Abraham Adeleke | Obafemi Awolowo University,Ile-Ife,Nigeria (original) (raw)

Papers by Abraham Adeleke

International Journal of Nonferrous Metallurgy

The response of Imogbara (Nigeria) gold ore to shaking tabling gravity separation methods was inv... more The response of Imogbara (Nigeria) gold ore to shaking tabling gravity separation methods was investigated in this research work. Gold concentration in runoff mines is usually as low as 0.005 ppm and must be upgraded in order to reduce the recovery process extraction costs. Gravity separation method (the focus of this work) is one of the readily affordable beneficiation methods. Shaking table is a developed separation equipment of gravity method that has been adopted to increase concentrate based on difference of specific gravity. The output result of the concentration process using shaking table is basically influenced by a number of variables, such as rotational shaking speed, particle size and deck slope. In this research, the range of rotational speed shaking was between 100 rpm and 200 rpm, the particle size was between (−300 µm > X < +75 µm) and (−75 µm) and deck slope was between 10˚ and 30˚. EDXRF was used to measure gold concentration in the concentrate as well as the tailings. The result shows that the optimum condition is obtained at a shaking speed of 100 rpm, with a slope of 10˚ and particle size less than 75 µm.

Pyrometallurgy - New Perspectives [Working Title]

The pyrometallurgical methods of the recovery of various critical metals have been established. C... more The pyrometallurgical methods of the recovery of various critical metals have been established. Certain pyrometallurgical approaches for niobium (Nb) and tantalum (Ta) extraction have been studied and investigated by several researchers. For instance, the conventional reduction of Nb mineral or Nb2O5 to Nb metal has been conducted over the decades. Albeit, the success level of this process, it however involves the consumption of lots of energy, high cost of equipment/equipment maintenance, somewhat low Nb and Ta recovery and limited effectiveness on low grade minerals; and thus, considered cost intensive and inefficient. In addition, the inadequacies of pyrometallurgical extraction of these metals from their complex, low grade mineral ores due to its difficulty and large energy requirement in melting the elemental impurities and gangue minerals have been a major concern. On this premise therefore, the study will provide insights into recent pyrometallurgical techniques of Nb and Ta ...

Hungarian Journal of Industry and Chemistry, 2021

Optimisation of the physical properties of rice husk ash (RHA) in ceramic materials was carried o... more Optimisation of the physical properties of rice husk ash (RHA) in ceramic materials was carried out using Response Surface Methodology. The independent variables, namely the firing temperature and residue content, were statistically combined in a Central Composite Design with the effects on water absorption, linear shrinkage, bulk density, apparent porosity and apparent specific gravity determined. Physical and microstructural analyses were carried out to obtain information on the processes that occurred within the ceramic materials. The results obtained were analysed to determine the optimum physical properties of the ceramic materials within the range investigated. The residue content had a significant influence (at 95% confidence level) on the bulk density, water absorption, apparent porosity and apparent specific gravity but not on the linear shrinkage. The firing temperature had a more significant effect on the linear shrinkage than on the residue content, so that when elevated...

IOP Conference Series: Materials Science and Engineering, 2018

The whole facilities at the Palabora Copper (PTY) Ltd (PC), Limpopo, South Africa (i.e. both exis... more The whole facilities at the Palabora Copper (PTY) Ltd (PC), Limpopo, South Africa (i.e. both existing and new) are under obligation to comply with the new plant MES by the 1 st of April, 2020. At the moment all processes on the PC mine conform to the MES for existing plant with the exception of the copper smelter and the associated sulphuric acid plant. Despite considerable investment by PC over the last few years in equipment and maintenance, due to the short comings of the copper smelting technology employed on site, certain relevant MES have proven to currently be unachievable. The generation of the waste CSD is considered a global issue and at PC the direct smelting process option is the recycling method currently being used to manage the generated waste CSD at the copper smelting plant. This recycling method is neither cost effective nor energy efficient and it leads to the production of worthless residues. As a result, an enhanced hydrometallurgical based recycling process option is recommended as an appropriate recycling process option. Hence, it was concluded that an industrial scale centrifugal separator like the Knelson or Falcon concentrators be stationed in the existing and proposed plants as a separate but integral part of the ore processing system, so as to reduced/removed the reactive materials it often contains before subjecting it to a hydrometallurgical and Nano technological processing, in order to recover the copper value in it as precipitates of nanoparticles.

Hungarian Journal of Industry and Chemistry, 2019

This study reports on the concentration of rutile in the sand recovered from tar sand in Ondo Sta... more This study reports on the concentration of rutile in the sand recovered from tar sand in Ondo State in Nigeria. The tar-free sand residue, approximately 90 % of which passes through a sieve with a pore size of 355 µm, was subjected to sieve analysis as well as sequences of panning gravity pre-concentration and shaking-table concentration at a slurry density of 25 % solids to improve the rutile content. The sand residue recovered in addition to the panned pre-concentrate and shaking table concentrates were also subjected to reflected light microscopy as well as transmitted light microscopy, counting using ImageJ software and X-ray fluorescence spectroscopy. The micrographs obtained showed that the samples contain rutile, dark-brown in color, interlocked with the major silica content and the content of rutile estimated by ImageJ software increased in the pre-concentrate from 7.90 % to 19.23 % in the final concentrate. X-ray fluorescence spectroscopy also showed that the rutile content increased in the pre-concentrate from 1.43 % to 31.02 % in the final concentrate. Therefore, the rutile content was successfully increased by the cheap gravity techniques of panning and shaking tables.

Cogent Engineering, 2018

This research has presented a three level-two factors full factorial experimental design that inv... more This research has presented a three level-two factors full factorial experimental design that investigated the process parameterization of a centrifugal concentrator for the separation of a waste copper smelter dust (CSD). This was followed by a theoretical contribution involving the development of a scheme of predictive models premised on the concept of constrained interpolant models. These were used for the experimental trend, pattern investigation and furthermore to provide expressions that depicts optimal experimental conditions in this research. Based on the experimental outputs, it was observed that a maximum grade of about 35.02 wt% Cu was achieved at a Rotational Bowl Speed of 120G, Water Flow Rate of 3.0l/min and constant experimental flow rate of 1.48l/min with a Liquid to Solid Ratio of 0.5. Similarly, a minimum output of 14.58% SiO 2 and 10.29% Al 2 O 3 was achieved at same experimental conditions. This clearly depicts a trend geared towards optimum experimental conditions aimed at maximizing Cu output and

Procedia Manufacturing, 2017

The minerals, metals & materials series, 2023

Journal of Minerals and Materials Characterization and Engineering, 2007

A mathematical model and its associated numerical search algorithm has been developed for routine... more A mathematical model and its associated numerical search algorithm has been developed for routine coal blending to include local coals for cokemaking at the Nigerian blast furnace-based Ajaokuta Steel Plant. A typical binary blend proposed using the model includes 28.38% and 29.00% of the ash-laden Lafia and non-caking Okaba coals, respectively. The proposed blends satisfy basic chemical and mechanical strength requirements at the lowest cost per ton of coal. The blending calculations showed that only low ash, low sulphur, medium volatile and high vitrinite reflectance prime grade coals such as the UK Ogmore should be imported for blending with the ash-laden medium coking Lafia coal. When the proposed blends are successfully confirmed with bench and pilot scale carbonization tests, cokemaking at Ajaokuta will be conducted with substantial savings in foreign exchange.

Blend formulation to maximize the inclusion of non-coking coals with the scarce and expensive cok... more Blend formulation to maximize the inclusion of non-coking coals with the scarce and expensive coking coals is an essential practice in the steel industry. This study demonstrated the use of Microsoft Excel based on a blending model to obtain probable cokeable blends between sample prime coking coals and non-coking Nigerian Lafia-Obi and Okaba coals; having high ash/sulphur and high volatile, respectively. The results obtained showed that optimal binary, ternary and quaternary probable cokeable blends are possible. A cokeable binary blend of 64.51% low volatile, high vitrinite reflecting Western Canada prime coking coal and 35.49% Okaba coal with a cost reduction per ton of 61.56wasobtained.Also,aternaryblendof74.0461.56 was obtained. Also, a ternary blend of 74.04% medium volatile prime coking UK Ogmore coal produced an optimal cokeable blend including 19.22 and 6.74 percents of Lafiia-Obi concentrate and Okaba (as-received); respectively with a saving in cost per ton of 61.56wasobtained.Also,aternaryblendof74.0439.05. Furthermore, a quaternary blend comprising 4...

A coal blend consisting of 95% Australian Agro-Allied coal and 5% Nigerian non-caking Okaba coal ... more A coal blend consisting of 95% Australian Agro-Allied coal and 5% Nigerian non-caking Okaba coal was carbonized in a 250 kg capacity coke oven at a flue temperature of 1,250 o C by normal wet and preheated charging for 18 and 15 hours, respectively. Screen distribution analysis and micum drum tests on the coke products gave M10 of 24.60% and 9.5% and M40 of 67% and 76.2%, for normal and preheated charge, respectively. These results showed that the coke produced from the preheated charge has a better resistance to abrasion (M10) and fragmentation (M40) and the micum indices obtained are similar to the micum characteristics of cokes produced in coke ovens in some other countries. Furthermore, the coke micum 10 and micum 40 strength are very close to the M10 and M40 specifications for coke to be used for blast furnace operations at the Ajaokuta Steel Plant, Nigeria.

Journal of Applied Sciences, 2007

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, Jun 1, 2014

Samples of the waste rock obtained from Marofengin South Africa ground 60, 70 and 80% passing 75µ... more Samples of the waste rock obtained from Marofengin South Africa ground 60, 70 and 80% passing 75µm were leached with cyanide in bottle roll tests. The results obtained showed that the percentage gold dissolution depends more on the ore size consists than on the cyanide concentration with the highest average dissolution rates of 88.75, 94.34 and 95.90% found at 600, 500 and 500 ppm, for 60, 70 and 80% passing sizes, respectively. It was also noted that the lowest average percents cyanide consumption of 62.91, 61.73 and 58.56 at 60, 70 and 80% passing 75 µm were obtained at the 500 ppm cyanide concentrations. It was further observed that a clear pattern of increasing residual lime content was only observed at the 70% grind size, with the least lime content of 150.37 ppm at 500 ppm cyanide concentration being higher than the least lime contents for the 60 and 80% grind sizes. The results obtained thus suggest the 70% grind passing 75 µm ore with the gold dissolution percentage very close to the conventional 80% passing size at the lowest cyanide consumption of 500 ppm, much lower daily power consumption of about 925 kWh and high residual lime content that indicated the minimization of cyanide loss as hydrogen cyanide,a good choice for the leaching of the waste rock.

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, Apr 1, 2019

This research was aimed at evaluating the efficiency of advanced gravity and magnetic separations... more This research was aimed at evaluating the efficiency of advanced gravity and magnetic separations on the recovery of chromite from the fine Platinum Group Metals (PGM) tailings consisting of particles 80% passing 75 µm with about 45% being >45 µm resulting in high chromite losses. The PGM plant tailings were subjected to X-ray fluorescence, scanning electron microscopy and particle size distribution analyses. The feed was then optimally classified with 60 mm diameter hydro-cyclone into underflow and overflow streams. The coarser underflow was further beneficiated using the spiral concentrator. The results obtained showed that the removal of fines increased the Cr2O3 grade for the spiral feed from 12.27% to 17.64% while spiral concentrate grade improved from 14.84% to 21.46% and recovery 69.85% to 95.53%. Magnetic separation efficiency was found to increase with particle size such that at >75 µm a concentrate with up to 17.13% grade and 61.5% recovery was achieved. The advanced Falcon concentration was also observed to be mainly particle size dependent and at <75>45 µm up to 17% grade and 60.3% recovery was achieved. The results obtained are based on particles >45 µm and the finer particles <45 µm are likely to give poorer results. The results obtained indicate that gravity and magnetic separation were reasonably efficient to pre-concentrate PGM tailings before flotation. However, the processes are mostly affected by particle size and should be preceded by size classification to improve separation efficiency.

Leonardo Journal of Sciences, 2018

The study was carried out to optimize the filtration of the hydrolysis cake obtained during the r... more The study was carried out to optimize the filtration of the hydrolysis cake obtained during the refining stage of platinu-rich liquor. The platinum refining stage cake was first filtered in the glove box and secondly in the filter press to optimize the recovery of platinum value. The results obtained indicated that the filter press operation gave the highest and lowest platinum recovery efficiencies of about 99.95 and 97.69% as against 99.39 and 97.21%, respectively, for the glove box. In addition, the trend lines obtained showed that the filter press operation results following almost a linear trendline as being more stable than the glove box with a steeper trendline. Furthermore, the filter press processing of the hydrolysis cake took only about five hours in comparison to about 14 hours for the glove box. The filter press has thus proven to be a more efficient method to optimize platinum recovery from hydrolysis cake.

Journal of Engineering Science and Technology, 2016

The Lower Group 6 (LG6) platinum group of metals (PGM) ore was subjected to batch and continuous ... more The Lower Group 6 (LG6) platinum group of metals (PGM) ore was subjected to batch and continuous industrial froth flotation with and without concentrate streams re-routing. The batch test indicated that the ore has a recovery of about 69%.However, the average PGM recovery before and after rougher stage rerouting during plant scale tests were 41.5 and 64.5%, respectively. The rerouting of roughers 4 to 6 streams thus successfully improved recovery by 23%.Similar results were also obtained for both PGM and PGM 4E recoveries in both cleaner and re-cleaner stages re-routing. The results obtained thus strongly suggest that the circuit PGM recovery was optimized by the re-routing. It was however further observed that the PGM grade decreased significantly while the chromium content of oxide origin increased in the concentrates after re-routing. The optimum grade and recovery combination for each metal value will thus have to be determined by the plant based on the Net Smelter Return (NSR) ...

Energy Technology 2020: Recycling, Carbon Dioxide Management, and Other Technologies, 2020

Mineral Processing and Extractive Metallurgy Review, 2021

Journal of Physical Science, 2016

To cite this article: Meso, M. F. et al. (2016). An evaluation of sodium ethyl xanthate for the f... more To cite this article: Meso, M. F. et al. (2016). An evaluation of sodium ethyl xanthate for the froth flotation upgrading of a carbonatitic copper ore.