Significant influence of self-possessed moisture of limonitic nickel laterite on sintering performance and its action mechanism

In consideration of the abundant moisture of limonitic nickel laterite mined, it is essential to determine whether the self-possessed moisture of limonitic nickel laterite after pre-dried is appropriate for sintering. Thus, based on the characterization of limonitic nickel laterite, the influence of its self-possessed moisture on sintering performance was expounded by sinter pot tests and the relevant mechanism was revealed by the systematical analyses of the granulation properties of sinter mixture, thermodynamic conditions during sintering and mineralogy of product sinter. The results indicate that the self-possessed moisture of limonitic nickel laterite indeed has significant influence on its sintering performance. At the optimum self-possessed moisture of 21 mass%, sinter indices are relatively better with tumble index, productivity and solid fuel rate of 48.87%, 1.04 t m−2 h−1 and 136.52 kg t−1, respectively, due to the superior granulation properties of sinter mixture and thermodynamic conditions during sintering, relatively large amount of silico-ferrite of calcium and alumina and tighter sinter microstructure. However, sintering performance of limonitic nickel laterite is still much poorer than that of ordinary iron ores. It is feasible to strengthen limonitic nickel laterite sintering by inhibiting the over-fast sintering speed and improving the thermodynamic conditions during sintering.

Objective Domain Boundaries Detection in New Caledonian Nickel Laterite from Spectra Using Quadrant Scan

Modelling of 3D domain boundaries using information from drill holes is a standard procedure in mineral exploration and mining. Manual logging of drill holes can be difficult to exploit as the results may not be comparable between holes due to the subjective nature of geological logging. Exploration and mining companies commonly collect geochemical or mineralogical data from diamond drill core or drill chips; however, manual interpretation of multivariate data can be slow and challenging; therefore, automation of any of the steps in the interpretation process would be valuable. Hyperspectral analysis of drill chips provides a relatively inexpensive method of collecting very detailed information rapidly and consistently. However, the challenge of such data is the high dimensionality of the data’s variables in comparison to the number of samples. Hyperspectral data is usually processed to produce mineral abundances generally involving a range of assumptions. This paper presents the results of testing a new fast and objective methodology to identify the lithological boundaries from high dimensional hyperspectral data. This method applies a quadrant scan analysis to recurrence plots. The results, applied to nickel laterite deposits from New Caledonia, demonstrate that this method can identify transitions in the downhole data. These are interpreted as reflecting mineralogical changes that can be used as an aid in geological logging to improve boundary detection.

Linking Serpentinization and Weathering of Peridotite: A Study on the Mineralogical and Geochemical Evolution of the Sta. Cruz Nickel Laterite Deposit, Zambales, Philippines

While there are extensive studies on the mineralogy and geochemistry of laterites worldwide, the temporal and spatial mineralogical development of a typical nickel laterite profile is still poorly constrained. In this study, we present a detailed mineralogical and geochemical characterization of samples systematically collected from a nickel laterite profile at the Sta. Cruz nickel laterite deposit, Zambales, Philippines, to describe the temporal and spatial development of the laterite profile. Wavelength-dispersive X-ray fluorescence spectroscopy (WDSXRF), mass balance-element mobility calculations, transmitted and reflected light microscopy, and previously reported results from coupled X-ray diffraction (XRD) and Rietveld refinement analyses, reveal that the laterite profile investigated is composed of two main horizons: the limonite and saprolite zones, separated by a thin transitional zone. The main zones are further subdivided into subzones based primarily on the mineral assemblage and major element chemistry: upper limonite, lower limonite, transitional zone, upper saprolite, and lower saprolite. Late-stage garnierite veins were observed cutting the upper and lower saprolite subzones. Investigation of the structure of goethite within the limonite zone via Rietveld refinement show that the crystallinity of goethite decreases with increasing Ni content and increasing crystallite size. This suggests that upwards through the limonite zone, as goethite ages, its crystallinity increases which possibly results in the removal of Ni from its crystal structure and eventual remobilization to the lower laterite zones. We propose a spatio-temporal model of the formation of the Sta. Cruz laterite consisting of four stages: (1) early-stage alteration, (2) continued serpentinization and volume expansion, (3) late stage serpentinization and incipient oxide formation, and (4) goethite ageing and garnierite formation.

SWOT Analysis in Determining Environmental Risk Management Strategy in Medium Scale Nickel Laterite Mining (Case Study in PT Rohul Energi Indonesia)

Nickel is an essential metal in modern infrastructure, with significant uses in the stainless-steel industry for less than 65%. Nearly 70% of the world’s nickel laterite production comes from Indonesia and the Philippines. The high demand for nickel-based materials globally and the availability of nickel laterite ore in Indonesia make laterite nickel mining in Indonesia inevitable. Medium and small mining companies are more likely to have a more significant impact on the environment than large companies. Therefore, it is necessary to evaluate the implementation of environmental risk and impact management, and develop a company strategy. The research was conducted by qualitative method, namely by descriptive analysis and SWOT analysis. The data was collected in interview text, questionnaire results, field notes, documentation, photos, and videos. SWOT is one of the methods to analyze the strategy of an organization by identifying and measuring strengths and weaknesses, and opportunities and threats of the organization. Result is obtained score 3.77 (the X-axis), and 0.34 (the Y-axis) and will be plotted into a quadrant graph of the SWOT analysis method. The research resulted in PT. REI is in quadrant I. Therefore, the strategy would be utilizing the strengths and opportunities of the organization.

Role of bedrock serpentinization on the development of nickel laterite deposit in Sorowako, Sulawesi, Indonesia

The objective of this research is to analyze the role of bedrock serpentinization on the development of Ni-Laterite deposits in Sorowako, Sulawesi Island, Indonesia. Samples were obtained from coring data in three areas, namely the West Block, East Block, and Petea, which are subject to mineralogical and geochemical analyses. Petrography of the bedrocks was conducted to analyze the mineral composition, texture, and serpentinization degree, and later correlated with the distribution of geochemical elements from X-ray fluorescence method in each laterite zone. The bedrock in the West Block is dunite which consists of predominantly olivine with low degree serpentinization. The bedrock in the East Blocks and Petea consists of peridotite in the form of lherzolite and harzburgite which have been moderate to highly serpentinized. The distribution of elements in each block shows that MgO, SiO2, and Ca elements significantly decrease towards the upper laterite profile while Fe, Al, and Cr are enriched in the limonite zone and Ni, Mn, and Co are significantly enriched in the saprolite zone. Ni, Fe, SiO2, Cr, MgO, and Mn in the West Block are relatively higher than the East Block and Petea. This study shows that Ni content is relatively higher in West Block compare to East Block and Petea in averages of 1.7%, 1.53%, and 1.3%, respectively. Olivine-rich bedrock and a low degree of serpentinization resulted in high-Ni concentration in the laterite profile, particularly in the saprolite layer. This means that bedrock characteristics and degree of serpentinization were responsible for the development of nickel.

Preliminary Study of Scandium Enrichment in Lateritic Profile from Weathered Ultramafic Rock in Lapaopao Area Kolaka Regency of Southeast Sulawesi

Scandium is one of the rare earth elements which is currently widely used for various needs such as the aerospace industry, solid oxide fuel cells, electronics industry and in metallurgical applications. Generally, Scandium appears in small amounts so its structural role in the host minerals cannot be readily identified. Some studies reported the scandium extraction from lateritic nickel deposit where may contain considerable amount of scandium in addition to nickel and cobalt. Preliminary research of scandium enrichment has been investigated from the ultramafik rock indicates that an enrichment of scandium concentration was found in the red limonite. The aim of this study was to investigate the potentially enrichment of scandium mineral from nickel laterite in Lapaopao Area. There are a total of 38 samples from 1 (one) diamond drill holes which represent the limonite, saprolite and bedrock profiles have been collected and studied to investigate the distribution pattern of Sc grades within the lateritic profile. These samples are being analized by XRF for major and minor element and ICP-OES method for rare earth element assaying. The study has confirmed that scandium is enriched in limonite layer of weathered ultramafic laterite profile. The scandium content from the ultramafic bedrock is 15 ppm and has enriched until 81 ppm of scandium in the limonite layer.

Nickel Laterites—Mineralogical Monitoring for Grade Definition and Process Optimization

Nickel laterite ore is used to produce nickel metal, predominantly to manufacture stainless steel as well as nickel sulfate, a key ingredient in the batteries that drive electric vehicles. Nickel laterite production is on the rise and surpassing conventional sulfide deposits. The efficiency of mining and processing nickel laterites is defined by their mineralogical composition. Typical profiles of nickel laterites are divided into a saprolite and a laterite horizon. Nickel is mainly concentrated and hosted in a variety of secondary oxides, hydrous Mg silicates and clay minerals like smectite or lizardite in the saprolite horizon, whereas the laterite horizon can host cobalt that could be extracted as a side product. For this case study, 40 samples from both saprolite and laterite horizons were investigated using X-ray diffraction (XRD) in combination with statistical methods such as cluster analysis. Besides the identification of the different mineral phases, the quantitative composition of the samples was also determined with the Rietveld method. Data clustering of the samples was tested and allows a fast and easy separation of the different lithologies and ore grades. Mineralogy also plays a key role during further processing of nickel laterites to nickel metal. XRD was used to monitor the mineralogy of calcine, matte and slag. The value of mineralogical monitoring for grade definition, ore sorting, and processing is explained in the paper.

Mapping The Distribution of Iron Content in Nickel Laterite Deposits Using Indicator Kriging and Ordinary Kriging Interpolation Method

Beside containing nickel (Ni), nickel laterite deposits also contain other elements, including iron (Fe) which have varying levels in each layer. In this study, the distribution of Fe content in the limonite layers was carried out using the indicator kriging method to analyze the probability distribution of iron levels and ordinary kriging to analyze the variability of iron levels spatially. Fitting the variogram was undertaken by using spherical, exponential and gaussian models. The selection of the best variogram model was carried out based on the smallest root mean square error (RMSE) value, while the estimation of resource potential was calculated by the polygon extended area method. The results of the interpolation show that the distribution of iron anomaly occupies ± 83,3% of the research area with a potential resource of ±64.522.110 ton of iron. The evaluation of the interpolation results base on the root mean square standardized prediction error (RMSP) indicates that the estimation results of iron content using the ordinary kriging method are underestimated.