Laterite Ore Research Articles

Novel applications of microwaves in the metallurgical processing of a nickel-ferrous laterite ore and an aluminum industry waste

Microwave radiation is a relatively new source of energy in the pyrometallurgical process. In this study, the application of microwaves in the carbothermic reductive roasting of a nickeliferous hematitic laterite ore and a red mud are investigated. The effective microwave heating (at temperatures above 900°C) of the aforementioned materials is attainable due to the relatively high values of their imaginary permittivity (ε")- In both two cases, the reduction of the included hematite was attempted, and the reduction degree was calculated as a function of: (a) the heating time and (b) the supplied microwave power. The mechanism of Fe+3 to Fe0 conversion was investigated using Mössbaurer spectroscopy revealing the formation of magnetite, fayalite and nano-structured metallic iron. Finally, it should be noted that that the gaseous products of the microwave pyrometallurgical process were analyzed using a mass spectroscopic technique, which is an important novelty.

Separation of cobalt and nickel from chloride leach solution of nickel laterite ore by solvent extraction

In order to separate Ni and Co from the chloride leach solution of laterite ores with high Fe content, solvent extraction and stripping experiments were performed. Various extractants, such as cationic extractants (Cyanex 272 (di(2,4,4-trimethylpentyl)phosphinic acid)), D2EHPA (di-2-ethylhexyl phosphoric acid), Versatic 10 (a carboxylic acid), amine extractants (Alamine 336 (tri-octyl/dodecyl amine), Aliquat 336 (a mixture of tri-octyl/decyl ammonium chloride), etc.), and neutral extractant (TBP (tri-butyl phosphate)) have been tested. Most of the Co together with some amount of Fe and Mn was extracted by Aliquat 336. The purified Co solution was obtained by extraction with Cyanex 301 (dialky1dithiophosphinic acid) after stripping the loaded Aliquat 336. Extraction of the filtrate with saponified Versatic 10 after precipitation of Al resulted in the separation of Ni and Mn from Ca and Mg. Ni was then selectively stripped by H2SO4 solution. The nickel solution with 99% purity was obtained from the batch simulation experiments.

High‐performance polymer‐supported extractants with phosphonate ligands for scandium(III) separation

As the market demand for scandium has grown, a great deal of interest has been generated in its recovery. To substantially simplify the process and provide a green alternative for scandium separation, novel polymer‐supported extractants containing di(2‐ethylhexyl) phosphonate and bis(2,4,4‐trimethylpentyl) phosphonate, [D201][DEHP] and [D201][C272] are proposed because they demonstrate improved adsorption capacity and selectivity toward scandium(III). Scandium(III) adsorption is significantly affected by the solution pH, with the maximum adsorption occurring at a pH of approximately 0.78. The batch adsorption data fit well with the Langmuir isotherm and pseudo‐second‐order kinetic models. A combination of the Fourier transform infrared and XPS spectra suggest that the complexation of oxygen atoms in phosphate groups with scandium(III) is the predominant adsorption mechanism. Additionally, the two resins were used to recover scandium from leaching liquor of nickel laterite ore. [D201][DEHP] exhibits unusual selectivity for scandium and low competitive behavior with other metals, thus increasing its market potential. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2479–2489, 2016

Reductive roasting of nickel laterite ore with sodium sulfate for Fe-Ni production. Part I: Reduction/sulfidation characteristics

ABSTRACTThe selective reduction of nickel and adequate growth of ferronickel grains are imperative for efficient preparation of ferronickel from nickeliferous laterite ore via the process of direct reduction followed by magnetic separation. In Part I, reduction/sulfidation behaviors of a saprolitic laterite ore in the presence of sodium sulfate were investigated, with an emphasis on thermodynamic analysis, selective reduction/sulfidation ratios and kinetics. To separate the interactions between Ni and Fe, chemical titration analysis was adopted to determine the contents of various Ni and Fe species in the roasted pellets, and a modified equation to assay metallic iron content was proposed.

Atmospheric pressure acid leaching of Caldag lateritic nickel ore

Nickel, cobalt and iron were extracted from Caldag lateritic nickel ore under atmospheric pressure acidic leaching conditions. The following variables were examined to understand their effects on extraction: sulphuric acid concentration, liquid-to-solid ratio, leaching temperature, leaching time, and particle size. After 6h of leaching, 91.9% Ni, 93.5% Co and 80.5% Fe were obtained under the following conditions: 2M H2SO4, 90°C, liquid-to-solid ratio=10/1(mL/g), stirring speed=500rpm, and laterite particles <0.053mm. The results indicated that there is no benefit gained in the leaching of nickel by grinding finer than 0.150mm under the conditions explored, whereas the greatest cobalt extraction was achieved with the use of the finest particles. XRD and SEM–EDX results verified that nickel was associated with asbolane, goethite/hematite and clay-like mineral phases. In addition, kinetic analyses of the nickel extraction revealed an activation energy of 51.6kJ/mol.

뉴칼레도니아산 니켈라테라이트광의 분급 연구

Nickel laterite ore is classified into two principal ore types: saprolite (silicate ore) and limonite (oxide ore). Saprolite-type ore characterized by high magnesia and silica contents is treated by pyrometallurgy process. On the other hand, limonite-type ore is subjected to hydrometallurgy process to produce nickel products. Hydrometallurgy process requires that a raw material to meet the demands that Si+Mg contents lower than 10% and Fe content over than 40%. It is therefore required that separation of saprilite-type ore to use nickel laterite ore as a raw material for hydrometallurgy process. In this study, separation of sparolite-type ore and limonite-type ore from nickel laterite ore from New Caledonia has been tried by dry classification. The results show that -5 mm size fraction and +5 mm size fraction of the nickel laterite ore contains mainly limonite-type ore and saprolite-type ore, respectively. To understand the moisture content of the raw ore on the dry classification, nickel laterite ore with different moisture contents of 23.0% and 9.1% were subjected to the dry classification. The results show that drying of the ore makes the separation more efficient as the amount of the fine product, that can be subjected to hydrometallurgy process without further separation or drying operations, was increased.

The effects of metals of emerging concern on the fertilization success of gametes of the tropical scleractinian coral Platygyra daedalea

The demand for nickel and cobalt as important commodities has increased significantly over the past decade and a decline in the global nickel sulphide reserves has resulted in a shift toward the exploitation of the less favourable nickel laterite ores. These deposits, which are found associated with cobalt, are located predominantly in the tropical regions of the world where there is limited understanding of the toxicities of their extracted products and wastes. This study investigated the effects of nickel, cobalt and combinations of nickel and cobalt on the fertilization success of the common and widespread scleractinian coral Platygyra daedalea. We also present the first assessment of the effect of copper on fertilization success of this species. The EC50 value for copper was 33 μg L−1 (95% confidence limits: 30–37 μg L−1) and is consistent with published values for other coral species. Our results provide the first EC50 value for the effect of nickel on fertilization success in a scleractinian coral, with an estimated value of 1420 μg L−1 (95% confidence limits: 1160–1780 μg L−1). Concentrations of cobalt as high as 2500 μg L−1 did not significantly reduce fertilization success nor did combinations of nickel (500 μg L−1) and cobalt (up to 1000 μg L−1). These are important findings given the emerging nickel-cobalt mining industry in the tropics and provide much needed toxicity data regarding the early-life histories of ecologically relevant tropical marine species.

Chlorination roasting of laterite using salt chloride

This paper introduces an application of chlorination roasting process followed by hot-acidulous water leaching that could cause a high extraction selectivity of Ni, Co and Mn over Fe and Mg which can concentrate Ni and Co in laterite ores. Thermodynamic analysis of possible chlorination reactions in roasting process was calculated and the Predominance Area Diagram of Ni–Co–Cl–H–O was shown to indicate the effect of partial pressure of HCl and H2O on the stability of NiCl2 and CoCl2. The mixture of NaCl and MgCl2·6H2O was selected as chloride agent and the chlorination mechanism was discussed comprehensively. The results show that the leaching rates of Ni, Co, Mn, Fe and Mg are 87%, 58%, 53%, 3.2% and 5.4% respectively at the optimal conditions, which showed that Ni, Co and Mn could be extracted effectively and the extraction of Fe and Mg was suppressed simultaneously. The Ni/Fe ratio and Ni/Mg ratio can reach 0.97% and 0.25% in leaching solution which can increase 15 times and 8 times respectively in comparison with the Ni/Fe and Ni/Mg ratio in raw ore.

Hydrometallurgical processing of nickel lateritic ores

Nickel production is a very important activity for the European Union because nickel is a unique constituent of stainless steel. Europe has lateritic (oxidic) ore deposits along a very well-known belt starting from the Alps and ending to the Himalayas. The lateritic belt passes through western Balkans and Greece and continues through Turkey to Asia. The known lateritic deposits in Serbia are located in three different areas called: Zapadna Morava (Rudjinci, Veluce, Ba), Sumadija (Lipovac, Kolarevici, Bucje) and Mokra Gora, which have many natural resources such as forests, rivers, etc. Therefore, it is very important to understand and show hydrometallurgical treatments of lateritic ores via mining and metallurgy in different parts of the world. In this paper, several exploitation scenarios for hydrometallurgical treatment and benefication of lateritic ores will be shown: Direct Nickel Process, Ravensthorpe and Murrin Murrin in Australia and Meta Cobalt Nickel in Turkey.

Kinetic study on leaching of nickel from Turkish lateritic ore in nitric acid solution

Dissolution kinetics of nickel from lateritic ore in nitric acid solution was investigated. Experimental parameters used were stirring speed (100-600 r/min), temperature (40-96 °C), nitric acid concentration (0.1-2 mol/L) and particle size (<106 µm). The shrinking core model was applied to the results of experiments investigating the effects of leaching temperature in the range of 40-90 °C and nitric acid concentration in range of 0.1-2 mol/L on nickel dissolution rate. The kinetic analysis shows that the nickel dissolution from lateritic ore could be described by diffusion model. The activation energy (Ea) for the dissolution reaction is calculated as 79.52 kJ/mol.

Bacterial bioleaching of low grade nickel limonite and saprolite ores by mixotrophic bacteria

Utilization of indigenous bacteria should be considered to establish a successful biohydrometallurgical process. In this study, mixrotrophic iron-oxidizing bacterial consortia consisting of Comamonas testosteroni, Alicyclobacillus ferrooxydans and Pantoea septic which were isolated from Indonesian mineral ores were examined to determine their abilities to recover nickel from limonite and saprolite ores in the bioleaching experiments using stirred tank reactors. The nickel bioleaching experiments inoculated with the bacterial consortia were carried out using coarse limonite ores and weathered saprolite ores with pulp density of 10% w/v. Abiotic controls were also carried out replacing the inocula by the sterile medium. The bioleaching processes were monitored by measuring Ni and Fe contents and pH of the leaching solution as well as the total bacterial enzymatic activity measured as FDA hydrolytic activity. The effect of leaching on the mineralogy of laterite ores was investigated by the scanning electron microscope equipped with energy-dispersive spectroscopy (SEM-EDS) and X-ray powder diffraction (XRD). After 28 days of incubation, the FDA hydrolytic activity was observed in both bioleaching experiments containing limonite (17.2 μg fluorescein/mL) and saprolite ores (16.9 μg fluorescein/mL). The leached Ni and Fe in the bioleaching experiments containing limonite ores (30% Ni and 5.6% Fe) was greater than that in abiotic controls (1% Ni and 0.1% Fe) with the pH range of 2.5 to 3.5. However, the bacterial consortia were less capable of bioleaching of Ni (2.5%) with the similar leached Fe (6%) from the saprolite ores. In abiotic controls, the medium pH remained relatively constant (pH 6). It was concluded that these bacterial isolated as the consortium were capable of nickel bioleaching (precious metal) more effectively than iron (gangue metal), thus being applicable to the commercial processing of the difficult-to-process low-grade nickel laterite ores in Indonesia.

Cobalt and Nickel Separation in Nitric Acid Solution by Solvent Extraction Using Cyanex 272 and Versatic 10

Recent trend in extraction of nickel and cobalt from laterite ore through hydrometallurgical route is by using leaching agents that can be effectively regenerated, such as hydrochloric and nitric acid. Despite success stories of nickel laterite leaching in nitric acid, investigations on separation of nickel and cobalt from pregnant leach solution in this leaching media are still poorly reported. Nickel and cobalt are mostly recovered in the forms of intermediate products such as mixed hydroxide precipitate (MHP) and mixed sulphide precipitate (MSP). In this paper, separations of cobalt and nickel in nitrate solution and in pregnant leach solution of nickel laterite ore from Indonesia are discussed. Series of solvent extraction tests using Cyanex 272 and a combination of Versatic 10 and Cyanex 272 were performed under variations of equilibrium pH, extractant concentration, temperature and volume ratio of organic to aqueous phase (O/A ratio). The investigation results demonstrate that Cyanex 272 can be effectively used to separate cobalt and nickel in a solution with low nitrate concentration at the absences of Fe and Mg. The increase of equilibrium pH, extractant concentration, O/A ratio and temperature tends to enhance cobalt extraction and co-extraction of nickel. The best condition for separation of Co and Ni was obtained at equilibrium pH of 5, Cyanex 272 concentration 20% (v/v), temperature 25oC and O/A ratio 1/1. Separation of Co-Ni and Mg from pregnant leach solution can be well performed by 2 stage-SX using Versatic 10 followed by Cyanex 272 and selective stripping of loaded organic from the second stage of the extraction by using 1 molar sulfuric acid.

Thermodynamics of the Reduction Roasting of Nickeliferous Laterite Ores

The global nickel sulphide resources are becoming more difficult to mine and, as a result, there is increasing interest in the current and future development of the oxidic nickel laterite deposits. In comparison to the sulphide ores, the nickel laterites cannot be readily upgraded by conventional means and growing attention is being focused on the development of new methods for processing these ores. In this paper, firstly, brief overviews of laterite ore mineralogy and the conventional techniques used to extract the nickel from both the limonitic and the saprolitic nickeliferous laterites are provided. Secondly, previous research on the thermodynamic modelling of the reduction of the laterites is discussed. Thirdly, an improved thermodynamic model is used to predict the equilibrium products arising from the solid state reduction of both the limonitic and the saprolitic ores. Based on these thermodynamic predictions, the reduction behaviors of the two ore types are compared in terms of nickel recovery and grade in the ferronickel product. The effects of reduction temperature, ore composition and carbon additions were studied. Finally, the results from the simulations are compared to the experimental data available in the literature.

Bioleaching of lateritic nickel ore with acidophilic bacteria

Bioleaching of lateritic nickel ore with acidophilic bacteria

赤泥中有价元素的提取和回收

赤泥是氧化铝生产过程中的强碱性固体粉末状废弃物，本文简要概述了赤泥的基本特性，着重阐述了国内外从赤泥中回收有价金属元素铁、铝、钛和其他稀土元素的工艺，并对其进行了评析。最后对赤泥的综合利用进行了展望，而赤泥与红土镍矿制备铁镍合金的方法前景广阔。 Red mud is a strong basicity solid waste residue of the digestion of bauxite ores with caustic soda for alumina production. This paper gives a overview of the basic characteristics of red mud and also puts great emphasis on the recycling technologies both at home and abroad, which mainly deal with those valuable metals come from red mud, such as Fe, Al, Ti and RE elements. And last, this paper points out there is a high trend towards the comprehensive utilization of red mud, hence, it is a booming prospective concerning the productive process of preparing iron nickel alloy by the smelting of red mud and lateritic nickel ore.

LEACHING BEHAVIOUR OF A TURKISH LATERITIC ORE IN THE PRESENCE OF ADDITIVES

This paper investigates the dissolution mechanism of a lateritic nickel ore from the Caldag Region of Manisa in Turkey. The ore sample contained 1.2% Ni, 24.8% Fe, and 0.062% Co. The optimum leaching conditions were found to be temperature 80 o C, particle size -74 µm, H2SO4 concentration 200 g/dm 3 , solids ratio (by weight) 10% and leaching duration 8 h. The extractions of 98.2% Ni, 98.6% Fe and Co 98.9% were obtained under these conditions. Additionally, the effects of additional substances such as NaCl, Na2S2O5, Na2SO4, and KCl were investigated in order to decrease the leaching duration. The results showed that the additives accelerated the leaching kinetics and achieved nearly the same nickel and cobalt extractions at the end of 4 h compared to the results obtained after 8 h without the additives. If the additives containing chlorine were used, it was determined that the iron extraction showed no increase, although both the nickel and cobalt extractions increased.

Solvent extraction of scandium from lateritic nickel- cobalt ores using different organic reagents

Scandium is the most important and strategic metal that can be recovered as a by-product from lateritic nickel-cobalt ores. In this research, different extractants were investigated in order to extract scandium from a sulfate medium by a using a solvent extraction method. Generally, the organic extractants are classified as acidic, neutral and basic organophosphorus compounds. However, in solvent extraction of scandium, the acidic and neutral organophosphorus compounds are preferred due to their higher extraction efficiencies. Thus, the aim of the present study was to compare the scandium extraction efficiencies of some acidic and neutral organic reagents. For this reason, Ionquest 290 (Bis(2,4,4-trimethylpenthyl) phosphonic acid), DEHPA (Di(2-ethylhexyl) phosphoric acid), Cyanex 272 ((Bis(2,4,4-trimethylpentyl) phosphinic acid) which are acidic organophosphorus compounds, and Cyanex 923 (Trialkylphosphine oxide), which is a neutral organophosphorus compound, were used. The extraction capacities of these organics were studied with respect to the extractant concentration at same pH and phase ratio. As a result of the study, DEHPA was found to have higher scandium extraction efficiency with lower iron extraction at pH = 0.55 at a phase ratio of 10:1 = A:O.

Development of Mixed-Chloride Hydrometallurgical Processes for the Recovery of Value Metals from Various Resources

Demand of nickel, titanium, aluminum and gold is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Chloride-based processes have several advantages over the conventional hydrometallurgical and smelting processes including higher leachability of complex ores, stability of chloro-complexes and regeneration of leaching reagents. Considering these advantages of the chloride chemistry, innovative mixed-chloride process flowsheets have been developed for the recovery of these metals from low grade laterite, ilmenite, bauxite and refractory complex ores and concentrates. These processes also produce value added byproducts such as cobalt, vanadium and iron oxide. Advantages of addition of magnesium chloride to hydrochloric acid, leaching and separation reaction mechanisms, and developed flowsheets are also discussed.

Thermodynamic analysis of the reduction process of Colombian lateritic nickel ore

The Colombian nickeliferous laterites are minerals used for the nickel extraction by hydrometallurgical and pyrometallurgical processes. In this work the thermodynamic behaviour of three Colombian lateritic mineral samples are described, with contents of 1.42%, 1.78% y 2.04% of nickel, when they are subjected to the calcination and reduction processes. The mineral was characterized using X Rays Diffraction and X Rays Fluorescence, giving evidence of the presence of mineralogical species such as nepouite (Ni3Si2O5(OH)4), goethite (Fe2O3.H2O), silica (SiO2), antigorite (Mg3Si2O5(OH)4) and fosferite (Mg2SiO4). The thermodynamic analysis was conducted using the software HSC Chemistry for Windows 5.1 and was focused in the quantitative determination of the chemical evolution of the mixture of these minerals with variable quantities of coal, in function of temperature. The results produced by the program showed, in the equilibrium, the feasibility of complete reduction of the nickel, and additionally, a considerable high percentage of reduction of iron oxides (up to 99%) using ratio C/O ≈1 at temperatures close to 1100 °C.

Life cycle assessment of ferronickel production in Greece

Ferronickel (FeNi) is predominantly produced from nickeliferous laterite ores which are converted into a product with a nickel content of around 20%. With increasing emphasis being put on energy efficiency and global climate change, it is important for the nickel industry to further explore energy saving issues and to evaluate a number of potential opportunities for reducing the greenhouse gas footprint of primary FeNi production. The present study adopted a life cycle assessment (LCA) approach to assess energy consumption and greenhouse gas footprints of the main processing stages of a typical Greek nickel laterite ore for the production of ferronickel. In this context, a detailed life cycle directory was created based on facility-specific data and used for a holistic cradle-to-gate LCA analysis (including mining and the main ore processing routes). The following energy and environmental indicators were assessed: global warming potential (GWP), acidification potential (AP) and primary energy demand (PED). Using current FeNi production as a baseline scenario (BL), two alternative scenarios, namely (i) the green energy (GE) scenario that involves 50% substitution of fossil fuels mix (lignite and coal) with biochar and 50% substitution of lignite with renewable resources for electricity production, and (ii) the waste utilization (WU) scenario that includes 65% utilization of slag in the construction sector, to improve energy and waste utilization, minimize the adverse environmental impacts and therefore achieve more sustainable FeNi production were investigated. Results showed that the best alternative scenario for energy savings and reduction of associated GHG emissions during FeNi production was the GE scenario. With this scenario energy savings and GHG emissions were about 17% and 35% lower compared to BL scenario, respectively. Lower reduction in energy consumption (7%) and GHG emissions (13%) compared to the BL scenario was attained when the WU scenario was considered.