AkzoNobel Specialty Chemicals is one of the major producers of sodium chlorate. Sodium chlorate is a stable and safe precursor for chlorine dioxide (ClO2), which is used in Elemental Chlorine Free (ECF) bleaching of pulp. Bleached pulp is used for the production of paper, cardboard, and many other kinds of cellulose-based materials.
Since its invention, we have taken a leading role in optimizing the chlorate manufacturing process through our own research and through collaborations with universities and other partners. Despite making significant improvements over the years there is still room for improvement. We want to take the sustainability of this process to the next level and are looking for new methods which are more energy efficient and free of materials of concern.
Today, sodium chlorate (NaClO3) is produced by generating chlorine (Cl2) on an anode, which is instantaneously hydrolyzed and at neutral pH forms an optimum ratio of 2HClO:ClO- for chlorate formation. This follows the formula below (disproportionation reaction):
2HClO + ClO- à ClO3- + 2Cl- + 2H+
The overall process requires the presence of small amounts of hexavalent chromium (Cr (VI)), which is a known compound of concern.
We are open to radically new approaches to producing sodium chlorate, such as (but not limited to):
If you have another solution or idea that answers our question, but might not exactly fit these specific requirements, please also submit it! All ideas are valuable and might be further developed to fit.
Our scope is very broad, but any proposed solution should not rely on materials of concern (like carcinogenic, mutagenic or reprotoxic chemicals). It should not result in a process with poor safety performance, poor energy efficiency, or create any major waste streams.
We are looking for all solutions contributing to the scope of this challenge. Aspects we evaluate the ideas on when selecting for the Imagine Chemistry finals include:
If you think you can help us produce chlorate in a sustainable, energy efficient way, we welcome you to join our Challenge on the Imagine Chemistry Challenge platform for open and collaborative innovation.
A review of chromium(VI) use in chlorate electrolysis: Functions, challenges and suggested alternatives. Balázs Endrodi, Nina Simic, Mats Wildlock, Ann Cornell. Electrochimica Acta 234 (2017) 108–122.