magnetic ore separator

When you hear “magnetic ore separator,” the first thing that comes to mind is a powerful magnet that pulls pieces of magnetite out of the stream. In theory, everything is simple, but in practice... In practice, the fun begins. Many people, especially those who are just getting into the subject, think that the main parameter is the strength of the magnetic field. And they are deeply mistaken. Working with different types of ores, from ferruginous quartzites to oxidized ores, you realize that the key is often not in “strength”, but in design, in the subtleties of material supply and even in the moisture content of the pulp. It’s these nuances that are rarely written in textbooks, but which decide everything in production, and I want to speculate.

From theory to the workshop: where the main difficulties lie

So, let’s say the task is classic: to increase the extraction of the magnetic fraction. Take the standard onemagnetic separator, you set it up according to your passport and... you get a result worse than expected. Is this a familiar situation? The problem is often that ore is a loose concept. The same brand, but from different parts of the quarry, may behave differently due to changes in the granulometric composition or the degree of grain opening. Sometimes a little thing, like a non-optimal belt angle or drum rotation speed, eats up several percent of the recovery, and this is a huge number on the scale of a factory.

I remember an incident at one of the Ural plants. The ore seemed to be standard, but separation occurred with great losses. They began to figure it out. It turned out that the ore had increased the content of fine sludge, which, enveloping the magnetic particles, interfered with their capture. Simply increasing the field strength did not help - the sludge still carried valuable particles into the tailings. I had to experiment with preliminary classification and washing of the flow before the separator. This added a step to the scheme, but ultimately gave an increase. Such situations show that the device is only part of the system.

Another point that is often underestimated is wear and tear. This is especially true for dry type separators operating on abrasive materials. The drum, the tape, the magnetic core itself - all these are consumables in the long run. I saw how in some old factories they tried to save money on the timely replacement of protective covers, which led to the rapid failure of expensive coils. Repairs later cost many times more. Therefore, now, when I look at equipment, I always evaluate not only the passport data, but also the maintainability and availability of components.

Design features: drum, roller, roller - which goes where?

The choice of separator type is always a compromise. Drums are good for wet enrichment of large classes, especially when large volumes of pulp need to be processed. But if we are talking about fine grades or a high degree of purity of the concentrate is required, then they often look asidemagnetic separatorswith a high-gradient field or roller structures. The latter, by the way, have their own specifics: they are sensitive to the uniformity of the material layer supply. ?The blockage? on nutrition - and efficiency drops instantly.

I once worked with lines for processing technogenic raw materials. The task there was to extract fine magnetite from old tailings. Dry methods were not suitable due to dust formation; conventional wet drum separators also could not cope with fine fractions. We settled on the option with a roll separator with an adjustable gap and a multiple cleaning system. Structurally, it is not the simplest solution, but it allowed us to achieve acceptable recovery. True, the energy consumption of such a scheme is noticeably higher; this also had to be factored into the economics of the project.

It is worth mentioning here about such a manufacturer asLONGI Corporation. I came across their equipment at several sites in the CIS. What I can note is that they have a fairly wide range of models specifically for different ore dressing tasks. From simple pre-concentration separators to complex multi-stage lines. I won’t say that everything is perfect with them - sometimes there were questions about adapting the automation to our networks - but in general, the design of the machines is well-thought-out and metal-intensive. On their websiteljmagnet.ruYou can see the technical solutions they offer. Company,?Shenyang Scientific Electromagnetic Co., Ltd. LONGJI?, has been operating since 1993, and this is felt in the approach - a lot of attention is paid to industrial rather than laboratory execution.

Settings: what to turn and what to leave alone

Setting up a separator is almost an art. There are basic parameters: the gap between the drum and the feed tray, rotation speed, field strength. But there are also hidden ones. For example, the position of flushing water nozzles on wet separators. I shifted them a couple of centimeters - and the flushing of the magnetic product became less effective; part of it returned to the tail stream. Or temperature. It would seem, what does she have to do with it? But if the separator is located in an unheated workshop in the winter and operates on a wet process, a problem with icing of the drain gutters or even with the viscosity of the pulp may arise.

One of the most painful lessons was connected precisely with neglecting “little things”. A modern separator was installed on the new line. All parameters were set according to the instructions and launched. The first day - everything is fine, the indicators are even better than the passport ones. A week later - a drop in extraction. They spent a long time looking for the cause: they changed the power supply, checked the magnets. It turned out that the design used a rubber band on the drum, which gradually began to wear out on the fastening elements of the feeding tray due to a slight misalignment during installation. The gap increased, and some of the material simply stopped falling into the active field zone. A small thing that led to downtime.

Therefore, now I always insist on a thorough commissioning with the participation of a technologist and mechanic. And I definitely take benchmarks not immediately, but after at least 50-100 hours of working on real material. The equipment should “settle down”, all components should be broken in.

Process economics: when separation becomes unprofitable

It all comes down to money.Magnetic Ore Separator- not a panacea. There are situations when the costs of its operation (electricity, water, wear and tear, repairs) begin to eat up the entire margin from increasing extraction. This is especially true for poor or complex ores, where the content of the magnetic fraction is low. In such cases, it is sometimes more economically feasible to sell ore or concentrate at a lower grade, but without the additional costs of deep beneficiation.

When calculating efficiency, many forget about the cost of water (for wet processes) and tailings disposal. If water is in short supply or needs to be treated before being released, it can ?kill? project. The same goes for tailings - if they require special storage (for example, due to possible dust formation or chemical activity), this is an additional expense. I saw a project where, due to failure to take into account the cost of constructing a tailings dump for new volumes of separation waste, all the economic benefits from installing new devices came to naught.

Here again we return to the importance of an integrated approach. It's good when a manufacturer likeLONGI, which positions itself as a large enterprise for the development and production of mining equipment, can offer not just a device, but a well-developed technological scheme with calculation of unit costs. Judging by the description, their site in Fushun has serious capacity - an area of ​​140,000 m2 and production of up to 4,000 units of equipment per year. This scale usually allows them to test solutions ?in metal? and give more down-to-earth recommendations that are not divorced from the reality of the workshop.

A look into the future: where is magnetic enrichment technology headed?

Nowadays there is a lot of talk about smart systems and sensors. Yes, this is a trend. The introduction of systems for online analysis of iron content in concentrate and tailings associated with automatic adjustment of separator parameters is no longer a fantasy. But, in my opinion, this will not be the main breakthrough. Much more interesting are developments in the field of creating new permanent magnets based on rare earth metals. They allow the creation of more compact and energy-efficient separators with a very high and stable field.

Another direction is combined devices. Not justmagnetic separator, and, say, magnetic-gravitational. This is especially promising for complex ores, where it is necessary to separate several useful components with different physical properties. For now, such solutions are mostly laboratory, but I am sure that in a few years they will become an industrial standard for a number of fields.

What will not change is the need for a deep understanding of the material you are working with. No artificial intelligence can replace the experience of a technologist, who can draw primary conclusions about the process based on the color of the tails, the sound of the machine, or the type of concentrate. Technology is a tool. But the most important tool is still located between the ears of the specialist who is standing next to this very separator. Therefore, when choosing equipment, whether fromLONGI Corporationor another manufacturer, always look not only at the numbers in the catalog, but also at whether you (or they) have people who can “negotiate” with this equipment.