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Lecture 11 – MINE 292. Main Applications 1. Tramp Metal Removal To protect crushers (electromagnets as well as metal detectors) 2. Magnetite Recovery.

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Presentation on theme: "Lecture 11 – MINE 292. Main Applications 1. Tramp Metal Removal To protect crushers (electromagnets as well as metal detectors) 2. Magnetite Recovery."— Presentation transcript:

1 Lecture 11 – MINE 292

2 Main Applications 1. Tramp Metal Removal To protect crushers (electromagnets as well as metal detectors) 2. Magnetite Recovery Primary iron ore processing (taconite ores) 3. Pyrrhotite Recovery or Removal Nickel recovery Gangue removal (zinc ores, gold ores, nickel ores) 4. Magnetic minerals removal Scheelite, talc, quartz, kaolinite,, industrial minerals 5. DMS Magnetite Recovery Media recovery and upgrading (purification) 6. Cleaning hematite concentrates (high-intensity) Final stage upgrading

3 Types of Materials Diamagnetic Repulsion by magnetic forces Paramagnetic Attraction to magnetic forces Rutile, ilmenite, chromite Ferro-Magnetic Very-highly attracted to magnetic forces 1,000,000 times effect of paramagnetism Effect disappears above Curie temperature (~620 °C) Iron, nickel, magnetite, pyrrhotite

4 Field Strength and Flux Density Magnetic Induction (flux) = B in Tesla Field Intensity induced through particle = H (A/m) Permeability = µ o (T·m/A) Magnetization Intensity = M (4π x T) - ignored B = µ o (H + M) B = µ o H For ferromagnetic materials, must consider magnetic susceptibility (S = M/H) B = µ o H (1 + S)

5 Magnetization vs. Field Intensity Slope = S (magnetic susceptibility)

6 Magnetization vs. Field Intensity for Fe 3 O 4 Slope = S (magnetic susceptibility) For H = 1 T, S = 0.35 Full saturation at 1.5 T Iron saturates at ~ 2.3 T

7 Magnetic Field Gradient Capacity depends on field gradient as well as field intensity Rate at which intensity increases as surface of magnet is approached F is proportional to H x dH/dl Introduction of magnetic particles has the same effect but agglomeration of particles will block the separator

8 Magnetic Induction Required for Different Minerals

9 Methods Low-intensity (LIMS) 600 – 700 gauss ( Tesla) High-intensity (HIMS) WHIMS (wet) 10,000 gauss (10 T) High-gradient (HGMS) Fine magnetic matrix 15,000 gauss (15 T) Permanent Rare-Earth Magnetic Separators (PREMS) 500-1,000 gauss ( T) Super-Conducting Magnetic Separation (SCMS) 50,000 gauss (50 T) Eddy-Current Magnetic Separation (ECMS) Application of current to mixture of substances Separation of metals in electronic waste

10 CBM (cross-belt magnetic separator) Magnets (5-6) located above belt Operating variables Field strength (up to 15 T) Pole gap typically 2 mm Belt speed (fixed) Splitter position (manually adjusted) Feed rate ~1.5 tph

11 Cross-belt Self-cleaning Separator

12 IRM (induced roll magnetic separator) Operating variables Field strength (up to 15 T) Pole gap typically 2 mm Roll speed (fixed) Splitter position (manually adjusted) Feed rate ~2.5 tph

13 Induced Roll - Magnetic Pulley

14 Suspended Magnets – tramp metal

15 LIMS Units Applied to coarse sized particles that are strongly magnetic Drum-type separators Dry for sizes > 0.5 cm Wet for sizes < 0.5 cm Called Cobbing Applied to DMS media recovery and upgrading Typical field strength = T Gap for Magnetite = mm Gap for pyrrhotite = mm down to 2 mm uses permanent ceramic or rare-earth magnets

16 LIMS Units DrumCylinderRotationCapacityFeed Power DiameterLength SpeedTop Size (mm)(mm) (rpm) (tph) (mm) (kW)

17 Drum Magnetic Separator

18 Counter-current Magnetic Separator

19 Magnetic Separator Stages

20 High-Intensity Magnetic Separation Dry High Gradient Magnetic Separator

21 WHIMS Must remove highly-magnetic material to prevent blocking Feed size > 1mm Constant supply of clean, high-pressure water Steady feed rate and density Generally applied for fine particle removal Final stage cleaning or upgrading Field Strength up to 15 T (electromagnetic) Feed rate = tph for 16-pole unit Gap typically 2 mm Splitter position varied to control process

22 Jones High-intensity Separator

23 Continuous Carousel Mag Sep

24 Superconducting Cryogenic Mag Sep

25 Eddy-Current Magnetic Separation Applied in recycling industry Diamagnetic materials can be separated Spinning magnets cause an eddy-current in Aluminum such that a magnetic field is created that repels Al particles

26 Grades of DMS Media

27 CARPCO EDS Lab Unit

28 CARPCO high-tension separator

29 Mineral Behaviour in EDS

30 Multi-stage EDS in practice

31 Beach Sand Processing for R-E and Zr

32 Beach Sand Processing for Zircon

33 EDS at Wabush Scully Mine

34 EDS applied to copper wire/glass/PVC

35 Automatic Sorting Sensors Cameras & Video cameras X-ray tubes lasers Types Photometric - colour/reflectance optical properties Radiometric - gamma radiation - Uranium UV - scheelite Conductivity - sulfides Magnetic - iron minerals X-rays luminescence- diamonds microwave attenuation hyper-spectral neutron absorption - boron Throughput 25 tph for mm (1 in to 0.2 in) 300 tph for mm (12 in to 32 in) > 1-2 inches in size with all fines scalped Reject a portion of feed to reduce comminution costs and possibly produce a very high-grade product. Talc, magnesite, limestone, phosphates, diamonds, kaolinite, unranium, Pb/Zn, gold ores, glass sands, industrial minerals,

36 Electronic Sorting

37 Principles of Photometric Sorting

38 End of Lecture


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