Lack of appropriate mix formulation has the tendency to degrade the strength of refractory bricks. This paper presents a model developed for evaluation and prediction of mix formulation for production of insulating refractory using Osiele and Ukpor fireclays blended with coconut shell particulates. The chemical compositions of the raw materials were analysed. The samples were prepared by mixing the clays and coconut shell of grain sizes 212 -600µm. Then air and oven dried for 24 hours at room temperature and at 110 o C respectively. Thereafter, sintered at temperatures between 950 to 1200 o C at 50 o C interval. The samples were tested for various properties. From the results, an Empirical Model relating the Composition and Property of the bricks was developed. 2 3 4 . The results of the model show the trend similar to experimental. Deviational analysis conducted indicates that the deviation of model-predicted data from the experimental is between 2.25 -8.9%hence, 91-97% accuracy.

Carbide precipitates in Thin Wall Ductile Iron (TWDI) used for automotive applications needs to be eliminated or reduced for improved strength, ductility, crack propagation resistance and good machinability. Ductile iron thin section profiles (≤3 mm) present danger of massive carbide precipitations in the as-cast sample. Precipitated carbide phase is brittle and negatively affects the mechanical properties of the iron matrix. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and innoculant alloys. This treatment is vital in ensuring that carbide precipitation, flake graphite structure and non-nodular graphite phases are reduced or completely eliminated in the TWDI castings. Therefore, the temperature and technique of treatment would influence the yield of the process, and ultimately the mechanical properties. In this study, the effect of nodularization and inoculation treatment temperature on the microstructure and mechanical properties of TWDI castings is examined. The results indicate that good nodularity and nodule count with better percent elongations are achieved using low treatment temperatures in descending order of 1490˚C, 1470˚C and 1450˚C, but have negative effect at lower treatment temperature of 1430˚C. However, TWDI castings have superior properties in terms of nodule counts and nodularity at 1450˚C. Treatment temperature does not produce significant influence on ultimate tensile strength (UTS) and hardness of TWDI castings. TWDI castings show poor nodularity, nodule count and ductility at higher inoculation treatment temperatures of 1550˚C, 1530˚C and 1510˚C.

Cement production is one of the most important industries on the planet, and humans have relied on is use dating back to the dawn of civilization. Cement manufacturing has increased at an exponential rate, reaching 3 billion metric tons in 2015, representing a 6.3% annual growth rate and accounting for around 5–8% of global carbon dioxide (CO2) emissions. Geopolymer materials, which are inorganic polymers made from a wide range of aluminosilicate powders, such as metakaolin, fly ash, and blast furnace or steel slags, have also been elicited for use due to concerns about the high energy consumption and CO2 emissions connected with cement and concrete manufacturing. This study focused on the mechanical and durability properties of metakaolin in concrete production. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) analyses were used to confirm the characteristics of kaolin and metakaolin. The results showed that 15 wt.% metakaolin can be used to partially replace cement, and that metakaolin, when synthesized with alkaline activators, can also be utilized as a geopolymer to totally replace cement in concrete production. For predicting the compressive strength of different concrete mixtures, few practical models have been presented. This research has shed light on the possibility of utilizing ecologically friendly materials in the building, construction, and transportation sectors to decrease carbon dioxide emissions.

Carbon fibers (CFs) are made mostly from a non-environmentally friendly polyacrylonitrile (PAN) and little from rayon. PAN-based CFs, require huge amount of energy for its production aside its contributions to the global CO2 emission. Therefore, there is recourse to a more environmentally friendly sources of CFs biomass. Recently lignin has been recognized as a potential renewable raw material for carbon fibers to replace PAN-based. The magnitude and quality of CO2 emission of lignin-based CFs are dependent on the processing route. On this premise; this review examines the various lignin-based CFs processing route adopted by researcher in the recent past to establish the most viable route with minimum carbon footprint emission. Outcome of the review shows that the major advantages of aromatic polymer (AP) generated precursor over PAN is the presence of higher quantity of guaiacyl units and oxygen content which makes the stabilization phase efficient and faster requiring less energy. Though there are several methods and options for the various stages of conversion of lignocellulosic biomass into CFs as highlighted in the study, establishing an optimum processing route will be a trade-off amongst various issues of concern; carcinogenic risk, carbon footprint emission, CFs Yield and mechanical strength of the CFs. Inferences from the study shows that the L-CF significantly produced reduced climatic impact in terms of CO2 emission.

Brake blocks are usually made from asbestos, metals and ceramics. It has been realised that asbestos discharges dangerous gases which can be harmful. This problem necessitated the search for human-friendly materials. Therefore, this paper studies the production and characterization of train brake blocks produced from clay reinforced with aluminum dross. This was done by producing samples of composite using clay from a deposit at Osiele and aluminum dross from Tower Rolling Mill Otta, both in Ogun state. The percentage composition of aluminum dross was varied from 0% to 25% to produce brake samples. Their wear rate, tensile strength, compressive strength, hardness, thermal conductivity and microstructure were analysed. The results from this project such as Ultimate tensile strength (UTS) of 7.4Mpa, Impact energy 6.92J, Hardness 28.8 HV, wear rate 0.0071g/sec and thermal conductivity of 0.01075 indicate that, with 5% aluminium dross it is possible to develop brake block that exhibits property recommended by Rail Industry Safety and Standard Board (RISSB). Keywords: Train, Brake blocks, Clay composite, Aluminum Dross, Mechanical properties.

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Thin wall ductile iron (TWDI) components are used in automobile and related sectors owing to weight savings without sacrificing functional properties. However, its application is hampered by low ductility owing to carbide precipitation and poor nodule characteristics in as-cast structure. In this study, mould thermal characteristics are adjusted using rice husk ash (RHA). Green sand was blended with 1-6 wt. % RHA to produce moulds for casting of 4 mm TWDIs, samples obtained were subjected to microstructural (Optical, SEM and EDS), hardness and strength analyzes. Elemental composition of carbide precipitates showed iron and carbon. Nodularity ratings > 90%, nodule count >1000 nodules/mm 2 and strength of 596 MPa were observed in samples cast in 4 wt. % RHA sand mix. Ductility of 6.1 occurred in 6 wt. % RHA/sand mix. The sand-RHA mix offers cooling rate control, reduction of precipitation of deleterious carbides and superior graphite characteristics in 4 mm TWDI castings.

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