Treatment effect on reactivity of Metakaolin using Azadirachta indica bark activated carbon

Abstract

Metakaolin (MK) is a new family of mineral admixtures that can be utilized as supplemental cementitious materials in the construction industry. It has technical and environmental benefits and can be used as a partial substitute for cement in concrete mixtures when finely processed. The effect of Azadirachta Indica Bark Activated Carbon (AIBAC) on the reactivity of Metakaolin (MK) was investigated in this work. Hydrochloric acid was used to make chemically activated carbon from Azadirachta indica bark, and Metakaolin (MK) was made from Kaolin Clay (KC). AIBAC (5, 10, 15 and 20% proportioned according to MK weight) were measured into four conical flasks, 200 g of MK was added to each of them, mixed homogeneously and 125 mL of distilled water was added to encourage reaction between AIBAC and MK samples. The mixtures were oven dried at 110 °C after 24 h. The aforementioned steps were repeated with the exception of addition of water to produce AIBAC + KC mixed samples. The resulting mixed samples (AIBAC + KC) were calcined in a muffle furnace for one to two hours at 700 °C, thereafter cooled. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF) were then used to characterize the prepared AIBAC, MK and their combined samples for surface morphology, mineralogical, and chemical contents, respectively. The AIBAC and MK samples were between 2 and 50 nm in size on SEM micrographs, and the intensity peaks of MK XRD plots ranged from 200 to 4000 cps. During calcination, the AIBAC (16.22%) was able to completely remove the undesirable compounds from MK while also increased the compositions of its major oxides (SiO2, Al2O3, Fe2O3, and CaO by 2.60, 64.00, 3.26 and 16.00 %, respectively). Finally, Azadirachta indica bark activated carbon can be employed efficiently in the treatment of metakaolin in the industrial setting.