Simulation of an Alternative Direct
Leaching Process for High Iron Content
Zinc Concentrates
Caio Cesar Spindola de Oliveira and Daniel Dayrell Pereira
Abstract Conventional RLE process (Roasting, Leaching, and Electrowinning)
usually avoids high iron content zinc concentrates due to roaster heat limitations
and high zinc ferrite formation, causing losses in zinc recovery. Alternatively, direct
leaching processes may recover zinc from this undesired type of concentrate with
high yields. In this work, we evaluate the sulfatation process (staged roasting process
at lower temperature that favorites the oxidation of sulfides to sulfates) as an alternative and compare it with traditional direct leaching and roasting processes. The
simulation showed that sulfatation process might be a good alternative for treating
high iron content zinc concentrates in future investments, reducing consumables and
generating an extra amount of steam.
Keywords Simulation · Sulfatation · Direct leaching
Introduction
The RLE Process
In the past decades, the RLE process (Roasting, Leaching, and Electrowinning) have
become the predominant route to obtain zinc from sulfide concentrates. Each company has its variations to optimize their opportunities, but they all follow these three
basic steps. They are economical and reliable stages in order to produce competitive
zinc in Special High Grade (SHG) specification.
The roasting step comprises of a fluidized bed reactor that converts ZnS to ZnO,
at approximately 950 °C, by blowing an intense flow of air (most of the time enriched
with pure O 2 ) to promote de reaction and fluidization. With the outlet gas, enriched
C. C. S. de Oliveira (B) · D. D. Pereira
Nexa Resources, BR040, Km 284, Tres Marias, MG 39206-000, Brazil
e-mail: caio.oliveira@nexaresources.com
D. D. Pereira
e-mail: daniel.pereira@nexaresources.com
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_35
405
Leaching Process for High Iron Content
Zinc Concentrates
Caio Cesar Spindola de Oliveira and Daniel Dayrell Pereira
Abstract Conventional RLE process (Roasting, Leaching, and Electrowinning)
usually avoids high iron content zinc concentrates due to roaster heat limitations
and high zinc ferrite formation, causing losses in zinc recovery. Alternatively, direct
leaching processes may recover zinc from this undesired type of concentrate with
high yields. In this work, we evaluate the sulfatation process (staged roasting process
at lower temperature that favorites the oxidation of sulfides to sulfates) as an alternative and compare it with traditional direct leaching and roasting processes. The
simulation showed that sulfatation process might be a good alternative for treating
high iron content zinc concentrates in future investments, reducing consumables and
generating an extra amount of steam.
Keywords Simulation · Sulfatation · Direct leaching
Introduction
The RLE Process
In the past decades, the RLE process (Roasting, Leaching, and Electrowinning) have
become the predominant route to obtain zinc from sulfide concentrates. Each company has its variations to optimize their opportunities, but they all follow these three
basic steps. They are economical and reliable stages in order to produce competitive
zinc in Special High Grade (SHG) specification.
The roasting step comprises of a fluidized bed reactor that converts ZnS to ZnO,
at approximately 950 °C, by blowing an intense flow of air (most of the time enriched
with pure O 2 ) to promote de reaction and fluidization. With the outlet gas, enriched
C. C. S. de Oliveira (B) · D. D. Pereira
Nexa Resources, BR040, Km 284, Tres Marias, MG 39206-000, Brazil
e-mail: caio.oliveira@nexaresources.com
D. D. Pereira
e-mail: daniel.pereira@nexaresources.com
© The Minerals, Metals & Materials Society 2020
A. Siegmund et al. (eds.), PbZn 2020: 9th International Symposium
on Lead and Zinc Processing, The Minerals, Metals & Materials Series,
https://doi.org/10.1007/978-3-030-37070-1_35
405