• To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Flotation.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

Deriving Flotation Tailing and Concentration Grade (4 replies)

Tony Verdeschi
12 months ago
Tony Verdeschi 12 months ago

I have encountered a problem for my project. I am working on mechanical flotation of barite and calculating its selectivity indices. I need to know how could I derive/calculate barite grade in both tailing and concentration for every flotation test without analyzing the products?
I was told there is a diagram (grade-density) for barite, so if I derive the density, I can derive the grade from the diagram. Is this approach correct?

Alan Carter
12 months ago
Alan Carter 12 months ago

Yes, if the gangue minerals have a different (known) density and this is consistent. You need to measure the density of the two product streams (or any two streams really but I suggest the products as they will have the lowest and highest densities and thus improve accuracy) - use a pycnometer to measure the densities - there are simple glass bottle types (with well known volume), or much fancier gas based devices.

Once you have the densities you also know the density can be derived from the mean density is the weighted harmonic mean when contents are mass based. Then
1. / Dmix = %barite / Dbarite + (100 - %barite) / Dgangue

%barite = 100 x (1 / Dmix - 1 / Dgangue) / (1 / Dbarite - 1 / Dgangue)

Yes there is a diagram, as this equation forms a linear plot between pure barite and pure gangue, just draw a line from the gangue's density on the left y axis (at 0% barite) to the barite density at a right Y axis (at 100% barite) - then you can read the proportion off at all intermediate densities - but again you need to know your gangue's density.

David Kano
12 months ago
David Kano 12 months ago

You can use Alan's equation but in that case the density of other minerals (Dgangue) is supposed to be constant. That is to say the mean density of gangue minerals is the same in concentrate and tailings.

If you can use the values from literature for barite density, it is more difficult to estimate the mean density of gangue minerals. You have then to measure the material density for feed, concentrate and tailings and calculate the material balance to estimate in the same time the barite contents and the gangue density. It is better to do that on many flotation tests (various operating conditions) over the same material and have a regression to reduce the uncertainty.

Paul Morrow
12 months ago
Paul Morrow 12 months ago

I use derivations of the same formulas, flipped over and resorted, to make them more convenient. I had to derive them myself starting with finding the volume of 100 grams of mix as an assignment back in college. It stuck with me since through some 40 years since.

Tony Verdeschi
12 months ago
Tony Verdeschi 12 months ago

Thank you guys

Please join and login to participate and leave a comment.