types of iron separators

When it comes totypes of iron separators, many immediately imagine the classification from the textbook: suspended, drum, tiled. But in reality, when choosing a device, you think less about the types, and more about the specific tape, the material that runs on it, and what “surprises” are there. this material may be hidden. A common mistake is to chase the power of the magnet, forgetting about the design or operating conditions. I went through this myself.

Hanging: not as simple as they seem

Here, it would seem, is the most common type - a suspended magnetic separator. Hangs over the tape and catches the iron. But which one exactly? If we are talking about large pieces of reinforcement or random tools, yes, it can handle it. What if the material is loose, wet and in a layer under 500 mm? This is where the nuances begin. The magnetic system must not only be strong, but also have the correct magnetic field depth. I remember an incident at one of the coal mines: they installed a standard suspended iron separator at the outlet of the crusher. Everything seems to be in the catalogue. But it did not capture the small metal inclusions that formed after crushing. It turned out that due to the high speed of the belt and the loose structure of the flow, the magnetic field “did not keep up?” pull out the particle. We had to review not the type, but the specific model and its settings for this material.

It is worth noting here that some manufacturers, such asLONGI Corporation, have been working on this problem for a long time. On their websiteljmagnet.ruyou can see that they offer not just iron separators, but entire series with different configurations of magnetic systems - for small fractions, for a deep layer. This is exactly the practical experience that migrated into the product. The company, founded back in 1993 and which has become a major manufacturer of mining equipment, has clearly faced similar challenges more than once.

And one more thing about pendants - execution. Dusty room, moisture, vibration. Case, cooling, protection. It would seem like little things. But they are the ones who determine whether the separator will work for several years or fail after a season. Often customers save on “extra” items. options, and then incur the cost of repair or replacement. This is not a theory, these are observations from objects.

Drum separators: for fine work

If suspended ones are more often used for large pieces, then drum magnetic separators are already a tool for finer cleaning, especially when metallomagnetic impurities need to be removed from the material flow itself, and not from its surface. The principle is known: a drum with a magnetic system inside, material is poured through it, the non-magnetic fraction flies along a trajectory, the magnetic fraction sticks to the drum and is removed. But again, the devil is in the details.

What drum rotation speed is needed for a specific material size? What is the gap between the drum and the casing? If the material is abrasive, such as some ores or sand, then drum wear becomes a critical factor. I saw installations where the drum was literally “eaten up?” for a couple of years of active work. The solution is either special wear-resistant coatings, which, by the way, are offered by serious manufacturers, or regular monitoring and scheduled replacements. This is not information that can be easily found in a general description, it is knowledge that comes with operation.

An interesting practical case is related to the recycling of construction waste. In addition to ferrous metal, you may also find weakly magnetic stainless steel. A standard ferrite magnetic core in a drum may not take it. Here you need to consider options with rare earth magnets (neodymium). They are more powerful, but also more expensive and more sensitive to temperature. The solution is always a compromise: based on the economic feasibility of extracting this particular fraction. In my time I participated in the selection, where they eventually installed a hybrid system fromLONGI— several reels in a line with different field strengths. It worked effectively.

Tile and lattice: for point protection

These are, one might say, “tactical”? iron separators. They are not installed on the main flows, but rather in transfer areas, in bunkers, at the exit of mills - for targeted protection of expensive equipment (crushing machines, pumps) from random metal that could have gone through the first stages of purification. A plate magnet is essentially a powerful magnetic plate built into the wall of a chute or bin.

It would seem that what is so difficult here? Set it and forget it. But no. The main problem is cleaning. If the magnetic plate is not cleaned regularly, it simply stops working, clogged with metal. In some industries where the maintenance schedule is tight, this is not a problem. And where the staff is busy with other tasks, they forget about cleaning. The result is that the metal slips further. I have seen implementations with a manual folding design or even with a pneumatic self-cleaning system. The second option is, of course, more expensive, but for continuous processes it can be justified. This is the case when, when choosing a type and model, you need to think in advance not only about installation, but also about service regulations.

By the way, about the quality of execution. The plate operates under conditions of constant impact and friction with the material. The quality of the magnetic elements and their fixation in the case is a key point. The detachment of a magnet or its destruction is not just a breakdown, it is a potential entry of the same magnet into the product, which is much worse. Therefore, when choosing, you should pay attention to manufacturers who control the entire cycle, from casting the magnetic system to assembly. As stated in the descriptionLONGI Corporation, they develop and produce equipment themselves, employing more than 1,200 people, most of whom are subject matter experts. For such a narrow segment as tile magnets, this is an important reliability factor.

Self-unloading models: automation vs. cost

A separate big topic is self-discharging iron separators. This is the next level when it comes to large volumes of metal being recovered or fully automated lines where manual cleaning is not possible. Essentially, this is the same overhead or drum separator, but with an automatic cleaning system - usually a short belt that carries the collected metal to the side.

The advantage is obvious: continuity of the process and savings on personnel. But the price of such a solution is many times higher. Are the costs justified? You always have to count. If your belt is 2 meters wide and it collects a bucket of scrap metal per shift, then most likely not. And if this is the main conveyor after primary crushing at a mining and processing plant, where metal can flow in an almost continuous flow, then self-unloading simply cannot be avoided. Otherwise, all people will do is clean the magnet.

Here lies another practical nuance - the reliability of the unloading mechanism. These are moving parts, drive, controls. In conditions of dust and vibration, they require attention. I had to deal with situations where the main magnet was working properly, but the drive roller of the self-cleaning belt failed due to fine dust getting into the bearing. Therefore, when choosing, you need to look at the degree of protection (IP) of these nodes. Manufacturers with extensive experience such asLONGI, which produces up to 4,000 pieces of equipment per year, usually already have proven and protected designs for difficult conditions, because their products are initially tailored for the mining industry.

Choices and mistakes: personal experience

As a result, talking abouttypes of iron separatorsalways depends not on their names, but on a combination of factors: the characteristics of the material (size, humidity, abrasiveness, flow rate), the conditions of the installation site (dust, temperature, vibration), the economics of the process (the cost of equipment downtime due to metal failure vs. the cost of the separator itself and its maintenance).

One of the most common mistakes I have observed is an attempt to save money by buying an iron separator “by eye?” or by taking a model that is not designed for specific conditions. For example, install a conventional separator for dry materials in a wet process. The result is rapid corrosion and loss of magnetic properties. Or incorrectly calculate the height of the suspension, which is why the efficiency drops significantly.

Another point is ignoring the trial stage. Serious suppliers who have their own production and testing facilities, like the 140,000 m2 company in Fushun, are often willing to conduct tests on customer material samples. This is not just marketing, it is a real tool to avoid mistakes. I myself have been to such tests, when they were “running out” on the stand. coal from a specific cut to select the optimal configuration of the magnetic system. After this, there is no doubt about the choice.

In conclusion, types are just a starting point. A real working device is always a compromise between theory, the practical capabilities of the manufacturer and the specific needs of the customer. And the main sign of a good choice is when, a couple of years after installation, the iron separator is simply forgotten, because it does its job quietly and properly. And if they remember, it’s only during scheduled maintenance. This is what we should strive for.