| 摘要 |
Method of making a bleached paper paste comprises digesting a raw cellulose fibre material in a liquor, sepg. the paste from the exhausted liquor, washing the paste to remove surplus liquor and adding this to the liquor first removed, applying several bleaches and chemical purificn. treatments, the bleaching agents contg. Cl and the chemical purificns. sodium, water washing the paste fibres to remove the bleaching agents and recovering the wash liquors which contain sodium chloride, submitting the wash liquors to various regeneration treatments comprising combustion of org. matls. contained in it and recycling the liquor to the digestion stage. During each bleaching process the aq. solns. are applied on one face of the paste which has the form of a carpet, transversely to the forward direction of movement through the bleaching plant. The solns. is passed through the carpet in a continuous contact phase with it so that the soln. is moving w.r.t. the fibres, to displace aq. solns. already present, to the other face of the carpet. The fibres are kept in approx identical posns. with respect to each other in the carpet. The effluent from the bleaching plant is discharged into the exhausted paste liquor and the NaCl is eliminated from the recovery operations after combustion and before recycling. Method prevents build up of sodium chloride in the system as "dead charge". |
