Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Production of carboxymethyl lignin from sugar cane bagasse: A cement retarder additive for oilwell application Paulo Henrique Silva Santos Moreira a, ⁎ , Julio Cezar de Oliveira Freitas a , Renata Martins Braga b , Renata Mendonça Araújo c , Miguel Angelo Fonseca de Souza c a Laboratório de Cimentos, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, 59072-970, Brazil b Jundiaí Agricultural School, Federal University of Rio Grande do Norte, Macaíba, Rio Grande do Norte, 59280-000, Brazil c Chemistry Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, 59072-970, Brazil ARTICLE INFO Keywords: Sugar cane Biomass Biorefinery Carboxymethyl lignin Cement retarder Additive ABSTRACT The use of residues generated during agro-processing to produce valuable products is in the concept of bior- efinery 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 re- tarder. 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. 1. Introduction The sugar cane biomass is a by-product of the sugar-alcohol industry that represents a large volume of up to 30% of the harvested cane in South Africa (Mashoko et al., 2013). Brazil is the largest sugar cane producer with about 39% of world sugar cane production (Silalertruksa et al., 2017). According to UNICA (Brazilian Sugarcane Industry Asso- ciation), the amount of sugar cane produced in the harvesting period 2015/2016 was 666.824 tons (UNICA, 2016), with estimated bagasse generation around 200.047 tons. Sugar mills only operate during har- vesting, whence the seasonality and storage of bagasse cause problems related with its degradation. Most of the bagasse is currently used as fuel in sugar mills and ethanol distilleries (Clauser et al., 2016). In re- cent years, the burning of lignocellulosic materials has been used as cleaner alternative to coal in the production of electricity, with su- garcane bagasse being one of the biomasses with highest potential (Mashoko et al., 2013). Environmental gains would be greater if the burning of the surplus were avoided and the biomass become feedstock for the production of new materials. Biorefinery concept is therefore gaining interest as a promising approach for enhancing competitiveness of the sugarcane industry, which is recognized as a key agribusiness in many emerging economies, by production system that integrates biomass conversion processes to produce fuels, heat, electricity and value-added products e.g. materials or chemicals from biomass (Clauser et al., 2016; Fontoura et al., 2015; Ma et al., 2016; Patrizi et al., 2015; Pereira et al., 2015; Silalertruksa et al., 2017, 2015). The wide variety of chemical structures present in lignocellulosic materials make these versatile for application in various industrial areas (Maziero et al., 2012). The building process of an oil well is based on cycles of drilling, casing and cementing job going down section by section until the in- terest zone. For each section a cement slurry is designed and displaced to fulfill the annulus space between formation and case. The slurry design is required to meet operational and wellbore conditions as pressure and temperature. Chemical additives are used to modify ce- ment slurry’s behavior in order to meet those requirements. Additives called retarders are used to increase thickening time (ThTi), thus postponing cement set and allowing more operational time https://doi.org/10.1016/j.indcrop.2018.01.073 Received 29 August 2017; Received in revised form 11 January 2018; Accepted 28 January 2018 ⁎ Corresponding author. E-mail addresses: phenrique000@ufrn.edu.br (P.H.S.S. Moreira), juliofreitasj@hotmail.com (J.C. de Oliveira Freitas), renatabraga.r@gmail.com (R.M. Braga), renata@quimica.ufrn.br (R.M. Araújo), miguel@quimica.ufrn.br (M.A.F. de Souza). Industrial Crops & Products 116 (2018) 144–149 0926-6690/ © 2018 Elsevier B.V. All rights reserved. T