Mineral identification 2

Flotation is the most important and versatile mineral processing technique used in mining industry... APPLICATION OF FLOTATION• Flotation can be successfully applied to both metallic an

INDUSTRIAL MINERAL CONCENTRATION TECNOLOGIES

Prof.Dr Muammer KAYA Osmangazi University Eskisehir-TURKEY

2007

To Final Product

From raw material

Principles of Flotation

Flotation concentration method utilizes the differences in physico chemical

surface properties of particles.

Hydrophobic (water repellent) particles float with air bubbles to form a froth.

Wetted hydrophilic particles sink.

Hydrophobicity increases with the contact angle btw particles and bubbles.

Chemical reagents are used in flotation.

Flotation is a selective separation process.

Flotation is the most important and versatile mineral processing technique used in mining industry.

APPLICATION OF FLOTATION

• Flotation can be successfully applied to both

metallic and industrial minerals given below for removing impurities and improving

quality:

• Apatite/Phosphate, Barite, Calcite, Dolomite,

Feldspar, Fluorspar, Graphite, Iron Ore,

Kyanite, Magnesite, Monazite, Potash,

Pyrochlore, Quartz/Silica Sand, Scheelite etc

MECHANICAL FLOTATION MACHINE

PHOSPHATE MINERALS

• Phosphate minerals are those minerals that contain the tetrahedrally coordinated

phosphate (PO 4 3-) anion along with the freely substituting arsenate (AsO 4 3-) and vanadate

(VO 4 3-) Chlorine (Cl-), fluorine (F-), and hydroxide (OH-) anions also fit into the crystal structure.

• The phosphate class of minerals is a large and diverse group, however, only a few species are relatively common.

• Rock phosphate can also be found on USA, Egypt ,

Israel , Morocco , Navassa Island , Tunisia , Togo , S Arabia and Jordan have large phosphate mining industries as well

USE OF PHOSPHATE

• Phosphates were once commonly used in laundry detergent in the form trisodium

phosphate (TSP), but, because of algae boom-bust cycles tied to emission of phosphates into watersheds, phosphate detergent sale or usage is restricted in some areas.

• In agriculture , phosphate is one of the three primary plant nutrients, and it is a component

of fertilizers Rock phosphate is quarried from phosphate beds in sedimentary rocks In former times, it was simply crushed and used as is, but the crude form is now used only in

organic farming Normally, it is chemically treated to make superphosphate ,

triple superphosphate , or ammonium phosphates , which have higher concentration of phosphate and are also more soluble , therefore more quickly usable by plants.

• Fertilizer grades have three numbers; the first is the available nitrogen , the second is the available phosphate (expressed on a P2O5 basis), and the third is the available potash

(expressed on a K2O basis) Thus a 10-10-10 fertilizer would contain ten percent of each, with the remainder being filler.

• Surface runoff of phosphates from excessively-fertilized farmland can be a cause of

phosphate pollution, leading to eutrophication (nutrient enrichment), algal bloom , and consequent oxygen deficit This can lead to anoxia for fish and other aquatic organisms in the same manner as phosphate-based detergents.

• Phosphate compounds are occasionally added to the public drinking water supply to

counter plumbosolvency

• The food industry uses phosphates to perform several different functions For example, in meat products, it solubilizes the protein This improves its water-holding ability and

increases its moistness and succulence In baked products, such as cookies and

crackers, phosphate compounds can act as part of the leavening system when it reacts with an alkalai, usually sodium bicarbonate (baking soda).

• Phosphate minerals are often used for control of rust and prevention of corrosion on

ferrous materials, applied with electrochemical conversion coatings

PHOSPHATE FLOTATION

• Collophane, the principal phosphate mineral occuring in the phospate deposits of the Southeastern US, floats readily with crude fatty acids and soaps, fuel oil and soda ash, caustic soda or amonia.

• “Double flotation” method is used in US Florida plants by using both

fatty acid and amine types of collectors.

• “Single flotation” is employed at N.Africa and Middle Eastern phosphate operations by using either a fatty acid or an amine type of collector.

• Cytec’s Aero 727, 727J and 728 promoters have been successfully used

where only fatty acid float approach is practiced.

• Cytec’s Aero 8651 fatty amine promer is utilized in operations running

US DOUBLE PHOSPHATE FLOTATION

Desliming (Hydrocyclones)

conditioner

Rougher fl.

Silica Sep Flot

Phosphate-Silica (final tails)

Conditioning with

H2SO4+washing

to remove reagents

pH=6.5-7 Fatty/ether amine Silica (gangue)

Phosphate Conc.

LIME STONE/CALCITE

• Limestone is a sedimentary rock composed

largely of the mineral calcite (

calcium carbonate : CaCO 3 ) l

• Limestone often contains variable amounts

of silica in the form of chert or flint , as well

as varying amounts of clay , silt and sand as disseminations, nodules, or layers within the rock

USES OF LIMESTONE

• The manufacture of quicklime (calcium oxide) and slaked lime

(calcium hydroxide);

• Cement and mortar ;

• Pulverized limestone is used as a soil conditioner to neutralize acidic soil conditions;

• Crushed for use as aggregate —the solid base for many roads;

• Limestone is especially popular in architecture as building

• Added to bread as a source of calcium

Iron impregnations in limestone

• Even very low amounts of graphite is detrimental to the brightness.

• Beneficiation of limestone by froth flotation utilizing Aero 845

promoter can be simple process.

• Limestone is floated with/without prior desliming with the emulsion of Aero 845 and number 5 fuel oil.

• Silicates can be depressed by Na2SiO3 (500-1000 g/t)

• Compared to fatty acids, Aero 845 promoter (Pet Sulphonate type

anionic collector) offer the advantage of better product control at a saving in total collector usage.

Sparingly soluble salts flot.

10 -06 10 -05 10 -04 10 -03

sodium oleate concentration, mol/dm3 0

20 40 60 80 100

calcite

R=100%

Mole/l R=0%

Calcite flot recovery depends on NaOl concentration and HC chain length of the collector In general, when the collector length of the HC chain is increased, the concentration of collector necessary for

flotation is reduced.

Complete flot.

No flot

pH:6- 9

• Graphite holds the distinction of being the

most stable form of solid carbon ever

discovered

• It may be considered the highest grade of

coal , just above anthracite and alternatively called meta-anthracite, although it is not

normally used as fuel because it is hard to ignite

CLASSIFICATION OF GRAPHITE

• There are three principal types of natural graphite,

each occurring in different types of ore deposit:

• (1) Crystalline flake graphite (53%) occurs as

isolated, flat, plate-like particles with hexagonal

edges if unbroken and when broken the edges can

be irregular or angular (Madagascar-open pit,

410-950 $/t)

• (2) Amorphous graphite occurs as fine particles

(Mexico-Underground mines, 240-260 $/t)

• (3) Lump graphite (also called vein graphite) occurs

in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular crystalline aggregates, and is probably hydrothermal in origin (Sri Lanka-Underground mines)

USE AREAS OF GRAPHITE

MAJOR USE AREAS

Amorphous or fine flaked

Carbon rising in molten steel Lubricating dies during hot metal extrution EXPANDED GRAPHITE

MINOR USE AREAS

BRIKE LINING/SHOES FOR HEAVY

IMPURITIES and PROPERTIES

• Minerals associated with graphite include quartz ,

• In 2005, world natural graphite production was

1.05 million t and China was the top producer of graphite with about 80% world share followed by India and Brazil.

• Graphite has various characteristics Thin flakes

are flexible but inelastic, the mineral can leave

black marks on hands and paper, it is

diamagnetic, adsorbant, conducts electricity, and displays superlubricity Its best field indicators are softness, luster, density and streak.

GRAPHITE BENEFICIATION METHODS

• Vary from a complex flotation at Europe and USA mills to

simply hand sorting and screening with/without milling of grade ores in Sri Lanka.

high-• Certain soft flake-type graphite ores, (like in Madagascar) need

no primary crushing and grinding.

• GRAPHITE MILLING ONLY

• Graphite can be ground to a fine powder for use as a slurry in oil drilling ; in

zirconium silicate , sodium silicate and isopropyl alcohol coatings for

foundry molds; and for calcined petroleum coke , which is used as a carbon raiser in the steel industry.

• Rough graphite is typically ground and packaged at a graphite mill Since

the Work Index of graphite is high, power consumption during grinding will

be high

• Environmental impacts from graphite mills consist of air pollution

including fine particulate exposure of workers and also soil contamination

GRAPHITE FLOTATION

• Since graphite is naturally hydrophobic (i.e floats easily),

impurites can easily be removed by direct flotation process.

• Flotation process can be applied to low carbon and high silica

containing graphite ores.

• 1 DESLIMING STEP for removing clay minerals,

• 2 ROUGHER FLOTATION to produce a concentrate with 60-70% C.

• 3 REGRINDING+CLEANER FLOTATION to reach 85% C.

• 4 SCREENING to produce 75-95%C.

• - 0.5 mm graphite can be floated using fuel-oil/kerosene as the

promoter and pine-oil/F-77/MIBC as frother at natural pH Na2SiO3/HF can be used as silicate depressant.

IRON ORES

• Iron ores are rocks and minerals from which

metallic iron can be economically extracted

The ores are usually rich in iron oxides and

vary in color from dark grey to rusty red The iron itself is usually found in the form of

magnetite (Fe 3 O 4 ), hematite (Fe 2 O 3 ), limonite or siderite Hematite ores containing 66% Fe can

be fed directly into iron making blast furnaces Iron ore is the raw material used to make

pig iron , which is one of the main raw

materials to make steel 98% of the mined iron ore is used to make steel

Brazillian hematite

Consumption and economics

• Iron is the world's most commonly used metal It is used

primarily in structural engineering applications, automobiles, and general industrial applications (machinery).

• Iron-rich rocks are common worldwide, but ore-grade

commercial mining operations are dominated by few countries

• World production averages one billion metric tons of raw ore annually The world's largest producer of iron ore is the

Brazilian mining corporation CVRD , followed by Australian

company BHP Billiton and the Anglo-Australian

Rio Tinto Group

• China, Japan and S Korea are currently the largest consumer

of iron ore/steel which translates to be the world's largest steel producing country

LOW GRADE IRON ORE

BENEFICIATION

• Due to the high density of hematite (5.3)

relative to silicates (2.7), beneficiation usually involves a combination of crushing and

milling as well as heavy liquid separation

• This is achieved by passing the finely crushed

ore over a bath of solution containing

bentonite or other agent which increases the density of the solution When the density of

the solution is properly calibrated, the

hematite will sink and the silicate mineral

fragments will float and can be removed

FLOTATION OF IRON ORE

• Due to increased demand for iron ore products low in silica and

phosphorous plus increased world competition, quality

considerations have become more and more important.

• Dephosphorization of iron ores is necessary.

• The results obtained in plant operations vary, depending on ore type

and the process.

• Direct flotation of iron ores was practiced for many years using

Aero899R promoter (1-2 kg/t) along with number 5 fuel oil at pH 3-5 adjusted by H2SO4 following high solids conditioning.

• Reverse flotation of silica with etheramine collectors+frother

(Aerofroth or Oreprep) has been the traditional route for many years to produce a final iron ore concentrate While removing silica from the iron ore, fine iron particles should not excessively lost.

FINE IRON ORE PELLETS

Iron ore fines and flotation concentrates should be pelletized with bentonite before being charged into the blast furnace to produce pig-iron which is used in steel production Iron pellets

HEAVY MINERAL SANDS

• Sand is a naturally occurring granular material

comprised of finely divided rock and mineral

particles

• Sand is transported by wind and water and

deposited in the form of beaches , dunes , sand spits , sand bars (placer deposits) etc

• The most common constituents of sands are silica (SiO 2 ), usually in the form of quartz , iron oxides,

zircon, rutile, ilmenite, monazite, garnet.

Heavy mineral sands are a class of ore deposit which

is an important source of zirconium , titanium ,

thorium , tungsten , rare earth elements , the industrial minerals diamond , sapphire , garnet, and

occasionally precious metals or gemstones.

Grade and Tonnage Distribution

• The grade of a typical heavy mineral sand ore deposit is usually

low The lowest cut-off grades of heavy minerals, as a total heavy mineral (THM) concentrate from the bulk sand, in most ore

deposits of this type is around 1% heavy minerals, although

several are higher grade.

• Of this total heavy mineral concentrate (THM), the components are

• Trash minerals, typically magnetite, garnet and chromite which

usually account for the remaining bulk of the THM content

• Slimes, typically minerals as above and heavy clay minerals, too

fine to be economically extracted.

• Modern open-pit mining practises tend to favor dry mining rather

than dredging operations, due to the advent of electrostatic

mineral separation processes.

Black sand conc.

USE OF SAND

• Sand is often a principal component of concrete

• Molding sand , also known as foundry sand, is moistened or oiled and then shaped into molds for sand casting This type of sand must be able to withstand high temperatures and pressure, allow gases to escape, have a uniform, small grain size and be non-reactive with metals

• It is the principal component in glass manufacturing

• Graded sand is used as an abrasive in sandblasting and is also used in media filters for

filtering water

• Brick manufacturing plants use sand as an additive with a mixture of clay and other

materials for manufacturing bricks

• Sand is sometimes mixed with paint to create a textured finish for walls and ceilings or a non-slip floor surface

• Sandy soils are ideal for certain crops such as watermelons , peaches , and peanuts and are often preferred for intensive dairy farming because of their excellent drainage

characteristics

• Sand is used in landscaping , it is added to make small hills and slopes (for example,

constructing golf courses)

• Beach nourishment - transportation to popular beaches where seasonal tides or artificial changes to the shoreline cause the original sand to flow out to sea [2]

• Sandbags are used for protection against floods and gun fire They can be easily

transported when empty, then filled with local sand

• Sand castle building is a popular activity There are competitive sand castle building

competitions (See sand art and play )

• Sand animation is a type of performance art and a technique for creating animated films

• Aquaria are often lined with sand instead of gravel This is a low cost alternative which some believe is better than gravel

• Railroads use sand to improve the traction of wheels on the rails