The Effect Of Organic Extractive Content On The Propertise Of Masson Pine BCTMP

This paper focuses on the extractive solvent in the BCTMP impregnatingand bleaching process of Masson pine. The content of the solvent extractiveschanges during the process, and with the change, we get the reason why and howthe impregnating and bleaching process is influenced by the solvent extractive.The paper also optimize the BCTMP process for a good quality of the pulp.Firstly, we optimized the impregnating and bleaching process, during theneutral Na₂SO₃impregnation, the conditions were obtained as:Na₂SO₃2.5%,NaHCO₃3%of DTPA0.2%carried out for20min under90℃. Results show thatthe pulp yield is high and the initial brightness43.4%is also higher than theprocess impregnated with NaOH. Then the bleaching progress was optimized too,and the results are as follow: with the NaOH impregnation, the condition shouldbe NaOH3.5%and for neutral Na₂SO₃, the usage of the NaOH should be4.5%,at the same time, the pulp consistency should be10%and the0.2%DTPA,Na2SiO3,3%, the process carried for80°C, under90min.We also divide the extractive solvent into different compositions, as acidiccomponent the neutral component, and the ArOH component. The phenolscomponents accounted for about64.66%of the total extraction, the neutralcomponent is about28.43%out of the extraction. The left substances phenols islittle but have a significant impact on the brightness of the pulp, it can beremoved in the impregnated part, more than80%. And about50%of the acidicsubstances is removed in the process too.Then we treat the pulp with the impregnating condition, the result show thatafter the bleaching treatment, the extractive is induced from2.28%to1.13%, andthe brightness of the pulp also have a decline of1.53%ISO. After the neutralimpregnating the extractive is induce for about42.11%, and the brightness isabout1.4%ISO declined.After pulp bleaching extractives of unbleached pulp and bleached pulp wastested, the dissolution rate of the extractives is36.44%after the neutral Na₂SO₃ impregnation and bleaching, and51.78%dissolution rate after the alkaliimpregnation and bleaching. These show that the addition of the Alkali andhydrogen peroxide can help the dissolution of the extractives.The separation of the extractives of the unbleached pulp was carried withthe Fisher’K method, and the analysis is carried by GC-MS. The result show thatafter the extract of the unbleached pulp, the extractives mainly consist of abieticacid and rosin acid, and the fatty acid composition is not expected high, that’sbecause during the impregnating treatment, the fatty composition is removedpartly. The neutral part, mainly consist of the Triglyceride （TG） is little, that’sbecause the TG is easy to saponificate, and after the saponificate, thecomposition is easily dissolved in the pulp and water system, causing theproperties of the product in the following process.The investigate of the bleaching pretreatment is also carried out, and theresult show us, after the pretreatment, the brightness of the pulp can increasedsignificantly, especially after the enzymatic treatment. The final brightness canreach75.63%ISO,which are much higher than the untreated and CaCl₂treatment.The research provide the industry a data support for the mill producing BCTMPof Masson pine.