The crop is more than just a treat for those with a sweet tooth: in 2017 the country’s sugar industry had an estimated value of more than R12 billion; of this, sugarcane production alone was worth R5.1 billion.
But the sugar industry is shrinking, at least partly because many people are eating less sugar, for health reasons. How, then, might sugarcane production continue to extract value? We believe the answer lies with the crop’s waste material.
Sugarcane bagasse is the fibrous material left over after the crop has been crushed to extract its juice to make sugar.
About 54 million tonnes of sugarcane bagasse is produced annually around the world. The inadequate disposal of this bagasse leads to environmental pollution and attracts many insects when left unattended.
But there are ‘jewels’ among the piles of ash that remain once bagasse is burned.
Scores of chemical processes are being tested and fine-tuned to extract silica from bagasse ash, and from there synthesising it into silicon particles.
Some tests are fairly advanced but nobody has yet cracked the code to producing high grade, pure silica at levels high enough to meet industrial demands.
Our recent work took a ‘green’ approach to the extraction process. First, we confirmed what a growing body of research has shown: that sugarcane bagasse ash is a natural resource of silica which should be harnessed for industrial purposes.
And, using organic acids and bases, we showed what processes might be used for a more environmentally friendly extraction procedure.