FLOW CHART FOR MINERAL BENEFICIATION PROCESS Smitirupa Biswal, G.Meghana Priya 2 nd Year Students Metallurgical & Materials Engineering Dept. National Institute of Technology Jamshedpur, India NIT JAMSHEDPUR

OUTLINES  Process flow chart  Mineral beneficiation  Brief idea about principal steps of mineral processing  Simplified flow chart for various stages involved in mineral processing  Example of iron ore

Process Flow Chart  A process flow chart is a graphical representation of the successive steps involved in a process using symbols interconnected with lines.  In case of mineral beneficiation, it is the diagrammatic illustration of various steps involved in the up-gradation of ores/minerals starting from their transportation till their final production to be used as raw materials in different downstream commercial industries.

 It helps us to visualize what's going on as well as helps us to understand the methods involved in each step.  Thus, process flow charts are used in analyzing, designing and managing the processes and mechanisms governing the mineral beneficiation of a specified ore/mineral. Process Flowchart (Contd..)

Mineral Beneficiation  Mineral beneficiation is the process to upgrade the mineral values of the ore by exploiting the physical properties of the associated minerals in the ore.  It aims at the following:- - Elimination of undesired mineral species - Elimination of undesired size - Selective separation of desired minerals  Thus, mineral beneficiation is simply the process of up-gradation of ores/minerals.

Brief Idea about Principal Steps of Mineral Processing The principal steps are:-  Size reduction of the ore/mineral to the liberation size of the desired minerals from gangue particles.  Separation of the minerals by exploring the properties of the size, density, shape, magnetic susceptibility, conductivity and surface properties to produce concentrate and the tailings from the low grade ores.  The four kinds of principal operations in the beneficiation process are comminution, classification, concentration and dewatering.

Comminution  Crushing:- Breaking by compression Equipment used: Jaw crusher, Gyratory crusher, Impact crusher, Roll Crusher & Cone Crusher  Grinding:- Breaking by abrasion and impact Equipment used: AG Mill, SAG Mill, Roll mill, Ball mill, Palla Mill, & Planetary mill  Comminution is the size reduction process of the ores/minerals.  The primary objective of the size reduction is to make easy transportation and unlocking the desired minerals from gangue minerals in the ore.  It starts in mines with blasting.  The operations involved in the comminution process are;

Classification  Classification is the size separation process based on the size, density and shape of the particles using the fluid as medium for separation. When air used as medium is called dry classification whereas water used as medium is called wet classification.  It provides the desired size range of the particles to treat in different beneficiation process to produce concentrate from low grade ores.  The two common types of classifiers are:- - Vibrating Screen: it is suitable for coarse particles - Hydrocyclones : it is suitable for fine particles  Apart from the above, hydrosizer, screw classifier, and settling cone are used for classification units.

Concentration Process  It is based on the mineralogical, physical and chemical characteristics of the mineral phases in the ores.  It increases the percentage of the valuable minerals in the concentrate.  Depending on the physical and surface chemical properties of the mineral phases associated in the low grade ores, the requisite process flow chart is selected.  The common separation processes used are gravity separation, magnetic separation, electrostatic separation, flotation and selective flocculation.

Gravity Separation Concentration Process (Contd…) It is based on the physical properties of the particles i.e. size, shape, density and fluid properties mainly density and viscosity. The equipments used in the gravity separation processes are jig, heavy media bath, heavy media cyclone, Wilfrey table, spiral concentrator, All flux separator, Floatex separator, Kelsey jig, multi-gravity separator, Knelson concentrator and Falcon concentrator.

Magnetic separation Concentration Process (Contd…) It depends on the magnetic susceptibility of the particles. Particles separate from each other in the induced magnetic field depending on their magnetic susceptibility. The equipments used in the magnetic separation processes are low intensity magnetic separator (LIMS), medium intensity magnetic separator (MIMS) and wet high intensity magnetic separator (WHIMS) and high gradient magnetic separator (HGMS)

Flotation Concentration Process (Contd…) Its working principle is based on surface properties of the particles. It separates hydrophobic particles from hydrophilic particles. By surface modification of the selective particles by flotation reagents, the surface properties change from hydrophilic to hydrophobic. The hydrophobic particles get attached to the air bubbles to form froth which is separated by the flotation machine. The equipments used in flotation processes are flotation cell flotation column, G cell (combination of flotation and gravity process).

Electrostatic Separation Concentration Process (Contd…) It works mainly on the conductive properties of the particles. It separates conductivity and non-conductivity materials using electro-static polarity to change the charge of the particles. Based on the positive and negative charge, the particles separate form each other by attraction of opposite poles. The equipments used in flotation processes are tribo-electro- static separator and high tension electrostatic rolls separator.

Selective Flocculation Concentration Process (Contd…) Valuable ultra fine particles (less than 10 micron particles) cannot be easily separated by magnetic or flotation processes. Hence by selective flocculation, the valuable ultrafine particles are recovered. The flocculent makes particular mineral phases to get converted to flocs. These flocs settle down very fast and the other suspended particles are decanted. The equipment used for selective flocculation is called clarifier..

Dewatering  The dewatering is done for both coarse and fines particles.  For coarse particle, the following equipments are used. - Vibrating screen - Screw classifier - Centrifuge - Dryer  For fine particles, the primary dewatering is carried out by thickener. The secondary dewatering is carried out by the following equipments; - Filter ( Vacuum, Pressure or both) - Centrifuge - Dryer ( Apply heat to remove the surface moisture)

Simplified Process Flow chart for Various Stages Involved in Mineral Beneficiation

Ore from mine Dry crushing plant screens Wet grinding plant concentration Classification/sizing concentratetailing dewateringdisposal Concentrate cake to smelterWater for reuse

Process Flow chart for Mineral Beneficiation of Iron ore Process Flow chart for Mineral Beneficiation of Iron ore

Iron ore fines Vibrating screen Screw classifier Pump box Pump box Pump box Pump box Pump box Pump box Pump box Primary ball mill Secondary ball mill Regrindiing ball mill Rougher spiral Cleaner spiral Primary hydrocyclone Desliming cyclone Derrick screen Rougher magnetic separator Cleaner magnetic separator Vibrating screen Tailings thickener Intermediate thickener Concentrate thickener Intermediate thickener Conditioner Pump Column flotation Tailings Conc. for BF Pellet Conc. for DRI Pellet Process flow chart Water -10 mm +10 mm

References  Mineral processing by S.K.Jain  Wills mineral processing technology, Elsevier  www. wikipedia. com  Mineral Processing by Hassan Z.Harraz, Tanta University

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