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Alternative beneficiation of tantalite and removal of radioactive oxides from Ethiopian Kenticha pegmatite–spodumene ores

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 727-735页

作者： berhe goitom gebreyohannes Velázquez del Rosario Alberto Abubeker Yimam Girma Woldetinsae Bogale Tadesse School of Materials Science and Engineering Jimma Institute of Technology Jimma University P.O. Box 378 Jimma Ethiopia Chemistry Department College of Natural and Computational Science Mekelle University P.O. Box 823 Mekelle Ethiopia School of Chemical and Bio Engineering AAiT Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia Research and Development Directorate Federal Democratic Republic of Ethiopia Ministry of Mines Petroleum and Natural Gas P.O. Box 486 Addis Ababa Ethiopia Department of Mining Engineering and Metallurgical Engineering Western Australian School of Mines Curtin University Egan St Kalgoorlie WA 6430 Australia

The beneficiation methods for Ethiopian Kenticha pegmatite–spodumene ores were assessed through mineralogical and quantitative analyses with X-ray diffraction（XRD） and energy-dispersive X-ray fluorescence（EDXRF）. The tantalite in the upper zone of the Kenticha pegmatite–spodumene deposit is 58.7wt% higher than that in the inner zone. XRD analysis revealed that the upper zone is dominated by manganocolumbite, whereas the inner zone is predominantly tantalite-Mn. Repeated cleaning and beneficiation of the upper-zone ore resulted in concentrate compositions of 57.34wt% of Ta_2O_5 and 5.41wt% of Nb_2O_5. Washing the tantalite concentrates using 1vol% KOH and 1 M H_2SO_4 led to the removal of thorium and uranium radioactive oxides from the concentrate. The findings of this study suggest that the beneficiation and alkaline washing of Kenticha pegmatite–spodumene ores produce a high-grade export-quality tantalite concentrate with negligible radioactive oxides.

关键词： beneficiation manganocolumbite pegmatite-spodumene radioactive oxides tantalite

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Applicability of Gravity Separation Method on the Ashashire Gold Ore Deposit from Benishangul Gumuz Region, Western Ethiopia

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International Journal of Nonferrous Metallurgy 2024年第2期11卷 21-31页

作者： Misganu Kabeta Mulugeta Sisay Cheru goitom gebreyohannes berhe School of Chemical and Bio Engineering Center for Ethio-Mines Development AAiT Addis Ababa University Addis Ababa Ethiopia Mineral Industry Development Institute Ministry of Mines Addis Ababa Ethiopia School of Materials Science and Engineering Jimma Institute of Technology Jimma University Jimma Ethiopia College of Natural and Computational Sciences Mekelle University Mekelle Ethiopia

The study was conducted to determine the applicability of gravity separation method on the Ashashire gold ore deposit Benishangul gumuz region, western Ethiopia. The Ashashire composite was produced to provide sufficient mass for this study and experiment, including sample preparation, mineralogical analysis of gold and associated elements, gravity concentration, and data interpretation and analysis. During the study, a grind optimization was conducted on the composites sample with varying grind size to evaluate the effect of grind size on gold recovery. The ore was moderately ground to the standard grind size of 80%, passing 106 µm, 75 µm, 53 µm and this nominal size was selected for the preliminary assessment for concentration optimization for this deposit. The gravity testing comprised three-stage concentration using Knelson concentrator. High recovery of gold from the gravity concentrates was achieved from the second gravity concentration. Based on the laboratory experimental result analysis, a grind size of P80 75 µm is selected as optimal size for the Ashashire gold deposit. Increasing the grind size from P80 of 75 µm to 106 µm decreases the recovery rate from 75% to 54%, or decreasing the grind size from P80 of 75 µm to 53 µm decreases the gold recovery rate to 37%. The native gold grain in the ores is mostly associated with quartz and fine gold is closely associated with pyrite. According to analysis of the fire assay, chemical, and mineralogical data, only gold and telluride is commercially valuable elements in the ores. Predominantly gold was occurred in the native form of Au-Te. The sample subjected to gravity separation assayed about 2.6 g/t Au.

关键词： Ore Gangue Ashashire Gravity Method Gold Telluride Concentration Knelson

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Total Volume and Aboveground Biomass Models for <i>Juniperus procera</i>Plantation in Wondo Genet, Southern Ethiopia

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Open Journal of Forestry 2019年第2期9卷 89-108页

作者： Tekleweini Gereslassie Ababo Workineh goitom Takele Muhamed Adem Leakemariam berhe Department of Pollution Ecology Institute of Wuhan Botanical Garden University of Chinese Academy of Sciences (UCAS) Wuhan China Department of Forestry Wondogenet College of Forestry and Natural Resources Hawassa University Shashemene Ethiopia Department of Forestry College of Agriculture and Natural Resources Madawalabu University Bale Robe Ethiopia

Species specific allometric equations are important for estimation and quantification of net volume and aboveground biomass of living trees. This study was basically focused on fitting total volume and aboveground biomass models for Juniperus procera plantations in Wondo Genet, Sidama Zone, Ethiopia. Data for fitting the total volume and aboveground biomass models were obtained by destructively sampling of trees from the ten diameter classes of the Juniperus procera plantation in the study area. A total of one hundred ten and fifty-one trees were destructively sampled to fit six total volume and six aboveground biomass models respectively. After important measurements of parameters have completed, model performance evaluation and selecting of best fit models were undertaken using standard error of estimates (SEE), coefficient of determination (R2), bias (B) and mean of the absolute value of errors (MAE). Accordingly, the total volume model Vt = -5.466 + 0.959Dbh0.005H003 and aboveground biomass model of B = 0.348Dbh0.57H0.032 were found to be the best predictive models for total tree volume and aboveground biomass respectively. In addition to the above results, diameter at breast height and total tree height data obtained from 69 circular sample plots of 0.01 ha area drawn from the plantation were used to estimate the total volume and aboveground biomass per hectare BEF which was estimated to be 0.64 Mg/m3. Generally, the selected models and computed BEF in this study are believed to be applied by different organisations and researches to estimate the total volume and aboveground biomass of the J. procera.

关键词： Biomass Expansion Factor Biomass Models Total Volume Models Juniperus procera

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