Effects of Caustic Extraction on Properties of Viscose Grade Dissolving Pulp

Abstract

Viscose, a cellulose-based commodity fibre, is produced by pulping and bleaching of wood, yielding a high quality “dissolving pulp” which is then spun. During pulping and bleaching, effective hemicellulose extraction is required to allow fibre production. We present a design of experiments (DoE) approach to optimise caustic extraction in a total chlorine free (TCF) bleaching sequence (O-CE-Z-P) of beech wood sulphite pulp. Temperature and sodium hydroxide concentration were varied to identify highest xylan extraction yield, and a maximum xylan removal of 83% was achieved at 20 °C and 120 g/L NaOH. Additionally, caustic extraction conditions were derived from the DoE model that led to pulps with high yield, high alpha cellulose content or uniform cellulose molecular weight distribution. Pulps from verification experiments exhibited good reactivity in viscose application tests. Hence, the presented O-CE-Z-P bleaching sequence can be considered as suitable for integrated viscose fibre production. We assume that the presented caustic extraction model will be useful for pulp and biorefinery researchers who work on caustic biorefinery processes involving hardwood feedstocks.

Influence of Hollander beater refining on xylan extraction from hardwood paper pulp by cold caustic extraction and xylanase treatment

“…In the context of paper pulp upgrade to dissolving pulp, the cold caustic extraction method shows promise (Sixta 2006;Hutterer et al 2016;Li et al 2016;Friebel et al 2019). Several factors affect the solubilization of hemicellulose fraction in alkali-treated pulp, including extraction temperature, residence time, pulp consistency, and alkali concentration (Sixta 2006;Hutterer et al 2016).…”

Cellulose Nanofiber Preparation Combined with Bioethanol Production from Fermented Sweet Sorghum Bagasse

“…Sweet sorghum stalk has a medullary-like structure for moisture holding, which hinders juice squeezing and liquid fermentation, but is conductive to solid-state fermentation . Traditional caustic extraction requires water addition, resulting in a large amount of black liquor, which is difficult to be processed through a conventional wastewater recovery system . Solid-state fermentation enables the yeast to grow on lignocellulosic fiber substrates and convert sugar to ethanol without free water .…”

“…19 Traditional caustic extraction requires water addition, resulting in a large amount of black liquor, which is difficult to be processed through a conventional wastewater recovery system. 20 Solid-state fermentation enables the yeast to grow on lignocellulosic fiber substrates and convert sugar to ethanol without free water. 21 Most of the intracellular water was retained during the fermentation process, so no additional fresh water was required for cellulose extraction.…”

Green Separation and Extraction Processes: Part I

“…New sources of biofungicides or bactericides are being developed to overcome the toxic effects of conventional pesticides [20]. Caustic extraction in a total chlorine free bleaching sequence was investigated for wood chips pulp to make viscose fibers, with complementary utilization of viscose lyes and hemicellulose as a co-product [21]. A feasible approach was established for the preparation of desired neoagaro-oligosaccharides with different degrees of polymerization by regulating the enzymolysis time of β-agarase from marine bacteria [22].…”

“…Caustic extraction in a total chlorine free bleaching sequence was investigated for wood chips pulp to make viscose fibers, with complementary utilization of viscose lyes and hemicellulose as a co-product [21]. The separation by a solvent extraction process of noble metals from concentrated hydrochloric acid solutions of secondary resources was developed, avoiding the scrubbing stage [35].…”