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Lignin

The LigniOx report can be obtained at www.vttresearch.com.

A Finland research and technology specialist serving Europe’s forested Nordic countries cites a technique to convert lignin, a wood fiber binder and pulp mill byproduct, to a plasticizing agent competitive with synthetic and lignosulphonate-based concrete admixtures.

VTT Technical Research Centre’s LigniOx technology converts lignin to a water-soluble agent through molecular oxygen, and is described in Senior Scientist Anna Kalliola’s 2015 doctoral thesis. In fresh concrete, VTT contends, LigniOx-derived solution outperforms commercial lignosulphonate-based plasticizer and provides a promising alternative to synthetic superplasticizers. It enables use of small volumes of water in a concrete mix design, producing a highly workable paste that hardens into a strong final product.

The oxidizing technology can be used to process different kinds of lignins; only the conditions need be tailored for each type. VTT’s further development projects are focused on making the LigniOx solution competitive against synthetic products and exploring its commercial potential. The firm cites a global market for lignin-based plasticizers of upward of 19 million tons annually, developing countries’ growth fueling higher demand.

In her detailed VTT report, “Chemical and enzymatic oxidation using molecular oxygen as a means to valorize technical lignins for material applications,” Dr. Kalliola concludes, “The promising results of applying the alkali-O2 oxidized lignin for concrete plasticizing encourage continuing the investigations. In these studies, it is important to emphasize more the structure-function relationship of the oxidized lignin, as well as its impact on cement hydration.”