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Assessment of Collectors for Reverse Iron Ore Flotation at LKAB
Mariana Tavares
LKAB
ABSTRACT: The beneficiation process of the Kiirunavaara iron ore includes multi-stage grinding and magnetic
separation, followed by flotation, for phosphorus reduction. The success of this stage relies on the performance
of one specific collector, used for decades. Recent investigations have shown an effect of heterogenous ore
mineralogy on process water quality reflected by increased ionic strength, which demands increasing dosages
binders, and affects the final product. To maintain pellet feed specifications, investigations on new collectors
have been conducted. Laboratory-scale flotation test work was carried out, and collectors 1708, 1709, 1673,
8915 and 0214 were effective on achieving the desired KPI’s (%P 0.030 and %Fe 69.00) without affecting
iron recovery significantly, when compared to the standard. When used at the same dosage as the standard
collector, collector 1708 was the one that presented the best results. However, further testing is needed to
prove its replicability, including collectors 1709 and 1673. With proven reproducibility and satisfactory results,
collectors 8915 and 0214 were already approved for future pilot scale tests. The collectors 1708 and 1709 yield
positive safety and environmental benefits for the process since it is a water-soluble product, not requiring
NaOH for saponification. Therefore, if results can be replicated for collectors 1708 and 1709, it is recommended
to evaluate these in pilot trials. Concentrate samples from flotation tests should be evaluated with regards to
agglomeration and pelletizing, in order to approve the efficiency of collectors.
Keywords: Iron Oxide Apatite (IOA) Reverse Iron Ore Flotation
INTRODUCTION
LKAB (Luossavaara-Kiirunavaara AB), located in the
northern part of Sweden, is the EU’s largest iron ore pro-
ducer. The LKAB mines are located in Kiruna, Malmberget
and Svappavaara. LKAB deposits are referred to as IOA type
(iron oxide-apatite) and are geologically hosted by metavol-
canic and metasedimentary rocks, having magnetite as the
main iron bearing mineral. The Kiirunavaara deposit is
regarded the largest of the apatite iron ores in Sweden. It
resides as a tabular ore body of around 5 kilometers length
and 100 meter thickness. Magnetite ore is mostly high-
grade, and its phosphorus content displays a clear bimodal
distribution. Two distinct ranges can be distinguished: less
than 0.05% P or exceeding 1.0% P (Bergman, et al., 2001).
Overall, the main LKAB product is iron ore pellets. The
beneficiation process of the Kiirunavaara iron ore includes
multi-stage grinding and magnetic separation, followed
by flotation. At this stage, calcareous phosphate minerals
are removed from iron oxides using an anionic fatty acid.
With addition of sodium silicate, selectivity and phospho-
rus recovery can be improved. However, increasing ionic
strength in the Kiruna process water, especially with respect
to calcium ions implies in adsorption of residual collector
in the magnetite surface. It accounts also in the presence of
depressant, compromising the product quality downstream
(Forsmo, et al., 2008 Potapova, 2011).
This occurs due to calcium ability of facilitate precipi-
tation of fatty acids, and it can lead to increases in con-
sumption fatty acid collector (Vermöhlen, et al., 2000).
Assessment of Collectors for Reverse Iron Ore Flotation at LKAB
Mariana Tavares
LKAB
ABSTRACT: The beneficiation process of the Kiirunavaara iron ore includes multi-stage grinding and magnetic
separation, followed by flotation, for phosphorus reduction. The success of this stage relies on the performance
of one specific collector, used for decades. Recent investigations have shown an effect of heterogenous ore
mineralogy on process water quality reflected by increased ionic strength, which demands increasing dosages
binders, and affects the final product. To maintain pellet feed specifications, investigations on new collectors
have been conducted. Laboratory-scale flotation test work was carried out, and collectors 1708, 1709, 1673,
8915 and 0214 were effective on achieving the desired KPI’s (%P 0.030 and %Fe 69.00) without affecting
iron recovery significantly, when compared to the standard. When used at the same dosage as the standard
collector, collector 1708 was the one that presented the best results. However, further testing is needed to
prove its replicability, including collectors 1709 and 1673. With proven reproducibility and satisfactory results,
collectors 8915 and 0214 were already approved for future pilot scale tests. The collectors 1708 and 1709 yield
positive safety and environmental benefits for the process since it is a water-soluble product, not requiring
NaOH for saponification. Therefore, if results can be replicated for collectors 1708 and 1709, it is recommended
to evaluate these in pilot trials. Concentrate samples from flotation tests should be evaluated with regards to
agglomeration and pelletizing, in order to approve the efficiency of collectors.
Keywords: Iron Oxide Apatite (IOA) Reverse Iron Ore Flotation
INTRODUCTION
LKAB (Luossavaara-Kiirunavaara AB), located in the
northern part of Sweden, is the EU’s largest iron ore pro-
ducer. The LKAB mines are located in Kiruna, Malmberget
and Svappavaara. LKAB deposits are referred to as IOA type
(iron oxide-apatite) and are geologically hosted by metavol-
canic and metasedimentary rocks, having magnetite as the
main iron bearing mineral. The Kiirunavaara deposit is
regarded the largest of the apatite iron ores in Sweden. It
resides as a tabular ore body of around 5 kilometers length
and 100 meter thickness. Magnetite ore is mostly high-
grade, and its phosphorus content displays a clear bimodal
distribution. Two distinct ranges can be distinguished: less
than 0.05% P or exceeding 1.0% P (Bergman, et al., 2001).
Overall, the main LKAB product is iron ore pellets. The
beneficiation process of the Kiirunavaara iron ore includes
multi-stage grinding and magnetic separation, followed
by flotation. At this stage, calcareous phosphate minerals
are removed from iron oxides using an anionic fatty acid.
With addition of sodium silicate, selectivity and phospho-
rus recovery can be improved. However, increasing ionic
strength in the Kiruna process water, especially with respect
to calcium ions implies in adsorption of residual collector
in the magnetite surface. It accounts also in the presence of
depressant, compromising the product quality downstream
(Forsmo, et al., 2008 Potapova, 2011).
This occurs due to calcium ability of facilitate precipi-
tation of fatty acids, and it can lead to increases in con-
sumption fatty acid collector (Vermöhlen, et al., 2000).