INDUSTRIAL MINERAL CONCENTRATION TECNOLOGIES Prof.Dr Muammer KAYA Osmangazi University Eskisehir-TURKEY 2007 From raw material To Final Product 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 Froth flotation is achieved when particles are separated based on their surface potential Hydrophobic particles are recovered to the froth, whereas hydrophilic particles are discharged with the tailings stream PHOSPHATE MINERALS • • • • • • Phosphate minerals are those minerals that contain the tetrahedrally coordinated phosphate (PO43-) anion along with the freely substituting arsenate (AsO43-) and vanadate (VO43-) 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 Examples include: triphylite Li(Fe,Mn)PO4 monazite (Ce,La,Y,Th)PO4 Apatite group Ca5(PO4)3(F,Cl,OH) – – – • • • • • • • • • • hydroxylapatite Ca5(PO4)3OH fluorapatite Ca5(PO4)3F chlorapatite Ca5(PO4)3Cl pyromorphite Pb5(PO4)3Cl vanadinite Pb5(VO4)3Cl erythrite Co3(AsO4)2·8H2O amblygonite LiAlPO4F lazulite (Mg,Fe)Al2(PO4)2(OH)2 wavellite Al3(PO4)2(OH)3·5H2O turquoise CuAl6(PO4)4(OH)8·5H2O autunite Ca(UO2)2(PO4)2·10-12H2O carnotite K2(UO2)2(VO4)2·3H2O phosphophyllite Zn2(Fe,Mn)(PO4)2•4H2O PO43- anion DEPOSITS • 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 an amine float In the reverse flotation, Cytec Acco-Phos 950 depressant (20-100 g/t) minimizes phosphate loses into the silica froth product using amine collectors In the treatment of sedimentary pebble phosphates, Aero 845 can be used in conjuction with fatty acids US DOUBLE PHOSPHATE FLOTATION - FEED Slimes (-10 µ) + Desliming (Hydrocyclones) conditioner PhosphateSilica Sep Flot 70%S F pH=9-9.5 T Rougher fl Silica (final tails) C (sodaash/NaOH) Conditioning with Crude fatty oil Silica Removal Reverse Flot H2SO4+washing Fuel-oil to remove reagents pH=6.5-7 Fatty/ether amine Cleaner fl Phosphate Conc conditioner Silica (gangue) Uses & Concentration of GARNETS Pure crystals of garnet are used as gemstones Garnet sand is a good abrasive, and a common replacement for silica sand in sand blasting Mixed with very high pressure water, garnet is used to cut steel and other materials in water jets Garnet sand is also used for water filtration media Garnets can be concentrated from sands by gravity+ electrostatic+magnetic separation methods along with monazite Pendant in uvarovite, a rare bright-green garnet Almandine in gneissic rock, hardness 6-7.5, abrasive Spessartine (the yellow mineral) gemstone OCCURENCE OF KAOLIN (Al2O3.2SiO2.2H2O) • • • Granite • Syanite • Porphyr • • • Feldspar Mica Primary Deposits alteration 20-30% Kaolin Cormwall/UK KAOLIN Quartz Rutile Ilmenite Sedimantary Deposits No-decomposition 95% Kaolin Georgia/USA LIBERATION OF KAOLIN • • Liberation size for KAOLIN 4-6 µ m Liberation size for FELDSPAR 200-300 µ m • Liberation size for QUARTZ 700 µ m • KAOLIN CAN EASILY BE CONCENTRATED BY CLASSIFICATION ACCORDING TO PARTICLE SIZE USING SCREENS AND HYDROCYCLONES • Before concentration:   For soft kaolins→Attrition scrubbing for dispersing clays   For hard kaolins→crushing/grinding are required • • (Due to remaining fine silica product, quality is low) CLASSIFICATION CONCENTRATION   DRY (Crushing+dry grinding+air classification) – (requires selective mining operation)   WET (Magnetic separation+flotation+hydrocyclones) – (complex flowsheet, but product quality is very high) • The production process includes: disintegration and classification, hydrocycloning, thickening, filterpressing and drying Product range: kaolin for ceramic, kaolin for paper, glass silica sand, dry and wet classified silica sand, ground kaolin, chamotte Process • • • • • The extraction plant is situated adjacent to the quarrying operation to enable the waste to be returned to backfill Crude kaolin from the quarry is first made into a slurry with water This slurry passes through a series of washing and classification steps in order to remove the quartz and mica impurities This results in a pure kaolin product which is completely devoid of free silica The kaolin is filtered in filter presses and the filter cake is pressed into pellet form prior to drying in gas-fired dryers The final kaolin pellets contain 10% moisture on average These are packaged and despatched to customers in the ceramic, paint, paper and other industries A dry powder product is also produced for those industries that cannot tolerate moisture, such as the rubber, plastic and pesticide industries The dry powder is produced by passing the kaolin pellets through an attritor and classifier with simultaneous drying with hot air Water from the drying process is recovered and recycled to the extraction plant through a return water pipeline MAJOR IMPURITIES (Kaolin is used in fine size range Flotation efficiency diminishes with the size of particles Kaolin is used as a white pigment thus colored impurities must be removed) • Anatase (TiO2): Fine sized anatase contains considerable amount Fe and gives brownish tint to the clays This mineral may be removed by fatty acid flotation after activating with divalent cations to produce coating grade (bright) clays Yoon et al (2003) found that alkyl hydroxametes were much more effective than fatty acids in floating colored anatase impurity from clays No activation is necessary and retention times in flotation are shorter than fatty acids • Iron oxides KAOLIN FLOTATION • CARRIER FLOTATION and CARRIERLESS FLOTATION can be used • Collector: Fatty acids Sparingly Soluble Salts 100 SDS 80 DDA 60 fluorite 40 NaOl 20 10 12 14 pH NaOl - sodium oleate, DDA-dodecylamine, SDS,- sodium dedecyl sulfite Class Sparingly soluble salts 100 chrysocolla 80 calcite 60 40 bastnesite 20 barite 0 10 12 14 pH Flotation with potassium octylohydroxymate Class Oxides and hydroxides 100 80 QUARTZ 60 40 20 18 16 14 12 10 -08 -07 -06 -05 -04 -03 -02 -01 00 10 10 10 10 10 10 10 10 10 amine concentration, kmol/m Amine flotation of quartz Class Soluble salts 100 80 Na2SO4×10H2O KCl K2SO4 60 40 20 -06 10 NaCl Na 2SO4 -05 -04 -03 10 10 10 10 dodecylamine hydrochloride, kmol/m -02 POTASH • Potash is the most important source of potassium in fertilizers • Flotation is one of the major methods to upgrade the potash • Normally fatty acids are used as collectors for flotation However, this type of collectors is not always suitable for the treatment of complex phosphate ores when calcite and dolomite are present • Calcite and dolomite tent to co-float with phosphate giving low concentrate grades • Potash can be separated from halite by reverse flotation [...]... but are available in a wide variety of colors Spec Gr is btw 3.1-4.3 • • • • • • • Major varieties X Y (SiO4)3 USE AREA Pyrope Mg3Al2Si3O 12 Almandine Fe3Al2Si3O 12 abrasive Spessartite Mn3Al2Si3O 12 gemstone Andradite Ca3Fe2Si3O 12 Grossular Ca3Al2Si3O 12 Uvarovite Ca3Cr2Si3O 12 gemstone • Garnet species’s light transmission properties can range from the gemstone-quality transparent specimens to the opaque... abrasive Spessartine (the yellow mineral) gemstone OCCURENCE OF KAOLIN (Al2O3.2SiO2.2H2O) • • • Granite • Syanite • Porphyr • • • Feldspar Mica Primary Deposits alteration 20 -30% Kaolin Cormwall/UK KAOLIN Quartz Rutile Ilmenite Sedimantary Deposits No-decomposition 95% Kaolin Georgia/USA LIBERATION OF KAOLIN • • Liberation size for KAOLIN 4-6 µ m Liberation size for FELDSPAR 20 0-300 µ m • Liberation size... 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... heavy mineral concentrate (THM), the components are typically Zircon, from 1% of THM to upwards of 50% of THM, Ilmenite, generally of 10% to 60% of THM Rutile, from 5% to 25 % of THM Black sand conc Leucoxene, from 1% to 10% of THM 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,... 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 Brazillian hematite • Iron ores are rocks and minerals from... 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 (SiO2), usually in the form of quartz, iron oxides, zircon, rutile, ilmenite, monazite, garnet Heavy mineral. .. organic colloids may make a fatty acid float of iron-bearing minerals preferable After desliming, the pulp is conditioned at high solids with Aero 700 series promoters at pH 8-9 adjusted with soda ash or caustic soda Fuel oil may be added to the flotation circuit for froth control • • crystal Molecular model GARNET X3Y2(SiO4)3 • Garnet is a group of minerals that can be used as gemstones and abrasives (Mohs... isolated, flat, plate-like particles with hexagonal edges if unbroken and when broken the edges can be irregular or angular (Madagascar-open pit, 410950 $/t) • (2) Amorphous graphite occurs as fine particles (Mexico-Underground mines, 24 0 -26 0 $/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... IMPURITIES and PROPERTIES • Minerals associated with graphite include quartz, calcite, micas, iron meteorites, and tourmalines • In 20 05, 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... 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 Complete flot 100 R=100% 80 pH:6- 9 60 fluorite calcite apatite 40 20 R=0% No flot 0 10 -06 10 -05 10 -04 10 -03 3 sodium oleate