Title Ore Beneficiation Plant 2 - Class Notes ✅

1. Raw Material Handling & Blending  Iron ore is received at the plant via conveyors and local trippers.  Different ore types (possibly from multiple sources or countries) are blended in the Raw Material Handling System (RMHS) to achieve a target grade, such as Fe 55%.  The blending process ensures consistent feed quality to the beneficiation plant, which is crucial when different ores have varying properties. 2. Storage and Feeding  After blending, ore is stored in silos. Silos are used to maintain a frequent and regulated material flow and to buffer the process from upstream supply variations.  The ore is withdrawn from the silo using belt feeders, which ensure continuous, controlled discharge for downstream processing.  Typical silo capacity may be around 500 tons. 3. Wet Screening  The material from the silo passes over conveyor CV01 and is fed to a wet screening station.  Wet screening uses water sprays to wash and separate particles by size, removing fines and clay, and preparing the ore for subsequent classification.[1] 4. Primary Classification & Crushing  The screened ore is separated: o Fines (minus 3 mm) move to the classifier. o Oversize (+3 mm) material is sent to the crusher for size reduction.  The primary classifier further sorts fine particles, usually based on hydrocyclone or settling tank designs. 5. Secondary Processing – Grinding and Additional Classification  Very fine fractions (less than 150 microns) are sent to linear screens or other classifiers.  The coarser fractions may go through scrubbers that use agitation and water to further remove impurities and liberate iron ore from alumina, silica, and magnesium compounds. 6. Spiral Gravity Separation  The classified material is subjected to spiral gravity separation, where heavier iron-rich particles separate from lighter waste (gangue) minerals through centrifugal action and fluid density differences. This yields three products: concentrate (iron-rich), middlings, and tailings.[1]  Multiple spirals or stages may be used to optimize the recovery of iron and quality of concentrate.
7. Magnetic Separation  A High-Gradient Magnetic Separator (HGMS) or similar magnetic equipment removes any remaining iron from the tailings stream and upgrades the concentrate by attracting magnetic iron (magnetite, hematite) and leaving non-magnetic waste behind.  These separators are mechanical systems with high-strength magnets and coils, not electrical systems.[1] 8. Dewatering and Product Handling  The final iron concentrate is dewatered using vibrating (dewatering) screens to remove excess water.  Dewatered product is sized—plus 150 microns and minus 3 mm fractions become the sinter feed or go to pelletization. 9. Downstream Use  The plant produces high-grade iron ore concentrate suitable for use in sinter plants, pellet plants, or direct shipping, upgrading low-grade ore to higher grade. 10. System Automation and Control  The plant is typically divided into models or modules (Model 1, Model 2, etc.), each operating with a series of cyclones (for example, 64 cyclones per module) for classification. Each cyclone separates lighter and heavier particles based on density using pressure (often around 1.1 bar).  Cyclones and classifiers can be monitored via distributed control systems, with feedback loops to adjust pressure, feed rate, and wash water for optimal separation.[1] Key Terms Defined:  Silo: Buffer storage, maintains steady flow.  Belt Feeder: Mechanical device to regulate material flow from storage.  Wet Screen: Uses water spray to help size separation and wash ore.  Classifier/Linear Screen: Separates finely sized particles (primary and secondary stages).  Scrubber: Removes clays/impurities through agitation.  Spiral Separator: Gravity-based separation for mineral density differences.  Cyclone: Uses centrifugal force/pressure for fine particle classification.  HGMS (High-Gradient Magnetic Separator): Extracts magnetic iron minerals from the ore.  Dewatering Screens: Vibratory screens to remove water from final product. Relevant Process Flow Overview (condensed and clarified as per actual industry practice): 1. Ore blending and storage (RMHS)