There are a few options depending on your question. XRD is the standard tool for identification, and with the right expertise can produce quantitative results. Infra red is also useful with potential for high volume measuement of drill core with spectral loggers, and opportunity to link metallurgical metrics to the spectra through pls modeling (a well established but under-utilized technique). Happy to elaborate further if more specifics are needed.

I'm aware of the procedure and semi quantitative results obtained by XRD. I guess the infrared technique with which you refer is the mineralogical analysis by VIS/NIR spectrometry. I'm more concerned about SEM with QEMSCAN or TESCAN and how all this information could be linked with a real process.. How could be useful? Thank you very much for the support.

In regard to automated SEM, clays are tricky due to their fine size relative to the interaction volume of the electron beam (~ 5um), and other potential issues. So, rather than the distinctive signature expected for most minerals, clays can be ambiguous in their identity. To gain increased confidence in the results, I would recommend calibrating the A-SEM data for respective sizes with Quantitative XRD. There are some micro-IR mapping techniques that could complement this, but I only know of one instrument (in Melbourne) so access might be difficult for routine testing.

Understanding the composition of clay minerals in the block model can be a very powerful tool for operations where rheological issues have an impact on processing. The presence of swelling clays can impact slurry density and lead to excessive crud formation in solvent extraction, hence knowing that they are there can allow for mitigation measures to be implemented. One of the big advantages of modelling clay distribution early in the process is that blending strategies can often be developed to reduce or eliminate the problem, without the need to capital intensive engineering solutions.

The High proportion of clay minerals as talk. chlorite, limonite, etc in the deposit will negatively impact the following operations:

- The milling by increasing the slimes generation.

- The flotation by contaminating the concentrate.

- The settling and filtration.

- Etc.

Consequently, the operating cost will be increased and the recovery affected.

Chemical and mineralogical characterization of clays is the first step to know what kind of clays you have (1:1 ; 2:1) according with this you define potential uses, also it is important to know the particle size distribution.

You can get a lot of caly's mineralogy and granulometry data looking to ceramic and light weight aggregate sites.

A clay is defined by size : less than 2 micron (geologists) or 1 micron (colloid chemists). There are four types of clays, kaolin (kaolinite, dickite, halloysite and nacrite), smectite (montmorillonite and nontronite), illite and chlorite.

So sizing and mineralogical identities would be important as initial characterisations.

There-after it depends upon the application and the separation. In flotation, clays are recovered in variable amounts to the concentrate due to entrainment while smectites swell with the addition of water.

Depending upon the application and the proportion of the clays present, desliming can be used while dispersants and low solids densities are employed to minimise their 'effects'.

Illite and chlorite are the main concentrate diluents that I have experienced in flotation while in heap leaching I have encountered the troublesome kaolins and smectites.

Be interesting to hear what people have done to minimise the impact of these clays.

Please specify what exactly is the problem and you want to achieve. Clays affect different mineral recovery processes in different ways as brought out by Mr. Andrew. Thus while in iron ore processing desliming could be effective, in base metal floatation one may need pulp density adjustment, addition of special reagents or even multi staging. In silica sand processing for glass grade or foundry application,clays sometimes are valuable by-products and need to recovered to the maximum possible extent. So it is necessary to understand your requirement.