Automated Mineralogy Research Papers - Academia.edu (original) (raw)

Increasing competition in the minerais industry and fluctuating coramodity prices require new ways of saving energy, lime, and general operational costs. A good understanding of physical processing or pre-processing streams that can potentially cut these costs requires detailed analyses of chemical and physical behaviours and processing responses during rainera]. processing. It is very useful to perform a detailed mineralogical and micro-textural characterization of materials (ore, tailings, and waste) that addresses, among other parameters, particle and grain sizes, as well as particle densifies. The choice and/or corabination of the 'best' processing approaches is crucial for processing efficiencies, and can be established and verified by using automated mineralogy with the associated software. A sample of low-grade iron ore from El Volcan, Mexico, serves as an example to demonstrate in a step-by-step approach how QEMSCAN® analyses provide processing information. Elements under consideration include iron, phosphorus, and sulphur.

The analysis of archaeological ceramics has rapidly evolved over the last decades by the application of new analytical techniques. An emerging analytical proposal to fully characterise archaeological ceramics using automated SEM mineralogy is presented. A case study is provided of sets of ceramics from the San Pedro de Atacama oases in the Atacama Desert, northern Chile. Ceramic fragments of different typologies (i.e., Los Morros, Loa Café Alisado and San Pedro Negro Pulido) found in the Ghatchi archaeological sites are analysed. Our results include automated mineralogical maps, which are used to define the components that form the ceramic pastes, i.e., clay matrix and non-plastic inclusions, as well as grain size and mineral abundance information. We show that the pastes that define the studied ceramic types are more complex than previously suggested. The overall composition for these pastes corresponds to clay mineral-rich matrices containing non-plastic inclusions, such as mineral grains, crushed ceramic fragments, and sedimentary to igneous rock fragments, that may vary in composition, size, and abundance among the studied ceramic types. This mineralogical information allows us to discuss possible sources of raw materials by comparing these paste components with geological information. Here we interpret Los Morros and Loa Café Alisado as foreign ceramic types to Ghatchi, whereas the San Pedro Negro Pulido fragments found in this site agree well with the pottery paste recipe typically recognised in the San Pedro de Atacama oases. The petrographic-approach employed here supports the automated SEM mineralogy as a valid option for archaeometric studies of ceramic pastes since includes precise quantitative data formulated from the chemical composition of each component of the paste, which may provide valuable evidence into raw materials and technological styles.

Mineral quantifications are challenging on Ni-laterites: XRD analyses provide useful information on mineral species present in samples but with limitations in the precise quantification of complex mineral assemblages containing different particle and grain sizes. The quantification of clay mineral rich samples presents particular challenges as described by Pevear (1989) and Reynolds (1989). Automated-SEM systems including MLA, Qemscan, and TIMA show also limitations with respect to the distinction of Mg-silicates with close chemical compositions (olivine, serpentine, talc, nontronite, saponite, pyroxene,…). MLA and Qemscan, and the associated software, provide analytical results as count proportions acquired by their respective detectors. These results are presented as element wt%. It should be noted, though, that these results are far from precise and need to be laboriously calibrated and converted in order to ascertain precise element wt% information that are necessary to calculate a structural formula of a mineral. The Mineralogic system allows very fast EDS analyses that provide element and oxide analyses that are acquired from Zeiss SEM analyses and are presented as precise element and oxide wt%. This Mineralogic methodology is a step change to methods employed by QMESCAN, MLA and TIMA. Mineralogic allows for each acquired EDS spectrum to have a matrix correction and peak deconvolution applied before a spectrum quantification. This methodology thus allows for accurate and precise elements quantification, which is subsequently classified using the designed mineral library. In contrast to MLA and Qemscan systems, Mineralogic data can be directly used to establish precise phase compositions, structural formulae, and to even distinguish mineral phases of very similar chemical compositions. The Mineralogic system enables the user to group mineral populations of minor chemical variation. The distinction and quantification of clay minerals and minerals that are grouped within the smectite group is only one field of application. An extensive database is currently under construction that allows a high-precision identification and distinction of minerals including those that were hitherto regarded as problematic with respect to their identification and, even more, quantifications.

- by Simon Blancher
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- Geometallurgy, Nickel Laterite Ore Processing, Automated Mineralogy, Mineralogic