Effects of solid deposits on the corrosion behaviour of titanium in high acidity and highly oxidising leaching solutions

Abstract

ABSTRACT Solid minerals are ubiquitous and common deposits on Ti-lined process vessels in the hydrometallurgical industry. This work revealed the effects of inert solid deposits on the corrosion behaviour of Ti-2 in high acidity and highly oxidising leaching solutions. It was found that the deposit-covered Ti-2 had a higher corrosion rate (CR) than bare Ti-2. CR increased with increasing deposit thickness (up to 6 cm) and temperature. Solid deposits mainly affected the corrosion process of Ti by limiting the mass transfer of the oxidising Fe(III) from the bulk solution to the underlying Ti, thus affecting the stability of the protective passive film, and resulting in an accelerated passive CR. High temperatures and solid deposition are both commonly encountered in the hydrometallurgical industry, and their combination may significantly limit the maximum service temperature of Ti-equipment, implying that there is a risk in using Ti-components under such conditions.