1. IRON ORE BENEFICIATION AND AGGLOMERATION S.Lakshmanappa Dy. Mgr (M.P) DIOM

2. ORE Aggregate or combination of minerals One or more metals/minerals may be economically extracted. MINERAL Natural occurring in organic compound. One or more metals in association with non metals. Fixed composition. Well defined physical and chemical properties. Types of Iron Ore: Hematite Fe 2 O 3 – 68% Iron Magnetite Fe 3 O 4 – 72% Iron Limonite Fe 2 O 3 ( H 2 O) - 50 – 60 % Iron Siderite FeCO 3 - 48% Iron

3. Grades of Iron Ore: High Grade (+65%Fe) Medium grade (+62 – 65%Fe) Low grade (-62%Fe) Fractions of DIOM Iron Ore : Lump - (+ 10 to – 40mm) CLO - (+ 10 to – 30mm) Fines - (- 10 mm)

4. BENEFICIATION It is process of physically separating the grains of valuable minerals from the gangue minerals, to produce concentrate. Removal of Al 2 O 3, SiO 2 particles from pulverized metal ore. Low grade iron ore can be upgraded.

5. Importance of Beneficiation  Reducing gangue.  Reduces smelter energy cost.  Smelter metal losses.  Improves metallurgical efficiency and milling costs.

6. Increase of Fe content in iron ore by 1%, Reduction of coke rate by 0.8 – 1.2% Increase in productivity by 1.5% - 2.0%. Reduction of Hot metal rate by Rs 60 – 70. Reducing alumina by 1% Reduction of Hot metal rate by Rs 200 – 300. Reducing Silica by 1% Reduction of Hot metal rate by Rs 50 – 100. Benefits of Beneficiation

7. Effects of High Alumina / Silica  Sinter / Pellet strength low.  Reduction and degradation properties are high.  Higher slag volume and viscous slag formation. Effects of Over size in CLO  Low metallization.  Incomplete reduction.

8. Effects of Undersize in CLO :  Form Agglomerates in rotary kiln.  Decrease the life of rotary kiln. Composition of DIOM Iron Ore (ROM) : Fe – 61.48%, SiO2 – 5.41%, Al2O3 – 3.35%, P – 0.073 – 0.08%, LOI 2.64%, Moisture 3.20-5 % ( SP/202/lll/2002)

9. Pulp Density  Amount of solids in a pulp.  Weight of a unit volume of pulp.  Eg: if 1 cm3 of pulp weights 2.4 gm PD 2.4 g/cm3 Specific Gravity: It is expressed as a ratio of the body to that equal volume of water.

10. Beneficiation equipments of DIOM:  Classifiers.  Hydro Cyclone Classifiers:  Continues revolving spiral moves the sand up the slop.  Operated at steeper slopes.  Agitation is less, it imparts the very fine material separation. Factors affecting the performance of classifiers :  Feed rate – 400TPH (HDO), 300 TPH  Speed of rake – 4 RPM  Pulp density of over flow – 1.25 to 1.28

11. SPIRAL CLASSIFIER

12.  Classifying device.  Utilizes centrifugal force for separating mixture of minerals 2 or more products.  Velocity of particles depends Specific gravity and shape of the particles.  Used for dewatering or thickening, desliming and degratting. Factors affecting on hydro cyclone Performance:  Inlet pressure - 1.5Kg/cm 2  Pulp density of over flow - 1.18 to 1.22  Vertex finder- 250 mm  Apex diameter- 100 mm

13. HYDROCYCLONE Conical Section Cylindrical Feed Chamber Cylinder Section Apex Vortex Finder

14. Beneficiation Existing Flow Sheet Primary Classifiers Dewatering screens Slurry pump Hydro cyclone Secondary classifiers Conveyor 303 O/F U/F Conveyor 400 Thickener Sand U/F O/F Sand O/F Sand Fine ore conveyor

15. Bottlenecks of existing beneficiation plant Sl.NoProblems 1 Slime Loss ( 10 to 20%) 2 Moisture in fine ore ( 10 to 20%) 3 Wastage of leakage water

16. Sl.N o Equipments Desirable PD Actual PD 1 Primary Classifiers Overflow 1.2 – 1.28 1.08 – 1.15 1.17 - 1.37 2 Cyclone Overflow 1.15 – 1.20 1.18 – 1.22 3 Cyclone Underflow 1.32 – 1.40 1.28 – 1.40 PD of HSCL / SSCL / Hydro Cyclone

17. Size Analysis of Cyclone Over flow & Under flow Size Over Flow WT/% ge Under Flow WT %ge + 65 # 1.14.8 + 100 # 1.38.4 + 150 # 2.814.3 + 200 # 6.828.5 + 325 # 14.942.8 - 325 # 73.11.2

18. Secondary cyclones and auto dilution density controlling valves to be installed at classifier feed to reduce slime loss. Belt filters to be introduced to reduce moisture content Sump pump to be installed to recirculate waste water or leakage water which is going to valley.

19. Proposed Beneficiation Flow Sheet Primary ClassifierSlurry Pump Dewatering Screens Primary Hydro Cyclone Secondary Hydro Cyclone Belt Filter Conveyor 303 U/F Over-Flow O / F U/F O / F Thickener Water Fine Ore cake Pelletizing Plant or Loading Plant U/F Modification of existing flow sheet

20. Beneficiation plant Flow sheet of JSW DWS Feed 8mm Screen Classifier - 8mm U/F DWS 10” Stub Cyclone 5” Stub Cyclone Horizontal Belt Filter Recirculated Thickener O/F recirculted O/F +8mm

21. Horizontal Belt Filters  Perforate rubber drainage deck.  Supporting a separate belt made from polyster cloth slurry flows by gravity.  Filtration partly due to gravity and partly due to the vacuum applied to the suction boxes  Cake which forms is dewatered, dried by drawing air through it.

22. Details of Delkor Horizontal Belt Filters MakeDelkor Type of filter Continuous HBF (Vacuum filter) Filler Cloth 4 ply Polyester Filtration Area 54 M 2 Feed rate 120TPH Permeability 33L/dm 2 /min Design Vacuum 760mm/Hg

23. Wash box Feed Box Main belt Vacuum box Cloth Wash box Discharge Roll Aligning Roll Take up Roll Cloth Form Roll Filter Cloth Horizontal Belt filter

24. PERFORMANCE VARIABLE  Feed Flow Rate  Belt Speed and  Percent of solids in feed / feed PD

25. Benefits of belt filters  Horizontal belt filters can be located in one floor, saving and construction.  Filtration surfaces are visible at all times minimizing operation attention.  Low maintenance cost.  Fines ore moisture can be effectively reduced.  Water recovery can be increased.  Sec Classifier can be removed.

26. Tega 5”/10” Stub Cyclone  High wear resistant poly urethane and light in weight.  Moulded poly urethane parts.  Steel plates and stainless steel studs.  Supplied in radials.  Radials can accommodate 4-16 number of cyclone.

27. Benefits of Tega Stub cyclone  Reduces turbulence and wear.  Operates at higher capacity.  Provided better separation.  Higher capacity.  Helps for better concentration.  Makes maintenance easier.  To treat abrasive feed material.

28. STUB CYCLONE

29. Cost Analysis Sl.NoDescription of ItemsAmount Rs. 1Cluster of small hydro cyclone2500000.00 2Buffer Tank3000000.00 3HBF ( Horizontal Belt Filter )32500000.00 4Electricity instruments and controls for HBF 7000000.00 5Erection & commissioning 1800000.00 Total46800000.00 ROM Target per Year............................. 50 L Tons Slime Loss (10%) …………....... 5 L Tons By installing Secondary Cyclone & HBF.….1 L Tons ( Minimum 2% slime can be recovered ) Cost Saving per Year …………….33 Crores (Cost will be recovered in 2 months time)

30. AGGLOMERATION AGGLOMERATION  Iron ore fines/blue dust cannot be charged in the blast furnace.  block the passage for ascending gas.  Agglomerated into larger lumpy pieces.  With additions of additives like Coke Breeze, Limestone, Dolomite, Bentonite binder etc.

31.  Utilize iron Ore Fines resources.  Stacking Problems will not be there.. AGGLOMERATION BENEFITS OF AGGLOMERATION

32. PELLETISATION  Rolling of moist Iron Ore Fines less than 100 mesh size.  Binder – Bentonite  Balls of 7-20 mm in size.  Green balls lack of strength  Dried, preheated and fired.  Hardened balls Excellent feed for blast furnace.

33. Pellets

34. Solutions to meet future requirement:  Scientific mining.  Increase agglomeration.  Use of pellets for DRI.  Technology for using slimes.

35. Conclusion  Beneficiation required for reducing gangue. gangue.  Secondary Cyclone help to reduce slime loss. slime loss.  Horizontal Belt filters are used to reduce moisture in Iron Ore Fines. reduce moisture in Iron Ore Fines.  Agglomeration process required for utilizing iron ore fines. utilizing iron ore fines.