Morphology of slags components by scanning microscopy

1. Morphology of slags components by scanning microscopy

2. Glaze Glaze is themain component of slags. Slags originating from the direct production of a metallurgical furnaceare rich in isotropic glaze with a smooth, uncracked surface. As a result of a devitrification process, glaze is covered with a lattice of cracks, which with the flow of time become larger causing its disintegration and occurrence of an amorphic substance. Isotropic glaze surrounded by iron oxides Transmitted light, magnification 100x, crossed nicols Concentration of elements [Mass%] – example

3. Glaze Fot. XN, 100x Glaze with hematite and magnetite Transmitted light, magnification 100x, crossed nicols

4. Glaze In the glaze there are metallic precipitations and crystalline nuclei of non-metallic phases. Fot. XN, 100x Glaze surrounded by metallic precipitations Reflected light, magnification 100x, one nicol Crystalline nuclei of melilites Transmitted light, magnification 100x, one nicol

5. Drops of metal Metallic precipitations form individual drops of pure metal or they appear in the form of polymetallic aggregates. In slags after the production of iron and steel they are first of all connected with iron concentrations, in slags after zinc and lead metallurgy metallic precipitations are rich in Zn and Pb, only sporadically silver drops can be found in them. Drops of iron SEM microphotography, scanning microscopy Drops of zinc BSE microphotography, scanning microscopy

6. Metalsare present in glaze, they form: inclusions in theother minerals, their own minerals (magnetite, hematite) and metallic aggregates and they are also present in the structure of other minerals (augite, mellite). Pyroxenes with inclusions of metals Transmitted light, magnification 200x, one nicol Quartz with cracks filled by metalic precipitations Transmitted light, magnification 100x, crossed nicols

7. Oxide phases identified in steelmaking slags include principally a number of iron oxides from wustite FeO, through magnetite Fe3O4 to hematite Fe2O3 and sporadic occurrence of goethite FeOOH.

8. Magnetite Hematite Iron oxides Wustite

9. Wustitecreates globular forms. Such a form of wustite is created through the oxidation of iron and by assuming by this phase morphological forms characteristic for the liberation of metals. Transmitted light, magnification 200x, one nicol SEM microphotography, scanning microscopy

10. Magnetite In the waste material we can distinguish two generations of magnetite. First generation is represented by the sharp grains characterized by the square section. Its were crystallized with the other minerals during the alloy self cooling . Second generation is represented by fine grains often mixed with the other compounds of the wastes. This generation was formed as a result of devitrification of glaze or silicate phases. Transmitted light, magnification 100x, one nicol

11. Hematitecan form several generations, from very fine grains dispersed among other phase components to larger, sharp-edged crystals. Yet, they are always characteristic of red-brown colouring, fine grains form pigment providing the glaze with red colouring. Transmitted light, magnification 100x, one nicol