Leading Magnetic Gravity Separator

The leading magnetic gravity separator is more than just equipment. This is the intersection of physics, engineering calculations and industrial practice. We saw how at ore processing plants in Kuzbass and on processing lines in the Ural region, it was this type of separators that solved a problem that neither ordinary magnets nor gravity tables could handle: separating weakly magnetic minerals with a similar density from waste rock at high humidity and variable size of the starting material. The leading magnetic-gravity separator works where other methods produce breakthroughs above 8-12%.

Why “magnetic-gravity” is not a marketing formula, but a physical principle

Many people mistakenly believe that such a separator is just a magnet plus an inclined plane. In fact, this is a synchronous interaction of three forces: magnetic induction, gravitational acceleration and controlled hydrodynamic flow. A non-stationary field with a gradient of up to 1.8 T/m is created in the working area, rather than a constant induction value. It is the gradient that captures particles as small as 0.04 mm, even if their magnetization is only 0.8·10⁻⁵ m³/kg. We tested this on hematite samples from KMA: when feeding 12 t/h of raw material, the concentrate yield was 63% with a Fe content of 64.2%. At the same time, losses in tailings did not exceed 1.7% - a figure unattainable for classical drum separators.

The key element is a rotor with a multi-pole excitation system and an adjustable speed from 12 to 45 rpm. It doesn’t just rotate: it generates a “magnetic wave” that moves particles along a trajectory specified by the angle of the gutter (from 5° to 18°) and the speed of water flow (0.3–1.2 m/s). This approach makes it possible to separate materials that differ in magnetic susceptibility by only 0.15·10⁻⁶ m³/kg - for example, ilmenite from monazite in sand placers.

Where money is lost - and how to avoid it

Some customers are trying to use magnetic-gravity separators as a replacement for electromagnetic filters for purifying process water. This is a mistake. Such equipment is not designed to capture colloidal particles or iron oxides in solution. Its task is dry or semi-dry separation in the range of 0.04–3 mm. We observed three typical failures:

• Installation without preliminary screening: when pieces >5 mm enter the separation zone, the chute is blocked and vibration increases sharply;
• Ignoring the temperature regime: when cooling below +5 °C, the water in the irrigation system freezes in the capillaries of the dispensers;
• Operating in the same mode when ore composition changes: Operators often do not adjust the rotor speed when moving from quartzite to skarn ores - the result: a 9-14% reduction in recovery.

The solution is not a “universal” mode, but adaptive control. All modern installations of the LONGI corporation are equipped with PLC controllers with preset profiles for 17 types of ores and technogenic dumps. The operator selects a profile using a button - the system itself sets the angle of inclination, rotation speed and water flow.

Technical maturity: from drawing to commissioning

Serial production of such separators began in 1998 at the Shenyang Scientific Electromagnetic Company LONJI. Today, the Fushun plant produces 4,000 pieces of mining equipment annually. Of the 1,200 employees, more than 720 are engineers and technicians with higher education. They don’t just assemble devices: they design magnetic cores taking into account the local magnetic anomaly, calculate the thermal loads on the windings when operating in Siberian conditions, and test each batch of rotors on a dynamic stand at 120% of the rated load.

Standard equipment includes:

• Rotor module with water-cooled windings;
• System for automatic adjustment of the gap between the rotor and the matrix (accuracy ±0.15 mm);
• Control unit with Modbus RTU interface and remote monitoring capability;
• Module for collecting and analyzing data on load, vibration and temperature in real time.

The average service life of the main unit is 12 years with two-shift operation. The warranty on the magnetic system is 5 years. Service centers operate in Yekaterinburg, Novosibirsk and Krasnoyarsk.

What to do next

If your task is to increase the extraction of iron from weakly magnetic ores, to obtain titanium concentrate from beach sands, or to purify secondary raw materials from ferromagnetic impurities with minimal losses of the useful component, the leading magnetic-gravity separator remains the most predictable solution. It does not require expensive reagents, does not generate wastewater and does not require complex preparation of raw materials. Its effectiveness is measured not as a percentage of the ideal, but in tons of additional concentrate obtained per month.

On the websiteljmagnet.ruTechnical data sheets, connection diagrams and video recordings of tests on real ore samples are available. But before choosing a model, take a sample. Send her to LONJI's laboratory. There they will carry out a trial separation and issue a report: with what extraction, what purity and under what parameters the equipment will operate on your material. Because separation doesn't start with the purchase - it starts with understanding the properties of your ore.