Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

Abstract

High amounts of lead in waste/recycled wood fuel are known to be a contributing factor to the increased corrosion often related to this type of fuel. In combination with potassium, usually present in the fuel, low‐melting point salt mixtures between lead chloride (PbCl 2) and potassium chloride (KCl) are expected to form. The purpose of this study is to investigate reactions in the mixed salt of PbCl 2 and KCl and its interactions with carbon steel P265GH and its oxide. Laboratory exposures were performed in an isothermal tube furnace with a salt mixture of PbCl 2/KCl (50/50 mol%) put on steel samples. The test duration was 24 hr at either 300°C or 340°C in an atmosphere of 100 ppm HCl and 20 vol% H 2O in synthetic air. After exposure, the salt mixture consists of distinct areas of KCl and PbCl 2 but also the compounds K 2PbCl 4 and KPb 2Cl 5. A general observation is that the oxide thickness increases with temperature and that areas with Pb/K‐mixed salt are frequently found in close connection to more corroded areas. Often the more lead‐rich phase KPb 2Cl 5 is located closest to the corrosion product indicating its importance for the corrosion.

Ni, Cr, and Fe surfaces corroded by molten ZnCl2

“…Along with these potentials of molten ZnCl 2 are challenges, such as the corrosion of structure and container alloys containing the elements Ni, Cr, or/and Fe by an eutectic of molten ZnCl 2 , the pollution of molten salts, and so on. In addition, in incineration plants, which are considered as a valid and efficient technology to treat municipal solid wastes, molten ZnCl 2 is one of the most common impurities in residues and can corrode boiler superheater tubes used in incinerators crucially …”