Processing Dross from Hot-Dip Galvanizing by Chlorination Roasting

Nurlan Kalievich Dosmukhamedov,Yerzhan Itemenovich Kuldeyev,Yeleussiz Bolatovich Tazhiev,Gulzada Myngyshkyzy Koishina,Arkady Kaplan,Valery Kaplan,Aidar Argyn,Erzhan Esenbaiuly Zholdasbay

doi:10.3390/su132212530

Nurlan Kalievich Dosmukhamedov, Yerzhan Itemenovich Kuldeyev + Show 6 more

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https://doi.org/10.3390/su132212530

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Abstract

Dross from hot-dip galvanizing is an important source of pure zinc ingots and zinc oxide for use as mineral additives in animal and poultry feed. Thermodynamic calculations have shown the possibility of solving the issue of dross processing by roasting using CaCl2 and NH4Cl. The influence of the consumption of chlorinating reagents, the roasting temperature on the degree of sublimation of Pb, Fe, Ni, Cu and Cd has been investigated. It has been shown that the best results are achieved when roasting the dross with the simultaneous use of CaCl2 and NH4Cl in amounts of 6 and 15% by weight of the feed material. The optimal roasting parameters were established: T = 1000 °C, duration—60 min, air flow—0.1 L/min. Recovered pure zinc oxide composition (%) was: 0.05 Pb, 0.15 Fe, 0.06 Ni, 0.003 Cu and 0.001 Cd. The degree of sublimation of copper, nickel and iron chlorides was ~75%, with lead and cadmium at 90–98% of their initial amount in the dross.

Highlights

Igor BurmistrovWorld zinc production is showing a slight increase, with consumption reaching~14 million tons per year [1,2]
High prices for zinc, which make up the main part of the cost of galvanizing, require its economical use and disposal of its waste, in particular, dross
In terms of its composition, dross mainly consists of zinc oxide, 30–40% of metallic zinc remains in it [4,5]

Summary

Introduction

Igor BurmistrovWorld zinc production is showing a slight increase, with consumption reaching~14 million tons per year [1,2]. World zinc production is showing a slight increase, with consumption reaching. The main uses of zinc include the processes of galvanizing products. Hot-dip galvanized steel accounts for 50% of global zinc consumption [3]. High prices for zinc, which make up the main part of the cost of galvanizing, require its economical use and disposal of its waste, in particular, dross. The amount of dross during galvanizing is around 0.5 to 3.5% of the mass of the treated products. In terms of its composition, dross mainly consists of zinc oxide, 30–40% of metallic zinc remains in it [4,5]. Zinc ash represents 12 to 15% of the total amount of zinc used for piece hot galvanizing (leaching of zinc from zinc ash originating from hot-dip galvanizing) [5]

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