Mineralogy and Pollution Status of Columbite-Tin Ore Contaminated Soil
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Advanced Journal of Chemistry-Section A, 2019, 2(2), 147-164 Research Article http://ajchem-a.com Mineralogy and Pollution Status of Columbite-Tin Ore Contaminated Soil Adams Udoji Itodo *, Raymond Ahulle Wuana, Bulus Emmanuel Duwongs, Davoe Danbok Bwede A R T I C L E I N F O A B S T R A C T Received: 16 January 2019 Mining activities are one of the numerous ways by which man impacts Revised: 27 January 2019 on his environment. In this study, two non-destructive analytical Accepted: 28 January 2019 techniques (XRF and XRD) were employed in the mineralogical Available online: 9 February 2019 characterization of Columbite-Tin ore and their contaminated soils. This investigates associated unnoticed minerals as well as the impact of mining on vicinity farmland soils on the Yelwa-Mbar mining site, Nigeria. The chemical characterization of Columbite ore using electron dispersive XRF revealed that most of the Columbite mineral deposits in the Plateau mining sites contain Niobium mineral in various K E Y W O R D S proportions and vary from deposit to deposit depending on the geochemical composition of the minerals that formed the parent rock. Pollution Index Tin content as determined by ED-XRF impart that the ore can be utilized Geo-Accumulation directly in the furnace because of its high cassiterite content (85.43%). Mineral The percentage elemental composition of soil around the mining Soil Columbite vicinity unveiled the presence of Radionuclides K-40, Rubidium and Tin Thorium in the soil. This is of great concern. The XRD mineralogical Plateau investigation of Columbite shows the presence of associated braunite, cassiterite, ilmenite, quartz, and zircon while the phase pattern for Tin ore confirmed the availability of cassiterite, magnetite and litharge. Pollution status based on contamination factor and geo-accumulation indices gave both radionuclides and heavy metal concentrations that depicts moderate to extreme contaminations. G R A P H I C A L A B S T R A C T * Corresponding author's E-mail address: [email protected], Tel.: +02348039503463 Department of Chemistry, Federal University of Agriculture, PMB 2373 Makurdi, Nigeria. Mineralogy and Pollution Status of Columbite-Tin Ore … Introduction unregulated mining activities poses threats to the environment and human. This One of the ways by which man impacts on research focus on the mineral his environment (both natural and built) is characterization of Tin-Columbite through mining activities [1]. Mining in contaminated soil. The study also Nigeria started as far back as the eighteenth investigates dearth information on the century. Over 500 occurrences and deposits classes of contaminants and the compounds of over different minerals are known so far that are unearthed as a result of mining to exist within the country with the activities. exploration of some of them being on a small scale [2]. The mining industry generates Sample Location and Site Description wastes which contain high concentrations of Yelwa-Mbar (Figure 1) is in Bokkos local metals and metalloids which contaminates government of Plateau State Nigeria. Plateau agricultural soils, air and water. These state (latitudes 9̊ 51’30’N; 10̊ 02’00’’N and pollutants can be mobilized, resulting in longitudes 8̊ 48’00’’E; 9̊ 59’00’’E) is located leaching into ground and surface water. in Nigeria’s middle belt, with an area of Most of these heavy metals are highly toxic 30,913 km2 (11,936 sq m). and are not biodegradable [3]. The state has an estimated population of In Jos, Plateau State, Tin and allied metals about three million people. Named after the mining started about 1902. Within this span picturesque Jos, Plateau is a mountainous of time the tin fields have been subjected to area in the north central of the state with a process of unregulated mining activity, captivating rock formations. Bare rocks are thereby devastate and depleted agricultural scattered across the grasslands, which cover lands by intensive and extensive the Plateau. The altitude ranges from around mechanized mining activities [4]. The early 1,200 meters (about 400 feet) to a peak of tin miners often overlooked the minerals of 1,829 meters above sea level in the Shere Niobium and Tantalum or had a great Hills range near Jos the state capital. It was difficulty in separating them from the tin. noted [5] that plutonic and volcanic rocks Consequently, all cassiterite concentrates predominate in the Jos Plateau, with some were contaminated with columbite-tantalite alluvium and other unconsolidated deposits. [4]. Years of tin mining have also left the area The contamination of agricultural soils and strewn with deep gorges and lakes. depletion of the environment as a result of 148 Adv J Chem A 2019, 2(2), 147-164| http://ajchem-a.com Itodo et al. Figure 1. GPS map showing sample collection sites as thick dark spots Materials and methods Employed for this work are Energy identified at the National Metallurgical Dispersive X-ray fluorescence spectrometer Development Center (NMDC) Jos, plateau (MiniPAL4 ED-XRF), Scanning Electron state. Microscope (MVE016477830 SEM), X-Ray Physicochemical parameters of soil Diffraction (Empyrean XRD), and Fourier Physiochemical parameters of the soil Transform Infra-red Spectrophotometer samples, including pH, conductivity and bulk (Agilent tech. Cary 360 FTIR). density were carried out using documented Sampling standard laboratory procedures [7]. Following documented protocol [6], 3 kg of Ore characterization the mineral ore samples were collected from SEM Analysis: SEM Phenomenon Prix model 3 different pits and locations of the Yelwa MVE016477830 was used for this analysis. Nono-Mbar, Bokkos mining sites of Plateau Columbite and Tin samples were prepared State. Samples were pretreated through using epoxy resins, polished and made washing, drying and grinding to particle size conductive by carbon coating in a Dentom of 2 mm to distinguish between small and vacuum, DV-502A. The morphology of the large particles. Agricultural soil samples Columbite and Tin ores were analyzed at an were collected from mineral deposit vicinity accelerating voltage of 20 KVA, real time of (10-100 m) while samples for control 21-36 and lifetime of 60 seconds. Images experiment was collected from neighboring were made using the back scattering, locations (300 – 500 m), from non-mine electron detectors. sites. The mineral and soil samples were 149 Adv J Chem A 2019, 2(2), 147-164| http://ajchem-a.com Mineralogy and Pollution Status of Columbite-Tin Ore … FTIR Analysis: The functional groups Soil pollution indices present in the Columbite and Tin ore Levels of pollution and degree of samples were investigated using the furrier contamination was investigated using the transform infra-red spectrometer. The Geo accumulation index and the mineral samples were ground and sieved contamination factor respectively. From employing a US standard test sieve with an eqn. 1, Bn is the average geochemical ASTM E-11 speciation. Fourier Transform background values for each metal in Infra-red Spectrometer (Agilent columbite and tin samples, Cm is the technologies Cary 360) was used for this percentage element in the oxide (measured analysis. total concentration of metals in soils) for Energy Dispersive X-Ray Fluorescence agricultural soil samples around mining site Analysis: The EDXRF characterization and 1.5 is the background matrix correction methods based on the instruction manual factor due to lithogenic effects [8]. The geo- and practiced by the National Metallurgical accumulation index (Igeo) is used to Development Centre NMDC was adopted. determine the level of soil contamination Optimum Efficiency Dry High-Intensity (Table 1). The Igeo for heavy metal is Magnetic Separator (Three Disc Rapid calculated from base 2 logarithm of the Magnetic Separator; 4-3-15 OG) was used in measured total concentration of the metal Beneficiating the Columbite and Tin ores over its background concentration as Eqn. respectively. 20.00 g of the ore samples was (1): finely ground (beneficiated) to pass through Igeo= log2 (Cm/1.5Bn) (1) a 200-250 mesh sieve. Depending on the Analytical results were subjected to nature of the sample, it was dried in an oven prescribed pollution indices. Contamination at 105̊C for at least 1h and allowed to cool. factor (CF) is channeled towards deriving a The sample was intimately mixed with a realistic estimate of the amount of binder in the ratio of 5.0 g sample(s) to 1.0 g contamination that impacts on the soil [10]. cellulose flakes binder and palletized at a Modified degree of contamination (mCd) is pressure of 10-15 tons/inch2 in a pelletizing used to calculate the degree of machine. At this stage the palletized contamination of metals in soils [11]. It is sample(s) was stored in a desiccator for given as Eqn. (2). analysis. The ED-XRF (MiniPAL 4) was used 1 N to investigate the chemical composition of mC CF d N i the soil, columbite and tin ore sample. i1 (2) 150 Adv J Chem A 2019, 2(2), 147-164| http://ajchem-a.com Itodo et al. Table 1. Muller classification for geo-accumulation index [9] Igeo Class Pollution status >5 6 Extremely contaminated 4-5 5 Heavy to extremely contaminated 3-4 4 Heavily contaminated 2-3 3 Moderately to heavily contaminated 1-2 2 Moderately polluted 0-1 1 Uncontaminated to moderately contaminated 0 0 Practically uncontaminated Where N is the number of elements to be x- ray patterns with enough intensities so as analyzed and CF is the contamination factor to produce lines to identify minerals at the calculated as shown in Eqn. (3). angles (50 – 1000). The scanning rate was C Sample 0.750 per minute. Minerals were identified CF m C Background using the JCPDFWIN software. Peak analysis m was also carried out using the Gaussian (3) curve fitting.