Thursday, 11 February 2016

What is a mineral processor?

The importance of mineral processing is taken for granted (at least by mineral processors), but it is interesting to reflect that only a century ago ore concentration was often a fairly crude operation, involving relatively simple gravity and hand-sorting techniques developed by mining engineers.
Workers on a 19th century Cornish tin mine, by the rag-frames which were used to concentrate the ore.
The women, or 'bal maidens' were often employed to hand sort the ore
The 20th century saw the development of minerals engineering as a serious and important professional discipline in its own right, and as available ore becomes leaner amd more refractory, and with the need to produce 'new metals' such as the rare earths, the importance of mineral processing ever increases. In fact I have argued before that it is probably the world's most important technology, as without it production of the metals essential to a modern society would be hopelessly uneconomic.
But how do we define mineral processing? This is a question that Lois Finch asked delegates at November's Flotation '15 in Cape Town, as part of a survey for this years IMPC in Canada, chaired by her husband Jim. The definition evolved as she interviewed delegates, and was further refined at this month's Canadian Mineral Processing Conference in Ottawa into:
"Mineral Processing is the discipline of liberation, separation and concentration of valuable minerals from their ores to produce essential products in an economical, efficient and safe manner that is environmentally and socially responsible."

Lois feels that this might be further refined, so your comments would be welcome.

Twitter @barrywills

13 comments:

  1. (A) 'Ore' may not be correct to use-
    'ore' is something from where element or metal can be extracted economically but a change in technology can make something a waste rock to ore or tailings can be source of element recovery.
    So the work carried out using these things will also be part of mineral processing.

    (B) Some work on utilization of ores ore minerals will also be part of mineral processing such as agglomeration, transportation, etc.

    I think given definition do not cover these areas.

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    1. 'Ore' was not in some of the first definition attempts. We recognize that mineral processing techniques are applied to other sources, such as tailings and solid wastes in general. That mineral processing techniques are used does not necessarily make them candidates for inclusion in the definition, on top of making it unwieldy. Nevertheless the point is taken.

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  2. what about chemical processing of the ore/waste rock/tailings such as leaching that is direct extraction of the metals from the ore? is it in the mineral processing discipline or not?

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  3. Good question. Definitions have always been a bit vague. I have always equated mineral processing to the physical separation of minerals from gangue, by flotation, gravity etc. Chemical means of extracting the metals from the minerals is extractive metallurgy. Grouped together I define mineral processing and extractive metallurgy as minerals engineering.

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    1. I tend to agree with MEI, restricting to physical processes. Some have argued for the words 'physical separation' to be in the definition, partly to distinguish from extractive metallurgy which involves breaking chemical bonds.

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  4. In fact we are neither do processing or engineering of minerals; for me we are doing "ore dressing" which is the age old title used; Let me make it more clear--"coal washing/coal preparation" clearly indicates that we handle coal as mined and wash it to get the grade. I wish we use "ore dressing" but perhaps many are not familiar with the definition of ore, we shifted to using mineral preocessing; may be to make engineers understand we started calling it mineral engn.
    Rao,T.C.

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  5. In practice, mineral processing or 'dressing' as T.C. Rao has noted, is much broader in application and now encompasses on-site hydrometallurgical processes such as leaching (tank or heap - cyanide as well as removal of concentrate impurities - e.g. galena from molybdenite concentrates at Henderson, leaching of calcite from tungsten concentrates, removal of silica and sulphides from graphite concentrates, etc.), which is more than the application of physical processes to achieve separation between selected minerals as noted by Anonymous.
    Also as noted, so-called conventional mineral processing/dressing encompasses comminution,separation - employing the various methods at various stages of the flowsheet cf. pre-concentration, dewatering - thickening, filtration, agglomeration, etc. - and no doubt more.
    Moreover, based on the recycling practices which are developing some momentum in Europe and employ mineral processing techniques, the term 'ore' needs to be broaden to include materials containing economic bearing species, which includes minerals, alloys, metallic phases (technically all minerals)- again along the lines by Anonymous.
    The final point is that mineral processing/dressing is also applied to materials for other reasons such as environmental...such as removal of pyrite from flotation tailings for separate impoundment and management, and the Key Lake uranium processing operation, which besides producing yellowcake, also addresses and 'fixes' the arsenic and nickel contained in Key Lake mining waste materials and McArthur River ores.
    Looks like I am going to be identified as Anonymous too!
    Andrew Newell
    RPM

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    1. The comments from TC and Andrew have a common theme, the word 'ore', one restricting the definition to it, the second expanding to other resources. While I'm not sure that using min pro techniques qualifies recycling etc as mineral processing I suspect we will have to broaden as the user community keeps coming back to this point. Expansion to include chemically-assisted separations is also getting some traction. However, having just finished edition 8 of the Wills classic text I shudder at trying to cover chemical metallurgical aspects as well in a single volume.

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  6. Mineral processing is the use of fluid dynamics and particle dynamics in order to separate one particle from other particles.for example magnetics from non magnetics, hydrophobic from hydrophilic ,conducting from non conducting etc..
    Regards
    Vikram jena

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  7. What I would advocate is the dropping of the generic term 'metallurgist' to describe anyone involved with mineral processing and extractive metallurgy. I graduated in metallurgy, but my degree was in physical metallurgy, which is the science of the properties of metals and alloys.

    We are Minerals Engineers, and Minerals Engineering encompasses mineral processing and extractive metallurgy. I would define mineral processing as the liberation and separation of mineral assemblies by physical means (comminution, gravity, magnetic, surface properties etc) and extractive metallurgy as the release of metals from minerals by chemical means (hydrometallurgy, electrometallurgy and pyrometallurgy).

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  8. Thanks to MEI and text book titles and contents, we know what one means when he says "Mineral Processing/Mineral Rngineering" and so let us not try to dissect too much. Hydrometallurgy/extractive metallurgy have been there on their own and so let us leave them as such.
    But I would still say that a good mineral engn should know the classical definition of "ore" and "mineral" because the techniques we use in beneficiation depend on the characteristics of ore and minerals therein.
    Rao,T.C.

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  9. Processing comprises of size reduction, liberation / opening up of surfaces, separation either by physical, physico-chemical and chemical means and further treatments like size enlargements, extraction yielding valuable usable products. This is carried out on minerals, fuels and wastes mostly solid particles. Processing of above materials mostly minerals, fuels and solid wastes producing a host of products with almost nil waste,with optimum profit in a safe environmental economic mode, as we have not inherited them but we owe them to next generations of life.

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  10. Let us start from the beginning--a rock is termed an ore if valuable minerals can be separated at the market conditions and with the technology available at that time. Then the ore, which comprises of wanted and unwanted minerals, is subjected to various physical processes to get a concentrate; of course we have to deal with the tailings we get. We may then extract the metal from the concentrate by various methods. Many times ores themselves may be treated (bio leaching etc) to directly extact the metal without going through physical separation.
    My intention of writing the above is to say that mine to metal is a wide canvas and lot of innovations are required at each of these steps.
    My apologies if I stated the obvious.
    Rao,T.C.

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