ISSN: 0090-3973
Page Count: 4

Expanded Windows for Titanium Use in the Pulp/Paper Peroxide Bleach Plant

Schutz, RW
Corporate Specialist-Industrial Technology and Corrosion Engineer,RMI Titanium Company,OH,

Xiao, M
Corporate Specialist-Industrial Technology and Corrosion Engineer,RMI Titanium Company,OH,

Abstract

A corrosion database for Grade 2 titanium derived from laboratory weight-loss testing has been developed in uninhibited and inhibited alkaline 0.2–0.3 wt% H²O² solutions at 65° to 85°C. Although titanium resistance to uninhibited hot alkaline peroxide solutions is very limited, useful resistance dramatically expands in solutions containing inhibitive species commonly existing in bleach plant processes. Effective inhibitors in descending order include Ca⁺² ions, silicates, and Mg⁺² salts. Addition of EDTA and DTPA chelants has no detrimental effect on Ca⁺² ion inhibition unless chelant is added to excess. Based on this corrosion database, expanded application guidelines for acceptable use of Grade 2 titanium in solutions containing a maximum of 0.3 wt% H²O² are derived at 65, 70, 80, and 85°C as a function of Ca⁺² ion concentrations.

Keywords:
hydrogen peroxide, pulp/paper, alkaline peroxide, bleaching, corrosion, titanium, inhibitors, chelants

Paper ID: JTE12685J
DOI: 10.1520/JTE12685J
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