pulley iron separator

When they talk aboutpulley iron separator, many people imagine just a magnetic drum that is placed on the head drum of the conveyor - and that’s all. But if everything was that simple, there wouldn't be so many problems in factories with damaged belts and worn-out crushers. In fact, choice and installation is a whole story, where little things make all the difference. I often come across the fact that people skimp on the thickness of the magnetic system or incorrectly calculate the belt speed, and then wonder why the fine fraction is not caught. I went through this myself.

A design that cannot be appreciated on paper

Take, for example, the classic design from the same LONGI. Their website https://www.ljmagnet.ru shows that they focus on the pole system. But you can’t write the main thing in the specifications: how the magnetic flux behaves during actual loading of raw materials, especially wet ones. I remember that at one of the plants in Kuzbass they installed a separator, which seemed to be suitable according to all calculations. And at the output there was constant sticking of small particles onto the pulley itself, so I had to stop the line for cleaning. It turned out that the casing design did not take into account vibration from the heavy belt, the gaps changed, and efficiency dropped.

Here it is important to look not at the catalog, but at the experience of use in similar conditions. ULONGI CorporationI have years under my belt since 1993, and I often see their equipment at coal and ore mines. But even this is not a guarantee. You need to understand that their production capacity in Fushun is one thing, but adaptation to a specific quarry is something else entirely. Their engineers, of course, help with calculations, but without a personal visit to the site and measuring belt loading levels, you can easily make a mistake.

The key point is thispulley iron separatorlike a drive drum. It not only separates, but also pulls the tape. Therefore, strength calculations and balancing are critical here. I have seen cases where, due to an imbalance in the magnetic assembly, premature wear of the bearings began, so fast that they failed within a year. And this is on a line that only worked one shift!

Magnetic core: subtleties that are not written about in manuals

Now many are switching to rare earth systems, and this really gives a gain in the strength of the magnetic field. But here's something that's rarely discussed: their sensitivity to overheating. On the same LONGI website it is stated that they produce more than 4000 units of equipment per year. Let's say that most of them are magnetic separators. But if you take their model with neodymium magnets for a high-speed conveyor, you must definitely look at the cooling system or, at least, at the temperature tolerances. In the crushing shop where the crusher is located, the temperature around it can be high, plus heating from the friction of the drum itself.

One day I had to deal with a situation whenpulley iron separatorbegan to lose efficiency after six months of work. They opened it - and there was partial demagnetization in the sectors that were closer to the hot side of the working furnace. The manufacturer, of course, said that the temperature regime was violated. But in real conditions it is not always possible to move the conveyor away or install a powerful hood. We had to modify it and install an additional heat sink. This is the very practice that is not in textbooks.

Another nuance is the drum coating. Rubber lining is standard, but its thickness and pattern greatly affect the release of non-magnetic material. A smooth surface is worse, especially when working with wet ore. Some manufacturers have options with a chevron pattern or increased wear resistance. You need to ask about this parameter, because replacing the lining means stopping the line for at least a day.

Installation and alignment: where the main risks lie

The most common mistake is careless installation. It seems that installing a magnetic drive drum is a simple matter. But if there is a misalignment of even a couple of millimeters relative to the axis of the conveyor, problems with belt removal begin. And if the tape goes away, then the contact with the magnetic field becomes uneven. Small ferromagnetic particles simply do not have time to be attracted to the area with a smaller gap.

ULONGI Corporationthe description of the enterprise states that more than 60% of the staff are specialists with higher education. This is good when it comes to design. But on-site installation is often carried out by contractors who may not delve into such subtleties. Therefore, in the contract I always try to include a clause on installation supervision or at least detailed instructions from the supplier. Even remotely, through the same drawings with strictly defined alignment tolerances.

Don't forget about vibration diagnostics after installation. I am used to taking measurements not only at idle, but also under load, after a week of work. It happens that the fastenings become loose, or the conveyor frame shrinks. And then that same imbalance appears again. It’s better to spend a day on diagnostics than to later deal with the consequences in the form of torn tape and downtime.

Working with different materials: why there is no universal solution

One and the samepulley iron separatorwill behave differently with coal, iron ore or, say, slag. What is important here is the depth of the material layer on the tape and its density. For coal, which is light and often has a coarse fraction, a powerful field on the surface is more important. And for heavy iron ore with a fine fraction - so that the magnetic field is deep enough to pull the particle out of the lower layers of the flow.

On the website https://www.ljmagnet.ru the company positions itself as a developer of mining equipment in general. This means that they most likely have a range of models for different tasks. But in correspondence it is necessary to describe the material in as much detail as possible: not just “iron ore,” but size, moisture content, bulk density, even the approximate content of magnetite. Otherwise, they will send a standard model that will work at 70% of what is possible.

I remember a story at a processing plant where they switched from one type of ore to another, smaller one. The old separator, which previously worked perfectly, began to allow too much fine iron to pass through. It was not the drum itself that had to be replaced, but rather the magnetic system with a more powerful one, with a different pole configuration. It was more expensive and longer than if a reserve for magnetic induction had been initially included, taking into account possible changes in the raw material base.

Economy and reliability: what is more important in the long term

Often the customer looks at the initial price. But cheappulley iron separatorcan cost a pretty penny due to frequent maintenance stops and low efficiency. The cost of downtime of a conveyor line at a large enterprise is tens, or even hundreds of thousands of rubles per hour. Therefore, you need to consider the total cost of ownership.

Here, for example, is the LONGI enterprise with its area of ​​140,000 m2 and a large staff. On the one hand, this can mean solid experience and proven technologies. On the other hand, large-scale production is sometimes less flexible to small but important “turnkey” modifications. for a specific customer. This must be taken into account at the stage of discussing the terms of reference. Sometimes it’s better to pay a little more, but get equipment that takes into account your nuances - the same non-standard diameter or special conditions for dust control.

Reliability also means the availability of spare parts. The magnetic system is a durable thing, but bearing units, seals, and lining are consumables. A reputable manufacturer should have a clear system for supplying spare parts, without months of waiting. This is also part of professional judgment: not only choosing a model, but also assessing whether you can maintain it in working condition for years.

As a result, choosing and operating a pulley iron separator is not about reading catalogs, but about analyzing the details and taking into account real experience, often bitter. There is no ideal device, there is one that is correctly selected and correctly installed for specific conditions. And this is perhaps the main conclusion that you come to after years of working with this seemingly simple assembly on the conveyor.