using AS. The treated soil was incubated for 60 d at 25 &amp;ordm;C and moisture was maintained at 60% of soil field capacity. After incubation, the soil was analyzed for pH, EC, Na, manganese (Mn), and zinc (Zn). Increasing rates of CS resulted in a small decrease in soil pH and a significant linear increase in soil EC, while the application of AS linearly reduced the soil pH and quadratically increased soil EC. The application rate of 200 kg ha-1 of N as AS resulted in a decrease of soil pH from 5.9 to 5.2, while the EC increased from 1.3 to 3.0 dS m-1. Extractable Na increased linearly with the application of AS due to its effect on the soil pH. The soil extractable Mn and Zn were not affected by the application of CS. Applications of AS resulted in a linear increase in soil extractable Mn and Zn concentrations, respectively. Results from this incubation study suggest that the use of large rates of CS for consecutive years may further impair soil conditions for cropping in areas with high EC in the irrigation water.

A Novel Circulation Process to Effectively Produce Electrolytic Manganese Metal (EMM) with Low-Grade Manganese Oxide Ores and High-Sulfur Manganese Ores

A novel circulation process of electrolytic manganese metal (EMM) production with low-grade manganese oxide ores (LGMO) and high-sulfur manganese ores (HSMO) was studied and developed. The unit operations mainly include dissolution of LGMO, purification of leach liquor and electrolysis for EMM preparation. Based on the theoretical thermodynamic analysis, a reductive roasting-acid leaching process for utilizing LGMO using HSMO as reductant was investigated. The leaching efficiency of Mn and Fe could get to 97.30% and 17.50% with conditions set as following, which have all been verified through a series of experiments: the material ratio of 1.67:1 (mass ratio of HSMO to LGMO, w/w), roasting temperature of 600 °C for 60 min, L/S ratio of 5:1, stirring speed of 150 rpm, sulfuric acid concentration of 1.0 mol/L and the leaching temperature of 60 °C for 35 min. Meanwhile, the reduction roasting-acid leaching process applies to the Mn extraction for assorted manganese dioxide ores in general. Furthermore, the leach liquor was purified in two steps, and following a scale-up electrolysis process was implemented to prepare EMM from the purified liquors. The uniform and dense α-Mn with bcc crystal structure, meeting the requirement of metallurgical industry standard (YB/T 051-2003), could be stably produced in 9-day incessant ongoing test.

Experiment-based geochemical modeling of Arsenic(V) and Arsenic(III) adsorption onto aquifer sediments from an inland basin

Natural occurrence of groundwater arsenic (As) exists in many aquifers and threatens the health of hundreds of millions of people. Adsorption of As is critical to its distribution in aquifer groundwater, as it can lower dissolved As concentrations and provide a source for As mobilization. However, little is known about As adsorption onto aquifer sediments in inland basins. To fill this gap, we investigated As(V) and As(III) adsorption onto a brown sediment hosting low-As groundwater and two gray sediments hosting high-As groundwater sampled from an approximate flow path of the Hetao Basin, China. Those three sediments had total Fe contents of around 1.3% and As contents of around 9.0 μg/g. Arsenic(III) adsorption were kinetically faster than As(V) adsorption on the sediments. The characteristics of As(V) and As(III) adsorption both exhibited nonlinear isotherms, with adsorption decreasing with increases in pH from around 7 to 9 (typical ambient groundwater pH of inland basins). Generally, As(V) adsorption was greater than As(III) adsorption at pH < 7.5, whereas the opposite was true at pH > 7.5. Phosphate competed more strongly with As(V) adsorption than As(III) adsorption, while HCO3 competed more strongly with As(III) adsorption. Aqueous As(III) was oxidized to As(V) by interaction with the brown sediment, mainly due to its high content of extractable Mn(IV) oxides. Arsenic adsorption onto the sediments was primarily controlled by the content and crystallinity of their Fe(III) oxides. The brown sediment showed weaker affinity for As(V) and As(III) than the gray sediments, possibly due to the better crystallinity of the Fe(III) oxides in the brown sediment. In the two gray sediments containing Fe(III) oxides with similar crystallinities, the As adsorption capacity was related to the content of Fe(III) oxides. Geochemical models were developed to quantitatively simulate As(V) and As(III) adsorption onto aquifer sediments. Experimental data were approximated well by these models, indicating that As(V) adsorption decreases at elevated pH and PO4 concentration, while As(III) desorption is favored at high pH and concentrations of HCO3 and PO4. According to the models, the extent and kinetics of As(III) oxidation are controlled by the number of free oxidation sites in Mn(IV) oxides, pH, and As(III) concentration. This study suggests that the characteristics of As adsorption are highly dependent on the mineral phases existing in the sediments, which must be fully understood to quantify the reactive transport of groundwater As in aquifer systems.

Ultrasonic-assisted supramolecular solvent liquid-liquid microextraction for determination of manganese and zinc at trace levels in vegetables: Experimental and theoretical studies

We present rapid, inexpensive and selective ultrasonic-assisted (UA) supramolecular solvent (Ss) liquid-liquid microextraction (LLME) method for the determination of Mn(II) and Zn(II) ions in vegetable samples. The presented method implies using of flame atomic absorption spectrometer (FAAS). We tried quercetin as a ligand to for Mn(II) and Zn(II) ions and observed complexation process in the solvent with pH = 8.0. The extraction of the obtained complexes was achieved by supramolecular solvent. This solvent was prepared with 1-decanol reverse micelles dispersed in tetrahydrofuran (THF)–water. Some experimental parameters (pH, ligand amount, THF volume, 1-decanol concentration, sonication time and matrix effect) were optimized to provide the most efficient extraction of Mn(II) and Zn(II) ions. Under optimized conditions, the working range, detection limit and sensitivity factor for Mn(II) ion were equal to 0.1–200 ng mL−1, 0.035 ng mL−1 and 107, respectively. The same parameters measured for Zn(II) ion were equal to 2–500 ng mL−1, 0.6 ng mL−1 and 88, respectively. Presented UA-Ss-LLME method was successfully applied for the extraction of Mn(II) and Zn(II) from certified vegetable samples prepared by microwave digestion. We also applied the density functional theory (DFT) to clarify atomistic details of interaction of Mn(II) and Zn(II) ions with quercetin. We computed structures, energies, electronic properties and quantum descriptors of metal ions-quercetin complexes. Calculated results are in reasonable agreement with the experimentally obtained data.

Optimization of process conditions for maximum metal recovery from spent zinc‐manganese batteries: Illustration of statistical based automated neural network approach

AbstractRecovery of the vital metals from spent batteries using bioleaching is one of the commonly used method for recycling of spent batteries. In this study, a statistical based automated neural network approach is proposed for determination of optimum input parameters values in bioleaching of zinc‐manganese batteries. Experiments are performed to measure the recovery of zinc and manganese based on the input parameters such as energy substrates concentration, pH control of bioleaching media, incubating temperature, and pulp density. It was found that the proposed model based metal extraction models precisely estimated the yields of zinc and manganese with higher values of coefficient of determination of 0.94. Based on global sensitivity analysis, it was found that for the extraction of zinc, the most contributing parameters are pulp density and pH while for extraction of Mn the most contributing parameters are pulp density and incubating temperature. The optimum parameter values for maximum recovery of zinc and maximum recovery of manganese are determined using optimization method of simulated annealing. The optimum parameter values obtained for maximum recovery of Zn metal are as substrates concentration 32 g/L, pH 1.9 to 2.0, incubating temperature 30°C, pulp density 10%, and substrates concentration 32 g/L, pH 2.0, incubating temperature 35°C, pulp density 8% for maximum recovery of Mn.

Magnetophoretic mole-ratio method in solvent extraction systems

The magnetophoretic mole-ratio method was applied to the solvent extraction systems of paramagnetic metal ions with bis(2-ethylhexyl)hydrogen phosphate in 2-fluorotoluene. In the extraction of Mn(II), Co(II), Ni(II), Tb(III) and Dy(III), the compositions of the extracted metal complexes were determined from the measurements of the magnetophoretic velocity of a single droplet as a function of the mole ratio of the metal ion and the ligand.

Extraction of Fe(III), Zn(II), and Mn(II) Using a System with a Green Solvent for Trioctylmethylammonium Thiocyanate

An environmentally friendly solvent, namely, polypropylene glycol 425, has been proposed for the extraction of metal ions from chloride solutions using trioctylmethylammonium thiocyanate. The quantitative characteristics of the extraction of Fe(III), Zn(II), and Mn(II) using trioctylmethylammonium thiocyanate in the polypropylene glycol 425–NaCl–H2O system have been found. For extracting Fe(III), Zn(II), and Mn(II), it has been shown that the patterns of the extraction of metal ions remain unchanged and the replacement of the solvent does not lead to the loss of extraction capacity for trioctylmethylammonium thiocyanate. The mechanism of the extraction of the metal ions under study has been determined. The proposed extraction system can be used to purify Mn(II) from Fe(III) and Zn(II).

Identification of a selective manganese ionophore that enables nonlethal quantification of cellular manganese

Available assays for measuring cellular manganese (Mn) levels require cell lysis, restricting longitudinal experiments and multiplexed outcome measures. Conducting a screen of small molecules known to alter cellular Mn levels, we report here that one of these chemicals induces rapid Mn efflux. We describe this activity and the development and implementation of an assay centered on this small molecule, named manganese-extracting small molecule (MESM). Using inductively-coupled plasma-MS, we validated that this assay, termed here "manganese-extracting small molecule estimation route" (MESMER), can accurately assess Mn in mammalian cells. Furthermore, we found evidence that MESM acts as a Mn-selective ionophore, and we observed that it has increased rates of Mn membrane transport, reduced cytotoxicity, and increased selectivity for Mn over calcium compared with two established Mn ionophores, calcimycin (A23187) and ionomycin. Finally, we applied MESMER to test whether prior Mn exposures subsequently affect cellular Mn levels. We found that cells receiving continuous, elevated extracellular Mn accumulate less Mn than cells receiving equally-elevated Mn for the first time for 24 h, indicating a compensatory cellular homeostatic response. Use of the MESMER assay versus a comparable detergent lysis-based assay, cellular Fura-2 Mn extraction assay, reduced the number of cells and materials required for performing a similar but cell lethality-based experiment to 25% of the normally required sample size. We conclude that MESMER can accurately quantify cellular Mn levels in two independent cells lines through an ionophore-based mechanism, maintaining cell viability and enabling longitudinal assessment within the same cultures.

Extraction of Cu, Fe, Mn, and Ni from Margarine Samples Using Extraction Induced by Emulsion Breaking Procedure Prior to Graphite Furnace Atomic Absorption Spectrometry and Comparison of Results to Provisional Tolerable Daily Intake Values.

The emulsion induced by emulsion breaking (EIEB) procedure was previously reported for the extraction of copper, iron, manganese, and nickel from liquid oil samples such as vegetable oil. To optimize the EIEB procedure for determination of copper, iron, manganese, and nickel in solid oil (margarine) samples by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The extraction procedure uses a surfactant in nitric acid to form an emulsion followed by heating to break the emulsion. Optimization included variation of the test portion size, the type and concentration of the surfactant, the concentration of nitric acid in the aqueous solution, the emulsion agitation time, heating temperature, and the time required to break the emulsion. Mean element concentrations of 11 margarine samples were in the following ranges: Cu 0.031-0.131 µg/g, Fe 5.7-24.9 µg/g, Mn 0.542-1.11 µg/g, and Ni 0.108-0.134 µg/g. Under the optimized extraction conditions, the detection limits (µg/kg) were 4.8, 13, 1.5, and 23 for Cu, Fe, Mn, and Ni, respectively. The accuracy of the extraction procedure was determined by comparison to commonly used microwave digestion procedure. The EIEB results were not statistically different from the microwave digestion results when analyzed by GFAAS as determined by the statistical tests. The EIEB procedure was shown to be equivalent to the commonly used microwave digestion procedure for extraction of analytes from margarine samples. The optimized EIEB extraction procedure is simple, rapid, low cost, and environmentally friendly. It has improved detection limits and allows calibration with aqueous standards.

Physicochemical assessment of a waste rock dump in the hidden valley gold mine: a case study for bioremediation in Papua New Guinea

Deforestation, environmental degradation, and pollution from the mining activities are much studied global environmental concerns. The effect of waste rock dumping from mining activity on the forest soil characters and suitability of waste rock dumps for bioremediation is least explored. Such information is necessary for making rehabilitation decisions. In this study, soil physicochemical characteristics and some index polluting elements were assessed in the waste rock dump stations (n = 16) and adjacent natural forest stations (n = 14) in a gold mine situated in the Morobe province of Papua New Guinea. Results indicated that the waste rock dump was poorer in organic C, but rich in available P, exchangeable Ca and Mg contents, and extractable Cu and Mn. Comparison of established diagnostic norms for potential sufficiency and toxicity of nutrient elements with those observed in the study indicated that organic carbon content, exchangeable K, Ca and Mg as well as, extractable Cu content was at an insufficient level in a majority of stations of waste rock dump for arable crops. Besides, the mean Cd content of waste rock dump was 15-times greater than that in forest stations while that of extractable Mn was 400-fold higher. Findings of the study warranted the use of adaptable and hardy forest species instead of arable crops for safe bioremediation of waste rock dump.

Reducing-Effect of Chloride for the Dissolution of Black Copper

Oxidized black copper ores are known for their difficulty in dissolving their components of interest through conventional methods. This is due to its non-crystalline and amorphous structure. Among these minerals, copper pitch and copper wad are of great interest because of their considerable concentrations of copper and manganese. Currently, these minerals are not incorporated into the extraction circuits or left untreated, whether in stock, leach pads, or waste. For the recovery of its main elements of interest (Cu and Mn), it is necessary to use reducing agents that dissolve the present MnO2, while allowing the recovery of Cu. In this research, the results for the dissolution of Mn and Cu from a black copper mineral are exposed, evaluating the reducing effect of NaCl for MnO2 through pre-treatment of agglomerate and curing, and subsequently leaching in standard condition with the use of a reducing agent (Fe2+). High concentrations of chloride in the agglomerate process and prolonged curing times would favor the reduction of MnO2, increasing the dissolution of Mn, while the addition of NaCl did not benefit Cu extractions. Under standard conditions, low Mn extractions were obtained, while in an acid-reducing medium, a significant dissolution of MnO2 was achieved, which supports the removal of Cu.