Ore Solutions Research Articles

Instability behavior of bubble supported organic liquid membrane in extraction of low-concentration rare earths from in-situ leaching solutions of ion-adsorption ores

Gas bubble supported organic extractant liquid membrane exhibits a promising potential in enhanced extraction and separation of low-concentration rare earths from the in-situ leaching solutions of ion-adsorption ores. However, instability of organic liquid membrane on the surface of gas bubbles might result in dissolution loss of organic extractant in the flowing-out aqueous raffinates and bring serious organic pollution if the raffinates are recycled for re-leaching of rare-earth ores. The present work focuses on the mechanism of the instability of organic extractant P507 liquid membrane on the surface of bubbles during rare-earth extraction. Various effects, including volume flow rate of aqueous feed solution, initial aqueous pHs and concentrations of co-existing impurity ions, saponification degree of P507 and pre-loaded concentration of rare earths in organic phase, on the stability of organic liquid membrane are discussed. Experimental results reveal that the stability of organic liquid membrane depends on three kinds of forces exerting on the surface of bubbles, i.e., the shear force Fs, the interface tension Ft and the dispersion force Fd. The occurrence of Ft and Fd are benefit for the stability, but Fs is not. The competition of the two component forces of Fs respectively with Ft and Fd will result in instability of organic liquid membrane and an increase in the concentration of total organic phosphorus in the flowing-out raffinates. The present work provides a theoretical basis about how to control the stability of organic extractant liquid membrane on the surface of gas bubble. Based on the suggested new technique by bubble supported organic liquid membrane extraction, a green and environmentally friendly strategy is suggested for replacing the traditional ammonium bicarbonate precipitation to extract low-concentration rare earths from in-situ leaching solutions of ion-adsorption ores.

Removal of thorium and uranium from leach solutions of ion-adsorption rare earth ores by solvent extraction with Cextrant 230

The removal of radioactive elements thorium and uranium from the leach solution of ion-adsorption rare earth ores by aluminum sulfate was studied using di(2-ethylhexyl) [N-(2-ethylhexyl)aminomethyl] phosphonate (Cextrant 230, L).The extraction of thorium, uranium, rare earths, aluminum and other elements was investigated in detail, especially for uranium. The extracted complex was inferred to be UO2SO4·2L, in which phosphoryl oxygen atom of Cextrant 230 was involved in the coordination of UO22+. The thermodynamic parameters, such as ΔH, ΔG, ΔS were calculated. The negative value of ΔH suggests that the extraction of U(VI) by Cextrant 230 is an exothermic process. The extraction capacities of 5% (v/v) Cextrant 230 for Th(IV) and U(VI) were determined to be 4.08 g/L and 6.16 g/L, respectively. The loaded U(VI) and Th(IV) can be stripped using common inorganic acids. By just one stage extraction, the concentrations of thorium and uranium in the simulated leaching solution decreased obviously from 2.73 mg/L and 0.82 mg/L to <0.1 mg/L.

Rapid capture of trace precious metals by amyloid-like protein membrane with high adsorption capacity and selectivity

A protein-based bilayer membrane can selectively sequester precious metal ions from leaching solutions of ores and WEEE, and exhibits an adsorption capacity for gold of 1034.4 mg g−1.

Modeling the Kinetics of Saline Minerals Dissolution in Dombrovsky Quarry at the Kalush-Golinsky Potassium Salts Deposit

The article deals with the peculiarities of the chemical composition formation of brines in the Dombrovsky quarry, primarily due to the dissolution of potash ore minerals and host rocks in water coming from the pebble horizon and atmospheric precipitation. The solubility of the ore body minerals has been studied, and it ranges from 333 to 502 g∙dm–3. The boundary conditions for the formation of a saturated salt solution were determined. The estimated concentration of saturated potash ore solution under normal conditions is 426 g∙dm–3. The mechanism of dissolution is considered from the standpoint of D.I. Mendeleev's chemical theory of solutions. The temporary dynamics of minerals dissolution of the ore body is studied experimentally. The parameters of kinetic-diffusion process are calculated. The rate of the dissolution process, which occurs in the kinetic region, significantly exceeds the rate of concentration diffusion of hydrated ions: from 5 to 400 times depending on the mineral composition of salts. Theoretically from the point of view of multistage process kinetics and experimentally in laboratory conditions it is proved that the process that determines the formation of the chemical composition of brines (the slowest stage) is the concentration diffusion of hydrated ions Na+, K+, Cl–. They enter the liquid phase due to the minerals dissolution of the ore body and host rocks of soil and sides of the quarry, in the direction of overcoming the concentration difference - from the lower layers of the brine to its surface. This conclusion is confirmed by the ratio of weight coefficients а1 and а2. The contribution of the process of the main minerals dissolution of the ore body to the chemical composition formation of the solution is significantly less than the concentration diffusion process.

Composition of minerals from the skarn deposits Väster Silvberg (Sweden) and Tumurtijn-ovoo (Mongolia): Indications of different element supply in submarine hydrothermal-sedimentary ore genesis

We compare chemical compositions of the main minerals from two submarine exhalative sulfide-bearing manganiferous iron-ore deposits, i.e.Väster Silvberg in Sweden (VS) and Tumurtijn-ovoo in Mongolia (TO). At VS, much Al is present in garnet (Fe-spessartine) and biotite, whereas at TO the ore-associated garnets are Al-poor (andradite) and minerals not associated with ore minerals are Al-rich (grossular, vesuvianite). The low-Al of andradite at TO agrees with the low-Al of volcanic ore-forming solutions from the modern oceans. The Al-rich minerals at both TO and VS indicate the assimilation of Al-rich volcanic material in both deposits. The elements Ca and Mg show opposite distributions: at VS much Mg is incorporated in kutnahorite, knebelite, biotite, and Mn-actinolite, Mg-rich minerals are absent at TO; in contrast, the garnets at TO contain more Ca than the garnets at VS. We explain these differences by the different carbonate minerals constituting the accompanying carbonate rocks at the two deposits, namely calcite and dolomite at VS, and only calcite at TO. These minerals primarily resulted from evaporation of seawater. Also during times, when they did not form massive carbonate rocks, they settled to the seafloor in minor amounts. There, they were partially combined with volcaniclastic Al-rich input. When the ore solutions spread on the seafloor and percolated through the bottomset they mixed with the seafloor mud producing ore-bearing sediments as precursors of Al-rich, Mg-rich skarn ores at VS and Al-poor, Mg-poor, Ca-rich skarn ores at TO. As a result, three sources supplied elements for the skarn-ore formation at the investigated deposits: volcanic ore solutions, Al-rich volcanic material and evaporitic carbonates of different composition.

Scandium adsorption from sulfuric-chloride solutions with activated carbons

The study covers scandium adsorption in batch conditions by VSK, DAS and PFT activated carbon grades (Russia) of different origin (сoconut shell, аnthracite, thermoset waste, respectively) from sulfuric acid-chloride solutions (pH = 2) simulating the composition of the underground leaching solutions of polymetallic ores. It was found that scandium adsorption by DAS and VSK carbons proceeds with the highest distribution coefficients (133 and 45.8 cm3/g, respectively). Isotherms of scandium adsorption with these carbons are linear and described by the Henry equation with constants 133 ± 21 and 46 ± 7 cm3/g, respectively. A limited solution volume method was used to obtain the integral kinetic curves of scandium adsorption. Their linearization according to the kinetic models of the pseudo-first, pseudo-second order, the Elovich model and the Weber–Morris intra-particle diffusion model indicates that the kinetics of scandium adsorption with VSK carbon having a higher correlation coefficient (0.999) is described using the pseudo-second order model. Description of the kinetic data obtained during the adsorption of scandium with DAS carbon showed that for all the models used the correlation coefficient is low (&lt;0.939), while the highest value is observed when using the intra-particle diffusion model. It was suggested that the scandium adsorption process occurs in the mixed diffusion region. The possibility of scandium elution from VSK and DAS carbons with sodium carbonate solution (10 %) was studied in batch conditions, where the degree of scandium desorption in two stages of elution was 84.0 and 90.4 %, respectively.

Enrichment of rare earths in magnesium sulfate leach solutions of ion-absorbed ores by extraction-precipitation

Magnesium sulfate (MgSO4), a leaching agent for ion-absorption rare earth (RE) ores, can reduce the production of ammonia nitrogen wastewater and supply magnesium (Mg) for soil. Three novel solid extractants, i.e., 2,2′-(1,4-phenylenebis(oxy))dioctanoic acid (PPBOA), 2,2′-(1,2-phenylenebis(oxy))dioctanoic acid (OPBOA) and 2,2′-(1,3-phenylenebis(oxy))dioctanoic acid (MPBOA) were synthesized and used to enrich RE by extraction-precipitation strategy, which showed better selectivity and faster equilibrium. The precipitation rates of PPBOA, OPBOA and MPBOA on RE could reach 95.1%, 93.5% and 96.7% at the large liquid/solid phase ratio (450/1). Meanwhile, the purities of RE in the stripping solutions reached 96.1 wt%, 94.1 wt% and 96.2 wt%. Chemical oxygen demand (COD) values of raffinates from OPBOA and MPBOA were 56 mg/L and 69 mg/L, being lower than that of China national emission standard (100 mg/L). The concentration of enriched RE solution by MPBOA was 238.0 g/L, solid extractant and MgSO4 raffinate could be recycled.

Recovery of rare earths from phosphate ores through supported liquid membrane using N,N,N′,N′-tetraoctyl diglycol amide

The rare earth elements (REEs) such as lanthanum, cerium, praseodymium, and neodymium were successfully recovered from the leaching solutions of phosphate ores through a Supported Liquid Membrane (SLM). The extractant, N,N,N′,N′-tetraoctyl diglycol amide (TODGA), was employed as novel carrier for REEs transport. Permeation rate was observed to be significantly fast and more than 95.0% of REE3+ was collected using 0.10 M TODGA as carrier. The mechanism of transport was investigated by studying various parameters, such as feed HNO3 and NaNO3 concentration, TODGA concentration in the membrane and the stirring rate etc. In view of practical application to the collection of REEs from the phosphate ore leaching liquor, the stability of the membrane was also studied. The result shows that the membrane was highly selective for lanthanides. This research would provide a new environmentally friendly and new sustainable green approach for the recovery of REE with SLM technique.

Comparative study of solvent extraction of molybdenum by various extractants

Solvent extraction of molybdenum from various acid media by Alamine 336, Aliquat 336, TOPO, and DEHPA in kerosene was studied. The extraction efficiency of molybdenum by diisobutyl ketone (DIBK), the effects of various parameters like diluents, mineral acids, extractant concentration, and applications of these extractants on molybdenum extraction contained in the uranium-bearing ore solutions were investigated. DIBK used as solvent can indeed extract the molybdenum without adding any extractants in the range of 20-50 mg/L. Molybdenum was extracted by Aliquat 336 in all mineral acids at more than 90%. On the basis of slope analysis, the compositions of the extracted species were expressed by R$_{3}$NH$^{+}$.${{HMoO}}_{{4}}^{{-}}$, MoO$_{2}$(NO$_{3})_{2}$(DEHPA)$_{2}$, and H$_{2}$MoO$_{4}$.TOPO. Extraction from synthetic solutions showed that molybdenum was extracted by TOPO, Aliquat 336, and Alamine 336 at 99% until [Mo] $=$ 5 g/L. For DEHPA the percentage of extraction was decreased from [Mo] $=$ 2 g/L. The application of these extractants for the extraction efficiency of molybdenum contained in uranium-bearing solutions showed that TOPO, Aliquat 336, and Alamine 336 extracted the molybdenum beyond 60% until the fifth contact. As for DEHPA, it was extracted effectively only at the first contact by 66%.

Evidence for vapor transport of the base and precious metals in the Panormos Bay Ag-Au-Te deposit, Tinos Island, Cyclades

Tellurium-bearing, base and precious metal sulfides from the Au-Ag-Te mineralization at Panormos Bay, Tinos Island, Cyclades, preceded and followed the main telluride-forming event. Ore petrography and chemistry of the sulfides suggest that they have precipitated under supersaturation conditions, i.e., grown with hopper habit, enriched in Zn, Fe, Ag, Cd and Pb, and Te in stage II, III and VI sulfides and incorporate nanoparticles with variable Ag/(Pb + Ag + Cu + Fe + Zn)% values. The noble gas, i.e., He, Ar and Ne isotope compositions obtained from these sulfides form two distinct populations, the “Liquids” and “Vapors”. All these features constitute overwhelming evidence that favors vapor transport for the base and precious metals by the vapor-like Panormos ore fluid.The widespread occurrence of CO2-effervescence and boiling at the Panormos Bay Au-Ag-Te ores provoked degassing of the CO2, HCl(g), H2S(g), H2Te(g), Te2(g), light noble gas isotopes (3He, 36Ar, 20Ne, and 21Ne), base- and precious-bearing laden vapors from the mineralizing fluid and transported a fraction of the base and precious metals to vapor. Geochemical simulation suggests that supersaturation in the vapor phase, rapid up-vapor transport, and subsequent condensation in the Panormos Bay ore solution of H2Te(g), Te2(g), and base and precious-bearing vapors led to the precipitation of sulfide (stages II, III and VI) and telluride (stage V) mineral assemblages.

Improvement Trail on Recovery of Cadmium from Low-Grade Sulfide Ore Through Bioleaching Using Acidithiobacillus ferrooxidans

Recovery of cadmium from its low-grade sulfide ore (synthetic solutions) adopting bioleaching process involving the microbe, Acidithiobacillus ferrooxidans, under aerobic conditions is taken up. Leaching rate of cadmium from the ore solutions is examined at various initial loadings of ore solutions, bacterial densities and different pH units and at various temperatures. Bioleaching of cadmium was found to increase with an increase in time as well as solid loading but decrease with an increase in bacterial loading as well pH. However, in the case of temperatures, an initial increase followed by subsequent decrease was observed with rise in the parameter. Best conditions for bioleaching of cadmium employing A. ferrooxidans were deciphered to be a solid loading of at least 5 g at a microbial density of 5% at 30 °C temperature and 1.2 units of pH.

СТРУКТУРООБРАЗУЮЩАЯ РОЛЬ ЗНАКОПЕРЕМЕННЫХ ДВИЖЕНИЙ В РАЗЛОМНЫХ ЗОНАХ ПРИ СДВИГЕ, ТРАНСПРЕССИИ И ТРАНСТЕНСИИ ПРИМЕНИТЕЛЬНО К УСЛОВИЯМ ЛОКАЛИЗАЦИИ АЛМАЗОНОСНЫХ КИМБЕРЛИТОВ (РЕЗУЛЬТАТЫ ФИЗИЧЕСКОГО МОДЕЛИРОВАНИЯ)

Purpose. The work is aimed at studying the faulting dynamics and the types of disjunctive structural traps for ore solutions under alternating movements in the zones of shear, transpression and transtension. Methods. Physical modeling was performed in the Laboratory of Tectonophysics, Institute of the Earth's Crust SB RAS on the Fault Installation, which allowed to set up both the direction and two speeds of stamp (plate) movement (10 -4 and 10 -5 m/s). The studies were carried out on the basis of the experiments of physical modeling with the use of an equivalent material in the form of an aqueous suspension of montmorilonite clay (viscosity of 10 6 -10 7 PA∙s). Each experiment included two stages. Stage I reproduced the conditions that correspond to shear, shear with tension (transtension) or shear with compression (transpression). Stage II included the simulation of structure forming under reverse movement of experimental installation stamps, i.e. under alternating shear of transtension or transpression. Results. The parageneses of fractures with the emphasis on extensional structures that can be favorable for kimberlite body location have been studied in the series of 8 experiments. The formation patterns of disjunctives are examined in terms of shear zone paragenesis formation in the models of known discontinuities. The extensional structures favorable for ore deposition are more characteristic of the experiments performed at slow speed. Another factor affecting the formation of the internal structure of fault zones is the vector of relative movement of stamps (plates), on which the dynamic conditions of the first and second stages depend. Consideration is also given to the combinations of right- and left-lateral shearing, transtension-transpression, and transpression-transtension. Conclusion. The physical modeling experiments have shown that the deformation rate has a significant influence on structure formation. In case of alternating movements in fault zones the deformation rate is the factor that affects the width of the fault zone and the distance between the fault systems as well as the specific set of elements in structural paragenesis. Extensional structure of the different types characterized by the highest tension amplitudes occur near the major joints of disjunction, where the dilatancy is the highest. The dilatancy is manifested most clearly in the fault zones which are formed in transpression conditions at the stage I and under transtension conditions at the stage II. The largest disjunctive structural traps associated with е-, R- and Y-fractures are observed in such fault zones.

Recovery of rare earths from nitric acid leach solutions of phosphate ores using solvent extraction with a new amide extractant (TODGA)

The rare earths in phosphate ores are not effectively utilized and they cannot be directly extracted from leach liquor with the traditional extractants, such as organic phosphoric acid. This paper presents a new solvent extraction method for rare earths from nitric acid leaching of phosphate rock using N,N,N′,N′-tetraoctyl diglycol amide (TODGA) without interfering with the normal route for fertilizer production. When the concentration of extractant increased to 0.1 mol/L, the extraction rate of lanthanum, cerium, praseodymium, and neodymium have been found to be 98.1%, 99.1%, 98.8% and 98.6%, respectively. The recovery rate reached to 99.9% when a three-stage countercurrent extraction was carried out on the simulated leach solution. There was almost no extraction of other impurity ions and the rare earths could be separated with TODGA from Ca2+, PO43−, Fe3+, and Mg2+. The presence of phosphoric acid in solution enhanced the extraction of rare earth ions. The stripping of the loaded rare earth in the organic phase was readily carried out with water under room temperature with high efficiency. The mixed rare earth oxides (REO) with an assay of >95% could be recovered as a final product.

Extraction of rare earths using bubbling organic liquid membrane with un-saponified P507

Extraction and enrichment of low-concentration rare earths from the in-situ leaching solutions of ion-absorbing type rare-earth ores using bubbling organic liquid membrane with un-saponified P507 was investigated. Experimental results revealed that saponification of P507 extractant are unnecessary for extraction of rare earths using bubbling organic liquid membrane. The equilibrium pH of the aqueous solutions flowing out from the extraction column would not decrease obviously, because the total volume of un-saponified P507 contacting with the aqueous phase in the column was very small, and the aqueous-to-organic phase ratios could be very large. Therefore, the loading capacity of rare-earth ions in the organic phase have no obvious changes, compared to that using saponified P507. Scale-up experiments in the pilot-scale columns connected in cascade for continuous countercurrent extraction of low-concentration rare earths about 100mg/L in the leaching solutions demonstrated that, the final residual concentrations of rare earths remained below 3.0mg/L, while total recovery of rare earths after extraction and stripping processes could reach above 90%. Bubbling organic liquid membrane extraction is in fact an interfacial chemical reaction of rare-earth ions with un-saponified P507 adsorbing at the surface of organic liquid membrane. During countercurrent extraction processes, shearing interaction of the aqueous solutions with dispersed organic bubbles rising in the extraction column would result in continuous exposure of fresh surface of organic bubbles, which is a main driving force to promote the mass transferring and enrichment of rare-earth ions into the organic liquid membrane layer.

Gamma Ray Spectrometry Method In Detecting The Low Sulfidation Type Epithermal Au+Ag Mineralization (Gümüşhane, Ne Turkey)

Summary The gamma ray spectrometry has been widely used in mineral exploration, geological mapping and environmental radiation monitoring. The Eastern Pontide orogenic belt, which constitutes an important part of the Alpine-Himalayan system, hosts various types of economic mineral deposits of massive sulfide, porphyry copper, skarn, and epithermal vein-type ore deposits. Potassium is generally the most useful pathfinder element for gold mineralization zones. High level K/eTh, K/eU and Efimov F-Parameter (KeU/eTh) anomalies showed the alteration zones transmitting hydrothermal ore solutions to the surface. As a result, the gamma ray spectrometry, which is fast and economics method, might be used for estimation of prospective Au ore zones associated with the K alteration..

Constraints on Conceptual and Quantitative Modeling of Early Diagenetic Sediment-Hosted Stratiform Copper Mineralization

Early diagenetic sediment-hosted stratiform copper (eSSC) mineralization results from low-temperature cuprous chloride complexes carried by saline aqueous solution circulating through footwall aquifers. Favorable copper solubilities are attained in moderately oxidizing, near-neutral pH solutions. That specific oxidation level is not determined by co-existence with hematite, with its near-indiscriminant control over Eh. Instead, redbed footwall aquifers are signatures of diagenetic oxidation. Relentless in-situ oxidation of ferrous minerals in redbeds produces pore waters too reduced to transport copper, thus eliminating compaction waters as ore solutions. Continuous early influxes of descending oxygen-rich meteoric waters which have assimilated evaporitic salts may redden aquifers and still retain oxidation levels capable of carrying copper to form downstream eSSCs.

Sulfur and lead isotope systematics: Implications for the genesis of the Riópar Zn-(Fe-Pb) carbonate-hosted deposit (Prebetic Zone, SE Spain)

The Zn-(Fe-Pb) deposits of the Riópar area (Prebetic Zone, SE Spain) are hosted by dolostones that replace Berriasian to Valanginian (Upper Jurassic-Lower Cretaceous) limestones. Mineralization consists of hypogene sphalerite, marcasite and galena, and supergene calamine zones. The hypogene ores are associated with a saddle dolomite gangue. The ore bodies occur as discordant and stratiform lenses, ore-cemented breccias, cm- to mm-wide veins and veinlets, disseminations and stylolite porosity filling within the host dolomites. The main ore controls include stratigraphy and/or lithology, tectonics (faults, fractures and breccias) and availability of metals and sulfur. The morphologies and epigenetic character of the hypogene ore bodies are consistent with the classification of this mineralization as a Mississippi Valley-type (MVT) deposit. The Ga/Ge geothermometer in sphalerite yielded a temperature range of 194–252°C, which represents the temperature of the source region of the ore solution. This value is comparable to the temperature obtained in the ore deposition site, 159±15°C from the Δ34S geothermometer in sphalerite galena pairs. This similitude points to a hydrothermal fluid that did not cool down significantly during flow from the fluid reservoir area to the precipitation site. δ34S values of base-metal sulfides (−7.5 to +3.5‰) are consistent with thermochemical reduction of Triassic sulfate (seawater and/or derived from dissolution of evaporites) by interaction with organic compounds (e.g., hydrocarbons, methane), which reduced sulfate to sulfide in the deposition site. The lead isotope ratios (206Pb/204Pb=18.736–18.762; 207Pb/204Pb=15.629–15.660; 208Pb/204Pb=38.496–38.595) of galena suggest that Pb, and probably other metals as Zn, is derived from continental crustal rocks. On the other hand, these relations points to a unique metal source probably derived from the Paleozoic basement rocks. The relationship between bedding-parallel stylolites, dolomitization, sulfide precipitation and Alpine tectonic affecting the MVT ore, suggests a relative timing range for the mineralization in the Riópar area of 95–20Ma (Upper Cretaceous-Tertiary). The sulfide mineralization and the associated dolomitization are thus explained by the contribution of two fluids that mixed in different proportions during dolomitization and mineralization: i) a fluid probably derived from Cretaceous seawater saturating Mesozoic sediments (Fluid A), characterized by being dilute and initially low temperature, which should have contained organic rich compounds in the ore deposition site (e.g., hydrocarbons and CH4 dissolved gas); and ii) a high salinity hydrothermal brine (Fluid B) rich in both metals and sulfate, circulated through the Paleozoic basement. During the pre-ore dolomitizing stage the fluid phase was dominated by the diluted fluid (Fluid A>Fluid B), whereas in a later fluid pulse, the proportion of the high salinity fluid increased (Fluid A<Fluid B) which allowed sulfide precipitation. MVT exploration in the Prebetic Zone should focus towards the SW of the Riópar mines, in the vicinity of the Alto Guadalquivir-San Jorge fault.

Enrichment of Low Concentration Rare Earths from Leach Solutions of Ion-Adsorption Ores by Bubbling Organic Liquid Membrane Extraction Using N1923

A new bubbling organic liquid membrane extraction using primary amine N1923 at large aqueous-to-oil phase ratios was suggested to extract and enrich extremely low concentration rare earths from the acidic sulfate leach solutions of ion-absorbing type rare-earth ores. It was revealed that bubbling organic liquid membrane extraction was in fact an interfacial chemical reaction of organic extractant molecules absorbing at the surface of the organic liquid membrane supported by gas bubbles with the target metal ions in the aqueous solutions. Rare earths with a concentration about 100 mg/L can be extracted selectively and enriched efficiently into the organic extractant liquid membrane layer covered on the surface of dispersed gas bubbles. However, Al in leach solutions was not extractable and remained in the raffinates, due to a kinetic nonequilibrium separation behavior of rare earths and Al on the surface of the organic liquid membrane. It was the differences in reaction rate of rare earths and Al with prim...

Способы управления процессом растворения сильвинитовых руд на галургических фабриках

Способы управления процессом растворения сильвинитовых руд на галургических фабриках

Functional nanofibers for separation of rhodium(III) and iridium(IV) chlorido species

Three quaternary diammonium-functionalized polyvinylbenzyl chloride nanofibers were prepared using hexamethylenediamine (HMDA) quaternized with methyl, ethyl and benzyl groups to produce F-QUAT HMDA-methyl, F-QUAT HMDA-ethyl and F-QUAT HMDA-benzyl, respectively. The synthesized nanofibers were characterized by means of FTIR, XPS, SEM, BET surface area, thermogravimetric analysis and elemental analysis. The materials were used to investigate the adsorption and separation of [RhCl5(H2O)]2− and [IrCl6]2−. Adsorption isothermal batch studies were conducted on both metal ion complexes ([RhCl5(H2O)]2− and [IrCl6]2−) using single metal aqueous solutions. The Langmuir isotherm confirmed monolayer adsorption for the uptake of both [RhCl5(H2O)]2− and [IrCl6]2− using F-QUAT HMDA-ethyl, F-QUAT HMDA-methyl and F-QUAT HMDA-benzyl. The adsorption process of these materials obeyed the pseudo second-order kinetics, suggesting that chemisorption was be the rate-determining step. Column studies were conducted for a binary mixture of the metal ions chlorido species, and the iridium loading capacities of 15.2(0.8)mg/g, 9.7(0.7)mg/g and 42.9(0.7)mg/g were obtained for F-QUAT HMDA-methyl, F-QUAT HMDA-ethyl and F-QUAT HMDA-benzyl, respectively. This order was interpreted on the basis of inductive effects of the three quaternizing groups. The results provided important insight into the effect of derivatizing the cationic center on the loading capacity for [IrCl6]2−. This study presents truly iridium-specific sorption materials which can be applied to solutions of low grade ores or secondary raw materials of PGMs.