Lignosulfonate of a certain quality and method of preparation of lignosulfonate of a certain quality

• Main Authors: Joensson Bengt, Grundberg Hans, Gustafsson Alf
• Format: Patent
• Language: English
• Published: 20.09.2016
• Subjects: ADHESIVES; APPARATUS THEREFOR; CHEMISTRY; COMPOUNDS OF UNKNOWN CONSTITUTION; DYES; IMPREGNATING OR COATING OF PAPER; MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FORELSEWHERE; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; ORGANIC CHEMISTRY; PAINTS; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRODUCTION OF CELLULOSE; PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCESFROM CELLULOSE-CONTAINING MATERIALS; PULP COMPOSITIONS; REGENERATION OF PULPING LIQUORS; SEPARATION; TEXTILES; TRANSPORTING; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKINGMACHINE

There is provided a process for improving the quality of lignosulfonate at least partly derived form a spent sulfite cooking liquor in at least two steps, comprising: one step in which a lignosulfonate-containing fraction at least partly derived from the spent sulfite cooking liquor is subjected to filtration using a membrane having a cut-off of 40-150 kD (high cut-off) at the pressure, flow rate and temperature of the step and the permeate is recovered; and another step in which a lignosulfonate-containing fraction at least partly derived from the spent sulfite cooking liquor is subjected to filtration using a membrane having a cut-off of 1-20 kD (low cut-off) at the pressure, flow rate and temperature of the step and the retentate is recovered. Products, uses thereof as well as a system are also provided.