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The largest use for sodium chlorate is for the generation of chlorine dioxide, which is used for bleaching chemical pulp. In 2008, this application represented 98% of total consumption in North America, 90% in Europe and 84% in Japan. Other minor uses include weed control, production of potassium chlorate and sodium chlorite, and several other smaller applications.
About 73% of world sodium chlorate capacity is operated by four companies: Eka Chemicals (28%), Canexus (17%), ERCO Worldwide (14%), and Kemira (14%).
After tremendous growth during the switch from chlorine bleaching to the elemental-chlorine-free (ECF) bleaching process, the global markets for sodium chlorate have matured, and average annual growth for North America and Europe has slowed. The areas of strongest growth for sodium chlorate consumption are Asia and South America, with access to fast-growing pulp raw materials acacia and eucalyptus, and Russia, which has 22% of the world’s forests and low-cost electricity. Worldwide growth of sodium chlorate consumption in the pulp and paper segment was lower than would be expected given the production growth in the pulp industry and a trend toward higher-brightness paper. The reason for this is the high cost of electricity, which is a major production cost for sodium chlorate and makes sodium chlorate expensive compared with hydrogen peroxide, which can replace sodium chlorate to some extent in the bleaching process.
The following pie chart shows world consumption of sodium chlorate:
Consumption of sodium chlorate in Japan is very small compared with that in the large bleached-pulp-producing regions of North America and Scandinavia. Despite the rather significant investment required and the weak Japanese economy, most Japanese paper producers have switched to ECF in recent years and only two mills still use chlorine.
The worldwide environmental problems arising from the use of chlorine as a pulp bleaching chemical appear to have been solved. Sodium chlorate and chlorine dioxide are a major part of the solution in North America, Europe and Japan. If the closed-cycle mill concept gains support in the future, chlorine dioxide is likely to be given favorable consideration and be part of a longer-term solution.
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