BS ISO 13605:2018 pdf download

BS ISO 13605:2018 pdf download.Solid mineral fuels — Major and minor elements in coal ash and coke ash — Wavelength dispersive x-ray
1 Scope
This document sets out a wavelength dispersive X-ray fluorescence (XRF) procedure for the determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium, manganese, phosphorus and sulfur. The method is applicable to coal ashes, coke ashes and boiler ashes having components within the concentration ranges specified in Table 1.
6.1 Crucible, made from a non-wetting platinum alloy.
The crucible shall have sufficient capacity to hold the flux and sample required for fusion. Normally, 15 ml crucibles are adequate for discs of 32 mm in diameter, and 25 ml crucibles for discs of 40 mm in diameter. NOTE Either platinum/gold or platinum/gold/rhodium alloys are suitable. Because the crucible and lid (if used) are to be used for fusion work, the normal precautions associated with the care of hot platinum ware should be observed. It is necessary, therefore, to have suitable tongs and a surface on which to rest the crucible. The hot crucible can be rested on a refractory surface, which shall be kept very clean. Although the crucible is fabricated from an alloy that is not wetted by the glass, for the greatest precision, the crucible should be cleaned between each fusion. The use of citric acid (mass concentration of 20 %), dilute hydrochloric acid (volume fraction of 10 % to 50 %) or dilute chlorine-free nitric acid (volume fraction of 10 %) have proven to be suitable for crucible cleaning. The use of an ultrasonic bath will accelerate this process. An alternative method of cleaning is to fuse several grams of flux in the crucible, moving the melt around so as to clean the entire inner surface. The molten flux is poured from the crucible. If a droplet adheres to the crucible, this can easily be flaked off when the crucible is cold.
6.2 Mould, made from non-wetting material. For example, platinum alloy is commonly used for casting discs, and aluminium or graphite is suitable for press quenching. In the casting technique, the bottom of the disc is the analytical surface. The mould should therefore be flat and sufficiently thick that it is not easily deformed. Casting moulds should be checked regularly for flatness and should be polished regularly, to ensure that the disc releases from the mould. Platens for press-quenching are constructed so that the depth gradually increases from the perimeter to the centre. The analytical surface for press-quenched discs is the surface which contacts the plunger head. Care should be taken not to choose the platen side for intensity measurements.