Objectif 1 To develop methods which can be used in the field of industrial hygiene to distinguish between authigenic and detritic quartz varieties in mixed dusts, and to analyse their surface aluminium content.2 To test the feasibility of these methods by analysing samples of mine dust taken from different grade workings.Analysis of surface aluminium in quartzTwo types of approach are possible. The first involves devising a means of extracting quartz from the other components of the mine dust without modifying the initial state of the mineral, and then of characterizing particles using classic spectroscopy methods (X-ray photoelectron spectroscopy, fluorescence spectroscopy using a molecule probe, paramagnetic electron resonance, etc.). The second approach involves exploring the possibilities offered by existing analytical techniques, and applying whichever one of these allows the surface of the quartz particles to be characterized without first having to separate off the other components of the mine dust.a) Developing a process for separating off quartz particles from the other mineral components of mine dustSeparation must be carried out in two stages: firstly, the quartz-bearing minerals must be separated from the coal/mineral mixture, then the quartz must be separated off from the other minerals. The first stage can be carried out in one of two ways: incinerating the dust is the easiest and quickest solution. Use could also be made of a low-temperature incineration technique involving oxygen plasma. This has a number of obvious advantages over air incineration at a higher temperature. The alternative method is to use a non-destructive physical method (density separation, agglomeration etc.); reference must be made to the various processes employed in the beneficiation or processing of suspensions containing coal particles before an exact choice can be made.During the next stage of the separation study, interparticle reactions will be brought into play by means of flocculation. At macroscopic level, flocculation of suspended particles produces different sedimentation rates, which can be assessed by turbidity tests or simple visual observation. Aggregation is then correlated with the wetting proeprties of the surfaces of the solid particles, with their polarity and with their hydrophobic/hydrophilic characteristics.Grain size characterization of the samples will be carried out using scanning electron microscopes.b) Prospects for analysing quartz particles within dustThese centre on spectroscopy techniques that allow the surface of particles to be analysed in great detail without the need to first extract these particles from the original powder. These techniques can be divided into two groups: 'microscopic' techniques, which gather information from a very small area of material, and 'global' techniques, which collect information from the surface as a whole.Microscopic techniques are based on electron energy loss spectroscopy (EELS), x-ray emission spectroscopy (XES), high-resolution Auger electron spectroscopy (AES) and high-resolution secondary ion mass spectroscopy (SIMS). These all use apparatus containing an electron gun, except SIMS which uses an ion gun.Global techniques combine X-ray photoelectron spectroscopy (XPS) and ion abrasion. Although XPS can only be used to analyse the surface as a whole, values for aluminium/silicon atomic ratios obtained before and after ion abrasion can be compared with data on the mineral composition of the dusts analysed.CathodoluminescenceCathodoluminescence is a technique currently being developed, and involves fitting a probe to a scanning electron microscope. Geological samples taken from various coalfields in France will first be used to develop the method, which will then be adapted to samples of airborne dust taken from the same workings. The quartz in these dust samples will be identified using elementary chemical microanlaysis, and its luminescence will then be measured. Programme(s) ECSC-MINEHYG 6C - Sixth research programme (ECSC) "Industrial Hygiene in Mines", 1990-1993 Thème(s) 3 - Dust measurement and determination of dust properties Appel à propositions Data not available Régime de financement Data not available Coordinateur INERIS PARC TECHNOLOGIQUE ALATA Contribution de l’UE Aucune donnée Adresse 60550 Verneuil-en-Halatte France Voir sur la carte Coût total Aucune donnée
