The Mechanism Research Of How Inorganic Ions And DCS Affecting Hydration Of Fines

For environment protection and economy reasons, closure and cycling reuse of white water is regarded more and more important. By the enhancement of water closure and cycling degree, the fresh water added into papermaking system and waste water emission reduced notablely. Dissolved and substances (DCS) as well as metal ions accumulated in the white water system strikingly. It is observed that by the increasing of conductivity and charge demand of furnish paper production and product quality is affected seriously. Enhancement of such substances not only affected sheet quality but also affect retention and drainage performance in the wet end.It was mainly measured Al3+,Ca2+,Fe3+,Mg2+,Na+ status in the pulp before deion and after deion with hydrochloric acid washing six times to remove all kinds of metal ions in the pulp.After treating the absorption amounts of Ca2+,Fe3+,Mg2+,Na+ decreased while the washing times of hydrochloric acid increased. The absorption amount of metal ions decreased sharply after the first washing and then trended to be stable slowly. It was decided to use the method which used hydrochloric acid washing four times and deioned water washing four times too.The precision of measuring WRV depended on the speed and treating time of centrifugal machine.So it was also studied and analysed the relationship between rotation speed and treating time of centrifugal machine. We used equaling 0.15g bone dry with certain consistency to measured the variation of WRV by changing speed and treating time of centrifugal and to confirm the properly working speed and treating time. We decided the rotation speed was 3000r/min and treating time was 10min.We also selected NaCl,CaCl2 and Na2SO4 which can affect conductivity to study how cationic ions affect fines hydration by comparing WRV and drainage time of fines that added NaCl and CaCl2 in the same conductivity and anionic ions. Normally multivalent anionic ions had stronger compressing action than monovalent ions which cause WRV was lower and drainage ability was better.Sodium polyacrylate, alkaline lignin, anionic abietic resin and carboxylic SBR were selected to simulate DCS. They were added into fines furnish to study how they affected hydration by measuring WRV and drainage time. Low molecular weight substances which had the function of dispersal decreased WRV and latex substances increased WRV.Finally, inorganic ions and anionic simulacrums were mixed and added into fines furnish with dosage of anionic simulacrums stably to change dosage of inorganic ions. By measuring WRV and drainage time of fines which was added simulacrums it is found that under the action of mixed ions and anionic simulacrums WRV trended to decline and resemble only under the action of ions which indicated compressing effect had no necessary relation with kinds of simulacrums. With the consistency of ions increasing WRV generally decreased fast at first then smoothly.Under the action of ions and anionic simulacrums drainage time of fines trended to decline. Although anionic simulacrums could rise dissolved charge conductivity had little affection on dissolved charge. There were no notable cooperating action between anionic simulacrums and inorganic ions. Inorganic ions played the main function.