Page 28 - Steel Tech India eMagazine Volume April 2022

VOL. 16 • NO. 3 • April 2022

one with sinter plant dust (50 % sinter AcP dust and
50 % sinter GcP dust) and another with steel melting
shop sludge. Stoichiometric amount of coke dust is
used as a reductant. Initially the fine samples (less
than 104 micron) are homogeneously mixed with
coke dust & adhesives and agglomerated to form
cylindrical briquette of diameter 25 mm with the help
of a pressure mould. Bentonite (5 wt %), molasses (4
wt %)and moisture (2 wt %) are chosen as adhesives
and the applied briquetting pressure is 50 kg/cm2.
the prepared briquette is allowed to dry at room
temperature for 24 hours. Drop test and abrasion test
is successfully performed to check the durability under
Fig. 5 : TG/DT analysis report of coke dust standard procedure. the mixing proportion is tabulated
in table no. 5.
Agglomeration of the Waste Samples
Table 5 : Mixing proportion for briquette preparation
For the agglomeration of the fines, briquetting prior to Carbo-thermic reduction
technique is chosen. two set of samples are prepared

S no. Oxidant Reductant Bentonite Molasses Water @ Total
@ 5 % @ 4 % 2% (gm) Briquette
Name Qty. (gm) Name Qty. (gm)
(gm) (gm) Weight
(gm)

1. IWSP 10 coke Dust 1.32 0.57 0.45 0.23 12.57
2. IWSMS 10 coke Dust 2.15 0.61 0.48 0.24 13.48

Carbo-thermic Reduction
A solid-solid carbo-thermic reduction of the briquetted sample is performed at 1000 deg c for 60 minutesin
carbon atmosphere in an electric tube furnace. the results are given below with extent of reduction and degree
of metallization.
Table 6 : Showing the results of carbo-thermic reduction of waste samples

Sl Sample Reduction Time of Briquette Weight Extent of Degree of
No Description Temperature Reduction Reduction Metallization
Before After
Reduction Reduction (based on
weight loss)
(deg C) (minute) (gm) (gm) (%) (%)

1 Sinter plant waste 1000 60 12.04 8.53 96.91 87.14
and coke dust

2 SMS sludge and 1000 60 13.48 8.61 97.48 85.41
coke dust
XRD Analysis of the Reduced Sample

the XRD plot shows (Fig.6) that the major phases present in the reduced sample is of metallic iron. Moreover the
reduced briquette is ferromagnetic in nature which reconfirms the formation of metallic iron.

26 Steel tech