Table 2 Interpretive source/material categories to which grain populations have been assigned, together with diagnostic or common true phase assemblage and translation to PARC groups (as listed in Table 1)

1

Converter slag^a

C2S/C3S + Mg-wustite + C2(A,F) ± lime/portlandite ± Fe-metal; weathering products of C2S and C2(A,F) with apparent enrichment in Al, P; oxidation products of Mg-wustite incl. magnetite solid solution

{Si, Ca} + {Mg, Fe} + {Ca, Fe)/{Al, Ca, Fe} ± {Ca} ± {Fe} mixing (specifically {Mg, Ca, Fe}); {Al, Si, Ca}, {Si, P, Ca}

2

Slopping-/rapid-quenched converter slag^b

Ca–Mg-olivine ± C2S/C3S ± Mg-wustite ± C2(A,F)

{Mg, Si, Ca} ± {Si, Ca} ± {Mg, Fe} + {Ca, Fe}/{Al, Ca, Fe} + mixing

3

Iron-ore sinter (sintered material)—high confidence^a

SFCA(-I/-II)/CF2/CF/CWF/C2(A,F) + FeOx (hem/mag) ± C2S/Ca–Mg-olivine/C2AS-C3MS2

{Ca, Fe} + {Fe} ± {Si, Ca} ± {Mg, Ca, Si} + mixing

4

Iron-ore pellet (fired material)—high confidence^a

FeOx (hem/mag) + variable lower-Ca-silicates than in sinter (original and reacted gangue) ± Mg-ferrite ± minor C2(A,F)/CF/CF2

{Fe} + {Si, Fe} ± {Mg, Fe} ± {Ca, Fe} + {Si, Ca, Fe} + mixing

5

Iron-ore sinter/pellet, including unreacted ore^a

Unreacted ore—FeOx (hem/mag) + diverse minor silicates; Undistinguishable relict ore particles—FeOx (hem/mag) + low abundances of (3) and (4) phases

Dominantly {Fe} ± lower abundance groups from (3) and (4)

6

Fe/FeOx particles with > 5% Zn-compound^b

High Fe/FeOx/FeO(OH) + Zn-oxide/Zn–Fe-oxide

High {Fe} + {Zn (La)}/{Zn (Lα), Fe}

7

Fe/FeOx particles with significant metal—including metal slivers^a

High Fe/FeOx of which a significant portion Fe-metal

High {Fe} with attendant {Fe, Fe (Kβ)} (probable Fe-metal pixels)

8

Rich in Zn-compounds—including Zn-rich scrap^a

High Zn-oxide/Zn–Fe-oxide/Zn-miscellaneous oxide

High {Zn (Lα)}/{Zn (Lα), Fe}

9

De-sulphurisation process material—potential^b

MgO + spinel (MgAl₂O₄)

{Mg} + {Mg, Al}

10

Ca-aluminate-rich steelmaking slags (giethalslak)^b

Rich in Ca-aluminates CA3/CA2/CA/C12A7/C3A ± lesser C2S ± other Ca–Al-silicates ± MgO ± spinel

{Al, Ca} ± {Si, Ca} ± {Al, Si, Ca} ± {Mg} ± {Mg, Al} + mixing

11

Dolomite (flux) or partly reacted residue thereof^a

Dolomite or thermal decomposition/weathering products thereof

{Mg, Ca} ± {Mg} ± {Ca}

12

Mg-(hydr-)oxide ± sulphate: residue after dolomite flux and potential refractory material^a

MgO/Mg-hydroxide ± intimately intergrown sulphate concentrated at rim/surface of particle

{Mg} ± {S}/{Mg, S}

13

Mg-rich olivine: likely flux, iron-ore sinter/pellet process^a

Mg-rich (forsteritic) olivine, lacking associated MgO

{Mg, Si} without abundant {Mg} in same particle

14

Olivine-MgO: potential tundish gunning mass^b

Mg-rich (forsteritic) olivine, with associated MgO

{Mg, Si} with abundant {Mg} in same particle

15

Alumina-bearing particles: source unclear

Particles containing or dominated by alumina (corundum)

{Al}

16

Ca–Al-silicate dominated: source unclear

Particles dominated by Ca–Al-silicate

Dominantly {Al, Si, Ca}

17

Ca-carbonate/hydroxide/oxide dominated: potential flux (iron-ore sinter/pellet, steelmaking processes)^a; weathering products of (converter-)slags^a; naturally occurring

Dominated by Ca-carbonate (calcite) /hydroxide (portlandite) /oxide (lime)

{Ca}

18

Silica + Ca-silicate-hydrates + Ca-hydroxide/-carbonate: potential cement/building material^c

Silica + Ca-silicate-hydrates + Ca-hydroxide/-carbonate

{Si} + {Si, Ca} ± {Ca}

19

Gypsum/anhydrite rich: potential building material, other sources unclear^c

Gypsum/anhydrite rich

{S, Ca}

20

Ti-oxide particles: source unclear^c

TiO₂ (rutile)

{Ti}

21

Ti-rich paint^c

Ti–Al-silicate

{Al, Si, Ti}

22

Qz–clay–fsp–mica, natural as well as potential iron-ore gangue component^c

Particles dominated by one or more of quartz (silica), clay minerals, feldspars, micas

Dominantly ± {Si} ± {Al, Si} ± {Na, Al, Si} ± {K, Al, Si} ± {Mg, Al, Si}

23

Chloride particles or gt50% of surface covered: sea-salt and surface covering/alteration of other particles^c

Dominantly salt (NaCl), artefact pixels from mixed signal of thin salt layer over variable substrate (particle surface)

Dominantly {NaCl} ± {Cl} ± {*, Cl, *}

24

Coal and cokes (minimum estimate)^b

Carbon rich with ash phases

High {empty spectra} + {Si} ± {Al, Si} ± {Na, Al, Si} ± {K, Al, Si} ± {Mg, Al, Si}

25

Undifferentiated carbon-rich material: may include graphite flakes, organic carbon-based materials and diverse sources

Carbon rich with or without other non-C phases

High {empty spectra}

26

Unassigned grains with lower carbon content

-

-