{"id":509,"date":"2026-10-09T01:01:42","date_gmt":"2026-10-08T17:01:42","guid":{"rendered":"http:\/\/www.ilicoco.com\/blog\/?p=509"},"modified":"2026-10-09T01:01:42","modified_gmt":"2026-10-08T17:01:42","slug":"how-to-choose-the-right-size-of-a-mechanical-stirring-flotation-machine-406f-67cf4d","status":"publish","type":"post","link":"http:\/\/www.ilicoco.com\/blog\/2026\/10\/09\/how-to-choose-the-right-size-of-a-mechanical-stirring-flotation-machine-406f-67cf4d\/","title":{"rendered":"How to choose the right size of a Mechanical Stirring Flotation Machine?"},"content":{"rendered":"

Hey folks, let\u2019s cut the crap\u2014if you\u2019re in the mining, mineral processing, or maybe even that niche recycling space where you separate fine particles like copper, gold, or even plastic flakes, you know picking the wrong mechanical stirring flotation machine (MSF) can turn your whole operation into a disaster. Last month, I got a call from a zinc mine up in northern Ontario\u2014they\u2019d just blown $120k on a machine that was too small, so their throughput was half what they needed, and the froth carry-back was so bad they were losing 15% of their valuable ore. I\u2019m not here to sell you a shiny box and run, I\u2019m here because I\u2019ve been supplying MSFs for 12 years, and I\u2019ve seen every \u201coopsie\u201d in the book. Let\u2019s break this down like we\u2019re chatting over a coffee (no corporate jargon, promise). Mechanical Stirring Flotation Machine<\/a><\/p>\n

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First off, let\u2019s get one thing straight: there\u2019s no one-size-fits-all. I see guys online spouting, \u201cJust get 100L per ton!\u201d like that\u2019s a magic number. Nah, that\u2019s garbage. The right size depends on three non-negotiables that most new ops sleep on: your feed rate, your ore\u2019s properties, and your desired concentrate grade. Let\u2019s start with feed rate because that\u2019s the easy one to mess up. Wait\u2014your feed rate is how much dry ore (wait, no, wet? Most of the time it\u2019s a slurry, 25-35% solids, so I\u2019ll say wet slurry flow rate per minute or hour) is going into the flotation circuit. If your mine\u2019s cranking out 500 tons of dry ore per hour, you don\u2019t need a 100L machine that can handle 5 tons max\u2014you need a series of machines that add up to your total volume. Let me explain: a 10m\u00b3 (cubic meter) MSF, for example, can handle roughly 80-120 m\u00b3 of slurry per hour, right? But that\u2019s a baseline. If your slurry is 30% solids, that\u2019s about 10 tons of dry ore per hour. So if you\u2019re doing 500 tons, you need 5 of those 10m\u00b3 machines, or a bigger one\u2014like a 20m\u00b3 that can do twice the slurry. But wait, don\u2019t just multiply. Because stir speed matters too. If you crank the stir too fast on a small machine to compensate for low capacity, you\u2019re going to shear all your air bubbles, so they don\u2019t stick to the ore particles. If you run too slow on a big machine, the slurry isn\u2019t mixing evenly, so some pockets have no air, and others get too much. That\u2019s a quick way to dead-end your flotation.<\/p>\n

Next, your ore\u2019s properties. This is where 90% of buyers go wrong, especially new ops. Let\u2019s split this into two big parts: particle size and mineral density. Fine particles\u2014like less than 10 microns\u2014need a different machine size and stir intensity than coarse particles, say 100 microns. Wait, fine stuff sticks to bubbles easier, but they also get dragged down by water flow more. So if you\u2019re processing fine gold, you don\u2019t need a giant tank because the agitation can keep the particles suspended without too much volume? No, wait, no\u2014wait, let\u2019s correct that. Fine particles have a higher surface area per unit mass, so they actually need more contact time with bubbles, which means a larger tank volume. But coarse particles\u2014like coarse copper sulfides\u2014are heavier, so you need a smaller, more agitated tank to keep them suspended, right? Because if you put a coarse ore in a big tank, they\u2019ll settle to the bottom, and you\u2019ll get dead zones. I had a guy last year with a iron ore project trying to use a machine he bought from a no-name brand\u201415m\u00b3 for coarse particles that needed 1500 RPM stir. The big tank couldn\u2019t spin the slurry fast enough, so 20% of the coarse ore settled out, and he had to shut down for 3 days to clean it. Ouch. Then there\u2019s mineral density\u2014heavy minerals like galena (lead ore) are way denser than quartz (gangue, the waste rock). If your ore\u2019s got a lot of heavy minerals, your slurry is denser, so you need a machine that has enough power to keep that thick slurry moving. A 10m\u00b3 machine for low-density coal slurry is totally different than a 10m\u00b3 for dense copper-gold slurry. Power draw\u2019s a big one here too\u2014bigger tank doesn\u2019t always mean more power, but the wrong power for the density will kill your mixing.<\/p>\n

Then there\u2019s desired concentrate grade and recovery. Do you need a high-grade concentrate for smelters, or are you just testing to see if the ore is worth processing? Let\u2019s say you\u2019re a small-scale explorer doing batch testing\u2014you don\u2019t need a 50m\u00b3 production machine. You need a 10L or 50L lab-scale or pilot-scale machine to test a few kilos of ore. That\u2019s why I tell all my new clients: start with a pilot test if you\u2019re unsure. Wait, but if you\u2019re a full-scale mine, you need to calculate the residence time. Residence time is how long the ore particles are in the machine before you pull the concentrate. For most sulfide ores, you need 5-10 minutes of residence time. For fine oxidized ores, it\u2019s more like 10-15 minutes. For coarse, heavy ores, it\u2019s 3-5 minutes. So let\u2019s do the math quick. If your slurry flow is 100 m\u00b3 per hour, and you need 8 minutes of residence time, that\u2019s (100 m\u00b3\/hour) * (8 minutes \/ 60 minutes) = ~13.3 m\u00b3. So you need a 15m\u00b3 machine, not a 10m\u00b3. That\u2019s a simple calculation, but most guys skip it and guess. I\u2019ve seen so many ops skip residence time, end up with concentrate that\u2019s too low grade because the particles didn\u2019t have enough time to attach to bubbles, or too high grade because they were pulling too much gangue (wait, no\u2014if residence time is too long, the particles stay too long, so they sink back into the slurry, right? That\u2019s carry-back. Yeah, carry-back is the thief of grade. If your machine is too big, residence time is longer than needed, so good ore gets carried back, and your concentrate grade drops. If it\u2019s too small, residence time is too short, so not enough particles attach, and recovery is garbage.<\/p>\n

Now, let\u2019s talk about the sneaky factors that no one tells you about. First, froth depth. The froth is that bubbly layer on top that has the valuable minerals. If your machine\u2019s tank is too short, the froth layer is too thin, so you can\u2019t skim enough concentrate. If it\u2019s too tall, the froth has to travel farther, so some bubbles break, and you lose particles. Froth depth is tied to size\u2014smaller tanks often have adjustable weirs to change froth depth, bigger tanks might have fixed or adjustable too, but you have to match that to your ore. Then there\u2019s pH and chemical reagents. Wait, chemicals change how the particles stick to bubbles, right? If you\u2019re using a lot of frothers or collectors, the bubble size changes, which affects how much volume you need to keep them suspended. More frother = smaller bubbles, so you need a machine that can keep those small bubbles moving without breaking them. Some guys buy a big machine, crank up the frother to make more bubbles, and end up with a mess of overflowing froth. That\u2019s a size problem. Also, circuit design\u2014are you doing roughing, scavenging, cleaning flotation? Roughing is the first step, so it\u2019s usually higher throughput, lower grade, so maybe bigger tanks. Scavenging is to recover any leftover valuable particles, so maybe smaller tanks with more agitation. Cleaning is to get the high-grade concentrate, so residence time might be a bit longer, so slightly bigger tanks. If you mix up roughing and cleaning sizes, your whole circuit is off.<\/p>\n

Wait, let\u2019s give a real example. I had a gold mine in Nevada last year\u2014they were processing 200 tons of dry ore per hour, particle size 20-50 microns (super fine), needed 12 minutes of residence time, and the slurry was 28% solids, density about 1.2 g\/cm\u00b3. Let\u2019s do the math: total dry ore = 200 t\/h = 200,000 kg\/h. Slurry density is 28% solids, so total slurry flow = (200,000 kg\/h) \/ (0.28) = ~714,285 kg\/h. Slurry density is 1.2 g\/cm\u00b3 = 1200 kg\/m\u00b3, so slurry flow volume = 714,285 \/ 1200 = ~595 m\u00b3\/h. Residence time needed: 12 minutes = 0.2 hours. Total required tank volume = 595 m\u00b3\/h * 0.2 h = ~119 m\u00b3. So split into 6 machines of 20m\u00b3 each, that works out perfectly. But wait, they initially came to me wanting 4 20m\u00b3 machines\u2014their math was wrong, they forgot the residence time. I showed them the numbers, they ordered 6, and their recovery went up 12% in the first month. They still call me to adjust the stir speed now, that\u2019s how it should be.<\/p>\n

Another common mistake: overlooking the footprint and power. A 15m\u00b3 machine isn\u2019t just a box that holds 15 cubic meters. It\u2019s 3 meters wide, 4 meters tall, weighs a ton, and draws like 50 kW of power. If your mine has limited space, you might need to go with a different configuration, like stacked flotation or smaller parallel machines, even if the total volume is the same. I had a client in Peru with a small mine that only had enough space for a 10m\u00b3 tank, but they needed the equivalent of a 12m\u00b3 total. So instead of getting a big 12m\u00b3 that wouldn\u2019t fit, they went with two 6m\u00b3 machines in parallel\u2014same total volume, fits their space, better mixing, because the slurry isn\u2019t spread out too much. That\u2019s a trick a lot of suppliers won\u2019t tell you, because they want to sell you the bigger single machine, but I\u2019d rather help you get the right setup than make a quick buck.<\/p>\n

Wait, what about if you\u2019re just starting out, doing lab tests or pilot plants? I get so many new ops asking, \u201cDo I need a big production machine right away?\u201d No. Get a pilot-scale MSF first, test your ore, get the residence time, particle size, slurry density all nailed down, then scale up. I\u2019ve seen guys drop $500k on a production machine before even testing their ore, because some sales rep convinced them it would work. That\u2019s insane. A pilot machine is like $5k-$20k, and you can test multiple ore samples, adjust the size and settings, so when you order the production machine, you know exactly what you need. I supply both lab, pilot, and production MSFs, so I always tell new clients: test first, then buy. No exceptions.<\/p>\n

Also, let\u2019s talk about wear and tear. Bigger machines can handle more wear? No, not necessarily. If you\u2019re processing abrasive ore like iron ore or granite, the impellers and liners in your MSF wear out fast. A bigger machine has a larger impeller, but if it\u2019s running at the right speed, wear is similar to a smaller one for the same throughput. But if you get a machine that\u2019s too big for your throughput, you have to slow the impeller way down, which causes more wear in other parts? Or wait, no\u2014if you run a big machine at low speed, the slurry isn\u2019t moving, so solids settle, which causes abrasion when you have to stir them back up. That\u2019s a double whammy. Too small, you run the impeller too fast, which wears out the impeller faster, and also shears bubbles. Too big, settling and abrasion. Find the sweet spot.<\/p>\n

Now, let\u2019s clear up some myths I hear all the time. Myth #1: \u201cBigger machines are always better.\u201d No, if you only need 10m\u00b3, a 30m\u00b3 machine is just wasting power, costing more to run, and taking up space. Myth #2: \u201cFeed rate is the only thing that matters.\u201d No, I\u2019ve had two mines with the same feed rate, same ore, different sizes, because one had finer particles needing more residence time. Myth #3: \u201cSales reps know the numbers.\u201d A lot of sales guys are trained to push the biggest, most expensive machine, not the right one. Always do your own math, or get a third-party test, or talk to a supplier who actually has mineral processing engineers on staff (I do, by the way, we don\u2019t just sell boxes, we help with the numbers).<\/p>\n

So let\u2019s recap the steps to pick the right size, no fluff: 1. Calculate your exact slurry flow rate (wet, per hour) and dry ore feed rate\u2014don\u2019t guess. 2. Test your ore to get particle size, density, and required residence time (get a pilot test, it\u2019s cheap insurance). 3. Do the simple math: total required tank volume = slurry flow (m\u00b3\/h) * (residence time in minutes \/ 60). 4. Factor in your space limitations, chemical reagents, froth depth needs, and wear properties. 5. If you\u2019re between sizes, go slightly smaller if you need finer particles (more agitation) or slightly bigger if you need more residence time, but always double-check.<\/p>\n

Wait, one last tip: when you\u2019re talking to suppliers, ask for their sizing worksheet. A real supplier will give you a custom worksheet that asks for all those parameters, not just \u201chow big do you want.\u201d If a supplier just says, \u201cJust get this 20m\u00b3 one, it works for everything,\u201d run. I have a worksheet that I send every client, it has 12 questions about their ore, feed rate, desired recovery, space, etc., and I plug the numbers in to give them a exact size recommendation. No generic stuff.<\/p>\n

<\/p>\n

At the end of the day, picking the wrong MSF size costs you money\u2014either lost recovery, lower grade, higher power bills, or even downtime to fix problems. I\u2019ve been in this game long enough to know that the best sale isn\u2019t the biggest machine, it\u2019s the one that works for your operation. If you\u2019re working on a new project, need help calculating the right size, or want to chat about lab\/pilot tests, just reach out. I\u2019m here to help you get the right setup, no hard sell, no hidden fees.<\/p>\n

Agitator<\/a> References:<\/p>\n

    \n
  1. Wills, B. A., & Finch, J. A. (2016). Wills’ Mineral Processing Technology: An Introduction to the Practical Aspects of Ore Treatment and Mineral Recovery (8th ed.). Elsevier.<\/li>\n
  2. McGill, S. L. (2011). Flotation Equipment Selection and Sizing. In Mineral Processing Plant Design, Practice, and Control (2nd ed., Vol. 2, pp. 1532\u20131555). Society for Mining, Metallurgy & Exploration.<\/li>\n
  3. Crozier, R. D. (1992). Flotation: Theory, Reagents, and Ore Testing. Society for Mining, Metallurgy, and Exploration.<\/li>\n<\/ol>\n
    \n

    Jiangxi Well-tech International Mining Equipment Co., Ltd.<\/a>
    Jiangxi Well-tech International Mining Equipment Co., Ltd. is one of the most professional mechanical stirring flotation machine manufacturers and suppliers in China, featured by quality products and good service. Please rest assured to wholesale customized mechanical stirring flotation machine at competitive price from our factory.
    Address: Guzhang Industrial Park of Shicheng County, Ganzhou City, Jiangxi Province, China
    E-mail: mily@benefication.com
    WebSite:     https:\/\/www.cn-welltech.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey folks, let\u2019s cut the crap\u2014if you\u2019re in the mining, mineral processing, or maybe even that … How to choose the right size of a Mechanical Stirring Flotation Machine?<\/span>Read more<\/a><\/p>\n","protected":false},"author":8,"featured_media":509,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[472],"class_list":["post-509","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-mechanical-stirring-flotation-machine-4055-680c10"],"_links":{"self":[{"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/posts\/509","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/comments?post=509"}],"version-history":[{"count":0,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/posts\/509\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/posts\/509"}],"wp:attachment":[{"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/media?parent=509"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/categories?post=509"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ilicoco.com\/blog\/wp-json\/wp\/v2\/tags?post=509"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}