1488
Chromium Ore Particles Circularity Measurement by
Digital Image Processing
André C Silva, Elenice M S Silva, Arthur Bergamini, Guilherme Sousa Rosa da Silva,
Itamar Luis Fernandes Júnior, Bruna de Oliveira Gomes, Joel Junior Fernandes
Universidade Federal de Catalão (UFCAT)
Pablo Souza de Oliveira, André Figueiredo Nascimento
Companhia de Ferro Ligas da Bahia (FERBASA)
ABSTRACT: Chromium (Cr) is one of the most versatile and widely used chemical element due to its resistance
to oxidation, which makes it an essential raw material in the metallurgical, chemical, and refractory industries.
Its main application is in the production of stainless steel, in the form of ferrochrome alloy (FeCr). This is a
crude alloy, consisting essentially of chromium (Cr) and iron (Fe), with carbon (C) content ≤ 1.2% (wt.) and
Cr content ≥ 10.5%. Chromium ore are widely concentrated by gravimetric routes. However, the complexity
of the Brazilian chromium ore is driving the development of flotation routes for this ore. Since is ore Bond’s
Work Index is around 14 kW/t the particles exit the ball mill with a spherical shape. Using optical microscopy
and digital image processing the PSD and circularity of a Brazilian chromium ore was measured after different
milling conditions.
INTRODUCTION
Chromium, due to its unique properties, finds application
in several industrial sectors, being classified as the fifth most
used metal in industry (Sampaio et al., 2005). However, its
relevance stands out mainly in the production of chromium
ferroalloys, where, according to Murthy et al., (2011),
approximately 90% of the extracted chromite ore is pro-
cessed by the metallurgical industry into different levels of
ferrochrome. The stainless-steel industry is responsible for
consuming around 80% of this ferrochrome.
In the Brazilian context, chromite production has
gained prominence in recent decades, driven by the growth
of the steel and metallurgical industries in the country.
Brazil has significant chromium reserves, mainly concen-
trated in regions such as the state of Bahia, Minas Gerais
and Amapá (ANM, 2022), contributing to the national
economy and strengthening the mineral sector.
Although chromite (FeCr2O4) is the only mineral
economically usable chromium mineral, several minerals,
mainly oxides and silicates, have Cr in their composition
(Koleli &Demir 2016 Pariser 2013 Murthy et al. 2011
Akyüziü &Eric 1992). Chromium ore is mined in more
than 20 countries, with the world’s main reserves concen-
trated in Kazakhstan (41.07%), South Africa (35.71%),
and India (17.86%) (USGS 2023 Kleynhans et al. 2012).
Brazil is considered the only Cr producer in the Americas,
with 0.5% of the world’s exploitable reserves (MME 2022).
The Brazilian reserves are in the states of Bahia (33.53%),
Amapá (32%), and Minas Gerais (20%) (Lima &Neves
2016). Between 2000 and 2020, most of the beneficiated
production of chromite comes from Amapá and Bahia
Chromium Ore Particles Circularity Measurement by
Digital Image Processing
André C Silva, Elenice M S Silva, Arthur Bergamini, Guilherme Sousa Rosa da Silva,
Itamar Luis Fernandes Júnior, Bruna de Oliveira Gomes, Joel Junior Fernandes
Universidade Federal de Catalão (UFCAT)
Pablo Souza de Oliveira, André Figueiredo Nascimento
Companhia de Ferro Ligas da Bahia (FERBASA)
ABSTRACT: Chromium (Cr) is one of the most versatile and widely used chemical element due to its resistance
to oxidation, which makes it an essential raw material in the metallurgical, chemical, and refractory industries.
Its main application is in the production of stainless steel, in the form of ferrochrome alloy (FeCr). This is a
crude alloy, consisting essentially of chromium (Cr) and iron (Fe), with carbon (C) content ≤ 1.2% (wt.) and
Cr content ≥ 10.5%. Chromium ore are widely concentrated by gravimetric routes. However, the complexity
of the Brazilian chromium ore is driving the development of flotation routes for this ore. Since is ore Bond’s
Work Index is around 14 kW/t the particles exit the ball mill with a spherical shape. Using optical microscopy
and digital image processing the PSD and circularity of a Brazilian chromium ore was measured after different
milling conditions.
INTRODUCTION
Chromium, due to its unique properties, finds application
in several industrial sectors, being classified as the fifth most
used metal in industry (Sampaio et al., 2005). However, its
relevance stands out mainly in the production of chromium
ferroalloys, where, according to Murthy et al., (2011),
approximately 90% of the extracted chromite ore is pro-
cessed by the metallurgical industry into different levels of
ferrochrome. The stainless-steel industry is responsible for
consuming around 80% of this ferrochrome.
In the Brazilian context, chromite production has
gained prominence in recent decades, driven by the growth
of the steel and metallurgical industries in the country.
Brazil has significant chromium reserves, mainly concen-
trated in regions such as the state of Bahia, Minas Gerais
and Amapá (ANM, 2022), contributing to the national
economy and strengthening the mineral sector.
Although chromite (FeCr2O4) is the only mineral
economically usable chromium mineral, several minerals,
mainly oxides and silicates, have Cr in their composition
(Koleli &Demir 2016 Pariser 2013 Murthy et al. 2011
Akyüziü &Eric 1992). Chromium ore is mined in more
than 20 countries, with the world’s main reserves concen-
trated in Kazakhstan (41.07%), South Africa (35.71%),
and India (17.86%) (USGS 2023 Kleynhans et al. 2012).
Brazil is considered the only Cr producer in the Americas,
with 0.5% of the world’s exploitable reserves (MME 2022).
The Brazilian reserves are in the states of Bahia (33.53%),
Amapá (32%), and Minas Gerais (20%) (Lima &Neves
2016). Between 2000 and 2020, most of the beneficiated
production of chromite comes from Amapá and Bahia