CTB Wet Drum
Magnetic Separator
Permanent magnet wet drum separator for magnetite concentration and iron ore beneficiation. No power consumption for magnets, three tank types, and 5 drum sizes from 15 to 140 t/h.
5
Drum Sizes
≥135 mT
Max Field
140 t/h
Max Capacity
How the CTB Magnetic Separator Works
A fixed permanent magnet assembly inside a rotating non-magnetic drum attracts magnetic particles to the drum surface. As the drum rotates, magnetic particles are carried out of the slurry while non-magnetic particles drain away.
01
Slurry Feed
Pre-ground ore slurry (20–40% solids) is fed evenly across the full drum width through a distribution box. Feed rate and % solids are the two most critical process variables.
02
Magnetic Attraction
The inner magnet assembly generates a radial field of ≥120 mT at the drum surface. Magnetite particles (SG 5.2, strongly magnetic) are pulled from the slurry and adhere to the rotating drum shell.
03
Washing
In CTB counter-rotation, the feed moves toward the drum while the drum surface moves away. This relative motion promotes drainage and washing of non-magnetic gangue particles off the concentrate layer.
04
Discharge
As the drum rotates past the magnet's coverage arc, the field weakens and magnetic concentrate falls by gravity into the concentrate launder. Tailings exit through the overflow end.
Three Tank Configurations
Feed and magnetic fraction travel in the same direction as drum rotation. Best for coarse feed (0.5–6 mm) with high concentrate grade requirement. Low capacity but excellent selectivity.
Most common configuration. Feed travels against drum rotation — maximises washing of the magnetic fraction for cleaner concentrates. Handles 0–3 mm feed at high throughput. Standard choice for magnetite pre-concentration.
Intermediate design: higher recovery than CTA, cleaner product than straight CTB. Often used when feed grade is low and maximum iron recovery is more important than concentrate grade.
Wet vs Dry Magnetic Separation
| Property | Wet (CTB) | Dry (Belt/Drum) |
|---|---|---|
| Mineral Type | Strongly magnetic (magnetite, ferrosilicon) | Strongly magnetic, medium magnetic |
| Feed Moisture | Slurry (20–40% solids) | Dry (<1% moisture) |
| Particle Size | < 3 mm | 0.1–20 mm |
| Field Strength | 120–200 mT (permanent magnet) | Up to 400 mT (strong magnetic) |
| Separation Efficiency | Very high for magnetite | Good for medium-magnetic minerals |
| Typical Application | Iron ore beneficiation, DM recovery | Iron removal from industrial minerals, conveyor tramp iron removal |
CTB Model Specifications
5 drum sizes. All models: permanent magnet, counter-rotation CTB tank, field strength ≥120 mT at drum surface, max feed size 3 mm.
| Model | Drum Size | Field Strength | Drum Speed | Capacity | Motor Power | Weight | Get Quote |
|---|---|---|---|---|---|---|---|
| CTB-618 | Φ600×1800 mm | ≥120 mT | 40 r/min | 15–30 t/h | 2.2 kW | 1.5 t | Quote |
| CTB-712 | Φ750×1200 mm | ≥120 mT | 35 r/min | 15–30 t/h | 2.2 kW | 2.1 t | Quote |
| CTB-924 | Φ900×2400 mm | ≥135 mT | 25 r/min | 30–55 t/h | 4 kW | 3.8 t | Quote |
| CTB-1030 | Φ1050×3000 mm | ≥135 mT | 22 r/min | 80–120 t/h | 7.5 kW | 6.2 t | Quote |
| CTB-1230 | Φ1200×3000 mm | ≥135 mT | 17 r/min | 100–140 t/h | 7.5 kW | 9.5 t | Quote |
* Capacity for magnetite ore slurry at 30% solids. Capacity varies with ore magnetic susceptibility and feed % solids.
Industry Applications
CTB separators are the backbone of magnetite ore beneficiation worldwide and are also critical in industrial mineral processing and waste recovery.
Magnetite Pre-concentration
Magnetite, titano-magnetite
Primary magnetic separation stage; upgrades ROM ore from 20–35% Fe to 55–65% Fe before wet ball mill grinding.
Iron Ore Tailing Recovery
Magnetite in tailings
Re-processing of historical tailings ponds to recover residual magnetite that was not captured in original circuits.
Steel Plant Slag Recovery
Iron-bearing steelmaking slag
Recovers metallic iron particles from granulated slag for recycling back to the furnace. Reduces waste disposal costs.
Dense Medium Recovery
Ferrosilicon, magnetite DM
Recovers dense medium (ferrosilicon or magnetite) from coal preparation circuits for reuse — dramatically reducing medium consumption.
Sand & Gravel De-ironing
Iron-stained quartz sand
Removes iron-bearing minerals from glass sand or ceramic raw materials where Fe content must be below 0.02%.
Non-ferrous Metal Pre-treatment
Copper, zinc ore with magnetite
Magnetic pre-concentration removes magnetite gangue before flotation, reducing reagent consumption and improving selectivity.
Main Components
Six key components — understanding each helps with troubleshooting concentrate grade and recovery problems.
Permanent Magnet System
Multiple magnetic poles arranged around the drum interior using high-energy NdFeB or ferrite magnets. Permanent magnets require no power supply and maintain field strength for 10+ years without degradation.
Rotating Drum Shell
Thin non-magnetic stainless steel shell rotates in the field generated by the fixed inner magnet assembly. Drum surface texture is smooth for easy concentrate discharge.
Tank / Trough
The feed slurry flows through the trough around the lower portion of the drum. Tank type (concurrent, counter-rotation, semi-counter) determines the separation mechanism and product quality.
Drive Unit
Low-speed motor and gear reducer drive the drum at 17–40 RPM depending on model. Drum speed affects residence time in the magnetic field and separation selectivity.
Concentrate Discharge
Magnetic concentrate clings to the drum surface and exits through a scraperless chute at the top of the arc, beyond the magnet assembly end, where the field weakens and releases the material.
Adjustable Splitter
A movable splitter plate between the drum and trough adjusts the partition between concentrate and middling/tailing streams to optimise grade-recovery balance.
Selection Guide
Four factors determine the right CTB model and circuit configuration for your magnetite project.
01
Confirm Mineral Type
CTB series is effective for strongly magnetic minerals: magnetite (Fe₃O₄), pyrrhotite, ferrosilicon, metallic iron. For weakly magnetic minerals like hematite (Fe₂O₃) or siderite, a high-intensity wet magnetic separator (WHIMS) is needed instead.
02
Choose Tank Configuration
CTB (counter-rotation) for standard magnetite concentration — highest throughput. CTA (concurrent) if maximum concentrate grade is priority over recovery. CTN if maximum iron recovery is priority (e.g., tailings reprocessing).
03
Select Drum Size by t/h
Drum diameter and length determine throughput. CTB618 (15–30 t/h) for small plants. CTB1030 or CTB1230 (80–140 t/h) for large-scale iron ore operations. Allow 25% spare capacity for feed variation.
04
Plan Circuit Position
CTB separators typically operate in 2–3 stages: rougher (first pass), cleaner (concentrate upgrade), and scavenger (tailing recovery). Each stage may use a different tank type to optimise overall performance.
Need a magnetic separation circuit design?
Tell us your ore type, feed grade (% Fe), target concentrate grade, and throughput. We'll propose a complete rougher-cleaner-scavenger CTB circuit with flow balance.
Maintenance Schedule
CTB separators are mechanically simple. Most issues arise from drum surface build-up, bearing water ingress, and feed slurry density variation.
Every Shift
- Check drum surface for scale or magnetite build-up — clean with water jet if concentrate layer is forming
- Verify feed slurry % solids — too thick clogs trough; too thin reduces residence time
- Inspect concentrate discharge chute for blockage
- Monitor motor current — rising current with constant feed indicates mechanical drag
Weekly
- Lubricate drum shaft bearings per schedule
- Inspect drum-end seals for slurry leakage into bearing housings
- Check splitter plate position — adjust if concentrate grade or recovery has drifted
- Inspect stainless drum surface for wear grooves or pitting from abrasive feed
Monthly
- Measure magnetic field strength at drum surface with gauss meter — compare to factory spec (should be ≥120 mT for CTB)
- Check drive reducer oil level and clarity — change every 6 months
- Inspect feed distribution box for wear and even flow across drum width
- Clean tank interior of non-magnetic settled material build-up
Why Choose MarsCrusher CTB Series
High recovery rate with optimized permanent magnet system
Wear-resistant rubber drum liner for long service life
Counter-rotation tank design improves separation efficiency
Adjustable magnetic field intensity to suit ore grade
Low maintenance with no field coils to service
CTB Magnetic Separator FAQ
Short answers to common procurement questions before requesting quotation.
Which ores are best suited for CTB wet drum separation?
CTB is most effective on strongly magnetic minerals such as magnetite and iron-bearing media recovery applications.
How do I choose CTA, CTB, or CTN tank type?
Choose based on your grade-recovery priority and feed characteristics. CTB is the most common general-purpose choice in magnetite circuits.
What operating parameter most affects separator performance?
Feed solids concentration and stable distribution across drum width are critical. Unstable slurry conditions quickly reduce grade and recovery consistency.
Can CTB be used in multi-stage magnetic circuits?
Yes. Many plants use rougher-cleaner-scavenger arrangements to balance throughput, concentrate quality, and overall iron recovery.
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