Department of Mining Engineering

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Browsing Department of Mining Engineering by Author "Achomo, Prisca"

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    Evaluating the effectiveness of tobacco-derived biochar for the adsorptive removal of cyanide from gold mine tailings case study : Greenstone resource and mining limited.
    (Busitema University, 2026-07) Achomo, Prisca
    Cyanide-containing gold tailings pose significant environmental and public health risks due to the high toxicity of cyanide compounds released during gold extraction processes. This study evaluated the effectiveness of tobacco-derived biochar (TBC) for the adsorptive removal of cyanide from gold mine tailings at Greenstone Resource and Mining Limited. Tobacco biomass waste was converted into biochar through slow pyrolysis at approximately 700°C under oxygen-limited conditions and subsequently characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). The characterization results revealed the presence of functional groups such as hydroxyl (–OH), carbonyl (C=O), and carboxyl (–COOH), as well as a porous and predominantly amorphous surface structure suitable for cyanide adsorption. Response Surface Methodology coupled with Central Composite Design (RSM-CCD) was employed to optimize the adsorption process by investigating the effects of adsorbent dosage, initial cyanide concentration, contact time, and pH on cyanide removal efficiency. Batch adsorption experiments were conducted using simulated cyanide solutions within concentration ranges of 65–325 mg/L. The optimum adsorption conditions obtained were an adsorbent dosage of 0.92 g/L, contact time of 148.79 minutes, and pH of 11.73, under which the model predicted a cyanide removal efficiency of 93.00%. Experimental validation using real gold tailings spiked to 65 mg/L cyanide concentration produced an average removal efficiency of 91.80% with an Absolute Percentage Error (APE) of 1.31%, indicating good agreement between the predicted and experimental results. Adsorption isotherm studies showed that the adsorption process followed both Langmuir and Freundlich models, while kinetic studies indicated that the pseudo-second-order model provided the best fit, suggesting that chemisorption was the dominant mechanism. The study demonstrated that tobacco-derived biochar is an effective, low-cost, and environmentally sustainable adsorbent for cyanide removal from gold tailings and offers a promising approach for waste valorization and environmental remediation in the mining industry.