Neodymium magnets wanted.. enough to cover 12x12

Hi id like some neodymium magnets to buy im hoping to try a magnetic sluice design using a 300mmx300mm (12 inch by 12 inch) sluice box using neodymium magnets and magnetite (black sand) in which i can manipulate the magnetic field of the magnets using a hardbachs array of magnets.
Id like n40 magnets and stronger either all the same shape or in sets of the same shape able to cover at least 30mm by 300mm each set.
Im trying to create a fluid magnetised bed of black sand with low density pockets to catch and trap heavy metals eg lead type mineral ore and gold.
Ive seen some working designs already using magnets (an entire bed and riffle designs) what work but think theres room for a huge leap forward in efficiency while still keeping a relatively simple design pattern.
Imagine an alternating high and low pocket density magnetic mat ?
Post or pm magnet pics shape and strengths pls il get back to you.
Il post experimental trials and results too
Thanks

Will the magnets from HDD work for you? If so I can probably work something out for you.

Jon

The only issue I see with the HDD magnets (most of them) is that there is a north and south pole on the same plane and basically the magnetic flux is "short circuiting" so to speak.

However some hard drives use a magnet that does not have the two poles in the same plane.


The top magnet has the two poles in the same plane and the bottom does not.

Unfortunately i dont think theyll be right for what i want but thanks for bringing them up. I spent a couple hours trying to work out a way to manipulate the irregular shape and quadrapolar magnetic field to suit but cant.

Cylinders cubes rectangles or square rods or bars if possible. I thought it would be a longshot but worth asking.

im1badpup1 said:

Cylinders cubes rectangles or square rods or bars if possible. I thought it would be a longshot but worth asking.

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There are 100's of types and strengths of neodymium magnets on both eBay and Amazon. Just do a search there.

James

I did n got a flexible neodymium 210mm mat 500 3mm cylindrical magnets 500 3mm cubes i guess theyll do for now the big magnets are out my price range

Anachronism what them magnet shapes may be very good for is an escrap eddy current separator of non ferrous metals from waste.
A link for an example https://youtu.be/ErqpSIqZjfk

Youd need a load of them stacked together and formed into a cylinder barrel type shape then use it as the end roller on a conveyer.
Non ferrous like copper aluminium silver etc are effected by the magnetic field they call it eddy current the convergence point where its strongest is i think the north tip of the magnet. The effect reverses in the magnet centre or divergence point.

If your fragging and crushing material down to screened sizes during processing itd make a good seperator in fact you probably already have one lol

How much would a approximately 9inch wide rack of them hdd magnets the same size ànd shape cost me please?

Hi Pup

Tbh I had never even thought of that as a use for these. The fields generated by the magnets in in the HDD are extremely strong. I've cut myself more than once by getting my fingers too close when pulling two apart. There's a matched pair in each HDD case and the cases sell for approx £600 per tonne with no boards so I reckon you'd have to figure out how many of these would be needed.

Jon

anachronism said:

Hi Pup

Tbh I had never even thought of that as a use for these.

Jon

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Serious question...do you not already have eddy current separation?

To the OP...ferrofluid of any use for your application? I only sort of understand what you are doing, and I'm just thinking of it's ability to take on shapes in response to magnetic fields.

I checked ferrofluid yesterday its unsuitable. Good idea though.

The amount of hdd magnets id want its cheaper for me to save n buy the big neodymiums by looks of it.

But save your hdd drive magnets jon youll need a lot for a good eddy current magnetic separator but the builds not hard. I saw some diagrams of schematics for one somewhere il post it when i find it. And itl be clear as day how to.build. they can separate quite a few different materials when ran at the right speeds too.

snoman701 said:

anachronism said:

Hi Pup

Tbh I had never even thought of that as a use for these.

Jon

Click to expand...

Serious question...do you not already have eddy current separation?

To the OP...ferrofluid of any use for your application? I only sort of understand what you are doing, and I'm just thinking of it's ability to take on shapes in response to magnetic fields.

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No I don't. I send tonnes of board product out as boards. Processing consists of grading and packing into the relevant containers dependent upon the grade and estimated yield. It takes very little time and labour to send a load out. This is one of the points I try to get over. Don't get involved in work that doesn't change anything in real terms. If you do, then you're just spending your profits.

Ten tonnes of boards yielding 270ppm gold will only yield 270ppm gold. That's a given fact. If you start shaving off components and concentrating then you might have a higher yielding concentrate but the gold remaining on the residual product will get eaten up in charges if the residual product is refined as a separate batch. Buy once, cry once, get charged once, get paid once.

Get it delivered, pick it, grade it, pack it, ship it. ONCE.

Don't disagree, however, shredding increases packing efficiency considerably. Usually an empty box ships for the same price as a heavy one. I figured that shipping to the other side of the world ate up some of the profit.

However...people that pack gaylords day in and out are also really really good at packing it in!!!


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The other reason I expected shredding is to build uniformity in your load so that your representative sample matches what you send in. But that can be done with skilled grading IF you have the quantity of uniform grade to prepare a uniform sample. Most on this forum will not...but most are selling to a secondary or tertiary packager as well.


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snoman701 said:

The other reason I expected shredding is to build uniformity in your load so that your representative sample matches what you send in. But that can be done with skilled grading IF you have the quantity of uniform grade to prepare a uniform sample. Most on this forum will not...but most are selling to a secondary or tertiary packager as well.
Sent from my iPhone using Tapatalk

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The underlined point is off base. Shredding does the polar opposite. It concentrates the values in the bottom of bags/containers/boxes and messes up the sampling terribly IF these samples are taken from the containers sent in. Refineries know this 8)

anachronism said:

The underlined point is off base. Shredding does the polar opposite. It concentrates the values in the bottom of bags/containers/boxes and messes up the sampling terribly IF these samples are taken from the containers sent in. Refineries know this 8)

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It makes sense.

The hardest thing to learn as a little guy is that the actual intrinsic value of the board is meaningless to us small operators.

For example. I have two piles of finger cards. One pile is board heavy chip light. The other is chip heavy board light. My calculations suggest that they should be worth more. Not a lot, but a little. It's a lot of work to strip BGA's, cut fingers, etc...then process them. And then I'm still only getting 75% of the boards value. Just sell them at the lower price, accept that it's part of your buyers average that makes them happy to have you as a seller, and keeps them at the ready to give you cash for your boards.

I DON'T want to nickel and dime my buyer. I want him to make money, hand over fist, so that he can continue to give me the best price on my scrap, and he can continue to pay for his operation...and that he's always willing to say, "the more the merrier" and have the money in my account the next day so I can go out and get more inventory. (and run multiple loads in the 90 days he takes to get paid on one load)

This is hard part of e-scrap for a smaller operator. Accepting the level that you are at...especially when the level you are at means that the actual intrinsic value of the board is meaningless to you. It is only a metric by which the buyer determines their business plan, and the rules by which they operate. Don't get me wrong, I'm not suggesting there isn't value in the knowledge...it's just not as valueable for me as it is for you. I'm better spending my time looking for larger operators that pay me more, and have grading rules that I can understand, and comply with, with as little headache as possible.

The yard i worked at in the 90s streamlined itself along the lines youre describing there jon.
We got industrial manufacturing scrap where one could separate a large volume and send it out as a mix to refiners with a known content value. It didnt pay anymore for the labour to separate completely so why break sweat doing it.
Fragged material was a dirty messy job. Funny how metal ripped apart like that smells so sweet though.
Whats escrap today with good value went in our no2 light iron we didnt even want circuit boards even telecom type.
The magnetic separator worked best on ferrous-non ferrous. And things like solder sweepings or lathe turnings from floor waste.

I suppose its down to what material you get in and what grades or mix refiners want or will accept keeping labour cost down. At one point we had a huge amount of separate material grades to sort.. approx 12 aluminium grades, 10 copper.. 10-15 brass gunmetal phospor bronzes about 10 steel and cast grades zincs pewter tin solder lead punchings turnings new production its a huge list.
All had to be clean of anything else. They allowed 1 or 2 visible wrong materials present when inspecting to sell or itd get knocked back.
Was much better when they streamlined and simplified the grading and refineries paid after smelting instead.