Page 29 - Mines and Minerals Reporter eMagazine - Volume October 2021

TECHNOLOGY

Table 1 Preliminary, elemental, and constituent analysis of the straw-type biomass (%). ple, biomass used as a reduc-
Preliminary analysis Elemental analysis Biomass constituent tant has a significant effect on
magnetized roasting [22]. The
M ad 6.26 Carbon 42.56 Cellulose 38.67 optimal magnetic separation
V ad 73.81 Hydrogen 5.60 Hemicellulose 17.06 indexes of roasted products
A ad 3.58 Nitrogen 0.44 Lignin 5.02 are obtained in the applica-
tions of waste coconut shells
FC ad 16.35 Oxygen* 41.44 Others 39.25 (CS), pine sawdust or other
– – Sulfur 0.12 – – plant residues [23–25]. Sub-
Notes: : based on ADB (air dried basis); Oxygen*: by difference. sequently, Rath et al. studied
ad
the reduction roasting process
of iron ore mines using cow
dung as the reductant, in this
study, the grade and recovery
were 64% and 66%, respec-
tively [26]. Studies on the mi-
croscopic scale have focused
on, alkali lignin, a component
of the biomass; it has been
shown that roasting lignin with
limonite ore increases the sat-
uration magnetization value of
iron oxides [27]. Furthermore,
direct reduction and co-pyrol-
ysis are the new ideas for bio-
mass utilization [28–31]. He et
Fig. 1. Schematic diagram of suspension roasting experiment system. al. and Zhao et al. used the cat-
alytic co-pyrolysis of biomass
to study optimal indexes, with
parameters can be obtained. SMR plays a significant role not the purpose of improving the yield of desired products such as
only in treating refractory ore but also in hazardous wastes tar, hydrocarbon, benzene and toluene [32,33]. Other green
such as red mud and hazardous tailings [6,7]. Thus, the indus- reductants that adhere to the concept of cleaner production
trialization of SMR is growing rapidly and the implementation are mentioned. For example, the carbon monoxide reductant
of suspension magnetization roasting technology should be released from the decomposition of siderite (FeCO3), mixed
expected in the future [8,9]. with refractory hematite has been explored in the SMR pro-
cess, resulting in the generation of magnetite [34,35]. Addi-
Although SMR has been widely adopted in the field of treating tionally, under an atmosphere of CO-CO2, pyrrhotite (Fe(1-X)
iron ore, the severe problem of environmental pollution from S) and troilite (FeS) are used to obtain iron concentrates and
using fossil fuel cannot be ignored [10,11]. Biomass, includ- to reduce the element contents of Sn and S.
ing plant residue and organic fertilizer, can be used as a green
and renewable reductant after it is processed to a fine pow- In general, the pyrolysis of biomass is somewhat complicated
der or other forms [12]. However, it should be pointed out and it is difficult to determine the gaseous products because
that the utilization of biomass is difficult and inefficient. For of the close coupling of the multiphase processes and the
example, the abundant renewable energy power was 100.7 variable contents of the biomass [36,37]. The main contents
TWh in 2017, and biomass energy accounted for only 4% of of biomass are cellulose, hemicellulose and lignin, but these
the total energy use in China [13,14]. As a sustainable and three pyrolysis profiles of biomass are totally different [38,39].
CO2-neutral resource, biomass can meet the greenhouse gas Although they can produce gaseous reducing products such
emission limits for the iron-making industry, whose emissions as CH4, CO and H2, the gas content and pyrolysis temperature
account for 7% of global anthropogenic CO2 [15]. Additionally, range of biomass are different [40,41]. Because of the com-
biomass could replace traditional fossil fuels and lessen the plexity and variability of biomass pyrolysis, and to avoid the
emissions of SOX and NOX formation in the future [16–19]. interaction between impurity elements in refractory iron ores
Because biomass includes a substantial variety of low cost and and straw-type biomass, pure hematite was used as a sample
renewable resources, discussing the application of biomass is to make the reduction mechanism clearer.
crucial [20,21]. Recently, the application of biomass has been
investigated and elucidated by many researchers. For exam- A few studies of gaseous products released from biomass

OCTOBER 2021 / MINES & MINERALS REPORTER 27