Particle-Size-Analysis of fine-comminuted tin ore

My big announcement!

First particle-size-analysis on an ore I have comminuted in my rod-mill!

I will return to explaining the meaning(s). Before that...

Getting there...

To now...

Specific to the ore featuring here...

"Stats" about the ore

Specifics

Do "deslime"

I was advised:

Another very pragmatic reason to "deslime"...
If you are going to sieve, performing sieve-analysis as particle-size-analysis, you must remove the fines else you will be choking on dust as you try to sieve (if done dry) - and that dust contains a predominantly silica, all recently fractured (not weathered at all - if that makes a difference?) - which is a severe hazard.
Have "slimes" - very fines - in the comminute and that becomes far further worse...

So: "deslime".

"Decantation" to "deslime"

What I do is a scaled-up version of "beaker decantion", and it works.
It looks crude; uses much increasing more water as your "cut" gets finer (you cannot re-use the water quickly, as the very-fines don't sediment out quickly enough in a day and quick re-use would re-introduce what you most want to remove); is time-consuming; and you get wet(!).
But yes it works and tentative indications are that it is accurate (in the "granite" tests where the Stokes' calculation said 10 seconds wait and did give 100% sieve pass of opaque turbidity supernatant, a 6 second wait resulted in some above-75micron on the sieve - whether that accuracy is maintained at smaller sizes is unverified).

As mentioned - specifying the outcome of decantation comes from applying Stokes calculations

My "cut" is at a Stokes sedimentation velocity of 1.3mm/s.
Being in water, this should give a "cut" at

given their different densities.

The ratio of sizes at the "cut" is to-advantage

Deflocculation

Taking this on-trust at the moment - "control tests" I could do to observe the effects are yet to be done.
I have observed "hindered settling" - it is vastly slower than "Stokes settling" - in the supernatant after vigorously stirring ore-in-water ("slurry") when the deflocculants tried were present - which I have not observed before. Promising... Comparison with a control of "untreated" comminute is one "control".

The amounts needed per small masses of ore are so small that I made-up "stock-solutions" and used a small syringe-barrel to dispense millilitre dosant quatities.

What is displayed, and what is seen

Redisplaying the plot:

A caution - my weighing-machine is accurate to only 1g - not fine enough for any differences to be seen to have significance.
These are rough tests using crude means; there is no case to use sophisticated expensive equipment - and these tests have got done...

Observations

Detailed dicussion(s)

Validity of "sub-sieve" and "decanted" positions on the horizontal axis:
Stokes calculations specify the decantation to "cut" at 38microns quartz - so the decanted supernatant *should(!)* 100% pass a 38micron sieve had one been available.
Hence the solids in the supernatant decanted are put at the next sieve size down in the "halving" series.
The justification begs proof that assumptions are holding-true.

Overall...

At the time of writing (afternoon of Tuesday 17 March 2026) I am pleased. I am obtaining data by sieve-analysis, processing it, and graphing the data using "scripts" in a "unix toolkit" working-environment on a computer.
Which hopefully means that new data can be processed through the same "pipeline" (that is a recognised term working at a "unix" command-line environment).

On the computation side - with the data being text-table files, and the processing being via "scripts" picked-up by the familiar "unix-environment" programs, the files to store are very small and easy to retain. Also the "unix toolkit" programs have remained unaltered at the user-interface in time over decades, so compatibility in time has never proved a problem.



(R. Smith, 16Mar2026 to 17Mar2026)