Magnetite Pre-concentration
Magnetite, titano-magnetite
A possible magnetic pre-concentration stage. Feed assay, liberation size, concentrate target, and recovery must be established by representative testwork.
Magnetic Separation
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.
- Drum Sizes
- 5
- Max Field
- ≥135 mT
- Max Capacity
- 140 t/h
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
- CTA
- Concurrent (CTA)
- Feed and magnetic fraction travel in the same direction as drum rotation. This arrangement may suit coarser feed and grade-focused duties, but the practical feed window, capacity, and selectivity must be confirmed from the ordered tank geometry and representative testwork.
- CTB
- Counter-rotation (CTB)
- Feed travels against drum rotation to increase washing contact between the magnetic fraction and the slurry. CTB is a common starting point for magnetite pre-concentration, but hydraulic loading, feed-size limit, grade, and recovery remain duty-specific.
- CTN
- Semi-counter (CTN)
- An intermediate flow arrangement that may be evaluated when the circuit prioritises recovery while retaining concentrate cleaning. Its grade-recovery response must be compared with CTA and CTB on representative feed.
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 | Confirm ordered model certificate (published models list ≥120 or ≥135 mT) | Up to 400 mT (strong magnetic) |
| Separation Efficiency | Ore-specific; confirm by testwork | Mineral-specific; confirm by testwork |
| 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 can be evaluated for magnetite beneficiation, dense-medium recovery, de-ironing, and selected waste-recovery duties after feed and product targets are defined.
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
May recover ferrosilicon or magnetite from coal-preparation circuits for reuse. The achievable recovery and resulting medium-consumption change require a measured circuit balance.
Sand & Gravel De-ironing
Iron-stained quartz sand
May remove iron-bearing minerals from glass sand or ceramic raw materials. The required Fe limit and achievable product must be confirmed by assay and testwork.
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.
01
Permanent Magnet System
Multiple magnetic poles are arranged around the drum interior using NdFeB or ferrite magnets. The permanent-magnet assembly requires no excitation power; field retention and service interval must be confirmed from the magnet grade, operating temperature, measurements, and supplier documentation.
02
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.
03
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.
04
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.
05
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.
06
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.
Step 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.
Step 02
Choose Tank Configuration
Compare CTB, CTA, and CTN against the required grade-recovery balance, slurry loading, feed size, and tank geometry. No tank arrangement should be selected as the universal throughput, grade, or recovery winner without representative testwork and the ordered model's hydraulic basis.
Step 03
Select Drum Size by t/h
Published model ranges run from CTB618 at 15–30 t/h to CTB1030 or CTB1230 at 80–140 t/h. Do not apply a fixed spare-capacity percentage: set design margin from measured slurry flow, solids loading, feed variability, availability target, wear condition, and the duty of each separation stage.
Step 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 basis
CTB separators are mechanically simple. Most issues arise from drum surface build-up, bearing water ingress, and feed slurry density variation.
Operating checks
- 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
Planned inspection
- 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
Condition-based service
- Measure magnetic field strength at the drum surface with a gauss meter and compare it with the ordered unit's supplier test certificate and published model specification
- Check drive-reducer oil level and condition, then change it at the maker's operating-hour or condition limit
- 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
- Permanent-magnet system with model-specific surface field values
- Replaceable rubber drum liner for abrasive slurry duties
- Tank-flow configuration must be matched to feed size and separation objective
- Field strength and drum loading should be verified against mineral test work
- Permanent-magnet circuit does not use powered excitation coils
FAQ
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.
- How should payment terms be verified?
- Payment method, deposit schedule, currency, beneficiary, and release documents must be stated in a supplier-issued proforma invoice or sales contract. Do not transfer funds based only on website copy; independently verify the beneficiary and document version before payment.
- How should shipping terms be confirmed?
- Available destinations and Incoterms depend on the quoted equipment and route. The quotation should name the port, Incoterms version, freight scope, packing method, export-document responsibility, insurance, and any exclusions; destination duties and local permits also need separate confirmation.
- What installation and commissioning scope should I confirm?
- Ask the quotation to state which drawings, manuals, remote support, site supervision, commissioning tests, and acceptance records are included. If on-site work is offered, the contract should also allocate travel, visa, accommodation, safety, tooling, and schedule responsibilities.
- How should I plan spare and wear parts?
- Request a wear-parts list with part numbers, material grades, recommended opening stock, quoted availability, and replacement lead time. Parts availability and interchangeability are not confirmed until they appear in the written supply scope.
- What must the warranty document cover?
- The warranty period, start date, covered components, exclusions, evidence required for a claim, and available remedy must be stated in the signed contract. Website information is not a warranty certificate; pay particular attention to wear parts and site-condition exclusions.
Need deeper context?
Process Validation
From ROM Ore to a Testwork-Defined Concentrate
A CTB circuit can be evaluated for liberated magnetite, but feed grade alone does not determine a saleable product. Establish the grade-recovery curve, impurity limits, moisture target, and circuit arrangement with representative testwork before setting commercial expectations.
Feed assay
Baseline Input
Measure Fe grade, mineralogy, magnetic susceptibility, and liberation before selecting the circuit.
Target assay
Concentrate Basis
Define the required product grade and penalty-element limits in the written testwork brief.
Testwork
Iron Recovery
No fixed recovery should be assumed; confirm the grade-recovery curve on representative feed.
< 3 mm
Liberation Feed
Grind to liberation first; the CTB separates the slurry below 3 mm.
Submit ore type, mineralogy, feed assay, size distribution, and testwork results so the circuit basis can be documented. Hematite and other weakly magnetic feeds require a separate process review; do not assume CTB performance applies to them.
Document Circuit InputsComplete Your Iron Ore Beneficiation Line
Magnetic separation is one stage in a larger process. Treat the equipment below as a sequence; liberation, capacity matching, and separation targets require a documented circuit design.
Project brief
Start with the operating duty, then narrow the equipment path.
Share four operating inputs so we can rule out unsuitable models early and explain the assumptions behind the shortlist.