Sciencemadness Discussion Board

Separating fine clay from H2SO4 leach

Gammatron - 18-9-2022 at 14:51

Most of my chemistry involves extracting metals from ore which means grinding the rocks into a fine sand and leaching with carbonate or acid. However, separating kilograms of clay from liters of solution is a long and difficult process as the particles are so fine that any disturbance mixes them into the solution so decanting all of the liquid is near impossible and filters are clogged immediately. In industry they use flocculants which would be fine for carbonate leach but I'm trying to find something that will work with H2SO4. I made some Al2(SO4)3 which did help things to settle quicker but it's still so fine that it flows out with the water when I try to decant. Does anyone have any techniques for doing such separations?

This question also applies for purified products such as yellowcake which I want to avoid adding chemicals to, normally I just decant what I can several times and then filter multiple times as the fine particles can pass through. This usually takes several hours or days of waiting on settling and slow filtering.

[Edited on 9-18-2022 by Gammatron]

Rainwater - 18-9-2022 at 15:35

Quote: Originally posted by Gammatron  

However, separating kilograms of clay from liters of solution is a long and difficult process as the particles are so fine that any disturbance mixes them into the solution so decanting all of the liquid is near impossible and filters are clogged immediately.

Google slush barrel.

So the idea is you don't separate the clay from the rock, you separate the rock from the clay. By controlling the crush size using mesh, and using water to remove soluble materials, all the rock/sand/heavy metals fall.

Im small scale, 100lbs at a time. My setup takes up 12 sq feet and a 120v outlet.
A ball mill with 50, 100, 150, 200 mesh screens. And a 1/4hp pump

I start big with 50 mesh material.
Use a pump and two large trash cans and circulate water from your ore can, overflowing into your settling can.
The high-pressure flow is directed into the bottom of the ore can, disturbing the material and flushing out the clays and low-density materials, mica. Organics

After this washing step, the ore is then crushed to 100 and repeated.
Quote:

Does anyone have any techniques for doing such separations?


Yes, no, maybe.
Never leached any ore, not cost effective for me, but as for filtering the impossible, you basicly have 3 options.

Belt filters (expensive amd huge)
High pressure filtering (dangerous if not properly implemented and a hassle in general)

Centrifuge (I've never done before)

Gammatron - 18-9-2022 at 16:20

Googling "slush barrel" brought up results for slushy machines?

Sounds like you got a pretty serious set up going on. What kind of ores do you process? I mainly work with uranium, the initial leach contains the U which I am mainly after but the left over mud also contains all the decay products which I also want to recover and concentrate. Because both the solution and remaining mud have products that I want to recover and I don't have a lot of ore it requires a pretty good separation.

I have pondered the idea of building a centrifuge that can work with at least a liter at a time. I have a lathe and metalworking tools so it wouldn't be terribly difficult to build, just has to be real sturdy.

Rainwater - 18-9-2022 at 16:31

Sorry.
sluice barrel. Just like a sluice box, but with a barrel. Not sure where i got slush from. I got the setup when i was extracting clay for pottery.
I was throwing the sand and rock left over away. When i started refining gold, i just reused what i had. And reversed what was waste.

Gammatron - 18-9-2022 at 18:31

Lol all good, I understand now. I originally would have been fine tossing the left over sand but now that my chemistry is a little more advanced I want to try exacting the decay products that are left in it, namely radium as it is a powerful alpha emitter.