Ash Content Declining Of Neutral And Alkaline Sulfite Aspen Pulping Waste Liquor

In this paper, adopting membrane—assisted electrolysis (MAE) technology andultrafiltration (UF) technology to decrease the inorganic ash content of neutral sodiumsulphite anthraquinone (NS-AQ) aspen pulping waste liquor and Alkaline sodium sulphiteanthraquinone (AS-AQ) aspen pulping waste liquor, get the optimum experiment conditionand investigate the characteristic of membrane technology.Processing NS-AQ waste liquor with membrane—assisted electrolysis technology, underfixed electrolysis temperature is 25℃,waste liquor volume: alkaline liquor volume is 1:2,precipitate charge is 0.06mol/L condition, the optimum experiment conditions are as follows:waste liquor solid content is 10％, alkaline liquor density is 0.1mol/L, electrolysis voltage is8v, anode area is 50cm~2, cathode area is 99cm~2, electrolysis time is 3h. After the aboveprocessing, the waste liquor inorganic ash content is decreased by 9.92％, from the original33.54％(as NaOH) to 23.62％.While processing AS-AQ waste liquor with membrane—assisted electrolysis technology,under fixed electrolysis temperature 25℃,waste liquor volume: alkaline liquor volume=1:2, precipitate charge is 0.06mol/L condition, the optimum experiment conditions areas follows: waste liquor solid content is 8％, alkaline liquor density is 0.1mol/L,electrolysis voltage is 8v, anode area is 37.5cm~2, cathode area is 81cm~2, electrolysis time is 3h.The waste liquor inorganic ash content is decline from the original 31.42％(as NaOH) to19.66％, it is descend 11.76％.When the temperature is 15℃, adopting ultrafiltration technology, the optimumexperiment conditions of NS-AQ waste liquor are as follows: ultrafiltration membraneintercept molecular weight is ten thousand, waste liquor solid content is 10％, operationpressure is 0.2Mpa, filtered liquor volume percentage is 30％.Under the optimum condition,ultrafiltrated waste liquor inorganic ash content is 24.51％,lignin cutoff rate is 79.98％,inorganic matter takeoff rate is 38.42％, organic matter takeoff rate is 20.72％. In this method,it can validly decrease inorganic ash content and the lignin can be keep validly.To AS-AQ waste liquor, under 15℃, the optimum experiment conditions are as follows: ultrafiltration membrane intercept molecular weight is ten thousand, waste liquor solidcontent is 10％, operation pressure is 0.25Mpa, filtered liquor volume percentage is 60％.Under the optimum condition, ultrafiltrated waste liquor inorganic ash content is 23.8％,lignin cutoff rate is 70.87％, inorganic matter takeoff rate is 60.99％, organic matter takeoffrate is 44.41％.In summary, to the processing of NS-AQ and AS-AQ aspen pulping waste liquor, MAE isbetter than UF in inorganic ash content decreasing, while UF is better than MAE in economy.