Akademik Veri Yönetim Sistemi
21st International Metallurgy and Materials Congress, İstanbul, Türkiye, 6 - 08 Ekim 2022, ss.231-234
In this study, the magnetization behavior of Türkiye’s
volcanic kafa ore (VKO) was investigated with
reduction roasting. The Kafa ore contains mainly
hematite which is the main source of iron along with a
small amount of goethite and gangue minerals namely
quartz and calcite. Since it is necessary to separate the
gangue from iron-bearing ore and low magnetic
susceptibility of hematite; the magnetization of
hematite was carried out by reduction roasting. By
doing so, it was aimed to separate the magnetized iron
ore from the gangue by magnetic separation. In order
to achieve this purpose, an experimental design was
planned which has 5 different sets of temperature and
3 different sets of coke mixture ratios. The temperature
ranges from 400⁰C to 900⁰C by 100⁰C increment in
every set. Similarly, the coke that was used as a
reducing agent mixture, takes values of 30, 40, and
50%. Following the experimental setup, roasted VKOs
were subjected to low-intensity dry magnetic
separation at 750 oersteds magnetic field strength. The
effects of temperature and amount of coke on the
transformation of hematite to magnetite and the
determination of mineralization of the concentrate
obtained after magnetic separation were investigated
by X-ray diffraction. Fe grade and recovery were
determined by using chemical analysis, and then the
optimization of the experiments was determined with
Fe% recovery that was obtained after magnetic
separation. X-ray diffraction patterns show that
magnetite transformation begins at 600 ⁰C after
reduction roasting. After magnetic separation, the
effect of the temperature and the effect of the coke
mixture on Fe% recovery were investigated. The
relationship between Fe% recovery and temperature
was shown as a linear correlation. The recovery rate
can be expressed as y = 0.2114x - 77,711 where y is
the recovery rate and x is the temperature. The fitness
of the model is very high with an R² = 0.886. However,
the effect of the coke mixture on Fe% recovery could
not be detected. The fitness of the model confirms this
indifference by R² = 0.0078. When the coke mixture
was kept constant, iron recovery efficiencies were
lower than 57% till 600°C and it sharply increased by
temperature and peaked at 800°C. A peculiar
condition was detected at 700°C and a 50% coke
mixture with a 90% Fe-recovery rate. Another highefficiency point was observed at 800⁰C and a 30%
coke mixture with an 89% Fe-recovery. In conclusion,
two optimal conditions were found with different
trade-offs The first one requires a lower temperature
while needs more coke. The second condition needs
more temperature while the coke requirement is lower
than the first one. These conditions can be traded
regarding the following conditions: availability of
energy, cost of marginal temperature increment,
availability of coke, and cost of coke.