Study On AKD Sizing Technology Of Magnesium Bisulfite Reed Pulp

At present,the papermaking industry is generally used in the neutral/alkalescence process,so the internal sizing is used to neutral/alkalescence sizing too. In this thesis, magnesium bisulfite reed pulp was studied comprehensively analysis and take a neutral sizing based on the practice of Liaoning's Jincheng Paper Mill.Studied on the fiber was modified with PAC technique to discuss the use of PAC to the fiber modification mechanism and the effect of the sizing degree of paper and physical properties,and also to provide the oretical foundation of sizing process to further improve and promote the provision for magnesium bisulfite reed pulp using AKD neutral sizing. Main results have been obtained as follows:Magnesium bisulfite reed pulp were more ash and silicon content than alkaline reed pulp, the mixture of benzene-alcohol and hot water extractives were also higher than alkaline reed pulp, the pentosan of alkaline reed pulp,1% NaOH extractives and Klason lignin content were higher than the magnesium bisulfite reed pulp. IR spectra picture reflects that the main structural has been changed in raw materials was not very clear when magnesium bisulfite cooking reed because of the chemical reaction was mild.From the SEM picture found that there were more parenchyma cell still exist in pulp of cooking process.In the dual retention system (CS/CPAM):When the dosage of CS at 1.0% can make sizing degree and retention rate to achieve the best results and the pulp available to a good rate of remove water; the dosage of CPAM between 0.15% to 0.225%, the paper sizing degree and retention rate to achieve the best dewatering velocity results improved significantly. The final paper can get a good sizing efficiency when pulp pH value of furnish system and the addition amount of tale was between 7.5 to 8.5 and 20% respectively and the addition order of chemical:CS→AKD→talc→CPAM.The optimum scheme confirmed finally by orthogonal experiments as:A1B2C1D3. Namely:the dosage of PAC was 0.2%; the time of pulp pretreatment was 40min; pulp processing temperature was 25℃; pulp treatment consistence was 2.5%. studied based on the best orthogonal experimental program to optimized, the both sizing also increase since the dosage of PAC increase when papermaking with tap water and paper mill white water respectively. the sheet can get a good sizing efficiency and the impact of formation has been less when the dosage of PAC was 0.2%. Zeta potential absolute value has decreaseed and the demand of cation charge reduced while the dosage of chemicals increased with a cation in the pulp. Under the normal process of papermaking, the sizing degree has been increased and both the tensile index and tear index has been decreased.The results show that it was difficult to improve the sizing degree used synthetic AKD sizing agent used in magnesium bisulfite reed pulp internal sizing,its brought by SiO2, because its presence in the epidermal cells and cell wall, and in the magnesium bisulfite pulping process because of the removal of lignin,and part of the degradation of cellulose or hemicellulose, these fragments with the SiO2 residue in the pulp to bring a inevitable impact of AKD sizing agent, in order to get a good sizing efficiency of final paper, with the PAC pretreatment of the pulp can be get a good sizing efficiency of sheet, which is in the Liaoning's Jincheng Paper Mill the trial process has also been confirmed, PAC pretreatment magnesium bisulfite reed pulp AKD sizing efficiency is obviously, sizing degree increased dramatically.