Demagnetizer for magnetic separators - a reliable solution for restoring efficiency 

Magnetic separators work flawlessly until they begin to lose power. We have seen this dozens of times: at a processing plant in the Kemerovo region, at a processing complex near Chelyabinsk, in a coal hub in the Krasnoyarsk Territory. After 2–3 years of operation, even the most expensive drum separators with neodymium magnets show a drop in efficiency of 15–25%. The reason is not wear, but the accumulation of residual magnetization in ferromagnetic particles stuck to the surface of the rotor and housing. They create “magnetic noise”, distort the field, and reduce the purity of separation. The solution is not replacing equipment, butdemagnetizer for magnetic separators.

Why a regular demagnetizer will not work?

Many customers try universal demagnetization units - those used for tools or machine parts. But they don't solve the problem. Why? Because the separator is not a separate part, but a complex magnetic system: a rotor with a high gradient zone, a stationary magnetic block, guide plates, a casing made of ferromagnetic steel. Residual magnetization here is localized, but multicomponent. The standard device produces a weak, uniform field - it does not penetrate into accumulation zones and does not reset “locked” domains in the steel of the body. The result is a short-term effect and a relapse after 2-3 weeks.

How does the specialized demagnetizer from LONGI work?

LONGI Corporation has developed a series of demagnetizersLDM, adapted for specific types of separators: LGS-2000, LGS-3000, drum models with Nd-Fe-B and electromagnetic iron separators RCYK-C. The key difference is the three-stage pulse cycle:

• Stage 1— preliminary demagnetization by an alternating field with a frequency of 50 Hz, eliminating surface magnetization;

• Stage 2— deep demagnetization by a pulse field of up to 200 kA/m, penetrating into the thickness of steel elements;

• Stage 3— a damped residual cycle, eliminating “magnetization reversal” when turned off.

The devices are integrated into the existing control system: connected to the PLC of the separator, launched automatically every 8–12 hours or at the operator’s command. The time of one cycle is 47 seconds. No process interruptions.

What gives real results - numbers, not promises

At the Sibrudmet plant (Krasnoyarsk Territory), after introducing LDM-3000 on two LGS-3000 lines, the concentrate yield was restored by 9.2% due to a reduction in magnetite losses in the tailings. At a coal processing plant in the Belgorod region, the iron content in the finished product was reduced from 0.83% to 0.19% - this made it possible to reach export standards to the EU. On average, for 37 implemented projects in Russia, we recorded:

• increase in separation efficiency by 12–18%;
• reduction in maintenance downtime by 65%;
• extension of the service life of the magnetic block by 2.3 years (confirmed by tests at Moscow State University for the Humanities).

Important: the demagnetizer does not restore degraded magnets. It only works with preserved Nd-Fe-B blocks and steel structures. If the magnets have already lost more than 15% of their induction, they need to be replaced. But in 9 out of 10 cases the problem is precisely the residual magnetization.

How to choose and implement - without risks

The choice depends not on the power of the separator, but on its design. The LGS-3000 requires an LDM-3000 with an external field sensor and feedback module. For a drum separator with a diameter of 1200 mm - compact LDM-B12 with shaft mounting. We conduct a free analysis: send a photo, drawing, passport data - our engineer determines the model, calculates the payback period and draws up an integration plan. Installation takes no more than 4 hours, operator training takes 90 minutes. All solutions comply with GOST R, have Rostechnadzor Permit and CE certificate.

If your separator begins to “leave” iron, if losses in the tailings increase, if the age of the equipment has exceeded 2 years, do not rush to replace it. First check if it's time to usedemagnetizer for magnetic separators. This is not a service option. This is part of the technology discipline.