Natural Ore Research Articles

Обзор: Извлечение металлов платиновой группы из каталитических конвертеров

Металлы платиновой группы (PGM) широко используются в каталитической промышленности благодаря своим выдающимся физико-химическим свойствам (высокотемпературная стабильность, высокая каталитическая активность). Они используются в медицине, электронике, нефтепереработке, производстве аммиака, топливных элементов, автомобилестроении и т.д. Каталитические отходы являются важным вторичным источником металлов, поскольку переработка отходов является более экономичным и экологичным способом получения металлов по сравнению с добычей из руд. Отработанный автомобильный катализатор является богатым источником металлов платиновой группы [PGM: платина (Pt), палладий (Pd) и родий (Rh)], которые содержат более высокие концентрации PGM, чем в природных рудах. В данной статье представлен критический обзор состояния методов извлечения металлов платиновой группы из утилизированных катализаторов, их преимуществ и недостатков. В результате были проанализированы все методы и выделены наиболее перспективные (наиболее экологичные и экономичные).

Review: Extraction of platinum group metals from catalytic converters

Platinum group metals (PGM) are widely used in catalytic industry due to their outstanding physical and chemical properties (high-temperature stability, high catalyst activity, high heat resistance, high corrosion resistances). They are used in medical fields, electronics, oil refining, production of ammonia, fuel cells, automotive industry. Catalytic wastes are an important secondary source of metals because recycling of wastes is more economical and ecological way of metals obtaining compared to mining from ores. Spent automotive catalyst is a rich source of platinum group metals [PGM: platinum (Pt), palladium (Pd), and rhodium (Rh)] which contains higher concentrations of PGM than found in natural ores. This review presents the analysis of the recovery methods of platinum group metals from spent catalysts and their advantages and disadvantages. As a result, all methods were analyzed and the most promising (most environmentally friendly and economical) was pointed out.

Green synthesis of ultrathin 2D nanoplatelets, hematene and magnetene, from mineral ores in water, with strong optical limiting performance

Hematene and magnetene nanoplatelets have been produced by liquid phase exfoliation of natural mineral ores, in a water solution of melamine under mild sonication.

Catalytic ozonation of sulfamethoxazole using low-cost natural silicate ore supported Fe2O3: influencing factors, reaction mechanisms and degradation pathways.

A low-cost natural silicate ore supported Fe2O3 (FeSO) was synthesized for catalytic ozonation of sulfamethoxazole (SMX). XRD, SEM-EDS, BET, FTIR and XPS results of the FeSO catalyst confirmed that the natural silicate ore was successfully modified with iron oxide. The effects of key factors, such as catalyst dosage, initial solution pH, reaction temperature, inorganic anions and initial concentration, on ozonation degradation were systemically investigated. The degradation rate of SMX (20 mg L-1) was 88.1% after 30 min, compared with only 35.1% SMX degradation rate in the absence of the catalyst, and the total organic carbon (TOC) removal reached 49.1% after 60 min. Reaction mechanisms revealed that surface hydroxyl groups of FeSO were a critical factor for hydroxyl radical (˙OH) production leading to fast SMX degradation in the ozone decomposition process. The degradation products were detected, and the possible pathways of SMX were then proposed. This study provides guidance for preparing a low-cost catalyst and analyzing the degradation products and pathways of SMX in the ozonation process, which is of significance in practical industrial applications.

Свойства нанокристаллических магнитных порошков системы Fe – O, полученных магнито-импульсной обработкой из железорудной пыли

The influence of the parameters of high-energy, thermal and magnetic-pulse processing on the formation of the phase composition and magnetic properties of nanocrystalline powders of the Fe – O system during their production from cheap problematic iron ore raw materials “blue dust” of the Indian deposit has been studied. The research results showed that the GR-1 concentrate “blue dust” in its properties refers to waste, and not to natural ore material. The presence of an oxide-salt layer on the surface of the particles and the high dispersion of the material do not allow it to be used in its pure form as a feedstock for blast-furnace production, and the development of a processing method requires a separate approach. From the analysis of the results of measuring the magnetic properties, it follows that as a result of the processing of iron ore material in a high-energy planetary ball mill, it was possible to obtain samples with properties characteristic of hard magnetic materials. The particle size is 1 µm and the values of the coercive force and remanent magnetization are 190 Oe and 0.5 kG, respectively. This makes it possible to recommend the use of this magnetic material as fillers for polymer films. The conditions of thermal and magnetic treatment are determined, which make it possible to increase the values of the coercive force by 27 – 35 % and the remanent magnetization by 1.9 – 2.6 times.

Физико-химические свойства наночастиц золота в рудах и катализаторах

Introduction. At present, in the instrumental study of the mineral forms of finding gold in geogenic and technogenic ores, more and more attention has been paid to free gold, with a size of several nanometers. Such gold has been found in almost all types of its geogenic ores: starting with deposits of primary sulfide ores and ending with various gold-bearing placers. A similar situation is observed with technogenic gold-bearing ores accumulated in numerous dumps and tailings. At the same time, with the increase in research on nanogold, not only its fundamental, but also practical importance grows, because. in theoretical and applied research, more and more of its actual physical and chemical properties and previously unknown phenomena and effects accompanying them are discovered and clarified. Research methods and materials. An important aspect is the instrumental study of the geometry of various forms of nanogold occurrence in natural (geogenic) and technogenic ores and minerals. The instrumental and analytical part of our research was based on the visualization of nanoparticles obtained from the Nanjing Research Institute of the Chemical Industry under Sinopec (PRC), carried out on a JEOL 2010F microscope. Research results. The studied gold nanoparticles were presented in the form: • spherical fullerene-like monoparticles; • fullerene-like gold cells, consisting of a different number (from 13 to 20 clusters) of gold nanoparticles; • self-organized «fractal» dendrites; • rather complex composites with the participation of nanogold; • various aggregates of nanoparticles, etc. The concentrations of gold nanoparticles vary significantly from one deposit to another and between individual ore facies (even within the same deposit). Discussion of the obtained results. It was found that nanogold can be contained in arsenopyrites in 2 main forms: a) as a structurally bound solid solution (Au + 1) located in the lattice of this mineral; b) in separate mineral inclusions of submicron size or nanoparticles. Gold nanoparticles (5-10 nm in size) detected in arsenopyrite in concentrations up to 4% mass fraction are sufficiently representative to account for their amount in gold-bearing ores. A gold nanoparticle with a size of 3 nm usually has an average coordination number CN = 9.5, similar nanoparticles with a size of 1 nm have an average CN = 6, and nanoparticles with a size of 0.5–1 nm have an average CN = 3.6. Conclusion. To date, a nanoparticle catalyst has been developed in which gold clusters are attached to metal oxides that are semiconductors. At the same time, their number is very limited and includes only Fe2O3, TiO2, CeO2, and MgO compounds, which can be used not only in the form of nanoparticles, but also nanofilms. Such an innovative nanocatalyst ensures the efficient flow of a number of oxidative and other processes with hydrocarbons at normal temperatures, which is difficult to achieve by other methods. Findings. The article presents the results of studies of the physicochemical properties of gold nanoparticles installed in ores and catalysts. The morphology of gold nanoparticles has been established. The character of gold speciation in various sulfides is determined. The presence of gold nanoparticles in ores and rocks in the state of colloids has been confirmed. The catalytic activity of nanoparticles of various shapes and chemical states was revealed, depending on the values of the ambient temperature. The results of the research can be useful in the enrichment of gold-bearing ores of upland deposits.

Comparative analysis of the radiation situation in the Stepnogorsk district in the Akmola region

The territory of the Akmola region is characterized by the presence of a number of radiation factors caused by natural and man-made manifestations of increased radioactivity, the main of which are numerous areas of anomalous increases in natural radioactivity, uranium deposits and ore occurrences, as well as long-term large-scale activities of uranium mines and enterprises for the extraction of other minerals, with associated uranium mineralization. In this article, we will show the results of a study of pollution in the Stepnogorsk district in recent years and demonstrate the analysis of the data. The article will analyze the research data of 2016 and 2020. Comparison of the results showed that the concentration of pollution is present in high doses, in particular, special attention is paid to the village of Aksu.

Effect of sonochemical pretreatment of slurry depressors on sylvin flotation performance

The main source of potassium fertilizers is sylvinite ores consisting primarily of halite (NaCl), silicate and clay-carbonate slurries (clay-salt slurries). Processing of natural potash ores is mainly carried out by the flotation method, which separates KCl, NaCl, and clay-salt slurry. The research is aimed at revealing the effect of sonochemical pretreatment of the depressor reagents, CMC and starch, on dynamic viscosity, aggregate size, electrokinetic potential of these reagent solutions and sylvin flotation performance. It has been established that sonochemical treatment of depressor solutions decreases the size of aggregates of starch molecules by more than 133 times and that of aggregates of CMC molecules from 6 to 4 nm. It has been revealed that sonochemical treatment of anionic CMC solution shifts the electrokinetic potential towards the area of negative values with an increase in acoustic power, while sonochemical treatment of any acoustic power has no effect on the zeta potential of nonionic starch. It has been found that the sonochemical treatment lowers the dynamic viscosity of CMC and starch solutions: the viscosity of CMC solution at a maximum acoustic power of 420 W decreases by 44 % and the viscosity of starch solution at the same acoustic (ultrasonic) power decreases by 70 %. Furthermore, sonochemical pretreatment of sylvin flotation depressors contributes to an increase in KCl recovery and a decrease in the slurry content in the flotation concentrate. The possibility of reducing the consumption of ultrasonic treated depressor is also demonstrated. It is expedient to test the obtained findings in pilot-plant conditions.

Germanium speciation in experimental and natural sphalerite: Implications for critical metal enrichment in hydrothermal Zn-Pb ores

The critical metal germanium (Ge) is recovered as a by-product of mining other commodities, such as zinc and thermal coal. We investigated the Ge incorporation mechanism in sphalerite synthesized under hydrothermal conditions like those of sediment-hosted Zn-Pb deposits. Sphalerite ± galena ± barite formed via reactions of Ge ± Fe ± Cu ± Ba-bearing brine with calcite and reduced sulfur at 200 °C and water vapor-saturated pressure. The products were examined using backscattered electron (BSE) imaging, electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD), synchrotron X-ray fluorescence (SXRF) and micro-X-ray absorption near-edge structure (μ-XANES). We show that Ge(IV) is incorporated into sphalerite and bonded with reduced sulfur, both in the experimental sphalerite and in natural zinc ore samples from the MacArthur River Zn-Pb-Ag deposits, Australia. Copper K-edge XANES spectra show that copper occurs as Cu(I) in the experimental sphalerite, consistent with previous studies on Cu in natural sphalerite. The experiments reveal that Ge(IV) substitution in sphalerite occurs with and without the presence of other metal ions (e.g., Cu(I)), indicating that Ge(IV) substitution can be accommodated via charge balance by vacancies as well as by coupled substitution in the synthesized sphalerite. Ab initio quantum chemical simulations confirm that sphalerite can readily accommodate Ge, with the crystal structure and average Zn-S, Zn-Zn, S-S distances retained when replacing > 3 mol% of the Zn sites with Ge(IV), Ge(II), Cu(I) or Fe(II), demonstrating the resilience and flexibility of the sphalerite crystal structure. These Ge incorporation mechanisms explain the previous observations of multiple ways of Ge incorporation in natural sphalerite. The study provides experimental and molecular simulation insights for understanding the processes related to the formation and extraction of Ge in zinc ores.

Solubility of Platinum in Pyrite and Pyrrhotite

A temperature range of processes leading to the concentration of Pt in the crust widely varies from high-temperature orthomagmatic to low-temperature hydrothermal and biogenic. Pyrite FeS2 and pyrrhotite Fe1–xS are important components of sulfide ores, which contain platinum-group elements. Fe sulfides typically host from a few hundreds to a few tens ppm of dispersed (invisible) Pt. In this work, we summarized the available data on the solubility of Pt in pyrite and pyrrhotite, supplement them with the results of synthesis of these minerals in the presence of Pt phases, and present a model that can describe the solubility of Pt in a broad range of temperature and S2 fugacity. The resulting equations allow the calculation of the solubility of Pt (ppm) in a temperature range of 300 < t < 1100°C and S2 fugacity up to the equilibrium with Sl. Tables with the solubility of Pt in pyrite and pyrrhotite depending on temperature and S2 fugacity are presented. Isopleths of the solubility of Pt in Fe sulfides are plotted on a log f(S2)–1000/T diagram. The analysis of the position of the main field of ore formation on this diagram showed that pyrite and pyrrhotite dissolve up to a few and a few hundreds of ppm Pt, respectively, upon conditions typical of ore formation: t < 700°C and log f(S2) < –4. These estimations coincide with maximum Pt contents determined in minerals of natural sulfide ores.

Synthetic oxygen carrier C28 compared to natural ores for chemical looping combustion with solid fuels in 80 kWth pilot plant experiments

Chemical Looping Combustion (CLC) is a highly efficient CO2 separation technology with no direct contact between combustion air and fuel. A metal oxide is used as oxygen carrier (OC) in a dual fluidized bed to generate clean CO2. The use of solid fuels, especially biomass, is the focus of current research, because of the possibility of “negative” CO2-emissions. The OC is a key component, because it must meet special requirements for solid fuels, which are different to gaseous fuels. Most frequently naturals ores or synthetic materials are used as OC. Synthetic OC are characterised by higher reactivity at the expense of higher costs. For this reason, so far not so many experiments have been conducted on a larger scale with synthetic OC on solid CLC. This work deals with the synthetic perovskite C28 and investigating the suitability as oxygen carrier in an 80 kWth pilot plant for chemical looping combustion with biogenic fuels. The experiments show a significantly increased combustion efficiency of 99.6 % compared to natural ores and a major influence of the solid circulation rate on general performance, whereby carbon capture rates up to 98.3 % were reached. Furthermore, the role of the fuel reactor's counter-current flow column and its impact on better gas conversion was investigated. C28 suffered no deactivation or degradation over the experimental time, but first traces of ash layer formation, phase shifting and attrition of fines could be detected. The focus of further research should lie on long-term stability and reactivity for their high impact on the economic scale up of C28.

New insights into the degradation and detoxification of methylene blue using heterogeneous-Fenton catalyzed by sustainable siderite

The huge application of synthetic dyes caused a severe impact in the environment. In the present study, a physico-chemical strategy of heterogeneous-Fenton catalyzed by the natural ferrous ore has been established for toxic chemical degradation, of which the complex and high-expense repetitive pH adjustment procedures were escaping. And this natural heterogeneous catalyst also could be recycled and sustainable for toxic substances treatment involved in synergetic adsorption and oxidation. The siderite, served as an adsorbent and catalyst for the degradation of methylene blue (MB). Siderite exhibited a better adsorption capacity with a saturated adsorption capacity of ∼11.08 mg/g. Batch adsorption experiments have verified that adsorption rate and adsorption equilibrium followed pseudo-second-order rate model and Langmuir isotherm equation, respectively. The combination with H2O2, showed significant enhancement of MB degradation without any pH adjustment. The effect of siderite dosage, H2O2 dosage, MB concentration, initial pH, and reaction temperature on MB degradation was investigated, which also has indicated the excellent catalytic performance of siderite. About 99.71% of MB was degraded in 480 min with initial pH of 7.0, reaction temperature of 25 °C, siderite, and H2O2 dosage of 2.5 g/L and 122.38 mM, respectively. It was found that siderite could be reused and remained high degradation efficiency on MB after 5 times reutilization, which also could demonstrate the sustainable and effective process to degrade organic pollution. The generation of reactive species including ·OH and O2·- have been confirmed based on scavenger test and electron spin resonance (ESR) analysis, which was dominated by heterogeneous reaction. The possible degradation mechanisms of MB have been predicted based on spectrum scanning and GC-MS analysis. Moreover, acute toxicity assessment with marine photobacterium Vibrio fisheri was conducted to investigate the toxicity change in the adsorption/oxidation coupled process. This sustainable heterogeneous-Fenton technology has been verified as a promising and applicable process for toxic organic chemicals removal due to effective mineralization and detoxification assisted with the natural ore mineral through the simple operation and mild condtions.

Cobalt pentlandite structured (Fe,Co,Ni)9S8: Fundamental insight and evaluation of hybrid supercapacitor

From the perspective of improving energy density, research efforts to design electrode materials that can be used in supercapacitors based on mature transition metal sulfides are already so common and efficient but insufficient. So it is a nice approach to empower the traditional transition metal sulfides with new vitality by composite structures to enrich the family of metal sulfides. In this study, we synthesized a kind of cobalt pentlandite structured (Fe,Co,Ni)9S8 originally existed only in natural ores by relatively mild means, and found that such structured materials have good potential for use in supercapacitors. The optimized (Fe,Co,Ni)9S8 sample presents a remarkably high specific capacity of 135 mAh/g at 1 A/g as well as favorable cycling stability. Density functional theory simulations confirmed the metallic properties of such sample, and Co sites are more favorable for the adsorption of OH–. Moreover, a button-type hybrid supercapacitor was fabricated utilizing our designed electrode material, presenting a relatively high energy density of 50 Wh kg−1 at 1353 W kg−1 and good cyclic stability. Moreover, two such hybrid supercapacitors can power a red LED for 22 min, which has shown its attractive and promising possibilities for practical energy storage devices.

Comparison of the efficiency of metal recovery from wet- and dry-discharged municipal solid waste incineration bottom ash by air table sorting and milling

Separating high-density fractions from municipal solid waste incineration bottom ash (BA) is a promising approach for collecting metal resources and harmful elements. Herein, the efficiency of the recovery of metals (Cu, Zn, Au, Ag, and Pb) in the high-density fractions of two air-dried BAs discharged from wet-based systems (WBA), was compared with that of two BAs discharged from dry-based systems (DBA). WBAs and DBAs (<8 mm) were sorted using sieving, magnetic separation, milling, and air table sorting techniques. Newton’s separation efficiency was used to evaluate three scenarios that combined various sorting processes. WBA contained high-density fractions (D1, 2.73–3.63 g/cm3) with a density similar to that of D1 in DBA (2.68–3.67 g/cm3), but the surface of the particles was covered by more minerals. When D1, and the metal particles were recovered after the milling of the low-density fractions, the overall separation efficiency in WBA (0.30–0.40) was lower than that in DBA (0.49) because of the lower separation efficiency for Zn and Pb compared to that for the other target metals. In contrast, no significant difference was recorded in the separation efficiency for Cu, Au, and Ag between WBA and DBA. D1 (18000–132000 mg-Cu/kg) and metal particles (29900–199800 mg-Cu/kg) in both WBA and DBA recorded abundant Cu contents. Moreover, the Au content in some D1 was similar to that found in natural ores. The elemental contents and separation efficiency results indicated that D1 and metal particles should be collected from both WBA and DBA.

Achieving High Thermoelectric Performance in Mixed Natural‐Synthetic Tetrahedrites

AbstractTetrahedrites, a class of naturally‐occurring sulfosalts, recently emerged as interesting thermoelectric materials due to their semiconducting electronic properties combined with glass‐like thermal transport. Here, we demonstrate that the high thermoelectric performance of synthetic tetrahedrites can be maintained while being mixed with tetrahedrite minerals. The combination of ball‐milling and spark plasma sintering yields chemically‐homogeneous, dense polycrystalline samples with thermoelectric performance equivalent to those obtained in purely synthetic compounds with peak ZT values of ∼0.6 at 623 K. While ball‐milling significantly lowers the crystallite size, a complete solid solution between both types of tetrahedrites is only achieved through the sintering process. Not only do these findings confirm interesting prospects for the direct use of natural ores in the preparation of tetrahedrites, but they also further evidence the importance of the chemical compositions of the two initial tetrahedrites on the optimization of the thermoelectric properties of the final compound.

Accelerated Removal of Acid Orange 7 by Natural Iron Ore Activated Peroxymonosulfate System with Hydroxylamine for Promoting Fe(III)/Fe(II) Cycle

In this study, peroxymonosulfate (PMS) was activated by cheap and readily available natural iron ore to remove Acid Orange 7 (AO7) in water with the assistance of hydroxylamine (HA). Results show that the presence of HA could accelerate the Fe(II)/Fe(III) cycle on the ore surface, promoting the activation of PMS to generate reactive oxidative species. The effects of ore dosage, PMS dosage, HA dosage and initial pH on the degradation of AO7 were investigated in the HA/Ore/PMS system. Under the optimal conditions, the removal of AO7 could reach 93.1% during 30 min, which was 41.4% higher than the ore/PMS system. The AO7 removal increased with the increase of HA, PMS and ore dosage, but was unaffected by the initial solution pH. Based on radical scavenging experiments and EPR tests, the dominant reactive species in the HA/Ore/PMS system were revealed to be the sulfate radical (SO4•−), singlet oxygen (1O2), superoxide radical (O2•−) and hydroxyl radical (•OH), which were responsible for the AO7 degradation. Furthermore, the possible reaction mechanism of PMS activation was proposed. This study provides an efficient technique for the removal of azo dye organic contaminant in water, which has great practical significance.

Evolution of freight spatial pattern of China's coastal ports facing the Polar Silk Road

The Polar Silk Road (PSR) opens up China's maritime trade route through the Arctic to Northwest Europe and influences the cargo transport pattern of China's coastal ports, resulting in changes in the freight spatial pattern of port system. This study uses Exploratory Spatial Data Analysis to predict and analyse the evolution of freight spatial pattern of China's coastal ports facing the PSR. Oil, liquefied natural gas, iron ore, coal, timber and container are selected as important cargos to be studied. Results show that the northern ports have higher attraction potential than the southern ports. All cargos facing the PSR show significant spatial agglomeration characteristics. The local spatial patterns of northern ports tend to change towards high values, whereas the southern ports are the opposite. The Bohai Rim and Yangtze River Delta have a certain hierarchical structure for the PSR. The gravity centre of China's coastal port system is in the northern area facing the PSR, where the comprehensive cargo convergence capacity of large ports in the Bohai Rim is stronger than that in other regions. The role orientation and development prospects of different port freight spaces are classified.

Red Raspberry Seed Oil Low Energy Nanoemulsions: Influence of Surfactants, Antioxidants, and Temperature on Oxidative Stability.

The aim of this study was to assess and improve the oxidative stability of red raspberry seed oil–RO, a potential topical ingredient derived from food industry by-products, on its own and when incorporated in low energy nanoemulsion (NE). The RO’s oxidative stability was assessed at 5, 25, and 40 °C during one month of storage and expressed in: peroxide value, p-anisidine, and thiobarbituric reactive substances—TBARS value, while for NEs, lipid hydroperoxides and TBARS values were monitored. Both synthetic (butylated hydroxytoluene—BHT and ethylenediaminetetraacetic acid—EDTA), and natural (oregano essential oil—ORE and oak fruit extract—OAK) antioxidants were used. Pure RO and RO with BHT or ORE were stable at 5 °C and 25 °C, but at 40 °C BHT showed only moderate protection, while ORE was prooxidant. NEs prepared with new biodegradable polyglycerol esters-based surfactants, with droplet sizes of < 50 nm and narrow size distribution, showed improved physicochemical stability at room temperature, and especially at 40 °C, compared to NEs with polysorbate 80, which required the addition of antioxidants to preserve their stability. Natural antioxidants ORE and OAK were compatible with all NEs; therefore, their use is proposed as an effective alternative to synthetic antioxidants.

Mechanism analysis of efficient degradation of carbamazepine by chalcopyrite-activated persulfate.

In this study, natural chalcopyrite (NCP) was used to activate peroxymonosulfate (PMS) to degrade carbamazepine (CBZ) oxidatively. Before and after the NCP reaction, the physical and chemical properties were characterized by SEM-EDS, XRD, XPS, XRF, and VSM. The effects of the amount of NCP and PMS, the initial pH value, and the reaction temperature on the catalytic performance of NCP were systematically studied. The research results show that the degradation efficiency of the NCP/PMS system for CBZ can reach 82.34% under the optimal reaction conditions, and the degradation process follows a pseudo-second-order kinetic model. The results of the radical quenching experiment and EPR analysis show that the active species in the system are OH·, SO4-·, and 1O2, of which SO4-· is the main active species. In addition, this study shows that the NCP/PMS system can degrade CBZ with high efficiency of 90.73% only with the assistance of 0.15g/L Fe0. This study determined the optimal reaction conditions for natural chalcopyrite to activate PMS to degrade CBZ and clarified the activation mechanism, which broadened the application of natural ores in the field of water treatment.

Cadmium Removal from Cadmium‐Containing Apatites by Ion‐Exchange Reactions

AbstractThe exchange reaction of cadmium by non‐toxic metallic cation ions in a cadmium‐containing apatite was studied. A cadmium‐containing apatite with characteristics close to those of natural phosphate ore was synthesized. Copper and then zinc ions have been found to be the most effective elements for the exchange reaction. After 4 h of treatment at room temperature, 25 % and 14 % of cadmium were removed using 0.1 m solutions of copper and zinc ions, respectively. At 60 °C, cadmium removal efficiency improved considerably. For copper ions, the efficiency reached 53 %, while it arrived at 25 % for zinc ions. The equilibrium study shows that the two reactions are thermodynamically feasible but balanced reactions with little reaction progress for small cadmium content. The reaction can be well modeled by the shrinking‐core model and is found to be controlled by the diffusion through the reacted layer.