Beneficiation of Low Grade Iron Ore in Kenya

A. Bett, S. Maranga


In Kenya there is great demand for industrialization and mineral exploration for her to be industrialized as stipulated in the vision 2030 and millennium development goals(mdgs). Kenya has ample iron ore deposits which are yet to be fully utilized for the development and economic growth of the republic. There are iron ore deposits in some counties like Taita Taveta (Manyatta), Tharaka (Marimanti) and Siaya (Samia) which have not been fully exploited  Beneficiation process is the upgrading of low grade iron ore/mineral so as attain a better grade to be used in furnaces. Iron ores have different metal (iron) composition ranging between 48-72%, the remainder being impurities/gangue. Very low grade iron ore cannot be used in metallurgical plants and needs to be upgraded to increase the iron content and reduce the gangue. Iron ore is being beneficiated all round the world to meet the quality requirement of iron and steel industries. The low grade ores are normally beneficiated using any of the following methods or a combination two or more: Gravity separation; Dense media separation; Froth flotation; Magnetic separation. After the beneficiation processes the concentrate and tailings are analyzed and the recovery of iron ore using the different methods calculated. The research focuses on two methods (froth floatation and magnetic separation) due the availability of the equipment at the geology and mines department (Ministry of Environment and Natural resources). The most challenging part is to collect the samples from various sites around the country. Froth flotation is a physico-chemical separation process that utilizes the difference in surface properties of the valuable minerals and the unwanted gangue minerals. Froth flotation involves three phases (solids, water, and froth). The attachment of valuable minerals to air bubbles is the most important mechanism and represents the majority of particles that are recovered to the concentrate. Iron ore minerals such as goethite and hematiteare floated by collectors such asamines, oleates, sulphanates, or sulphates. Processing involves preconcentration by gravity or magnetic separation, followed by flotation. Magnetic separators exploit the difference in magnetic properties between the ore minerals and are used to separate either valuable minerals from non-magnetic gangue, e.g. magnetite from quartz, or magnetic contaminants or other valuable minerals from the non-magnetic values. The research is carried out on the mined ores from the sampled sites. The ores are crushed to standard sizes using the crushers available in the mines and laboratories (Geology and Mines Department of the ministry of Environment and Natural Resources and Taita Taveta campus). The desired ore size will be obtained through sieve analysis. At the end of the research it is expected that efficient methods for iron ore beneficiation for the deposits will be projected and results will be used to invite investors to build the first steel smelting plant in Kenya.


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