3817
Optimization of the Chromium Ore Milling Replacing a Bar Mill
by a High-Pressure Grinding Rolls (HPGR)
André C Silva
Universidade Federal de Catalão (UFCAT)
Pablo S Oliveira
Companhia de Ferro Ligas da Bahia (FERBASA)
Elenice M S Silva
Universidade Federal de Catalão (UFCAT)
ABSTRACT :Mining was, and continues to be, one of the main pillars of the Brazilian economy. However,
companies in the sector must make sustainable decisions and always be open to technological innovations to
remain competitive, optimizing their processes and seeking continuous reduction of costs and waste. Bench-
scale tests were carried out to technologically characterize samples of chromium ore (with an average Cr2O3
grade of 38%) from the Ipueira mine of Companhia de Ferro Ligas da Bahia (FERBASA), national leader in the
production of chromium concentrate and its leagues. A laboratory crusher model HRC D1000 was tested and
compared with the grinding currently carried out in the company’s bar mills. The results obtained indicate that
it is possible to dry comminute the chromium ore, adjusting its granulometry to the gravimetric concentration,
as well as reducing operating costs with grinding.
INTRODUCTION
Mining was and remains fundamental for the development
of society and its modernization. It generates raw materi-
als that maintain various sectors of the economy, such as
transport, civil construction, telecommunications, avia-
tion, etc. Therefore, its importance for the Brazilian econ-
omy is undeniable (Chaves 2016). Chromite (Fe2+Cr2O4),
typically composed of 67.9% Cr2O3 and 32.1% FeO, is
the main chromium ore mineral. The chromite produced
in Bahia represents 65% of the entire country’s produc-
tion, with Companhia de Ferro Ligas da Bahia (FERBASA)
being the largest producer of this mineral (Lima 2009).
FERBASA operates in the Vale do Jacurici mineral district,
the largest and most important chromite reserve in Brazil,
estimated at more than thirty million tons of ore. As the
largest national producer of ferrochrome alloys, accounting
for more than 90% of these alloys, and providing inputs for
the special steel industry, mainly stainless steel (Sampaio
et al. 2001). Table 1 presents the majority mineral phases,
determined by X-ray diffraction, present in the ore from
Vale Jacurici/BA.
The Ipueira mine, operated by FERBASA, is located
in the municipality of Andorinha-BA. Its operations began
in 1973 and, since then, the processing of chrome ore has
been carried out gravimetrically with the use of jigs and spi-
rals. Comminution is the operation that aims to adapt the
particle size for subsequent operations, release the mineral
of economic interest and/or increase the surface area of the
particles. In revolving tubular mills, comminution is typi-
cally carried out through abrasion and impact, generated by
Optimization of the Chromium Ore Milling Replacing a Bar Mill
by a High-Pressure Grinding Rolls (HPGR)
André C Silva
Universidade Federal de Catalão (UFCAT)
Pablo S Oliveira
Companhia de Ferro Ligas da Bahia (FERBASA)
Elenice M S Silva
Universidade Federal de Catalão (UFCAT)
ABSTRACT :Mining was, and continues to be, one of the main pillars of the Brazilian economy. However,
companies in the sector must make sustainable decisions and always be open to technological innovations to
remain competitive, optimizing their processes and seeking continuous reduction of costs and waste. Bench-
scale tests were carried out to technologically characterize samples of chromium ore (with an average Cr2O3
grade of 38%) from the Ipueira mine of Companhia de Ferro Ligas da Bahia (FERBASA), national leader in the
production of chromium concentrate and its leagues. A laboratory crusher model HRC D1000 was tested and
compared with the grinding currently carried out in the company’s bar mills. The results obtained indicate that
it is possible to dry comminute the chromium ore, adjusting its granulometry to the gravimetric concentration,
as well as reducing operating costs with grinding.
INTRODUCTION
Mining was and remains fundamental for the development
of society and its modernization. It generates raw materi-
als that maintain various sectors of the economy, such as
transport, civil construction, telecommunications, avia-
tion, etc. Therefore, its importance for the Brazilian econ-
omy is undeniable (Chaves 2016). Chromite (Fe2+Cr2O4),
typically composed of 67.9% Cr2O3 and 32.1% FeO, is
the main chromium ore mineral. The chromite produced
in Bahia represents 65% of the entire country’s produc-
tion, with Companhia de Ferro Ligas da Bahia (FERBASA)
being the largest producer of this mineral (Lima 2009).
FERBASA operates in the Vale do Jacurici mineral district,
the largest and most important chromite reserve in Brazil,
estimated at more than thirty million tons of ore. As the
largest national producer of ferrochrome alloys, accounting
for more than 90% of these alloys, and providing inputs for
the special steel industry, mainly stainless steel (Sampaio
et al. 2001). Table 1 presents the majority mineral phases,
determined by X-ray diffraction, present in the ore from
Vale Jacurici/BA.
The Ipueira mine, operated by FERBASA, is located
in the municipality of Andorinha-BA. Its operations began
in 1973 and, since then, the processing of chrome ore has
been carried out gravimetrically with the use of jigs and spi-
rals. Comminution is the operation that aims to adapt the
particle size for subsequent operations, release the mineral
of economic interest and/or increase the surface area of the
particles. In revolving tubular mills, comminution is typi-
cally carried out through abrasion and impact, generated by