Laterite Ore Research Articles

X-Ray mapping and the mineralogy pattern of nickel laterite ore: Bavanat, Fars, Iran

According to the classification of the nickel laterite, this paper describes mineralogy test is to reveal where valuable elements are located in the ore, in which mineralogical form. The purpose of the sieving test was to study if some specific particle size contains most of the valuable metals. Based on its chemical composition nickel laterite is classified as a limonite type and the nickel and cobalt content was 0.7 and 0.04%, respectively. Nickel is predominantly associated with hematite and goethite. Based on the mineralogical analysis of the ore, it is observed that remarkable part of nickel is located in hematite. Therefore, nickel cannot be released from hematite lattice. The nickel content in the laterite was 0.7% and the cobalt content 0.04%. The chemical composition of laterite equals with the occurrence of 38.9% iron oxides, 26.9% carbonates, 26.9% quartz, 4.8% chromite, 2.7% magnetite and 1.9% other minerals. EDS line profile analyses were completed on hematite/goethite ooids and there was a slight correlation in the quantities between iron and nickel in each individual ooid. However, iron and nickel do not always show a positive correlation. Nickel grade could be enriched from 0.7 wt.-percent to 0.91 wt.-percent; however nickel recovery was only 45%.

Nitric acid pressure leaching of laterite ores

Nitric acid pressure leaching of laterite ores

Sodium-Salt-Assisted Reductive Roasting for Separation and Enrichment of Valuable Components from Lateritic Iron Ore

The dual effect of sodium-salt-assisted reductive roasting for iron recovery and chromium enrichment from lateritic iron ore was investigated. Iron oxides were reduced to metallic iron through reductive roasting, while Al- and Si-bearing components were transformed to sodium aluminosilicate and/or diaoyudaoite. Thus, direct reduced iron (DRI) was recovered by magnetic separation, while Cr(III) element was enriched as nontoxic picotite in a Cr-bearing concentrate through sulfuric acid leaching. Na2CO3 was preferred due to its positive effect in activating Al- and Si-bearing components and contribution to good chromium enrichment. In contrast, Na2SO4 exhibited a stronger ability to improve the growth of metallic iron, resulting in better magnetic separation. Addition of Na2SO4 generally led to inferior aluminum leaching performance due to the formation of insoluble diaoyudaoite (NaAl11O17). When using combined addition of sodium salts in the optimized proportion in reductive roasting, DRI with 89.21% Fe and chromium concentrate with 40.42% Cr2O3 were obtained.

Investigations on mineralogical characteristics of Indonesian nickel laterite ores during the roasting process

Nickel is obtained from laterite ores by a metallurgical process to produces ferronickel. Nickel metal is present in a carrier mineral, a nickel magnesium silicate hydrate compound called garnierite. Garnierite is the common name of magnesium silicate hydrate minerals including chlorite, clay and serpentine. This study to investigate the phase formed when the nickel ore is roasted from a temperature of 600°C to a temperature of 1000°C under atmospheric enviromental. Microscopic analysis of roasted samples was analyzed by SEM-EDX and the dehydroxylation and recrystallization was studied using DTA-TGA. The endothermic peak was appear at 78.8°C, 293.7°C and 638.0°C, this corresponds to the release of free water and the release of crystalline water. While the exothermic peak occurs at 828.0°C. The exothermic temperatures associated with structural changes due to dihydroxylation of serpentine into a forsterite phase. Based on the XRD graph it is known that the sample of the roasting will produce the olivine and forsterite phases.

HYDROMETALLURGICAL PROCESSING OF NICKEL LATERITES- A BRIEF OVERVIEW ON THE USE OF SOLVENT EXTRACTION AND NICKEL/COBALT PROJECT FOR THE SEPARATION AND PURIFICATION OF NICKEL AND COBALT

In this study, a brief overview of the solvent extraction (SX) application for the separationand purification of nickel and cobalt in hydrometallurgical processing of laterite nickel ores ispresented. This paper consists of two parts: firstly, the SX of nickel and cobalt from sulphateleach solutions is described; and secondly, the development of hydrometallurgical plants forthe processing of laterite nickel ores that involve solvent extraction technique is discussed. Themost important extractants are shortly given in the first part of the study. It is seen that theextraction and separation of nickel and cobalt from the impure leach solution of laterite nickelores can be performed by either using a single extractant system that is called as a direct solventextraction (DSX) or a mixture of two or more extractant which is known as a synergistic solventextraction system (SSX). Mixed sulphide precipitation (MSP) and mixed hydroxide precipitation(MHP) processes are mentioned. This paper is also addressed advantage and disadvantages ofeach extraction system. It is shown that capital investment expenditure, operational investmentexpenditure and mineralogical content are the most important factors that can affect the selectionof the appropriate hydrometallurgical process for lateritic nickel ore.

Study on Phases Development and Mechanical Properties in a Fe-Ni-Al Carbide Free Bainitic Steel Based on Lateritic Steel After Warm Rolling

The abundant reserve of lateritic ores in Indonesia is currently processed and studied to fulfil the national steel demand in several sectors, one of which is for railway application. The development of lateritic steel (Fe-Ni) as carbide free bainitic steel is carried out by adding Al to the Fe-Ni alloy. In this research, the effect of warm rolling and Al addition to the formation of carbide, phases development and mechanical properties was studied. The warm-rolled thermomechanical process (TMCP) was carried out by heating the material at 945°C for 20 minutes followed by second heating to 400°C, 450°C and 500°C with holding time for 30 minutes. The materials then warm rolled with 50% and 70% reductions using 20 tons capacity roller machine and then air cooled outside the furnace chamber. The microstructure of the as-rolled materials was characterized using optical microscope (OM) and scanning electron microscope (SEM), while the phases, the chemical distribution and the possibility of carbide formation were examine using X-Ray Diffraction (XRD) pattern and energy dispersive X-Ray spectroscopy (EDS). The mechanical properties of the material were observed using macro Rockwell hardness test. It was revealed that the addition of Al altered the phases of Fe-Ni lateritic steel significantly. Furthermore, Al addition gives positive effects to the Fe-Ni lateritic steel by increasing hardness. The reductions applied during warm rolling were observed to have effect on the growth of the grains in the Fe-Ni-Al lateritic steel.

Study on Leaching and Biosorption Processes of some Economic Metals using Escherichia coli from Laterite Ore, Sinia, Egypt

The potentiality of Escherichia coli dead biomass for biosorption of rare earth elements (REEs) and uranium (VI) from chloride leach liquor of laterite ore was evaluated. The effects of different acid, different concentration of hydrochloric acid, contact time, solid/liquid phase ratio and temperature on leaching efficiency of laterite ore were investigated.

Optimal conditions for selective reduction process of Nickel Laterite Ore

A low-grade nickel laterite ore from Indonesia was selected to investigate the effect of temperature and time of reduction upon the extraction of nickel through the selective reduction-magnetic separation process to produce the ferronickel. The nickel ore was mixed with5 wt.% of anthracite coal and 10 wt.% of sodium sulfate additive. The mixed ore was pelletized into 10-15 mm of diameter. A series of selective reduction processes were carried out into the pellet ores at various temperatures of 950-1150 °C for 60-120 minutes. The optimal selective reduction parameters of nickel laterite ore were observed clearly. The experimental results indicated that the reduction reactions proceed more completely at a higher temperature and longer reduction time. The optimum of nickel grade and recovery in the ferronickel concentrate was obtained at the reduction temperature of 1150 °C for 120 minutes, which was 8.45% and 72.1%, respectively. The increasing of temperatures and times of reduction process resulted in higher of troilite phase formation which suppressed the iron metallization and also increased the ferronickel particle size.

Metallurgical Beneficiation of Iron Laterite Ores with the Formation of a Metallic Nickel–Cobalt Concentrate

A new process is developed for metallurgical beneficiation of iron laterite nickel-containing (limonite) ores with the formation of a metallic nickel–cobalt concentrate. This process includes reducing roasting of the ores with sulfur-containing additions in the temperature range 1100–1200°C, the fragmentation of the roasting product, and the magnetic separation of metallic and slag phases. The coarsening of metallic particles in roasting is shown to occur with the participation of a low-melting-point phase (iron oxysulfide Fe(O,S)). In this case, nickel and cobalt concentrate in a metallic phase in the form of an alloy with iron (ferronickel). At the optimum charge composition and reducing roasting parameters, ferronickel particles coalesce and grow to 40–100 μm, which creates favorable conditions for the subsequent beneficiation of the roasting product (cinder) by magnetic separation. After wet magnetic separation of a fragmented cinder, the extraction of nickel and cobalt into a magnetic fraction is 92 and 84%, respectively. When a poor limonite ore (1.03% Ni, 0.05% Co) is processed according to the developed technology, the synthesized metallic concentrate contains up to 8.3% Ni and 0.37% Co.

Effect of sodium sulfate and sodium chloride in two-stage thermal upgrading of low-grade Nickel Lateritic Ore

Selective reduction process and magnetic separation of nickel lateritic ore were conducted through the two-stage thermal mechanism with the addition of sodium sulfate and sodium chloride as the additives agent. The first thermal process was pre-heating at the temperature of 500°C and holding for 90 minutes. Afterward, the reduction continued at the temperature of 1150°C for the same holding time. The mineralogical composition of the reduced samples was determined by XRD. The microstructure of reduced nickel laterite ore was also examined using SEM-EDS. The optimum composition of the additive was the combination of 10% Na2SO4 + 10% NaCl, which produced a concentrate with 5.52% and 85.89% for nickel grade and nickel recovery, respectively.

Surfactant-assistant atmospheric acid leaching of laterite ore for the improvement of leaching efficiency of nickel and cobalt

Atmospheric acid leaching has attracted great attention from scientists due to the mild leaching conditions. However, the leaching efficiency of nickel is lower than that using high pressure acid leaching. Herein, we report the use of a surfactant (e.g., stearyltrimethyl ammonium chloride, STAC) to improve the leaching efficiency of Ni. The effects of surfactant type, ore-surfactant ratio, leaching temperature, and leaching duration on the leaching ratio of Ni were investigated. The use of STAC resulted in the high efficiency for Ni leaching at 100 °C with an ore-surfactant ratio of 15 and leaching duration of 8 h. The leaching efficiencies of Ni and Co were significantly higher than that of atmospheric acid leaching. The surface tension and viscosity of the leaching solution, and the zeta potential of the leached residue were analyzed to investigate the mechanism of the leaching process. The changes of interfacial properties improved ionic diffusion and decreased metal adsorption, which further lead to the increasing of leaching efficiency.

Experimental study into the beneficiation of a ferruginous rare earth bearing lateritic ore by magnetising roasting and magnetic separation

The beneficiation of ferruginous rare earth bearing ores derived from lateritic deposits by conventional mineral dressing processes is usually difficult due to characteristics of these ores such as fine grain size, complex texture and similar physical characteristics between rare earth minerals and iron oxide gangue. The removal of iron oxides would offer significant advantages with respect to downstream rare earth mineral processing. The purpose of this study was to demonstrate at bench scale the feasibility of magnetically separating iron oxides from a ferruginous lateritic rare earth ore after the ore had been subjected to reduction roasting to convert feebly magnetic iron (III) oxides to magnetite. The effects of magnetic field strength and feed top size on the efficiency of low intensity magnetic separation (LIMS) was explored through rougher magnetic separation tests using a Davis tube tester and chemical and mineralogical analysis of the rougher magnetic concentrates and tails was performed. Magnetic separation was successful in removing iron (as magnetite) to the concentrate at a minimum field strength of 0.2 T; this was however non-selective, with significant amounts of rare earths reporting to the magnetic fraction. The rare earth enriched tails showed decreased grade and recovery and this was due to a number of factors including insufficient liberation, presence of iron oxide coatings on mineral surfaces and heteroflocculation. The findings of this study provided insight towards the potential optimisation and viability of the proposed process of magnetising roasting and low intensity magnetic separation as a means to beneficiate ferruginous lateritic rare earth ores.

New insights into nanomineralogy and geochemistry of Ni-laterite ores from central Greece (Larymna and Evia deposits)

Nickeliferous laterite ores from two typical central Greece deposits (Larymna and Evia), currently used in the LARCO GMMSA smelting plant to produce ferronickel, were characterized using a combination of diffraction, microscopic, and analytical techniques. X-ray diffraction patterns of various fractions, with emphasis to the clayey material (<2 μm), after glycolation and heating at 550 °C, indicated that both materials contain crystalline Fe3+ oxide (hematite) and chlorite-group phyllosilicates, whereas the Evia sample contains additional illite. Transmission electron microscopy investigations revealed that the LARCO laterite ores consist of complex nanoscale aggregates of the above-mentioned phases. Different Ni-bearing Mg-Fe-phyllosilicates (mainly chlorite-group minerals), occur in mixture with hematite. Nickel is present in all examined phases, and therefore the separation of pure Ni-phases, by physical or chemical methods, is practically unfeasible. Trace element bulk analyses showed that there no significant differences, with regarding to Ni content concentrations (ca. 0.6–0.7 wt.%), between the initial ore and the clay fraction, for both the Larymna and Evia laterites (ca. 30% and 26% wt.% enrichment respectively). However, the Larymna ore contains double quantities of Co and it is enriched in rare earths compared to Evia (ΣREE = 774 ppm and 76 ppm respectively), while Sc concentrations are comparable in both mining areas (64 ppm and 42 ppm respectively). Discrimination diagrams (e.g. Th/Sc vs. Zr/Sc and Ce/Ce* vs. Eu/Eu*) showed that LARCO laterite Ni-ores do not exclusively originate in ultrabasic -ophiolitic- rocks as previously considered.

The effect of hot rolling on hardness properties and microstructure of laterite steel

Nickel containing pig iron (NCPI) is one of important materials for stainless steel and other iron-nickel alloys production. The natural source of NCPI in Indonesia is laterite ore. Large deposit of laterite ore has been found in South East Sulawesi. High grade laterite ore (saprolitic type of laterite ore) in this region has been used for ferronickel making, whereas low grade laterite ore (limonitic type of laterite ore) has not been processed, due to its too low nickel conten. However, laterite steel has not been widely reviewed as potential candidate for top national product comprehensively. Therefore, this study is aimed to know several aspects of its intrinsic properties by using hot roll process. A variety of thickness reduction on steel is used by rolling to know its mechanical properties especially hardness, followed by microstructure observation, and then compared with its as-cast. The result has shown that the highest hardness (282HRB) obtained in 31-35% reduction which is increased by 47,7% of as cast steel. Optical microscope images showed that ferrite phase and grain refinement which is caused an increasingon hardness. This study is expected as a reference for further research. The chemical composition of steel Laterite as more likely as HSLA steels with certain specialized alloys to obtain specific mechanical properties. Meanwhile the hardness of Laterite steel is possible for some products similar to AISI416 standard.

Structural characterisation of lateritic nickel ore of Indian origin

ABSTRACT This paper presents results on characterisation of a lateritic nickel ore of Indian origin (Sukinda, Orissa) by various physical, chemical and thermal techniques. The study also includes quantitative phase analysis (QPA) of high resolution XRD plot using Rietveld structural refinement with the aid of pseudo-Voigt peak shape model. The overburden sample contained four major crystalline phases, namely quartz, goethite, iron chromite and aluminium silicate hydroxide. The information obtained from various techniques corroborated well with the results of Rietveld structural refinement.

Kinetic analysis on nickel laterite ore calcination using model-free and model-fitting methods

Calcination and partial reduction at temperatures below 1000 °C is a primary step in pyrometallurgical extraction of nickel from laterites. Identifying the main reactions that occur during this process and investigating their kinetics provide valuable information on the rates of the reactions and their degree of completion. The main reactions were identified using thermal gravimetric analysis-differential scanning calorimetry (TGA-DSC), X-ray diffraction, and scanning electron microscope energy dispersive spectroscopy (SEM-EDS) tests. Transformation of goethite to hematite, dissociation of lizardite to forsterite and silica, and decomposition of silicate were identified as the main reactions. The kinetic parameters for the three main reactions were obtained using both model-free and model-fitting methods. Comparing the activation energy obtained by the two kinetic approaches, Avrami-Erofeev model was selected as the kinetic model for the aforementioned reactions.

Oxidative dissolution of nickel matte in dilute sulfuric acid solutions

Nickel matte (Ni3S2) is the most common feedstock for producing nickel oxide and nickel metal in associated refineries. Nickel matte is produced from sulfide or laterite ores, and contains around 73 wt% nickel. This study investigated the dissolution parameters of nickel matte in dilute sulfuric acid media in the presence of air as oxidant with the goal of presenting a cost-effective process for leaching nickel matte. The dissolution experiments were carried out to examine the following effects: air flow rate, stirring speed, S/L ratio, acid concentration, reaction temperature, reaction time and the amount of ferrous sulfate added. Nickel extraction of 90% and cobalt extraction of 80% were achieved using dilute H2SO4 and sparging of air as a source of oxygen. To increase the dissolution percentage of the matte, ferrous sulfate addition was studied and the oxidation and reduction potential (ORP) was measured to investigate the effect of ferrous ions on nickel and cobalt recovery. The highest nickel dissolution percentage (95%) was observed with the initial addition of 1200 mg/L Fe (II). Characterization of samples has been carried out with quantitative X-ray diffraction (XRD) and scanning electron microscopy, along with an energy dispersive system (SEM-EDS).

Assessing the Influence of NaCl on the Reduction of a Siliceous Laterite Nickel Ore Under Caron Process Conditions

The reduction by hydrogen and the thermal decomposition of a siliceous nickel laterite ore in the presence of NaCl were studied using thermogravimetric analysis (TGA). Reduction tests on H2 atmosphere in rotary kiln were performed in the presence of NaCl and the product of the reaction was leached in ammoniacal solution. The presence of only 1 pct of NaCl in the furnace increased the nickel extraction values from ≈ 3 to ≈ 90 pct when the experiment was carried out at 850 °C. According to the results of X-ray diffractometry and TGA, the presence of NaCl in the system and the reducing atmosphere of H2 promote the segregation of nickel according to the following steps: (1) Nickel oxide reduction by hydrogen: NiO + H2(g) → Ni + H2O(g). (2) Formation of HCl: Al2SiO5 + 2NaCl + SiO2 + H2O → 2HCl(g) + 2NaAlSiO4. (3) Chlorination of metallic nickel by HCl: Ni + 2HCl(g) → NiCl2 + H2(g). (4) Reduction of nickel chloride by hydrogen: NiCl2 + H2(g) → Ni + 2HCl(g).

Cost-combined life cycle assessment of ferronickel production

PURPOSE: Ferronickel is irreplaceable in modern infrastructure construction because of its use in stainless steel production. This study explored the cost-combined environmental impacts of ferronickel production in China which is the largest producer and consumer of ferronickel in the world. METHODS: Life cycle impact assessment was combined with life cycle costing analysis to assess the environmental and economic performance of ferronickel production in China. Both internal cost (e.g., raw materials, energy, transport, infrastructure, tax, and labor) and external cost (i.e., human health, ecosystem quality, and environmental emission) were considered. RESULTS AND DISCUSSION: The environmental burden of ferronickel production in this study was mainly attributed to the damage on resources and human health as endpoints caused by indirect processes, such as electricity supply, transportation, coke production, lateritic nickel ore acquisition, and coal mining. Carbon dioxide, mercury, particulates, methane, sulfur dioxide, nitrogen oxides, coal, and nickel ores were the substances pivotal for optimizing environmental performance. The total economic cost was 2734.8 $/t, of which 2333.3 $/t was internal cost and 401.5 $/t was external cost. Lateritic nickel ore, electricity, human health cost, and transport contributed 44.9%, 20.6%, 14.2%, and 4.8% to the total economic cost, respectively. The remaining economic burden was mainly divided to coke, coal, argon, labor, equipment, and tax. CONCLUSIONS: A win-win case for the environment and economy can be achieved by optimizing electricity and lateritic nickel ore quality, including its transport. Application of other power types (e.g., hydro, wind, and solar electricity) as a substitute for thermal power can also reduce environmental impacts considerably. Sites with high steel yield, low thermal power ratio, and high port proximity, such as Fujian Province, are the primary choices for ferronickel production. Finally, although the economic benefits of coke and coal are minimal, their efficiency in environmental improvement is crucial.

Reactive Transport Modeling Applied to Ni Laterite Ore Deposits in New Caledonia: Role of Hydrodynamic Factors and Geological Structures in Ni Mineralization

AbstractThis study is devoted to understanding the impact of topography and hydrodynamics on the formation of high‐grade supergene nickel deposits. The investigation proposes a new conceptual mineralization model that describes the formation of various exceptionally Ni‐enriched hot spots observed in lateritic profiles. Numerical analysis of the effects of local hydrodynamics on deposits formation is performed by means of PHREEQC geochemical simulator and COMSOL Multiphysics software. These are coupled through an iCP Java interface that allows to code their level of interaction and facilitates the exchange of parameters. The model developed extends the currently existing geochemical formulation of nickeliferous laterite formation from peridotite carried out in 1‐D and is additionally capable of simulating mass solute transport and geochemical processes within complex fractured‐porous systems. The simulations improve our understanding of metal enrichment in saprolite and bedrock zones. It was shown that, although the initial development of nickel lateritic ores takes a few million years, they are prone to relatively quick leaching and subsequent redistribution of Ni when the topography changes in response to tectonic processes. The latter leads to the formation of rich nickel deposits at the bottom of the slope, mostly due to leaching of the saprolite material. In addition to the role of changes in topography, the critical impact of fractures and fracture networks on metal mobility and distribution was identified. The model developed provides significant insight into the distribution of mineral resources, in particular Ni deposits, and can be of great help for future mineral prospecting in industry.