232
F. M. Teixeira et al.
slag [3]. Nexa Resources has developed the first and only industrial Waelz process
in South America in order to recover zinc out of EAFD from steelmaking companies
from Brazil.
The Waelz circuit from Juiz de Fora unit has an installed capacity to treat 200,000
tonnes of secondary materials but is currently operating at around 60% of its capacity
due to market availability of EAFD [4]. During 2014–2018, the generation of dusts
from steel mills in Brazil has varied from 86 to 100 kt.
Considering this idle capacity of the Waelz kiln, the company has investigated
other sources of zinc, among them: batteries, effluent treatment sludge, and low grade
concentrate from Vazante mine, a non-sulphide zinc orebody.
The objective of the present study was to investigate the performance of the Waelz
process feeding low grade concentrate produced at the Vazante mine as a zinc bearing
feed material in association to EAFD for the recovery of zinc oxide in a pilot scale
Waelz kiln. The optimum conditions and parameters for these processes were also
described.
Materials and Methods
The essays to evaluate the performance of the low grade zinc concentrate were
conducted in the premisses of Nexa Resources Juiz de Fora, in a pilot scale horizontal
rotary kiln seizing 4 m in length and 0.3 m of internal diameter coupled to a gas
treatment system containing a dust catcher, cyclone, and bag filters.
Materials
The low grade zinc concentrate utilized in this study is generated on the flotation
of carbonates to enrich the main zinc concentrate of Vazante mine. It is a silicate
composed mainly of the following minerals: willemite (58.63%), dolomite (24.08%),
and quartz (3.64%).
The EAFD sample used on the tests is a typical residue provided by a Brazilian
steel mill. The mineralogy of EAFD dusts vary in content from the supplier; however,
in all of them the main compounds found are: franklinite, zinc oxide, monticellite,
and magnetite. The chemical compositions of both materials are presented in Table 1.
Test Parameters
Each test consumed 306 kg of raw materials and 108 kg of coarse coke charged in
the kiln for a period of 36 h using a proportioning scale to guarantee continuous and
even charging. The internal and kiln housing temperatures were measured every hour
F. M. Teixeira et al.
slag [3]. Nexa Resources has developed the first and only industrial Waelz process
in South America in order to recover zinc out of EAFD from steelmaking companies
from Brazil.
The Waelz circuit from Juiz de Fora unit has an installed capacity to treat 200,000
tonnes of secondary materials but is currently operating at around 60% of its capacity
due to market availability of EAFD [4]. During 2014–2018, the generation of dusts
from steel mills in Brazil has varied from 86 to 100 kt.
Considering this idle capacity of the Waelz kiln, the company has investigated
other sources of zinc, among them: batteries, effluent treatment sludge, and low grade
concentrate from Vazante mine, a non-sulphide zinc orebody.
The objective of the present study was to investigate the performance of the Waelz
process feeding low grade concentrate produced at the Vazante mine as a zinc bearing
feed material in association to EAFD for the recovery of zinc oxide in a pilot scale
Waelz kiln. The optimum conditions and parameters for these processes were also
described.
Materials and Methods
The essays to evaluate the performance of the low grade zinc concentrate were
conducted in the premisses of Nexa Resources Juiz de Fora, in a pilot scale horizontal
rotary kiln seizing 4 m in length and 0.3 m of internal diameter coupled to a gas
treatment system containing a dust catcher, cyclone, and bag filters.
Materials
The low grade zinc concentrate utilized in this study is generated on the flotation
of carbonates to enrich the main zinc concentrate of Vazante mine. It is a silicate
composed mainly of the following minerals: willemite (58.63%), dolomite (24.08%),
and quartz (3.64%).
The EAFD sample used on the tests is a typical residue provided by a Brazilian
steel mill. The mineralogy of EAFD dusts vary in content from the supplier; however,
in all of them the main compounds found are: franklinite, zinc oxide, monticellite,
and magnetite. The chemical compositions of both materials are presented in Table 1.
Test Parameters
Each test consumed 306 kg of raw materials and 108 kg of coarse coke charged in
the kiln for a period of 36 h using a proportioning scale to guarantee continuous and
even charging. The internal and kiln housing temperatures were measured every hour