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Corrosion Characteristics of As-Cast Aluminium Bronze Alloy in Selected Aggressive Media

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Journal of Minerals and Materials Characterization and engineering 2013年第5期1卷 245-249页

作者： Bukola Joseph Babalola Michael Oluwatosin Bodunrin Joseph Olatunde Borode Kenneth Kanayo Alaneme Metallurgical & Materials engineering Department Federal University of Technology Akure Nigeria prototype engineering development institute Ilesa Nigeria

This research work investigated the corrosion characteristics of aluminium bronze alloy in four selected aggressive media which are H2SO4, HCl, NaOH, and NaCl. Aluminium bronze alloy was produced locally via sand casting method. Copper coils and aluminium materials which constitute waste to the environment were used in producing the alloy. Test specimens were produced from the as cast alloy and immersed in H2SO4, HCl, NaOH, and NaCl environment. The concentrations of the environment were varied as 0.1 M, 0.3 M and 0.5 M. The aluminium bronze produced from sand casting has mechanical properties that are closer to the standards proposed by CDA [1]. The corrosion rate was determined by weight loss method at an interval of 3 days. It was observed that the corrosion behaviour exhibited by aluminium bronze in acidic media followed similar trends in 0.1 M, 0.3 M and 0.5 M respectively. However, the corrosion rates increases with increase in the concentration of H2SO4 and NaCl media, but the attack was more aggressive in HCl medium. The aluminium bronze samples in NaOH and H2SO4 media show gradual decolouration from its as-cast yellow golden colour to brown and dark colour respectively. NaCl environment shows high resistance to corrosion and slight decolouration effect even at increased concentration.

关键词： Corrosion Aluminium Bronze Aggressive Media Sand Casting Aluminium

Application of Geophysical Methods to Building Foundation Studies

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International Journal of Geosciences 2013年第9期4卷 1256-1266页

作者： Folahan Peter Ibitoye Felix Vincent Ipinmoroti Mudasiru Salami Kunle Joseph Akinluwade Adeyinka Taofeek Taiwo Adelana Rasaki Adetunji 1Department of Applied Geophysics Federal University of Technology Akure Nigeria 2Prototype Engineering Development Institute National Agency for Science and Engineering Infrastructure (NASENI) Ilesa Nigeria 1prototype engineering development institute National Agency for Science and Engineering Infrastructure (NASENI) Ilesa Nigeria 2Department of Materials Science and Engineering African University of Science and Technology (AUST) Abuja Nigeria 1prototype engineering development institute National Agency for Science and Engineering Infrastructure (NASENI) Ilesa Nigeria 2Department of Materials Science and Engineering Obafemi Awolowo University Ile-Ife Nigeria prototype engineering development institute National Agency for Science and Engineering Infrastructure (NASENI) Ilesa Nigeria

A geophysical survey involving the electrical resistivity method utilizing the Vertical Electrical Sounding (VES) and Electrical Imaging Techniques was conducted around the premises of an area within south-western nigeria with the aim of studying structural defects which may be responsible for future problems and characterizing the soil conditions of the site. A total of 15 VES stations were occupied using Schlumberger Configuration with AB/2 varying from 1 to 65 m. In the electrical imaging, dipole-dipole array was adopted and the two traverses were occupied in the S-N and E-W directions close to where wall cracks and subsurface problems were manifested. Five main geoelectric sequences were delineated within the study area;these include the topsoil (clay and sandy clay), lateritic clay, weathered bedrock (clay, sandy clay and clayey sand), fractured bedrock and fresh basement. A major discontinuity (fracture zone) was discovered along the S-N direction, while a weak zone was also discovered along E-W direction. The result of this research has shown that the causes of the cracks and distress on the walls within the site may have been influenced by the differential settlement resulting from the incompetent subsoil materials and the fractured bedrock on which the foundation of the building was laid.

关键词： Foundation Bedrock Basement Cracks Subsurface Instability

Beneficiation and Characterization of Gold from Itagunmodi Gold Ore by Cyanidation

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Journal of Minerals and Materials Characterization and engineering 2014年第4期2卷 300-307页

作者： Olasupo Daniel Ogundare Mosobalaje Oyebanji Adeoye Adelana Rasaq Adetunji Olusegun Oyeleke Adewoye engineering Materials development institute Akure Nigeria Department of Materials Science and engineering Obafemi Awolowo University Ile-Ife Nigeria prototype engineering development institute Ilesa Nigeria African University of Science and Technology Abuja Nigeria

This paper has reported the beneficiation and characterization of gold from Itagunmodi gold ore in Atakumosa West LGA in the State of Osun nigeria using cyanide solution obtained from cassava and commercially available sodium cyanide analar grade. Cyanide solution extracted from cassava variety TMS 30572 leaves obtained from Obafemi Awolowo University (O.A.U) Research and Teaching Farm was discovered to have the highest free cyanide (CN-) among the ten different cassava varieties evaluated. The samples were exposed to varied concentrations from 0.25% to 2.00% CN at intervals of 0.25% CN from cyanide solution obtained from cassava and commercially available sodium cyanide analar grade. The result showed that after 24 hours of cyanidation and concentration of 2% CN- on 10 g gold ore concentrate, the analar grade sodium cyanide yielded 0.123 g of gold while the cassava based cyanide yielded 0.098 g. The cyanidation performance of analar grade sodium cyanide is greater than cassava based cyanide by a difference of 0.25%.

关键词： Gold Cyanidation Itagunmodi Gold Ore Cassava Commercial Sodium Cyanide Cyanide from Cassava

2<sup>k</sup>Factorial Experiments on Factors that Influence the Recovery of Gold during the Upgrade of Ilesha-Itagunmodi Gold Ore through Froth Flotation

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Journal of Minerals and Materials Characterization and engineering 2014年第1期2卷 32-39页

作者： Kayode Emmanuel Oluwabunmi Abraham Adewale Adeleke Adelana Razak Adetunji Samson Olaitan Jeje Abiodun Ayodeji Abioye Olusola Adedayo Adesina Fatai Afolabi Ayeni Folahan Peter Ibitoye Department of Chemical engineering Landmark University Omu-Aran Nigeria Materials Science and engineering Obafemi Awolowo University (O.A.U.) Ile-Ife Nigeria prototype engineering development institute (PEDI) Ilesa Nigeria prototype engineering development institute (PEDI) Ilesa Nigeria Materials Science and engineering Obafemi Awolowo University (O.A.U.) Ile-Ife Nigeria

A low-grade gold ore from Ilesha-Itagunmodi, south western nigeria was panned, dried and ball-milled before sieving into fractions. The morphological, mineralogical and chemical composition was studied by optical micro-scopy (Reflected and Transmission), X-ray diffraction (XRD) and Energy Dispersive X-ray fluorescence (XRF), respectively. The sieved fractions were subjected to chemical analysis (AAS). The +106 μm sieve had the highest concentration of the mineral and was then selected for the upgrade through froth flotation using standard reagents. In this paper a report on a 2k factorial experiment that provides an understanding of the impact of operational variables on the quantity of gold mineral obtained from the ore during froth flotation is presented. Analysis results showed that Ilesha-Itagunmodi gold ore is non-refractory with fine grain particles, amenable to froth flotation and contained about 20 other associated minerals, gold had a concentration of about 0.0024%. A com-bination of P-Xanthate and amine glycol collectors at a pH of 9.2 only produced a considerable increase in gold yield. This translated to about 87.13% increase in recovery of gold from the ore. Analysis of variance (ANOVA) was carried out and the model equation obtained was subsequently optimised to obtain a model equation that could be used in predicting the recoverable quantity of gold, indicating that F11,1-values for Collector concentration, Frother concentration, pH and Conditioning time were 156.86, 6.96, 43.81, and 56.77 respectively. A model with an F value of 88.41 was obtained which indicated that the model was significant. The model equation obtained was subsequently optimised to be able to predict the recoverable quantity of gold. A “Pred R-Squared” value of 0.9365 (93.65%) was also obtained and is in reasonable agreement with the “Adj R-Squared” value of 0.9534 (95.34%). It was established that Ilesha placer gold ore is amenable to froth flotation using standard reagents.

关键词： Factorial Froth Flotation Collector Frother Concentration Surface Graph Conditioning Time

Physico-Chemical and mineral analysis of composts fortified with NPK fertilizer, Ammonium Chloride and Kaolin

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Journal of Agricultural Chemistry and Environment 2013年第2期2卷 27-33页

作者： Margaret Ojone Ogundare Labunmi Lajide Department of Chemistry Federal University of Technology Akure Nigeria Department of Chemistry Federal University of Technology Akure Nigeria prototype engineering development institute Ilesa Nigeria

This work presents the physicochemical and mineral analysis of compost samples made from waste materials of cassava, vegetable, banana, orange, and cow dung fortified each with 100g of NPK, 100g of kaolin and 100g of ammonium chloride. Microbial analysis of the fresh compost samples revealed that the unfortified compost possesses more microbial load than the fortified samples. The physicochemical analysis showed that the kaolin fortified compost (KFC) has the highest ash content and phosphorus content while the unfortified compost (UC) contains the highest organic matter. All the compost samples have little nitrogen when compared with NPK chemical fertilizer. However, the fortification with kaolin, NPK and ammonium chloride increased the percentage of nitrogen over that of the unfortified compost by 38.8%, 56.23%, and 71.17% respectively. The fortification with kaolin, NPK, and ammonium chloride also increased the phosphorus content over that of the unfortified by 56.31%, 53.21% and 36.75%, respectively. The result of the mineral content showed that the fortification with NPK and ammonium chloride increased the magnesium content of the compost sample while fortification with kaolin increases the magnesium and calcium content. The nitrate and sulfate contents are reduced by the fortification with kaolin, NPK and ammonium chloride.

关键词： Compost Fortification Microbial Mineral Physicochemical

Comparative Study of Corrosion Sensitivity of Selected Ferrous Metals in Crude Oil

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Journal of Minerals and Materials Characterization and engineering 2012年第6期11卷 559-568页

作者： O. Ogundare I.M. Momoh O.J. Akinribide A.R. Adetunji J.O. Borode S.O.O. Olusunle O.O. Adewoye Department of Metallurgical and Materials engineering Federal University of TechnologyAkure Nigeria. engineering Materials development institute Akure Nigeria. National Agency for Science and engineering Infrastructure Abuja Nigeria. prototype engineering development institute Ilesa Nigeria.

Corrosion characteristic of selected ferrous metal samples (plain and alloyed ductile iron, low carbon steel and austenitic stainless steel) in crude oil was investigated using weight loss method. The microstructures of the coupons were taken before and after corrosion test. It was observed that all the materials experience gain in weight within the first 10 days in the medium. This weight gain is attributed to the formation of hard and passive phases which acted as strong protective barriers to corrosion. It was also observed that the rate of corrosion decreased with increase in the number of days of exposure for all the coupons, this may be probably due to the deposition of corrosion products that tend to shield the corroding surface from further corrosion attack, there by depressing the rate of corrosion. This result shows that despite initial low corrosion resistance of plain ductile iron, it can still be considered, alongside other materials, for application in pipelines and storage facilities for crude oil.

关键词： Corrosion agitation ductile iron Austenitic Stainless Steel Mild steel and crude oil.

Numerical Optimization of Sand Casting Parameters Using the Dantzig’s Simplex Method

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Journal of Minerals and Materials Characterization and engineering 2013年第5期1卷 250-256页

作者： John Ogheneortega Oji Simon Godenaan Datau Kunle Joseph Akinluwade Adeyinka Taofeek Taiwo Dayo Adeyemi Isadare Sunday Hendrix Pamtoks Adelana Rasaki Adetunji Department of Materials Science & engineering Obafemi Awolowo University Ile-Ife Nigeria Department of Materials Science and engineering African University of Science and Technology Abuja Nigeria Department of Mechanical engineering Federal Polytechnic Bauchi Nigeria prototype engineering development institute (PEDI) Ilesa Nigeria

This study adopts the Dantzig’s Simplex method to investigate optimization of sand casting parameters for optimum service performance. Some process variables and mechanical properties were adapted into the Simplex method. Aluminium alloy samples were cast, machined and subjected to a series of mechanical tests. From the body of data collected, linear functions and constraint equations were formulated and employed in the Dantzig’s Simplex method for optimization of process parameters. The results showed that the Simplex method can be adapted for studying performance opti- mization of castings.

关键词： Sand Casting Dantzig’s Simplex Method Optimization Constraint Equations Aluminium Alloy

Atmospheric Corrosion Studies of Ductile Iron and Austenitic Stainless Steel in an Extreme Marine Environment

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Journal of Minerals and Materials Characterization and engineering 2012年第9期11卷 914-918页

作者： Olasupo Ogundare Babaniyi Babatope Adelana Razaq Adetunji Samuel Olugbenga Oloruntoba Olusunle Department of Materials Science and engineering ObafemiAwolowo University Ile Ife. Nigeria Department of Physics ObafemiAwolowo University Ile Ife. Nigeria National Agency for Science and engineering Infrastructure Abuja. Nigeria prototype engineering development institute ilesa nigeria

This paper presents the corrosion characteristics and the accompanying changes in the microstructure of unalloyed duc-tile iron (DI) and austenitic stainless steel (ASS) in table salt medium representing an upper limit in an extreme marine environment. The individual corrosion rates of DI and ASS was evaluated for the maximum time period of 1200 hr. Using the immersion test technique, the corrosion rate of DI was evaluated and found to be four-orders of magnitude greater than that of ASS. The corrosion product morphologies of the DI showed that the nodular matrix was gradually covered up as immersion time progressed while the corrosion channels and volume of pits that initially formed in ASS respectively deepened and increased with increased exposure time. This work is important as a reference point for the quantification of the corrosion effectiveness of alloying DI. The microstructures of the corroded samples showed corro-sion initiation and gradual accumulation of corrosion products.

关键词： Atmospheric Corrosion Ductile IronL Austenitic Stainless Steel Sodium Chloride And Microstructure

development of Computer Software for Evaluating Performance Index of Fairly Used Vehicle Engines

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材料科学与工程（中英文A版） 2014年第7期4卷 249-254页

作者： Morufu Oyekola Oduola Kayode Oke Kunle Joseph Akinluwade Adelana Rasaki Adetunji Department of engineering Prototype Engineering Development Institute llesa Nigeria Department of Mechanical engineering Federal University of Technology Akure (FUTA) Akure Nigeria