Shredding and ageing stages

The aged crumbs, which contain about 30% cellulose, are then transferred to a jacketed, cooled, hexagonal shaped xanthation vessel. A vacuum is applied and about 10% CS2 added with great care, as it is an extremely flammable substance. The vessel is slowly rotated on its axis, churning the two components for about 3 h to form a deep orange, thick, viscous mass of sodium cellulose xanthate. 

The color is due to the presence of trithiocarbonate (Na2CS3), sulfides and polysulfides. 

2CS2 -H 6NaOH NaiCSs -H Na2C03 + NaiS + 3H2O 

The excess carbon disulfide and other odorous compounds are removed after xanthation by the application of a vacuum, since in practice only about 70% of the requisite CS2 is required. 

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