Skip to main content

Table 3 Key to grain populations shown in the flow-chart in Fig. 5, showing brief descriptions of diagnostic (mineralogical) characteristics and preferred interpretation per population

From: A method for analysis of nuisance dust from integrated steel works: chemical and mineralogical characteristics of contributing sources

ID

Population's key phases/characteristics

Preferred interpretation

Source/material ID

w

 < 15% Fe/FeOx: Ca-silicate with Ca–Al-silicate or P-rich Ca(-Mg–Al)-silicate

Weathered converter slag

1

x

As above, with > 5% sulphate

Weathered converter slag; additional covering of sulphate phases on surface

1

y

 < 15% Fe/FeOx: Ca-silicate ± Ca-(hydr)oxide/-carbonate with sum of both > 40%

Converter-slag particles rich in C2S, C3S and Ca-hydroxide/-carbonate

1

z

As above, with > 5% sulphate

As above, with additional covering of sulphate phases on surface

1

aa

 < 15% Fe/FeOx: Ca(-Al)-ferrite with apparent Mg–Ca–Fe-oxide from Mg–Fe-oxide + Ca-ferrite mixed pixels

Converter-slag particles rich in brownmillerite intergrown with Mg-wustite (and the latter’s finely intergrown oxidation products)

1

ab

As above, with > 5% sulphate

As above, with additional covering of sulphate phases on surface

1

ac

 < 15% Fe/FeOx: Mg–Fe-oxide with apparent Mg–Ca-Fe-oxide from Mg–Fe-oxide + Ca-ferrite mixed pixels

Converter-slag particles rich in Mg-wustite (and its finely intergrown oxidation products)

1

ad

As above, with > 5% sulphate

As above, with additional covering of sulphate phases on surface

1

an

 > 20% total Ca-ferrite + Ca(-Fe)-silicate, < 2% FeOx, with apparent Ca-aluminate pixels (probable aluminous brownmillerite)

Converter-slag particles rich in brownmillerite

1

v

 < 15% Fe/FeOx: Ca–Mg–Al-silicate with Ca-silicate

Possible converter slag, rapidly cooled

2

q

Ca-silicate with > 15% Ca–Mg-silicate

Rapidly cooled converter slag—possible slopping material or formed during discharge of slag into cooling pits

2

ao

 > 20% total Ca-ferrite + Ca(-Fe)-silicate with > 2% FeOx

Sintered iron-ore material, rich in Ca-ferrites (chiefly SFCA and SFCA-I) and/or C2S

3

aq

 < 20% total Ca-ferrite + Ca(-Fe)-silicate, with low apparent Fe-silicate

Probable sintered iron-ore material with 1–20% Ca-ferrites (chiefly SFCA and SFCA-I) and/or C2S

3

ai

FeOx with apparent Fe-silicate (including with minor Na, K, Al below peak threshold), < 1% Ca-ferrite

Probable pelletised iron-ore material with highly silicic secondary silicate formed from reaction of ore gangue and FeOx during firing

4

aj

FeOx with Mg–Fe-oxide (probable Mg-ferrite), < 1% Ca-ferrite

Probable pelletised iron-ore material with Mg-ferrite-rich spinel solid solution phase formed by reaction with Mg-flux during firing

4

ap

 < 20% total Ca-ferrite + Ca(-Fe)-silicate, with high apparent Fe-silicate

Probable pelletised iron-ore material with highly silicic secondary silicate and Ca-ferrites or Ca–Fe-silicate: limestone-fluxed pellets only

4

r

Mg–silicate (probable olivine) with Ca-ferrite ± Mg–Ca-silicate

Partially reacted Mg-olivine (forsterite) flux in sintered or pelletised iron-ore material

5

ah

Apparent Ca–Fe-silicate (including mixed FeOx—Ca-silicate pixels) or Mg–silicate with < 5% FeOx and < 1% Ca-ferrite

Rare sintered ore particles

5

al

 > 80% FeOx, < 1% Ca-ferrite

Most commonly iron-ore particles with little adhering/intergrown binding matrix from sintering or pelletising process; also potentially oxidised metal/scrap

5

ak

FeOx rich, < 1% Ca-ferrite

Most commonly iron-ore particles, potentially with intergrown/adhering gangue phases

5

am

FeOx dominated, < 1% Ca-ferrite, Zn(-Fe)-oxide > 5%

FeOx dominated particles with significant content of Zn-oxide or Zn-Fe-oxide phase: potentially ore (agglomeration) material or Zn-rich scrap

6

ar

Possible Fe-metal bearing, < 1% Ca-ferrite, > 80% Fe + FeOx

Likely Fe-metal bearing particles/metallic slivers

7

as

Possible Fe-metal bearing, < 1% Ca-ferrite

Likely Fe-metal bearing particles/metallic slivers

7

at

Possible Fe-metal bearing with Ca-ferrite or Ca-silicate

Likely Fe-metal bearing particles/metallic slivers

7

e

Zn-oxide/Zn–Fe-oxide with FeOx/Fe

Particles rich in Zn-oxide/Zn–Fe-oxide: possible Zn-rich scrap

8

f

Zn-oxide/Zn–Fe-oxide

Particles rich in Zn-oxide/Zn–Fe-oxide: possible Zn-rich scrap

8

o

Mg-(hydr)oxide/-carbonate with Mg–Al-spinel

Possible de-sulphurisation process material

9

af

Ca-aluminate rich

Ca-aluminate rich slags from steelmaking processes

10

ag

Ca-aluminate with Ca–Al-silicate with sum of both > 60%

Ca-aluminate rich slags from steelmaking processes

10

n

Dolomite/burnt-dolomite bearing

Particles containing (burnt-)dolomite flux or thermal decomposition products thereof: iron-ore agglomeration and steelmaking processes

11

p

Mg-(hydr)oxide/-carbonate ± sulphate/sulphide

Combination of (at one time) MgO + sulphate is characteristic of partially reacted dolomite flux in iron-ore agglomeration; potentially also refractory material

12

l

 > 60% Mg-silicate: probable forsteritic olivine

Most commonly Mg-olivine flux used in iron-ore sintering and pelletising

13

m

 > variable threshold % Mg-silicate: probable forsteritic olivine (set here to 60%)

Most commonly Mg-olivine flux used in iron-ore sintering and pelletising

13

k

Mg-(hydr)oxide/-carbonate with Mg-silicate (probable olivine)

Possible tundish gunning-mass material: diagnostic phase combination of Mg-(hydr)oxide + Mg-olivine

14

ae

Al2O3 or Al bearing

Commonly alumina-dominated particles, otherwise alumina-bearing; encountered in iron-ore sinter reference materials but origin unclear

15

s

Ca–Al-silicate rich

Coherent population of particles dominated by Ca–Al-silicate pixels; unclear origin, speculative relationship with weathered converter slag

16

t

Ca-(hydr)oxide/-carbonate rich

Particles rich in Ca-(hydr)oxide/-carbonate lacking C2S or other Ca-silicates, Ca-ferrites and FeOx: potentially lime(stone) flux, particles of converter slag fully covered in a carbonate layer, as well as natural carbonate material

17

u

Ca-(hydr)oxide/-carbonate rich with Ca-ferrite or FeOx

Probable limestone flux residue from iron-ore sintering or pelletising with traces of reaction with FeOx (ore)

17

j

Silica with Ca-silicate ± Ca-(hydr)oxide/-carbonate

Possible cement/building material

18

d

Gypsum/anhydrite dominated

Likely urban dust, building material

19

au

Ti-oxide bearing

Source unknown, possibly ore-related

20

av

Ti(-Al)-silicate bearing

Probable paint chips/splinters

21

g

Silica dominated

Most commonly natural sand (quartz)

22

h

Feldspar dominated

Most commonly natural sand/rock

22

i

Silica–feldspar–clay–mica mixture (any)

Most commonly natural sand/rock

22

c

 > 50% chloride/NaCl

Most commonly salt from sea-spray/maritime influence

23

a

Carbon rich with qz–clay–fsp–mica

Probable coal/coke material with silicate ash phases

24

b

Carbon rich

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

25

aw

Unassigned grains, < 40% empty spectra

Unassigned grains with relatively low carbon content

26

  1. Assignment of grain populations to source/material categories as defined in Table 2 is also shown