808
S. Stoychev et al.
Fig. 8 Installation for washing and leaching of Waelz oxides flowsheet
The installation for washing includes three sections, which allow the flow of oxides
with a counter current flow of the filtrate. Each of the sections includes interconnected
reactors and a filter press. The filtrate from the pre-washing is sent to our wastewater
treatment plant.
The sodium carbonate consumption varies, depending of the fluorine and chlorine
content in the Waelz oxides (90–140 kg/t WO).
The acid leaching of the washed Waelz oxides is done with spent electrolyte. The
process ends at final acidity 15–20 g/l H 2 SO 4 .
After settling and filtration of the acidic pulp, lead cake is generated.
Thanks to the realized technological scheme and the flexible management of the
flows, the fluorine is successfully removed to the levels, which allow treatment of
the resulting zinc sulphate solution to SHG zinc. The current system parameters
ensure fluorine levels in the neutral solution, sent to the electrolysis, up 35 mg/l.
Summary
With the investments made and technologies implemented by KCM AD, the circle
of the recycles and residues between the zinc plant and the lead plant was closed, as
displayed in Fig. 9. This increases profitability and competitiveness of the company
and contributes to the circular economy.
S. Stoychev et al.
Fig. 8 Installation for washing and leaching of Waelz oxides flowsheet
The installation for washing includes three sections, which allow the flow of oxides
with a counter current flow of the filtrate. Each of the sections includes interconnected
reactors and a filter press. The filtrate from the pre-washing is sent to our wastewater
treatment plant.
The sodium carbonate consumption varies, depending of the fluorine and chlorine
content in the Waelz oxides (90–140 kg/t WO).
The acid leaching of the washed Waelz oxides is done with spent electrolyte. The
process ends at final acidity 15–20 g/l H 2 SO 4 .
After settling and filtration of the acidic pulp, lead cake is generated.
Thanks to the realized technological scheme and the flexible management of the
flows, the fluorine is successfully removed to the levels, which allow treatment of
the resulting zinc sulphate solution to SHG zinc. The current system parameters
ensure fluorine levels in the neutral solution, sent to the electrolysis, up 35 mg/l.
Summary
With the investments made and technologies implemented by KCM AD, the circle
of the recycles and residues between the zinc plant and the lead plant was closed, as
displayed in Fig. 9. This increases profitability and competitiveness of the company
and contributes to the circular economy.