suspended electromagnetic iron separators

When they talk aboutsuspended electromagnetic iron separators, many imagine just a powerful magnet that hangs over a conveyor and catches nails. In fact, if you think like that, you can seriously miss the choice and settings. The difference between ?works? and “works efficiently and for a long time?” - it’s just in the details, which are often not written in catalogs, but you only find out on site, sometimes at the cost of failure.

From theory to practice: where the pitfalls lie

The main parameter that everyone looks at is magnetic induction. They take more, they think it’s more reliable. But here’s a case: they installed a separator at the outlet of the crusher, where a large fraction flows at high speed. The magnet is strong, but large pieces simply knocked the already captured small metal inclusions back onto the tape. It turns out that the magnet itself did its job, but could not hold it - the design of the cut-off device (slag dumper) was not designed for such a size and flow dynamics. I had to redo it on the spot.

Another point is nutrition. It would seem that what is so difficult here? But in old production facilities there are voltage sags, and the ambient temperature also has an effect. I saw how, in cold weather of -35°C, after a long period of inactivity, the coil did not reach its nominal parameters for about twenty minutes until it warmed up. And during this time, how much passed along the conveyor? Therefore, for critical areas, we now always look not only at the passport data, but also recommend a control system that monitors the real field strength online.

And of course, the location itself. It is not enough to just hang it in the center. It is necessary to take into account the sagging of the tape, possible lateral displacements of the material, and the angle of inclination. Once it was necessary to dismantle an already installed unit and move it a meter forward - because at the installation point the tape created a “hump” due to the rollers, and the distance to the material became critically large, the magnetic field was “not sufficient”. These were unnecessary costs and downtime that could have been avoided.

Experience with LONGI products: durability against aggressive environments

In recent years, we have often worked with equipment fromLONGI Corporation. Their websitehttps://www.ljmagnet.ruis a good source of technical data, but live experience is more valuable. Company,?Shenyang Scientific Electromagnetic Co., Ltd. LONGJI?, has been operating since 1993, and this is felt in the approach to engineering solutions, especially for the mining industry.

They were placed at one of the coal minessuspended electromagnetic iron separatorsto the loading area. The environment is difficult - coal dust, moisture, vibration. What I noted is high-quality winding insulation and housing protection. Not that cheap paint that peels off over the course of a season, but a truly durable coating. After three years of operation, there is almost no visual corrosion, which is an excellent indicator for such conditions. Colleagues from the enterprise confirm that they produce about 4,000 units of equipment per year, and this volume apparently allows the technology to be developed to the level of reliability.

An important nuance is maintainability. At the same facility, there was a situation where the power cable was damaged due to third-party intervention. The design of the terminal box and access to the connections of their separators are well thought out. We didn’t have to remove the entire unit; we unscrewed the panel and replaced a section of the cable—the job took a couple of hours. It’s a small thing, but when the conveyor is stopped, every minute counts.

Non-obvious selection criteria: what to ask the supplier in addition to technical characteristics

In addition to dimensions, weight and magnetic force, there is a list of questions that I now always keep in my head. The first is the cooling system. For round-the-clock operation in a workshop with temperatures above 40 in the summer, air cooling (IC 41) may not be enough. You need to look at the temperature class of the insulation and real thermal tests. Ask for continuous heating schedules.

The second is compatibility with automation systems. A modern plant is not a lonely hanging magnet, it is a link in a chain. The device must be able to provide status signals (on/off, overheating, loss of power) and receive commands, for example, from a metal detector. For some models this is an option, for others it is standard equipment. Check right away.

Third, maintenance recommendations. How often should I check the fasteners? Do the bolts need to be tightened? How to clean the surface from adhering material (especially important for sticky clays or fine ore)? An ideal supplier such as LONGIE, with their more than 1,200 employees, many of them engineers, will usually provide not just a data sheet, but a detailed operating manual with these nuances. If this is not the case, this is a reason to think about it.

When savings lead to costs: a few words about the quality of the magnetic core

The core is not just a piece of metal. Its material, assembly form (stacked or monolithic), steel quality directly affect efficiency, heating and field stability. I came across a situation where two outwardly identical iron separators from different manufacturers showed a 15% difference in field strength with the same power parameters. We took it apart - it turned out that the cheaper one used steel with worse magnetic properties and poor-quality assembly of the package, there were gaps.

This relates to the question of why products with a history likeLONGI, which is located on an area of 140,000 m2 and has been around for a long time, is often preferable. They control the chain from steel to assembly. Judging by the autopsies, their magnetic circuit is always smooth, dense, and without scale. This is a guarantee that the declared power will not be on the tag, but in the real gap above the tape.

And yes, the shape of the core. For hanging models, they are often made rectangular or cylindrical. Cylindrical (drum) gives a more focused field directly below it, good for thin layers. Rectangular (sectional) has a wider coverage area, which is better for wide belts. This is not marketing, but physics. The choice should depend on the task.

Instead of a conclusion: thinking out loud about the future of such systems

Nowadays there is a lot of talk about permanent magnets on rare earth metals. They certainly do not require energy to create the field. But the suspended version for difficult conditions is not yet a panacea. Their strength is fixed and cannot be adjusted on the fly. What if you need to turn it off? You will have to mechanically remove it from the tape. Plus they are afraid of strong shocks and high temperatures. Soelectromagnetic iron separatorsThey will be in demand for a long time where flexibility and reliability in tough conditions are needed.

Working with different factories, I see a trend towards integration. Don’t just buy a magnet, but integrate it into the digital circuit of the workshop. So that data on the amount of metal extracted, energy consumed and downtime goes into the general efficiency accounting system. Manufacturers who likeLONGI Corporation, have their own scientific and engineering departments (more than 60% of the staff have higher education - this is serious), are in a more advantageous position for the development of such smart solutions.

So, choosing todaysuspended electromagnetic iron separator, in essence, you are choosing not just a device, but a potential partner for the next 10-15 years. It is important to look not only at the price tag here and now, but at whether the supplier can support, finalize, and provide adequate advice. Because there are almost no ideal conditions, as in the textbook, in real production, and the equipment must be able to work in spite of them.