DENSE MEDIUM CONTROL | MEDIUM BALANCE
Magnetic Content Meter
The Magnetic Content Meter measures magnetite concentration in the suspension using electromagnetic induction, which is the basis for medium balance in dense medium circuits and is also applicable to ferromagnetic ore grade and magnetic slurry level in iron ore plants.
0 – 1,000 / 2,000 g/L
Measuring Range
±0.5%
Accuracy
1 g/L
Minimum Sensitivity
Full-bore flanged spool, no insertion element
Design
DEFINITION & OVERVIEW
What is a Magnetic Content Meter?
A magnetic content meter measures the magnetite concentration of a suspension using electromagnetic induction, the same underlying principle used across dense medium circuit instrumentation, applied specifically to quantifying how much magnetite is actually present in the medium at any given moment.
This measurement is the basis of medium balance in a dense medium circuit: knowing the magnetite concentration accurately allows an operator or control system to make correct decisions about medium make-up, dilution, and overall circuit density management, rather than working from an assumed or estimated figure. It is one of four instruments in our Dense Medium Control System.
The same measurement principle extends beyond coal-dense medium circuits; it's equally applicable to ferromagnetic ore grade measurement and magnetic slurry level detection in iron ore processing plants, and John Finlay's unit is also available in a low-range execution for magnetic separator tailings duty, the measurement behind our Magnetic Separator Medium Loss Monitoring system.
No Insertion Element
A full-bore flanged spool design means there's no insertion element sitting in the slurry stream to wear or foul.
Basis of Medium Balance
Accurate magnetite concentration measurement is what makes correct medium make-up and dilution decisions possible.
Low-Range Execution Available
A dedicated low-range version is available for magnetic separator tailings duty, where concentrations are much lower than in the main circuit.
Parameter | Value |
|---|---|
Measuring Range | 0 – 1,000 g/L · 0 – 2,000 g/L |
Accuracy | ±0.5% |
Minimum Sensitivity | 1 g/L |
Output Signal | 4–20 mA, isolated |
Power Supply | 220 V AC, ≤ 60 W |
Load Resistance | 0 – 500 Ω |
Nominal Bore | DN100 · DN150 · DN200 |
Process Connection | Flanged, DN100 / DN150 / DN200 |
Ambient Temperature | −5 to +45 °C |
KEY FEATURES
Key Features & Performance Highlights
Full-Bore Flanged Spool Design
No insertion element sits in the slurry stream; the measurement is taken across the full bore of a flanged spool piece, eliminating a wear point that an insertion-type sensor would introduce.
Dual Range Options
Available in 0-1,000 g/L and 0-2,000 g/L measuring ranges, covering both typical dense medium circuit concentrations and higher-range applications, with 1 g/L minimum sensitivity.
Low-Range Execution for Tailings Duty
A dedicated low-range version is available specifically for magnetic separator tailings, the same measurement principle applied where concentrations are much lower than in the main circuit, directly relevant to magnetite loss diagnostics.
WORKING PRINCIPLE
How the Magnetic Content Meter Works
Electromagnetic induction measures magnetite concentration without any element contacting the slurry stream directly.
Full-Bore Installation
The meter is installed as a flanged spool piece in the process line at DN100, DN150, or DN200, depending on line size.
Electromagnetic Induction Measurement
The instrument measures magnetite concentration across the full bore using electromagnetic induction, with no insertion element in the flow path.
Signal Processing
The measured concentration is processed and output as an isolated 4-20 mA signal.
Medium Balance Calculation
The concentration reading feeds medium balance calculations, supporting make-up and dilution decisions in the dense medium circuit.
Integration with Control System
The 4-20 mA output integrates directly into the plant's control system, typically alongside the other instruments in the Dense Medium Control System.
TECHNICAL SPECIFICATIONS
Magnetic Content Meter | Full Specification
Parameter | Value |
|---|---|
Measuring Range | 0 – 1,000 g/L · 0 – 2,000 g/L |
Accuracy | ±0.5% |
Minimum Sensitivity | 1 g/L |
Output Signal | 4–20 mA, isolated |
Power Supply | 220 V AC, ≤ 60 W |
Load Resistance | 0 – 500 Ω |
Nominal Bore | DN100 · DN150 · DN200 |
Process Connection | Flanged, DN100 / DN150 / DN200 |
Ambient Temperature | −5 to +45 °C |
COMPARISON
Full-Bore vs. Insertion-Type Concentration Measurement
Full-Bore Magnetic Content Meter
Insertion-Type Concentration Sensor (Typical)
Applications of the Magnetic Content Meter
This instrument is used wherever magnetite concentration needs to be measured accurately and continuously, not estimated.
Dense Medium Circuit Medium Balance
The core application is accurate magnetite concentration measurement as the basis for medium make-up and dilution decisions.
Magnetic Separator Tailings Monitoring
The low-range execution measures magnetite concentration in magnetic separator tailings, feeding directly into magnetite loss diagnostics.
Ferromagnetic Ore Grade Measurement
The same electromagnetic induction principle applies to ore grade measurement in iron ore processing plants.
Magnetic Slurry Level Detection
Also applicable to magnetic slurry level detection in iron ore plant applications.
Dense Medium Control System Integration
Deployed as one of four instruments in the complete Dense Medium Control System (S1), alongside density, level and pressure instrumentation.
About John Finlay
Dense Medium Instrumentation Supplier in India
Why John Finlay?
1 g/L
Minimum Sensitivity
Full-bore electromagnetic induction measurement with no insertion element in the slurry stream.
130+
Coal Washery Projects
Completed EPC projects worldwide, including Asia’s largest coking coal washery at 30 MTPA.
EPC
Full Circuit Supply
Supplied as part of a complete instrumentation and automation offering across the coal preparation flowsheet.
IN
India-Based Support
Manufactured at Hefei John Finlay Mining Equipment Co., Ltd. and supported locally in India for installation, commissioning, spares and service.
Magnetic Content Meter | Frequently Asked Questions
Common questions from coal washery process engineers evaluating magnetite concentration measurement.
esses evaluating early-warning blockage detection.
Magnetite concentration in a suspension, using electromagnetic induction as the basis for medium balance calculations in a dense medium circuit.
No, it’s a full-bore flanged spool design, so there’s no insertion element sitting in the flow to wear or foul.
0-1,000 g/L and 0-2,000 g/L as standard, plus a dedicated low-range execution for magnetic separator tailings duty, with 1 g/L minimum sensitivity and ±0.5% accuracy.
The meter is rated for −5 to +45 °C ambient. At sites where summer ambient reaches or exceeds 45 °C, mounting position and shading should be settled at the specification stage. Send us your site conditions, and our engineers will advise.
Yes, the same electromagnetic induction principle applies to ferromagnetic ore grade measurement and magnetic slurry level detection in iron ore processing plants.
Yes, it’s one of four instruments in John Finlay’s Dense Medium Control System (S1), alongside density, level and pressure measurement, plus the control scheme that ties them together.
Not sure how accurately your medium balance is actually being measured?
Our engineers can help you specify magnetite concentration measurement for your dense medium circuit.
Talk to an ExpertRelated Equipment
Dense Medium Control System (S1)
The full packaged system this instrument is part of.
Magnetite Quality and Granulometry
What the medium balance calculation actually depends on.
Magnetic Separator Medium Loss Monitoring (S9)
Uses the same low-range measurement principle for tailings loss diagnostics.