Iron separator with permanent magnetic system

When you hear “iron separator with a permanent magnetic system,” many people immediately imagine just a powerful magnetic block above the belt. In fact, if you look into it, this is a whole story about reliability in conditions where electronics have nothing to do - dust, vibration, temperature changes, and maintenance personnel do not always have time for fine adjustments. This is where the time-tested design of permanent magnets such as ferrite or, better yet, neodymium comes to the fore. But even here there is a catch: not everyone is a “constant” person. equally useful. You can install the most powerful magnets, but if the design of the casing or the self-cleaning system is lame, all effectiveness is for naught. I personally encountered when a customer bought a cheap analogue, and after six months the fine fraction and scale still broke through - the magnetic field was strong, but poorly focused. So this topic is far from being as simple as it seems at first glance.

The essence of the system: why ?permanent? is a synonym for “trouble-free”?

The main advantage for which they are chosen is complete energy independence. No coils, no rectifiers, no cooling system. I placed it over the conveyor and forgot about it. In theory. In practice, you need to constantly monitor the gap between the tape and the magnetic system, and the wear of the tape itself, so that there is no rubbing. This is especially critical in heavy areas where, say, coal or ore with a large fraction is transported. Vibration from falling pieces can gradually weaken the fastenings.

Structurally, the heart of such an iron separator is an assembly of magnetic blocks. They are often placed in a checkerboard pattern or at a certain angle to create a magnetic field of the desired configuration - not just strong, but also deep, with a good gradient. This is where the art of the manufacturer lies. I remember once we were disassembling a sample fromLONGI Corporation— a clear logic was visible inside: the blocks of sintered NdFeB were fixed in a durable stainless steel frame not with simple glue, but with mechanical clamps, which immediately indicated that they were designed to withstand impact loads. This is the very little thing that you only see in person.

Self-cleaning is another key component. There are models with manual cleaning, but for continuous processes an automatic one is needed - usually this is either a short endless belt (conveyor) or a chain scraper mechanism. It is important that the trajectory of the discharge of impurities is clear and that reverse adhesion does not occur. At one of the plants I saw a problem: the scraper was set too sharply, and flying ferromagnetic particles sometimes fell back onto the main product. I had to modify the angle and speed of the cleaning belt.

Where and how it is used: not only mining

Of course, the classics are processing plants and coal mines. But the spectrum is wider. For example, in the processing of cullet or in lines for the production of building materials, stray iron also needs to be removed to protect the crushers. Or at woodworking plants - a nail in a board can ruin both the saw and further products.

An interesting case was with an enterprise for processing industrial waste. There the flow was heterogeneous, with a large amount of dust fraction. The standard overhead iron separator was simply choking. — dust adhered to the magnetic blocks, forming a thick layer that sharply reduced the capture efficiency. The solution was found in a combination: a preliminary vibrating screen was installed to filter out dust, and after that -iron separator with permanent magnetic system. Productivity has recovered.

An important point is installation. It would seem that hang it and that’s it. But everything depends on the installation height, the speed of the belt, and the thickness of the material layer. There are empirical formulas, but it is better when the manufacturer gives clear recommendations based on tests. On the websitehttps://www.ljmagnet.ruLONGI, by the way, saw quite detailed technical notes on this matter, which is rare - usually only dry catalogs are given.

Mistakes and pitfalls: what experience teaches

The most common mistake is underestimating the environment. Permanent magnets, especially neodymium ones, are afraid of strong heat. We installed such a separator in the workshop near the drying oven. The temperature in the installation area was consistently above 80°C. After a few months, the strength of the magnetic field dropped noticeably. We had to shield the heat or, as an option, consider systems with electromagnets, where cooling is built into the design.

Another stumbling block is corrosion protection. Humid environment, aggressive dust. If the magnetic blocks are poorly encapsulated, and the case is made of ordinary steel, then rust will eat it up in a couple of years. Quality manufacturers, the same ones included inLONGI Corporation, use stainless steel or at least highly resistant powder coating for the body. This can be seen with the naked eye - by the welds, by the quality of the flanges.

There was also a curious, but revealing story. We ordered an iron separator from a food production facility, but saved money by purchasing a model without a protective design. As a result, when washing the workshop, a jet of water under pressure got right inside. There was no short circuit (the magnets are permanent), but the water stagnated, froze in winter, and the ice broke several fastenings. The equipment has failed. Moral: even for ?simple? magnetic system, you need to choose the IP protection index correctly.

Choosing a manufacturer: what to look for besides price

Price is, of course, important. But when it comes to industrial equipment that must operate for years without stopping, the key issue is reliability and maintainability. A good sign is when the manufacturer openly indicates the brand and characteristics of the permanent magnets used, and does not write vaguely “strong neodymium”. For example, sintered NdFeB N35 or N42 is already a specificity by which you can estimate the holding force.

It is very useful to study the history of a company. Here?Shenyang Scientific Electromagnetic Co., Ltd. LONGJI?, created back in 1993, over the years has clearly gone from simple production to complex solutions. The fact that they have their own large production area in Fushun and more than 1,200 employees, most of whom have specialized education, speaks of serious scale and, importantly, their own quality control at all stages. This is not an assembly from purchased components in a small workshop.

For me personally, an important criterion is the availability of complete documentation in Russian - not only a passport, but also installation diagrams and operating recommendations. And, of course, the availability of spare parts. Case from practice: the drive motor on a self-cleaning scraper broke down. The original manufacturer had the motor in stock in the Russian Federation, and it was replaced in three days. Another supplier would have to wait a month for delivery from abroad, and the downtime of the conveyor would be a huge loss.

A look into the future: the evolution of ?permanents?

It would seem that the technology is established. But there is progress. I see a trend towards smarter use of materials. For example, the use of anti-adhesive coatings on the surface in contact with the material to reduce the adhesion of sticky dust or wet ore. Or a more accurate calculation of the magnetic circuit using field modeling software, which allows you to optimize weight and dimensions without loss of efficiency.

Another trend is modularity. When the magnetic section can be relatively easily removed for maintenance or replacement without removing the entire frame from the conveyor. This greatly reduces repair time. Some models now have folding structures on hinges - a smart solution.

Let's go back to the beginning.Iron separator with permanent magnetic system- this is not archaic, but a very living and in-demand class of equipment. Its future lies not in a fundamental change in the principle, but in fine-tuning the details to perfection: in materials, protection, ease of maintenance. And the choice here, as always in industry, comes down to finding a balance between price, reliability and the competence of the manufacturer, who understands how his equipment will work in real, not ideal conditions. It is manufacturers like LONGI, with history and their own factories, who set the tone here.