Process for reducing the amounts of zinc (Zn) and lead (Pb) in materials containing iron (Fe)

Abstract

The present invention relates to a process for reducing the amounts of zinc and lead in starting materials comprising iron which comprises the steps of: - selectively leaching Zn and Pb comprised in the starting materials by mixing the starting materials with hydrochloric acid and an oxidizing agent comprising at least 5 wt-% of manganese dioxide in one or several reactor(s) at a temperature superior or equal to 35 DEG C and at a p H comprised between 0,5 and 3,5, - filtrating the mixture obtained in order to separate the solid and the filtrate, - washing the solid with water, the resulting solid comprising mainly Fe, a reduced amount of Zn and Pb compared to the original starting materials, - recovering the filtrate of step b) and the washing water of step c) which comprise chloride, solubilized Zn and Pb in one or several reactor(s), - precipitating solubilized Zn, Pb in the recovered filtrate and the washing water by mixing with a neutralizing agent, - filtrating and washing the solid residues obtained in step e) in order to remove the chloride from the solid residues which comprise at least Pb and Zn. The present invention also refers to the use of the materials obtained after treatment in a in a sinter plant and blast furnace or in all pyrometallurgical furnace which value iron such as electrical arc furnace (EAF), cupola furnace, oxycup furnace, submerged arc furnace (SAF), a plasma furnace, rotary hearth furnace.

Description

technical field [0001] The present invention relates generally to the treatment of starting materials comprising iron (Fe), zinc (Zn), lead (Pb) and possibly carbon (C) by hydrometallurgical methods, and in particular to the removal of Zn from these starting materials and Pb. Background technique [0002] The chemical and metallurgical industries generate various forms of waste containing polluting elements. For example, the steelmaking industry involves the use of blast furnaces for smelting to produce industrial metals such as pig iron and basic oxygen furnaces (BOFs) to produce steel from pig iron. Blast furnaces and BOFs generate large amounts of dust and sludge at the outlet of the gas cleaning plant during operation. These slurries or ashes consist of different metals. In particular, these slurries or ashes contain iron, carbon, zinc and lead. In order to reduce the operating costs associated with the operation of such industries, it is desirable to recycle these m...

AI Technical Summary

Problems solved by technology

[0012] However, for industrial applications, operation at high pressure and high temperature as described in this document is not economically and operationally preferred because it requires pressure vessels made of expensive high-grade materials and involves higher safety requirements

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