Chlorate Synthesis Cells and Technology

Introduction

Chlorate has been industrially produced for over a century, in the beginning primarily produced as potassium chlorate (KClO₃) for safety matches but today mainly as sodium chlorate (NaClO₃) used for bleaching in the pulp and paper industry. At the pulp mills chlorate is converted to chlorine dioxide, which is used to bleach chemical pulp.

The first chlorate plant was built in Switzerland as early as in 1886 [1] and since then the technology has much improved. An important example of chlorate process development is the introduction of DSA in the late 1970s. This allowed operation at higher temperature and higher current density, see “Chlorate Cathodes and Electrode Design”, which triggered the development of new cell systems. Another important example is the development of closed loop plants. Earlier it was common that electrolyte from the chlorate plants was shipped as product to the pulp mills, and used in the chlorine dioxide generators. Today most often a dry product,...