Production of carboxymethyl lignin from sugar cane bagasse: A cement retarder additive for oilwell application

The use of residues generated during agro-processing to produce valuable products is in the concept of biorefinery applied in recent times. This concept is attractive for being an alternative to solve disposal issues while processing a more added value product to residues. This work suggests a process to produce Carboxymethyl Lignin using Sugar Cane Biomass (SCB) as raw material and to test its efficiency as retarder additive for oil well cement slurry. The soda/anthraquinone pulping process was used to extract lignin from cellulose present in biomass. The lignin was isolated and chemically modified to produce Carboxymethyl Lignin (CML). The CML was tested through Thickening Time tests. The linear increment on the thickening time of cement slurries containing different concentrations of CML was observed reaching up to 104% of increase on thickening time in relation to a reference. Two mechanisms of action were proposed to explain its effect as cement paste set retarder. The results showed that Carboxymethyl Lignin production from sugar cane biomass can be an interesting process to a line of biorefinery associated to sugar industry. That process can reduce the disposal issues with crops and bagasse, avoiding its burning and generating more valuable biochemical.