FLOW CHART FOR MINERAL BENEFICIATION PROCESS

Smitirupa Biswal , G.Meghana Priya2nd 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

concentrate tailing

dewatering disposal

Concentrate cake to smelter Water for reuse

Process Flow chart for Mineral Beneficiation of Iron ore

Iron ore fines

Vibratingscreen

Screwclassifier

Pumpbox

Pumpbox

Pumpbox

Pumpbox

Pumpbox

Pumpbox

Pumpbox

Primary ball mill

Secondaryball mill

Regrindiingball mill

Rougherspiral

Cleanerspiral

Pri

mar

yh

ydro

cycl

on

eDeslimingcyclone

Derrick screen

Roughermagnetic separator

Cleanermagnetic separator

Vibratingscreen

Tailingsthickener

Intermediatethickener

Concentratethickener

Intermediatethickener

ConditionerPump

ColumnflotationTailings

Conc. forBF Pellet

Conc. forDRI 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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