Mineral Processing-II Slides

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MINERAL PROCESSING-II Prepared By: Ali Bux Wassan (12MN65)

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Mineral Processing-II notes prepared by Ali Wassan

Transcript of Mineral Processing-II Slides

  • MINERAL PROCESSING-II

    Prepared By: Ali Bux Wassan(12MN65)

  • AGGLOMERATIONBy: Ali Bux Wassan (12MN65)

  • AGGLOMERATION

    The act or process of converting separate particles into mass or cluster.

    An enormous amount of fines is generated during mining and ore processing operations.

    Since the fines can not be used directly in the blast furnace.Since the fines can not be used directly in the blast furnace. It is necessary to agglomerate them into lumps; pellets and

    briquettes. The particulate matter may require size enlargement to

    make it sellable or to improve its physical properties The process is used for changing the size of concentrate

    particles, when the particle size of an ore is too small for the use in latter stage of treatment (e.g. in the blast furnace), it must be reformed to lumps of appropriate size and strength.

  • AGGLOMERATION:

    Most of the mineral products are agglomerated by four basic processes.

    a) Sintering

    b) Pelletizing

    c) Briquetting

    d)Nodulizing

  • (1) SINTERING:

    The sintering of iron ore is one of the most important methods of ore treatment

    It may be defined as the process of heating concentrate particles to an elevated temperature below its melting point.

    It is one of the processes in which a bed of small ore particles is bonded into clinker by high temperature fuel combustion.is bonded into clinker by high temperature fuel combustion.

    Excessive fine material in an ore will result in a greater fine dust loss at blast furnace

    The rate of temperature is controlled by drying and blowing air through the bed. The temperature approaching 1400C in the narrow combustion zone.

    Sintering has the largest industrial application and many million tons of iron ore concentrate are annually converted into sinters by this process.

  • (2) BRIQUETTING :

    It can be defined as a process of agglomeration where by particulate matter is consolidated into briquettes

    Iron ore fines ------> binder -------->Mixing--->Mechanical pressure = iron ore Briquettes>Mechanical pressure = iron ore Briquettes

    Briquetting process is based on the principle of applying pressure on iron ore fines so that a compact mass can be obtained in specific size.

    In this process ore fines and concentrated are mixed with suitable binder (lime or Petroleum bitumen or pitch) and fed into a double roll Briquetting process to be moulded into shape

  • (3) PELLETIZING

    The formation of raw iron ore pellets are known as palletizing.

    It is another process of agglomeration in which fine grained moist ore is rolled in drum, so that the particles cling together and rollup into small, spherical pellets.Making larger spheres from the finely ground iron ore has Making larger spheres from the finely ground iron ore has several purposes.

    Not only is handling and transport easier with pellets but they are also a requirement in subsequent iron and steel making processes.

    If the iron ore material is too fine , the process suffocates in the same way as when sand is thrown on an open fire.

    Pellet size, high iron content and a good balance of additives also provide steel works with technical and financial production advantages.

  • PELLETIZING:

    A binder should be used to provide strength to the pellets during the stress of transference, transport and use.

    The concentrate pellets are practically always heat hardened for the same reason.

    A wide range of organic grinding material like tar, pitch A wide range of organic grinding material like tar, pitch and inorganic binding material like, lime some, cement, bentonite clay etc, have been used with varying proportions.

    The process of pelletizing combines with mixing of the raw material , forming the pellet and a thermal treatment baking the soft raw pellet to hard spheres. The raw material is rolled into the balls and then fired in a kiln for heat hardened in order to make it suitable for blast furnace.

  • (4) NODULIZING

    Nodulizing is a process of size enlargement by fusion in which strongest nodules or small rounded lumps are formed.

    Iron ore fines + Tar + Rotary kiln furnace = nodule

    In nodulizing ore concentrates along with tar pass In nodulizing ore concentrates along with tar pass through a fired rotary kiln, the material begins to soften at high temperature and the rotation of the material causes the sticky material to roll into lumps.

    The temperature inside the kiln is just sufficient to soften the ore but not enough to fuse the ore.

  • NODULIZING:

    The kiln used may be 100ft long 6 ft in diameter at entrance and 10ft diameter at the discharge end.

    It is slightly inclined to the horizontal and rotates at the speed of 1to 2 rpm.

    The agglomeration continues as the ore proceeds The agglomeration continues as the ore proceeds through the kiln and heated at temperature of 1200 to 1500C.

    A great cooler usually cools the nodules.

    The size of nodules depend upon the temp:, quality of tar and speed of rotation of kiln.

  • MAGNETIC MAGNETIC SEPARATION

    By: Ali Bux Wassan (12MN65)

  • MAGNETIC SEPARATION

    It is one of the methods applied in mineral processing for separation of magnetic minerals from non-magnetic minerals.

    Initially it was employed to separate strongly magnetic ores(magnetite) from gangue.ores(magnetite) from gangue.

    Before 1939,only few ferromagnetic materials were available for industrial application.

    With the advancement of technology and design of machines , this method is adopted now for the separation of ores which are feebly magnetic.

    For Example:Hematite, limonite, siderite, etc, can now be separated

    from their gangue by application of high intensity magnetic fields.

  • MAGNETIC SEPARATION:

    Magnetic separation is a method of concentration of an ore used when:

    1) The ore is magnetic but gangue is non-magnetic2) The ore is non-magnetic but gangue is magnetic The magnetic separation is effective due to distinct The magnetic separation is effective due to distinct

    movement of magnetic particles towards the magnetic field and non-magnetic particles away from it.

    Broadly minerals can be classified into three groups on the basis of their behaviour in a magnetic field:

    1) Attracted2) Repelled or3) Unaffected

  • MAGNETIC SEPARATION:

    Further more, there are three main classifications of magnetic minerals w.r.t their interaction with the magnetic field:

    1) Paramagnetic Minerals (Feebly Attracted)1) Paramagnetic Minerals (Feebly Attracted)

    2) Ferromagnetic Minerals(Strongly Attracted)

    3) Diamagnetic Minerals (Non-magnetic)

  • PARAMAGNETIC MINERALS

    These minerals are slightly attracted by the magnetic field and dont retain their magnetic properties when the external field is removed.

    These minerals are attracted in the direction in which the magnetic field increases( i.e. towards a the magnetic field increases( i.e. towards a concentrated magnetic field)

    A magnetic response is obtained at a flux density greater than 2000 gauss and less than 20000 gauss.

    Examples include:

    Chromite,Hematite,Limonite,Monazite,Aluminum,Tin, Platinum

  • FERROMAGNETIC MINERALS

    These are themselves magnets and have very high susceptibility to magnetic force and they exhibit the strong attraction to the magnetic field.

    They are attracted in the same way, however they can be quite easily magnetized by a low intensity of magnetic field.

    A magnetic response is obtained at a flux density of

  • DIAMAGNETIC MINERALS

    These are repelled or unaffected in the direction of magnetic field intensity (in practical terms non-magnetic)

    No magnetic response at a flux density

  • GAUSS

    The amount of magnetism induced in a body by a magnetic force is called Flux density and is measured in gauss.

    The intensity of a magnetic field refers to the no. of The intensity of a magnetic field refers to the no. of lines of flux passing through a unit area .

    Lines of flux are measured in gauss( lines/cm2 or Tesla)

    1 Tesla = 10,000 gauss

  • TYPES OF MAGNETIC SEPARATORS

    INTRODUCTION:

    Magnetic separators are devices which are designed to various material compositions on the basis of their magnetic properties. They are used in industries like mining, and smaller versions are utilized in scientific labs to process some smaller versions are utilized in scientific labs to process some types of samples. Numerous companies make magnetic separators for various applications, and there are several different styles available for people to choose from, depending on the application and their needs.

    A basic magnetic separator consists of a magnet of some kind. As materials are passed below, over, through, or around the magnetic separator, it attracts undesirable impurities, pulling them out and cleaning the process stream.

  • TYPES OF MAGNETIC SEPARATORS:

    WHERE MAGNETIC SEPARATORS COULD BE USED?

    Magnetic Separators could be used in two cases:

    The ore is magnetic but gangue is non-magnetic

    The ore is non-magnetic but gangue is magnetic The ore is non-magnetic but gangue is magnetic

    All the materials are affected in some way when placed in the vicinity of magnetic field, although with most substances the effect is too slight to be detected.

    The mechanism for the separation is distinctive movement of magnetic particles towards the magnetic field and non-magnetic particles away from it.

  • TYPES OF MAGNETIC SEPARATORS:

    APPLICATION OF MAGNETISM AS SEPARATOR:

    For the removal of tramp iron in coarse and intermediate-crushing circuits, as a protection to the crushing machinery.

    For the concentration of magnetite ores For the concentration of magnetite ores

    For the concentration of iron ore other than magnetite, after preliminary conversion of iron minerals to artificial magnetite by suitable Roasting

    For the removal of small quantities of iron ore minerals form ceramic raw materials

  • TYPES OF MAGNETIC SEPARATORS:

    ELEMENTS OF DESIGN OF MAGNETIC SEPARATORS:

    Following are the elements while selection and designing of a magnetic separator:

    Production of suitably converging magnetic field

    Even feeding of ore particles as a stream or sheet

    Control of speed of passage of ore thorough the magnetic field Control of speed of passage of ore thorough the magnetic field

    Avoidance and/ or correction of occlusion or non-magnetic material between or within magnetic flux

    Provision of suitable means for disposing off separated products

    Provision for production of a middling

    Elimination or reduction to a minimum of moving (wearing) parts

  • TYPES OF MAGNETIC SEPARATORS:

    CLASSIFICATION OF MAGNETIC SEPARATORS:Magnetic separators can be classified according to: the medium in which the separation is made the mode of presentation of the feed the mode of disposal of the products and the mode of disposal of the products and whether the magnets are stationary or movingOn such basis some might be as: High intensity magnetic separators Low intensity magnetic separators Dry separators Wet separators etc

  • TYPES OF MAGNETIC SEPARATORS:

    IMPORTANT TYPES OF MAGNETIC SEPARATORS: There are many types of magnetic separators but some

    important types are described as under: EDISON SEPARATOR: This magnetic separator consists of a bar magnet. The This magnetic separator consists of a bar magnet. The

    ore as thin stream falls in front of the poles, susceptible particles being deflected towards and non-susceptible particles continuing to fall un-deflected.

    This magnetic separator was not wholly successful because of inability of control flow of solid in a thin sheet, and because of lack of control over the speed of the falling particles.

  • TYPES OF MAGNETIC SEPARATORS:

    MAGNETIC DRUM SEPARATOR:

    These are important magnetic separators that remove ferrous metal from dry bulk products in free-flowing processing systems. They are self free-flowing processing systems. They are self cleaning unit consisting of drums and housing normally of stainless steel. The magnets used by the magnetic drum separators are either ceramic magnets or rare earth magnets. The magnetic drum separators are available both in single or double drum configuration

  • TYPES OF MAGNETIC SEPARATORS:

    HOW IT WORKS?

    The processing materials enter the top of the magnetic drum separator and flow across the surface of the drum. The rotary drum in the magnetic field captures the ferrous tramps whereas the non-ferrous falls free from the drum into the cleaned material flow. As the drum rotates, the ferrous metal so captured is carried past the diverter and released outside of the magnetic field.diverter and released outside of the magnetic field.

    TYPES:

    Its types are as under:

    Electro drum separators

    Wet drum separators

    Single drum separators

    Double drum separators

  • TYPES OF MAGNETIC SEPARATORS:

    APPLICATIONS:

    The magnetic drum separator is ideal for separating iron particles from granules and powders; it is widely used in the following industries:

    Glass

    Ceramic

    Chemical Chemical

    Fertilizer

    Plastic

    Food industry

    Iron and steel slag treatment

    Reduced pyrite ash separation

    Calcined limestone production

    Metal powder production

  • TYPES OF MAGNETIC SEPARATORS:

    BALL NORTON SEPARATOR:

    Unlike most magnetic separators which are used to remove relatively small amounts of metal, the ball Norton separator is designed to handle large amounts of ferrous material-removing other undesirable elements. A unique combination removing other undesirable elements. A unique combination of alternating magnetic poles and vibratory conveying works to clean the magnetic material.

    APPLICATIONS:

    Its applications include:

    Foundry shot

    Crushed borings

    Slag and magnetic ores

  • TYPES OF MAGNETIC SEPARATORS:

    ROLLER TYPE MAGNETIC SEPARATOR:

    This is meant to separate ferrous contaminants from the flimsy magnetized dry granular metallic and non-metallic materials. It has wide applications in industries and mineral processing. This separator uses high powered rare earth magnets with very low dimensional tolerance. The other components of machine are conveyor and vibratory feeder. The magnetic rolls are available in conveyor and vibratory feeder. The magnetic rolls are available in different widths and magnetic strength.

    HOW IT WORKS?

    The material is discharged on the belt by the feeder. The magnetic roll is enveloped by the conveyor. The Para and Ferro magnetic ingredients remain stuck to the belt whereas non-magnetic ingredients pass freely at the end of the conveyor.

  • ROLLER TYPE MAGNETIC SEPARATOR:

    APPLICATIONS:

    It has applications in the following areas like:

    Glass industries

    Abrasive refractory Abrasive refractory

    Quartz cleaning

    Upgrading of graphite

    Recovery of metals from slag removal of Ferro silicates

    Chemical industry.

  • TYPES OF MAGNETIC SEPARATORS:

    GRAVIT FEED MAGNETIC SEPARATOR: This separates ferrous tramp metal through gravity system;

    these magnets are constructed out of welded stainless steel structure. The gravity magnet comes in different shapes and sizes and is ideal for narrow chute applications. Gravity feed magnets are normally used in vertical flow system.feed magnets are normally used in vertical flow system.

    APPLICATIONS: Gravity magnetic separators have different industrial and

    commercial usage. They are applied in industries like: Food industry Chemical industry Grain processing industries Pharmaceutical industries

  • TYPES OF MAGNETIC SEPARATORS:

    MAGNETIC COOLANT SEPARATOR:

    It is a device which cleans the coolant liquid of very fine ferrous particles. It removes the iron chips from the milling or grinding liquid. It is light and compact the milling or grinding liquid. It is light and compact structure having strong magnetic power which can remove very fine ferrous particles. For precise grinding operations uninterrupted flow of oil is must. The coolant magnetic separator ensures the uninterrupted flow of the liquid

  • TYPES OF MAGNETIC SEPARATORS:

    WET DRUM SEPARATOR: Wet drum magnets have high magnetic recovery and

    discharge. The feed slurries recover the magnetics. These are available in single or multiple drum applications. These recover magnetic solids in as clean a magnetic concentrate as possible. Permanent magnet a magnetic concentrate as possible. Permanent magnet assembly eliminates coil burn-outs. The magnet/pole elements are bolted to a mild steel shaft. The drum is made from thick stainless steel for long service of life. Wet drum separators are available in different configuration like single drum, double drum and multiple drum. In double drum two separators are arranged back to back with a common feedback.

  • WET DRUM SEPARATOR:

    APPLICATIONS:

    Glass industry

    Chemical industry

    Plastic industry Plastic industry

    Mining industry

    Food industry

    Pharmaceutical industry

    Foundry industry

  • FROTH FLOTATIONBy: Ali Bux Wassan (12MN65)

  • FROTH FLOTATION

    Floatation is the process by which mineral particles are induced to become attached to the air bubble & float and other particles to sink, so that valuable mineral are concentrated and separated from the worthless gangue or waste.Floatation is widely used in mineral processing industry Floatation is widely used in mineral processing industry with the aim of concentrating valuable to obtain high grade concentrate and simultaneously separate gangue.

    Before floatation the mined ore is mechanically ground ,to powder of desired grain size and mixed with water and chemicals to form slurry or pulp for flotation process.

  • FROTH FLOTATION:

    In the floatation cell air is introduced into slurry to produce air bubble that naturally move upward and produce froth on the top of the slurry .

    The mineral grains depending on their mineral contents tend either to float or sink in the liquid .contents tend either to float or sink in the liquid .

    During the floatation process particles of desired mineral which are commonly hydrophobic attached to the rising air bubble from bottom of the cell where air is injected with the particles of gangue material (which are hydrophilic) remain in slurry or pulp and discarded through tailing gate.

  • FROTH FLOTATION:

    Froth flotation can be adapted to a broad range of mineral separations, as it is possible to use chemical

    treatments to selectively alter mineral surfaces so that they have the necessary properties for the separation. It is currently in use for many diverse applications, with a few examples being: examples being:

    separating sulfide minerals from silica gangue (and from other sulfide minerals);

    separating potassium chloride (sylvite) from sodium chloride (halite);

    separating coal from ash-forming minerals; removing silicate minerals from iron ores; separating phosphate minerals from silicates

  • FROTH FLOTATION:

    Flotation process can be categorized as:1) PLAIN FLOTATION: it was 1st practised in MP to obtain

    one type of concentrate from sulfide ore. 2) BULK FLOATATION Generally mineral ores contain more than one valuable Generally mineral ores contain more than one valuable

    mineral. In case of sulphides, minerals usually occur together e.g. chalcopyrite and galena, chalcopyrite and pyrite. In some ore bodies many minerals may floats out together and discard the gangue.

    Such flotation process in which more than one valuable mineral ore floated together is called bulk flotation.

    Or the rising of a mineralized froth, of more than one mineral, in a single operation.

  • FROTH FLOTATION:

    3) DIFFERENTIAL FLOTATION: Later on this mixture of valuable minerals is further floated after bulk floatation to recover individual mineral one by one is called differential flotation.

    It was later developed to recover progressively more It was later developed to recover progressively more than two kinds of concentrate from complex sulfide ore bearing many valuable minerals.

    In differential flotation , valuable minerals are recovered individually.

    In this , sulfide concentrate is accomplished by 1st

    destroying the hydrophobic coating and then by recovering another concentrate.

  • FLOTATION EQUIPMENT

    Flotation can be performed in rectangular or cylindrical mechanically agitated cells or tanks.

    Mechanical cells use large mixer at the bottom of the tank to introduce air and providing mixing the tank to introduce air and providing mixing action.

    Flotation cells use spargers to introduce air at the bottom of the cell.

  • FROTH FLOTATION:

    Most of the minerals usually do not possess enough floatability and it is difficult to float these minerals without the aid of chemical agent.

    In order to achieve satisfactory separation of In order to achieve satisfactory separation of valuable minerals from gangue various floatation reagents classified as collector, frothers and modifiers are used.

  • 1) COLLECTORS/SURFACTANTS

    Collectors are reagent that adsorb on the mineral surface to form a thin ,coating and make them hydrophobic .

    Collectors provide hydrophobicity on the mineral surface to enhance the mineral to air bubble surface to enhance the mineral to air bubble attachment .

    Hydrophobicity has to be imparted to the most of the minerals in order to float them .

    in order to achieve hydrophobicity ,surfactants known as collectors are added to the slurry and time is allowed for adsorption during agitation that is its conditioning period

  • COLLECTORS:

    Common collectors and their uses:

    Reagents Main uses

    Xanthates Floatation of sulphide ore

    1.(Ethyle ,propyle ,butyl and ammyl,(Copper,silver,gold,iron,zinc, (Copper,silver,gold,iron,zinc,

    xanthates) nickel)

    2. Dialkyl,Dithophosphate Floatation of copper and zincsulphide from galena.

    3. Dialkyl, Dithocarbonate Similar properties to xanthates but

    more expensive.

  • COLLECTORS:

    4. isopropylthiono carbonate: Selective floatation of copper, sulphides from pyrite.

    5. sulphonates or sulphatesFloatation of iron ore.

    6. petrochemical productsFloatation of coal.

    (diesel,liquid paraline)

  • XANTHATES

    These are highly selective collectors for sulphideminerals as they chemically react with the sulfide surfaces and dont have any affinity for common non-sulfide gangue minerals.

  • 2) FROTHERS

    Frothers are reagents used to produce froth of adequate stability and its main function is to stabilize the bubble that transport the hydrophobic valuable minerals to the surface of froth zone where they can easily be separated.

    Froth generation require the use of frothers and they must be to some extent soluble in H2O, otherwise they would be distributed very unevenly in an aqueous solution and their surface active properties would not be fully effective.

  • FROTHERS:

    The most effective frothers include

    Pine oil

    Cresol (cryslic acid)

    Aliphatic alcohol Aliphatic alcohol

    Polyglycol

    Hydroxyle ,carboxyle ,carbonyle

    Esters

  • FROTHERS:

    Apart from the ability of frothers to form froth , they have other important roles including:

    Creating finer bubbles, whereby the dispersion of air in the flotation cell also improves.air in the flotation cell also improves.

    Reducing the rate of bubble rise from the mixing zone to the froth zone

    Increasing the strength of the bubbles and stability of the froth

  • 3) MODIFIERS/REGULATORS

    Modifiers are used extensively in flotation to modify the action of collectors.

    The function of modifiers is neither collecting nor frothing but the main function of modifier is to modify the action of collector either by enhancing or by reducing its hydrophobic collector either by enhancing or by reducing its hydrophobic effect on the mineral surface.

    In the presence of modifiers, the collector only adsorb on the particles that are targeted for recovery and make the collector action more selective towards certain mineral.

    The purpose of regulator or modifier is to prepare the surface of various solids for selective adsorption of the surfactants in such a manner that only the desired particles are made hydrophobic.

  • MODIFIERS:

    According to their function the modifying reagents may be classified into the following groups:

    Activators

    Depressants Depressants

    PH Regulators

  • ACTIVATORS

    Activators are reagents that alter the surface of mineral so that it can more readily adsorb a collector and float.

    Copper sulphate (CUSO4): is an activator widely Copper sulphate (CUSO4): is an activator widely used that reacts with the surface of mineral particle resulting an increase in the adsorption and consequently improved floatability.

    The mineral processing industry has found its application as an activator in the concentration of cobalt, gold, zinc, lead and other sulphides.

  • DEPRESSANTS/DE-ACTIVATORS

    Depressant, is any reagent which prevents the adsorption of a collector by the mineral particle and there by prevents its flotation.

    Depressants can also remove the collector coating from mineral surface causing depression of the mineral.mineral surface causing depression of the mineral.

    Potassium per magnet (KMNO4) has depressing effect on most of the sulphide minerals.

    Cyanide salts are used as depressants for sphaterite, pyrite, during lead, copper, zinc floatation.

    Sodium sulphide is an excellent depressants used in mineral processing industry.

  • PH REGULATORS

    PH regulators are used to adjust the pH of the pulp. The effectiveness of all classes of flotation reagents

    depends to large extent on the degree of alkalinity or acidity of the pulp.

    Floatation is carried out at alkali pH (above 7) because most of the collectors are stable at higher pH.

    Floatation is carried out at alkali pH (above 7) because most of the collectors are stable at higher pH.

    This produces optimum processing result while also preventing corrosion of metal equipment or flotation cell.

    Lime and sodium hydroxide and soda ash to increase the pH (alkalinity) and sulphuric acid (H2SO4) and HCL to decrease the pH (acidity).

  • FLOCCULATION FLOCCULATION AND DISPERSION

    By: Ali Bux Wassan (12MN65)

  • FLOCCULATION AND DISPERSION

    INTRODUCTION:

    All those mineral processing operations, which use slurry or pulp are concerned with the dispersion and flocculation.

    Ore particles can be unattached to one another (dispersed) or clumped together(flocculated) depending (dispersed) or clumped together(flocculated) depending upon the process of treatment.

    Both these operations find applications in classification, thickening, filtration and froth flotation.

    These conditions are desirable under certain circumstances where we may be interested in recovering solid, liquid or both

  • DISPERSION

    It is the uniform mixture of solid particles in a liquid , where the solids are insoluble in that liquid.

    In dispersion, the suspended particles are uniformly distributed in suspension with the individual particles distributed in suspension with the individual particles being essentially separate.

    In dispersion, the suspended particles remain in suspension for longer period of time during which the pulp is processed.

  • DISPERSION:

    Dispersants or dispersing agents are used to improve the separation of the particles and to prevent settling or clumping of the particles.

    Dispersants include: Dispersants include:

    Sodium Silicate

    Sodium hexametaphosphate

    Sodium Polyacrylate

  • FLOCCULATION

    Flocculation refers to the process by which fine particles are caused to clump together to form floc.

    In this process, the suspended particles in slurry come closer to each other, making cluster and settle to the bottom of the liquid each other, making cluster and settle to the bottom of the liquid or float to the top of the liquid depending on their weight.

    Mineral industry world wide need to process finely mineralized ores and recover mineral values from slimes.

    Mostly desired minerals in the form of concentrate of coarse particles are recovered whereas the slimes may be discarded while containing mineral values.

  • FLOCCULATION:

    Because of losses of mineral values , it is necessary to convert slimes into coarser particles by the process of flocculation.

    Flocculation is achieved by agitation and flocculants which encourage the clumping of slime.Once, suspended particles are flocculated into larger particles Once, suspended particles are flocculated into larger particles they can usually be removed from liquid by filtration.FACTORS AFFECTING THE FLOCCULATION ARE:

    concentration of particles in the pulp (pulp density) temperature of pulp PH of pulp Size of particles

  • FLOCCULATION:

    Rate of flocculation

    depends upon the following factors:

    (a) Particle population in the fluid. (a) Particle population in the fluid.

    (b) Size of the particles.

    (c) Sequence of other events.

    If some other phenomenon happens before flocculation the condition may change and may affect the subsequent rate of flocculation.

  • FLOCCULATION:

    Flocculants or flocculating agents are chemicals used to facilitate the settling of suspended particles in slurry.

    Flocculants include: Lime Lime Starch Lime + starch Alum Gypsum Ferric Chloride Aluminum sulphate

  • HEAP LEACHING HEAP LEACHING OF COPPER ORE

    By: Ali Bux Wassan (12MN65)

  • HEAP LEACHING OF COPPER ORE

    DEFINITION:

    Leaching is the process of extracting minerals from a solid by dissolving them in a liquid, either in nature or through an industrial process OR

    Heap leaching means leaching ores that have been mined, crushed, and transported on impervious pads for leaching by sprinkling and percolation transported on impervious pads for leaching by sprinkling and percolation of the solution through the ore

    OR

    Heap leaching is a tried and tested mining technique enabling the processing of different kinds of ores which could not otherwise be exploited under viable economic conditions

    OR

    The separating or dissolving out the soluble constituents from a rock or ore body by percolation of water is called Heap Leaching/Leaching.

  • HEAP LEACHING OF COPPER ORE:

    Leaching is the process by which inorganic, organic contaminants or radio nuclides are released from the solid phase into the water phase under the influence of mineral dissolution, desorption, complexation processes as affected dissolution, desorption, complexation processes as affected by pH, redox, dissolved organic matter and (micro) biological activity. The process itself is universal, as any material exposed to contact with water will leach components from its surface or its interior depending on the porosity of the material considered.

  • HEAP LEACHING OF COPPER ORE:

    Leaching is extensively used in metal processing industries. The useful metal may occur in mixtures with very large amounts of undesirable constituents, and leaching is used to remove the metals as soluble salts. The use of acids is to remove the metals as soluble salts. The use of acids is prevalent in the metal processing industry, Sulphates are normally used to remove metals from the solid phase, and these produce harmful environmental byproducts such as sulphates.

  • HEAP LEACHING OF COPPER ORE:

    STEPS IN THE PROCESS OF HEAP LEACHING OF COPPER ORE:

    Crushing and throwing of oxide ore on clay lined leach pad

    Showering of weak sulphuric acid on the heap

    Collection of solution (water+acid+ore) in the pond

    Transporting solution to the Solvent Extraction Plant to produce copper cathodes

    Electrowining process is applied

    Pure copper is transported and water is recycled back to the pad

  • HEAP LEACHING OF COPPER ORE:

  • HEAP LEACHING OF COPPER ORE:

    HEAP LEACHING PROCESS: The mined ore is usually crushed into small chunks and heaped on an

    impermeable plastic and/or clay lined leach pad where it can be irrigated with a leach solution to dissolve the valuable metals. While sprinklers are occasionally used for irrigation, more often While sprinklers are occasionally used for irrigation, more often operations use drip irrigation to minimize evaporation, provide more uniform distribution of the leach solution, and avoid damaging the exposed mineral.

    The solution then percolates through the heap and leaches both the target and other minerals. This process, called the "leach cycle," generally takes from one or two months for simple oxide ores (e.g., most gold ores) to two years (for nickel laterite ores).

  • HEAP LEACHING PROCESS:

    The leach solution containing the dissolved minerals is then collected, treated in a process plant to recover the target mineral and in some cases precipitate other minerals, and then recycled to the heap after reagent levels are then recycled to the heap after reagent levels are adjusted.

    Ultimate recovery of the target mineral can range from 30% of contained (run-of-mine dump leaching sulfide copper ores) to over 90% for the easiest to leach ores (some oxide gold ores).

  • HEAP LEACHING PROCESS:

    In recent years, the addition of an agglomeration drum has improved on the heap leaching process by allowing for a more efficient leach.

    The rotary drum agglomerator works by taking the crushed ore fines and agglomerating them into more uniform particles. fines and agglomerating them into more uniform particles.

    This makes it much easier for the leaching solution to percolate through the pile, making its way through the channels between particles.

    The addition of an agglomeration drum also has the added benefit of being able to pre-mix the leaching solution with the ore fines, to achieve a more concentrated, homogeneous mixture, and allowing the leach to begin prior to the heap.

  • HEAP LEACHING PROCESS:

  • HEAP LEACHING PROCESS:

    COPPER LEACHING COUPLED WITH SX/EW CONSISTS OF THE FOLLOWING STEPS:

    Application of a sulfuric acid solution to the top of a heap.

    Interaction of the leach solution with the ore and Interaction of the leach solution with the ore and gangue minerals within the heap.

    Stoichiometric exchange of one copper ion for two hydrogen ions in the SX plant.

    Recirculation of the copper depleted solution back onto the heap.

  • HEAP LEACHING PROCESS:

    The preceding four points state that oxide copper leaching with SX/EW takes place within a system that is closed to all elements save copper and sulfur.

    Sulfur is added as fresh leach solution.Copper is removed from the system in the SX/EW plant. Copper is removed from the system in the SX/EW plant.

    Sulfide dump or heap leaching, where all acid is derived from the dissolution of pyrite and other sulfides, is closed to all elements save copper.

    For all other elements and compounds, copper heap leaching is a closed system.

    The characterization of copper leaching as a closed system has profound implications to the chemistry of leaching

  • HEAP LEACHING PROCESS:

    SOLVENT EXTRACTION AND ELECTROWINING:

    SOLVENT EXTRACTION:

    It is more commonly used to refine copper.

    An organic solvent in which copper is soluble is introduced. An organic solvent in which copper is soluble is introduced.

    As the copper is more soluble in the organic layer than the aqueous, it enters an organic-copper solution and is separated.

    Sulfuric acid is added to strip the copper from the organic solvent into an electrolytic solution.

  • HEAP LEACHING PROCESS:

    ELECTROWINING:

    The copper is refined by electrolysis.

    The anodes cast from processed blister copper are placed into an aqueous solution of 34% copper sulfate and 10an aqueous solution of 34% copper sulfate and 1016% sulfuric acid.

    Cathodes are thin rolled sheets of highly pure copper or, more commonly these days, reusable stainless steel starting sheets.

    A potential of only 0.20.4 volts is required for the process to commence.

    At the anode, copper and less noble metals dissolve.

  • HEAP LEACHING PROCESS:

    More noble metals such as silver and gold as well as selenium and tellurium settle to the bottom of the cell as anode slime, which forms a saleable byproduct

    Copper ions migrate through the electrolyte to the cathode. At the cathode, copper metal plates out but cathode. At the cathode, copper metal plates out but less noble constituents such as arsenic and zinc remain in solution. The reactions are:

    At the anode: Cu(s) Cu2+

    (aq) + 2e

    At the cathode: Cu2+(aq) + 2e Cu(s

  • ENVIRONMENTAL ISSUES CAUSED BY LEACHING AND THEIR IMPROVEMENTS:

    Heap leaching systems have the potential to contaminate groundwater.

    Infiltration of leach solutions must be prevented with the use of appropriate liners and sub-surface drainage systems to collect and appropriate liners and sub-surface drainage systems to collect and recycle solution for treatment.

    Pipelines should be provided with secondary containment and leak detection equipment should be installed

    Impoundments to hold dirty water or untreated process effluents must also be lined.

    Groundwater monitoring for contamination levels and quality must be carried out

  • HEAP LEACHING PROCESS:

    ADVANTAGES OF HEAP LEACHING:

    Much more environmentally friendly than pyrometallurgy.

    Compared to pyrometallurgy, only a fraction of the gases liberated into the atmosphere.liberated into the atmosphere.

    Low capital cost

    Ability of complex and low grade ores extraction

    A major advantage of heap leaching is the elimination of expensive milling operations since the ore body need not be crushed to sizes much smaller than 20 to 25 mm

  • HEAP LEACHING PROCESS:

    DISADVANTAGES OF HEAP LEACHING:

    Large amount of water used,

    greater potential for contamination.

    Difficulties in solidliquid separation

    Impurities problems in purification process

    Much longer time needed for high metal recovery

  • NAGAR PARKER CHINA CLAY CHINA CLAY PROCESSING

    By: Ali Bux Wassan (12MN65)

  • NAGAR PARKER CHINA CLAY PROCESSING

    CHINA CLAY- AN INTRODUCTION:

    It is a common name used for Kaolin, and is derived from kaolinite, a Chinese word meaning high ridge

    This was the name of a hill near Jauchau Fu, China, where This was the name of a hill near Jauchau Fu, China, where kaolin was first mined several hundred years ago for ceramics.

    It is white powdery mineral, containing impurities like silica sand, mica etc

    The removal of these impurities makes it suitable for various industrial applications.

  • CHINA CLAY- AN INTRODUCTION:

    The important properties of china clay are that, it has good plasticity , doesnt swell in water, withstand high temperature ( up to 1300 0C and even temperature ( up to 1300 0C and even above) and is non-conductor of electricity.

  • NAGAR PARKER CHINA CLAY PROCESSING:

    FORMATION OF CHINA CLAY:

    China clay is a white kaolin formed due to alteration of feldspars and also when granite is alteration of feldspars and also when granite is changed by hydrothermal metamorphism.

    It occurs naturally as hydrated aluminum in the compositions usually 2 SiO2.Al2O3.2H2O

  • NAGAR PARKER CHINA CLAY PROCESSING:NAGAR PARKER CHINA CLAY: The Geological Survey Of Pakistan discovered the Nagar Parker

    deposits and investigated these deposits with the help of detailed Geological mapping, sampling and by physical and chemical testing.testing.

    In Nagar Parker area, deep weathering and alteration of granitic rocks have produced china clay.

    The china clay is in the form of several large pockets which occur in a plain area at shallow deposits.

    The deposits are largely covered by a thin layer of soil and further confirming that Kaolinite is the major constituent of Nagar Parker china clay and the measured reserves are 3.6 Million tons.

  • PROCESSING OF NAGAR PARKER CHINA CLAY

    To beneficiate Nagar Parker china clay for various industrial uses, it should be processed for the removal of undesirable minerals such as quartz, gypsum, calcite etc.

    Wet processing is preferred for the beneficiation of Nagar Wet processing is preferred for the beneficiation of Nagar Parker china clay as dry process is simpler and produces a lower quality product than wet process.

    Wet processing is more efficient in concentrating fine china clay .This method involves two main steps of the process:

    1) Liberation of particles

    2) Separation of particles

  • PROCESSING OF NAGAR PARKER CHINA CLAY:PROCESSING MECHANISM : Wet processing of kaolin at Nagar Parker begins with

    blunging of raw china clay with water to produce slurry using agitator.Where china clay is liberated from its impurities through the Where china clay is liberated from its impurities through the action of agitation.

    The slurry is then allowed to pass through tank opening designed at the bottom of the tank.

    The fine china clay particles are carried along the moving steam and coarser particles(silica sand) are allowed to settle down in channels.

  • PROCESSING MECHANISM :

    The water carrying china clay particles are then passed through fine sieve to separate small size silica particles and stored in settling tanks.

    After settlement of kaolin particles , most of the water is After settlement of kaolin particles , most of the water is removed through pumping and thick pulp of china clay is left behind.

    The water is squeezed off from the pulp using disc type filters.

    The moist agglomerated china clay is then dried for transportation to consumer or for further refining.

  • USES OF CHINA CLAY

    China clay is extremely useful mineral, its properties of white color, softness, smoothness, small particle size and chemically inertness makes it possible for no. of different applications.

    Kaolin has a wide variety of industrial applications including:Ceramics Ceramics

    Refractories Insulators Paint industry Paper coating and filling plastic

  • USES OF CHINA CLAY:

    Rubber and textile industries Glass industry Dyes and inks Cosmetics Cosmetics Pharmaceuticals Adhesives and cement Chemical industry Medicines Leather Soaps and detergents powder etc.

  • GLASS MANUFACTURING MANUFACTURING PROCESS

    By: Ali Bux Wassan(12MN65)

  • DEFINITION:

    Glass is an amorphous, hard, brittle, transparent or translucent super cooled liquid of infinite viscosity, having no definite melting point obtained by fusing a mixture of a number of metallic silicates or a mixture of a number of metallic silicates or borates of Sodium, Potassium, Calcium, and Lead.

    An inorganic product of fusion which has cooled to a rigid condition without crystallizing.

  • PROPERTIES OF A GLASS

    The following are the properties that are exhibited by the glass:

    BrittleAmorphous Amorphous High viscous Supper Cooled liquid Capacity to absorb different colors without

    affecting

  • PROPERTIES OF A GLASS:

    Transparent and translucent

    Low thermal conductivity

    Electrical insulator

    transparency transparency

    Hardness

    Chemically inert

    High refractive index

    High dispersion

  • RAW MATERIALS USED IN GLASS MANUFACTURING

    Sand

    Soda Ash Forms basic part of glass

    Sodium nitrate Accelerates melting

    Cao Forms basic part of glass Cao Forms basic part of glass

    Silica Forms acidic part of glass

    Barium Sulphate To remove impurities in the form of the Scum

  • RAW MATERIALS USED IN GLASS MANUFACTURING:

    Feldspar Retards de- vitrification

    Potassium Oxide Used as softening agent

    Borax Increase hardness or refractive index

    Boric Oxide Improves chemical or corrosive Boric Oxide Improves chemical or corrosive resistivity

    Phosphoric Oxide To impart bright appearance

    Magnesia In manufacture of electric bulbs

  • COLORING AGENTS :

    Cadmium Oxide Red color

    Copper Oxide Ruby red

    Titanium Oxide Light yellow

    Cobalt Oxide Deep blue Cobalt Oxide Deep blue

    Cuprous Oxide Greenish Blue

    Chromium Oxide Emerald green

    Manganese Oxide

  • MANUFACTURING STEPS:

    Major Steps In Glass Manufacturing Are As Under:

    Selection of raw materials

    Size reduction

    Melting of raw materials Melting of raw materials

    Forming and Shaping

    Annealing

    Finishing

  • MANUFACTURING STEPS:

  • MELTING PROCESS

    Raw materials in proper proportions are mixed with cullets.

    It is finely powdered and intimate mixture called batch is fused infurnace at high temperature of 1800C ,this charge melts and fusesinto a viscous fluid.

    CaCO3 + SiO2 CaSiO3 + CO2

    Na2CO3 + SiO2 Na2SiO3 + CO2

    After removal of CO2 decolorizes like MnO2 are added toremove traces of ferrous compounds and Carbon.

    Heating is continued till clear molten mass free from bubbles isobtained and it is then cooled to about 800C.

  • FORMING, SHAPING, AND ANNEALING

    FORMING AND SHAPING

    The viscous mass obtained from melting is poured intomoulds to get different types of articles of desired shape byeither blowing or pressing between the rollers.ANNEALINGeither blowing or pressing between the rollers.

    ANNEALING

    Glass articles are then allowed to cool gradually at roomtemperature by passing through different chambers withdescending temperatures. This reduces the internal Strain inthe glass.

  • FINISHING

    Finishing is the last step in glass manufacturing.

    It involves following steps.

    CleaningCleaning

    Polishing

    Cutting

  • TYPES OF GLASS:

    There are nine types of glass according to the minor additions and variations in the ingredients used and according to the methods of manufacturing.

    The different types of glasses are different in their properties and uses.properties and uses.

    1.SODA GLASS OR SODA-LIME GLASS:

    About 90% of all glass is soda-lime glass

    It is prepared by heating Sodium carbonate and silica.

    The approximate composition is Na2CO3.CaO.6SiO2.

    They are low cost, resistant to water but not to acids.

    They can melt easily and hence can be hot worked.

  • TYPES OF GLASS:

    Uses:

    Window glass, Electric bulbs, Plate glass, Bottles,Jars, cheaper table wares, test tubes, reagent bottlesetc .etc .

    2. COLORED GLASS:

    Small amounts of metallic oxides are mixed with thehot molten mixture of sand, sodium carbonate andlimestone.

    The desired color determines the choice of the metallicoxide to be added, as different metallic oxides givedifferent colors to the glass.

  • TYPES OF GLASS:

    USES:

    Colored glass is much in demand.

    It is used for decorating walls, making sunglasses, and for making light signals for automobiles, trains and aero planes.for making light signals for automobiles, trains and aero planes.

    3. PLATE GLASS:

    Plate glass is thicker than ordinary glass.

    It has a very smooth surface.

    It is made by floating a layer of molten glass over a layer of molten tin.

    It is used in shop windows and doors.

  • TYPES OF GLASS:

    4. SAFETY GLASS:

    It can also be called shatterproof glass.

    It is made by placing a sheet of plastic such as celluloid between sheets of glass.

    The special quality of this glass is that in case of breakage The special quality of this glass is that in case of breakage the broken pieces stick to the plastic and do not fly off.

    You must have noticed a broken window-pane of a bus or a car still in its place.

    It is used in automobiles.

    It is also used for making bulletproof screens

  • TYPES OF GLASS:

    5. LAMINATED GLASS:

    It can also be called bulletproof glass.

    Several layers of safety glass are bound together with a transparent adhesive. transparent adhesive.

    The larger the number of layers used the greater is the strength of the glass.

    It is stronger than safety glass.

    It is used in aero planes and windshields of cars

  • TYPES OF GLASS:

    6. OPTICAL GLASS:

    Optical glass is softer than any other glass.

    It is clear and transparent.

    Potassium and lead silicates are used in making optical Potassium and lead silicates are used in making optical glass.

    It is also called flint glass.

    The main use of flint glass is in the manufacture of lenses, prisms and other optical instruments.

  • TYPES OF GLASS:

    7. PYREX GLASS:

    Pyrex glass is highly heat resistant.

    In ordinary glass, silica is the main constituent.

    In Pyrex glass some of the silica is replaced by boron oxide.

    Boron oxide expands very little when heated, thus, Pyrex

    In Pyrex glass some of the silica is replaced by boron oxide.

    Boron oxide expands very little when heated, thus, Pyrex glass does not crack on strong heating.

    Pyrex glass is also called borosilicate glass. It has a high melting point and is resistant to many chemicals.

    Laboratory equipment and ovenware are made of Pyrex glass.

  • TYPES OF GLASS:

    8. PHOTO-CHROMATIC GLASS:

    Photo chromatic glass acquires a darker shade when exposed to bright light and returns to its original lighter shade in dim light. shade in dim light.

    This happens because silver iodide is added to this glass. (silver iodide gets colored with the intensity of light.)

    Uses:

    In making tinted car glasses and goggles.

  • TYPES OF GLASS:

    9. LEAD CRYSTAL GLASS:

    Lead crystal glass has high refractive index, and so has the maximum brilliance.

    It sparkles and is used for high quality art objects and for expensive glassware.expensive glassware.

    It is also called cut glass because the surface of the glass objects is often cut into decorative patterns to reflect light.

    In order to increase the refractive index, lead oxide is used as flux in crystal glass, therefore it is also called lead crystal glass.

  • AUXILIARY AUXILIARY OPERATIONS

    By: Ali Bux Wassan (12MN65)

  • AUXILIARY OPERATIONS

    The operations which do not perform any of the dressing operation directly but without them the actual dressing operation cannot be carried out are called Auxiliary operation. The auxiliary operation includes storage, feeding, sampling are called Auxiliary operation. The auxiliary operation includes storage, feeding, sampling weighing and assaying.

  • (1) STORAGE

    In processing plant the raw material may be stored for processing operation, so that no delays or stoppage can take place within the plant.

    The storage is of two types:

    (1) Long term storage (1) Long term storage

    (2) Short term storage

    In processing plant the material may be stored for a long time must meet the requirement of processing operation so that no delays or stoppage can takes within the plant. The storage can be accomplished in the following important ways depending upon the nature of the material.

    (a) Stock piles (b) Bins (c) Tanks or ponds

  • STORAGE:

    Stock piles are often used to store coarse ore of low value outdoors. In designing stock piles it is necessary to know the angle of repose of the ore, volume or the broken ore and tonnage.

    For continuous feeding of crushed ore to the grinding secti8on feed bins are used or transfer of the coarse material For continuous feeding of crushed ore to the grinding secti8on feed bins are used or transfer of the coarse material from belts and road takes. They are made of wood, concrete or steel. They must be easy to fill and must all steady fall of the ore the discharge gate pulp storage on a large scale is not as easy as dry ore storage. Conditioning takes are used for storage suspension of fine particles to provide time for cynical reaction to proceed. These tanks must be agitated continuously not only to provide mixing but also to prevent settlement a chocking up

  • (2) FEEDING

    Feeing is conveying operation in which the raw material is conveyed to feeder.

    Feeding is essentially a conveying operation in which the distance traveled is short and in which close e regulation of the rate of passage is required. Where succeeding operation is at same rate it is unnecessary to interpose the rate of passage is required. Where succeeding operation is at same rate it is unnecessary to interpose feeder.

    Feeders are necessary whenever it is desired to deliver a uniform stream of dry or moist ore. Where, however principal operations are interrupted by a storage step. A typical feeder consists of a small bin which may be an integral part of a large bin with a gate and suitable conveyor. Feeders of many types have been designed notably chain feeder, rotary feeder revolving feeder, vibrating feeder.

  • (3) SAMPLING

    It is an art of getting representative part (small in size) of an ore. Sampling is the means where by a small amount of material is taken from the main bulk in such a manner that it is representative of that large amount. Great responsibility rests on a very small sample, so it is essential that samples are truly representative of the bulk.representative of the bulk.

    Where ever possible samples should be taken of the material when it has been reduced to the smallest particle size consistent to the process.

    To obtain the best sample should be made as homogenous as possible. Ores and concentrates containing cores particles are less homogenous than those containing five particles.

    Sampling system requires primary sampling devices or cutter, and a system to convey the collected material to a convenient location for analysis

  • (4) WEIGHING

    It means to find out the quantity of ore.

    There are numerous ways to determine the quantity of dry ore. Some of them are as follows.

    (a) By weighing ore cars and trucks and weighing of the tare, this requires an operator. this requires an operator.

    (b) By weighing the concentrate and multiplication of this number by the ratio of ore in tones is calculated from assay of feed concentrate and failing.

    (c) By weighing the ore stream at some convenient point and by making an allowance for the moisture contents

  • (5) ASSAYING

    The term assaying means testing of an ore by chemical examination to determine the

    nature, proportion etc of ingredients it contains. The ore or concentrate sample must be analyzed or

    assayed, so that the exact chemical composition of the assayed, so that the exact chemical composition of the material is obtained. Assays are of great importance, as they are used to control operations and to calculate profitability.

    Modern methods of assaying are very accurate on-stream X-rays analysis.

  • ASSAYING

    A new dimension has been added in the last few years by installation of non-stream analysis enables a change of quality to be detected and corrected rapidly and continuously, obviating the delays involved in laboratory testing. Basically it consists of a source of radiation which is absorbed b the sample and consists to give off fluorescent testing. Basically it consists of a source of radiation which is absorbed b the sample and consists to give off fluorescent response of each element; it enters a detector which generated a qualitative output signal as result measuring the characteristics radiation of one element from the sample.

    The detector output signal is generally used to obtain an assay value which can be used for process control