Black Sand Concentration Simplified

[Traveller11]

Hello

I have just read a post on another prospecting site by a fellow who seems to have found a simple way to concentrate gold and other PM's in black sand.

He says that he has built a small roller mill housed partially in a five gallon pail. With this, he crushes his black sands to 600 mesh.

His next piece of equipment is an ultrasonic jewellery cleaner he purchased used on e-bay for $80. Its cup holds about a cup and a half of black sand. When turned on, he claims that the high speed vibrations make the gold descend to the bottom of the cup; along with other PM's, and the black sand to lay above it. He adds more black sand, a tablespoon at a time, and black sands are tailed over the side of the cup as more gold settles out. Samples of the tailings from this process showed that it retained over 95% in the ultrasonic cup.

What an incredibly simple idea! I immediately thought of making this unit larger and shovelling bank run material, screened to -20 mesh, of course, into it and letting vibrations do the separation.

Some adjustments to design might be necessary, though.

Regards

Bob

 

[T3sl4]

Do they still make those monster vibrators like they used putting together the Hoover dam? One of those should do a fine job. I can't imagine it has to be ultrasonic. In a pinch.. you could use an orbital sander (without sandpaper). Or any number of other vibrating, erm, devices...

Tim

 

[Traveller11]

Tim

LOL yes yes I'm sure one of those...ermm, uh, you knows...would work quite nicely, too. However...

But, seriously, what a crazy, simple but potentially successful idea. I've spent the whole evening experimenting with a vibrating rifle cartridge polisher I came into possession of recently. I'm using regular sand about 4" deep and dropping things like lead shot and steel nuts into it. Although the bowl has circular sides and bottom to keep things of different specific gravities circulating in a polishing loop, it still sends the denser items to the bottom quite nicely.

The sand I used was somewhat damp and I found the addition of two cups of water enhanced the separation process and negated the circulation effect. However, although the liquefaction of the sand was beneficial, I found, after shutting it off and digging into the bowl, the sand at the bottom of the bowl was quite compacted. This could possibly interfere with the separation process.

So, what if the concentration chamber was 24" in diameter on the open top and was shaped like a funnel with the point down; say, 24" tall as well and the diameter of the point about the same as a beer can. To this point would be threaded a clear plastic catch cup about the size of a beer can. (notice how I'm using relatively sized objects that everyone can relate to) The concentration chamber would be mounted on four steel legs to a flat platform with a vibration motor mounted to its underside; the whole thing being spring mounted to a stationary platform below it. A vibration motor is simple; take an electric motor and attach an offset weight to its output shaft.

To deal with the compaction of sand in the bottom of this unit and to fluidize the chamber to take maximum benefits from liquefaction, a ball valve is mounted to the bottom of the catch cup and a garden hose to the ball valve. While in operation, a steady flow of water is fed into the catch cup, fluidizing the concentrate and allowing denser particles to settle out past less denser particles. The ball valve will stop the flow of PM's down the inside of the garden hose once the water is shut off. As this water may channel in a narrow stream upwards from the catch cup, additional fluidization ports may be added to the chamber periphery close to the bottom.

I do not fully understand the factors involved in liquefaction and I think it may become necessary to carefully classify concentrates to narrow ranges to get the proper effect here. Then again, initial classifying to -20 or -30 mesh may be all that is necessary.

Again, although I keep referring to concentrates, I see no reason why bank run material (classified, of course) could not be processed in this unit.

Regards

Bob

 

[T3sl4]

Compaction, yeah that could be a problem.

Surfactants and additives could help that. For instance, a few drops of sodium silicate worked into a hunk of clay turns it into a sloppy mess! The term for this is a flocculant, and it keeps particles suspended by electrical forces, so you can use less water, get a lower viscosity, and the particles settle out slower. The whole field of rheology, as it is called, is very important in drilling, since drill mud is a mixture of all sorts of things, engineered for one specific purpose.

You'd want to be very careful to use as little additive as possible, and use an environmentally friendly method, if you're working on-site for instance.

Tim

 

[Traveller11]

Hello

Well, no sooner do I get down to doing some serious research on liquefaction and what do I see on another prospecting site but a link to a company selling the "Quicksand Concentrator" for the princely sum of $60. A supplementary 12 volt pump is sold with it for another $30.

Here is the link:

Fine Gold Recovery from the Quicksand Concentrator

The fellow writing the post mistakenly thought this was an elutriation tower.

I e-mailed the retailer and it turns out it is indeed a liquefaction unit; maintaining a water saturated slurry and applying vibration to make the denser particles settle out to the bottom of the unit.

LOL good thing I wasn't in too much of a hurry to get to the patent office.

This concentrator may just turn out to be the greatest thing since sliced bread. I think I'll put a halt to my research and order one.

Or maybe even two, just in case I lose one. 8)

Regards

Bob

 

[Elfs]

For finishing cement they use a large vibrator

http://www.google.com/products?q=cement+vibrator&oe=utf-8&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=UTF-8&ei=kuGnTKWWCcTflgfeh7jDDA&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CDIQrQQwAA

Powerful dildos....

 

[Anonymous]

There is a dredge manufactuer in southern california that makes a unit that is a container that shakes back and forth with a water manifold in the bottom of the container that keeps the screened material fluidized so the high density gold ,sulfides, ect fall and collect at the bottom. light material overflows as feed is added. The gold pan and many other machines have been invented that use the fluidized bed principal for concentration. A plastic ice cube tray can even be used as a concentrator and it wont take long to figer out that a larger hand powered device can be built that will process a 5 gallon bucket full of sand in about 5 minutes.

 

[solarsmith]

they are called gold jigs . watch gold rush alaska to see one in use.
I like the mini gold fluid bed idea you got going.. I may have to try it with my mill output. thanks BRYAN IN DENVER COLORADO I BUY CATALYTIC CONVERTERS 303 503 4799

 

[Arrowood]

If you take a container of different sized sand or gravel and tap the container side with your finger, you will notice that the larger objects move up to the surface too. So this concept could be incorporated into the vibration settling device as a classifier using the same vibration motor too. Just a thought.

 

[solarsmith]

feed water from bottom up and the lower half of the vibration chamber shoul hold steal ball bearings sitting on top of a sreen or mesh. also you may want to look a a granger cataloge at the air powered vibrators rated for very large wts...thanks BRYAN IN DENVER COLORADO

 

[seawolf]

Hmm just a thought would this separate the fine gold wires from incinerated and crushed flat packs prior to acid digestion?
Mark