carbon magnetic separator

I’ll say right away - many, especially in new areas, think thatcarbon magnetic separatorIt’s such a simple thing: I put a magnet over the tape, and that’s it, the iron is gone. And then they wonder why pieces of reinforcement or brackets from fastenings again appear in the concentrate, why equipment wear is higher than calculated, and why the quality of the output coal is unstable. The problem is precisely this simplistic view. A separator is not a separate apparatus, but an element of a system, and its operation is strictly tied to a dozen parameters: from coal granulometry and humidity to belt speed and, critically, the type and configuration of the magnetic field itself. If you approach without understanding this, your money is down the drain.

From theory to practice: where the pitfalls lie

When I first started working with enrichment, I also believed that the main thing was the strength of the magnetic field, the more powerful the better. We ordered separators with super-powerful neodymium systems for one of the mines in Kuzbass. According to the passport - excellent indicators. But on site it turned out that the coal dust that inevitably forms sticks to the drum, mixes with the extracted metal impurities and forms a dense, sticky layer. It had to be cleaned off almost every shift, conveyor downtime, additional people. The power was excessive for that faction, but the self-cleaning design was not thought out for such conditions. This was the first lesson: passport characteristics must always be adjusted to the specific conditions of the slaughterhouse and preparatory factory.

Another point that is often overlooked is the depth of the coverage area. If the separator hangs too high above the belt, it simply won't reach. smaller, but no less harmful metallic inclusions that lie in the lower layers of the flow. And if you lower it too low, there is a risk of the tape catching or disrupting its trajectory, especially with “runners”. It was necessary to empirically select the height, taking into account the amplitude of vibration of the belt under load. This is not in any manual, only experience.

And of course, the type of magnetic system. Permanent magnets, for example, from the sameLONGI, good for their autonomy and reliability, do not require power. But when it comes to processing large volumes with a high content of fine metal (crushed rock with drilling technology, for example), sometimes electromagnetic systems are more effective. They make it possible to adjust the field on the go, but require infrastructure, protection from moisture and a reliable power supply. The choice is always a trade-off between extraction efficiency, cost of ownership and operational complexity.

Case study: setting up for “wet” conditions. process

We had a project at a processing plant where coal was processed in a wet process. The task was to remove the metal to the mills. It would seem a standard story. But the separator, which worked perfectly on a dry belt, began to act up here. Water changed the friction, the particles behaved differently, and the magnetic drum itself, if it was not intended for a humid environment, quickly lost its properties, and corrosion of the fastening elements began.

I had to dive deeply into the topic. We settled on a solution with a magnetic drum in a stainless steel case and a special sealing system. It was important not just to buy “moisture resistant?” separator, namely, choose a model designed for a constant pulp flow. Here we just turned to the technical documentationLONGI Corporation— they had separators for different media in their assortment, and from the specifications it was clear that engineers laid down different protection tolerances for dry and wet processes. This is an important detail that distinguishes just a manufacturer from someone who understands the nuances of mining.

After installation and launch, another month was spent fine-tuning: the drum rotation speed, the vanishing angle, and the system for flushing the extracted metal from the surface. Sometimes it seemed that everything was perfect, but after analyzing the samples it turned out that some small ferromagnetic particles still slipped through. We added a preliminary stage - a pulley separator at the beginning of the route. This increased capital costs, but ultimately saved expensive crushing equipment downstream. The economics of such a decision turned out to be positive, although it was not initially included in the estimate.

Mistakes that are best not to be repeated

I would like to separately highlight one gross but common mistake - neglecting regular maintenance. The magnetic separator seems to be a “set it and forget it” device. Especially with permanent magnets. But in reality, you need to monitor the gaps, check the integrity of the protective casing (especially against abrasive wear), and clean the surface from adhesion. At one of the enterprises, due to untimely cleaning of the drum, the frozen layer of coal with metal actually isolated the magnetic field, and the separator ran idle for half a month until it was scheduled for repairs. The wear and tear damage on the crushers was significant.

Another story involves improper installation. The separator must be firmly and accurately secured to the belt. If there is vibration or displacement, efficiency drops catastrophically. I remember a case when installers, in order to quickly, secured the structure not to the supporting beam, but to the sheathing. As a result, vibration from the conveyor caused vibrations in the separator itself, and it “missed”. They didn’t find the problem right away; it was due to a weak magnetic field until they checked everything for level and reinstalled it.

And of course, saving on little things. For example, on metal level sensors in a compartment or on an automatic reset system. It seems that you can clean it manually. But in practice, this leads either to downtime or to overflowing of the compartment and back contamination of the coal. Automation in this regard is not a luxury, but a way to ensure process stability. Large manufacturers, likeLONGI, such options are usually found in the base or advanced configurations, and they are really worth considering.

Choosing equipment: what to look for besides price

When I select equipment now, first of all I look not at the beautiful numbers in the catalog, but at the design features. How does the demagnetization system work? How is protection from dust and moisture ensured? What materials are the drum and casing made of? How easy is access for maintenance? Here is the websitehttps://www.ljmagnet.ru- there atLONGI Corporationit is clear that they focus on durability and maintainability. This is important because in a mine or processing plant the device operates in an aggressive environment, and the ability to quickly replace a worn part without dismantling the entire structure is a huge plus.

It is very useful to study real application cases, preferably in similar industries. A company that has been on the market for a long time, like the sameLONGI(they, by the way, have been operating since 1993, and have a production area of about 140,000 m2), usually have a portfolio of completed projects. You can ask for contacts of technologists from enterprises where their separators are already installed and find out about the pitfalls. first-hand. This does more than any advertising brochure.

And lastly, you should never take a separator “blindly”. It is best to provide the supplier with coal samples, belt performance data, and layout diagrams. A good manufacturer will conduct laboratory tests and make recommendations on the model and settings. If this stage is brushed aside by offering a “universal solution”, this is a red flag.Coal Magnetic Separatorby definition, cannot be completely universal; it always needs to be adapted to a specific technological chain.

Instead of a conclusion: thinking out loud

Nowadays there is a lot of talk about digitalization and smart systems in mining. And in the context of separation, this is also relevant - the introduction of control sensors, integration with automated process control systems. But the basis, like twenty years ago, is the physics of the process and understanding of the material. You can install the most modern separator, but if the installation points are incorrectly determined or the specifics of coal are not taken into account, the result will be mediocre.

Working withcarbon magnetic separator— this is a constant dialogue with production. The device is not installed for a year, and its operating conditions may change: the formation changes, mining equipment changes, and therefore the nature of metal impurities. You need to be prepared for periodic re-evaluation of his work, sludge analysis, and inspections. This is not “set it and forget it”, but part of a living technological system.

Therefore, returning to the beginning, the main conclusion is this: the success of magnetic separation in coal preparation is determined not so much by the apparatus itself, but by an integrated, thoughtful approach to its selection, integration and operation. And experience here is the most valuable asset. Technical solutions, albeit from a trusted supplier likeLONGI, which produces thousands of pieces of equipment per year, is just a tool. And how to apply it is decided by the one who stands at the conveyor and sees the entire process.