The Development And Application On Non-silicon Stabilizer For Hydrogen Peroxide Bleaching

Eucalyptus chemithero-mechanical pulp(CTMP) as a kind of high yield pulp is widely produced and used in the pulp and paper mills in China. During the production of CTMP,peroxide(H2O2) is widely used in the pulp bleaching. However, the hydrogen peroxide decomposition which is catalyzed by the transition metal ions such as Mn2+, Cu2+and Fe2+/Fe3+affects the bleaching efficiency negatively. sodium silicate(Na2SiO3) is mostly used as stabilizer in peroxide bleaching for the improvement of peroxide bleaching efficiency,However, sodium silicate can cause very serious fouling problem,The chelating agents such as DTPA are used as stabilizers in peroxide bleaching for the improvement of peroxide bleaching efficiency, but the low biodegradability and low chelating efficiency at alkaline condition limits their application in alkaline peroxide bleaching.So the research and development of silicon type hydrogen peroxide stabilizer instead of sodium silicate and DTPA in the pulp and paper industry has a positive practical significance.The different types of hydrogen peroxide stabilizer at home and abroad for Eucalyptus TMP hydrogen peroxide bleaching is Chosen to pick up the stabilizers for alkaline hydrogen peroxide bleaching.The experimental results show that::under the conditions of H2O210%、NaOH 6 %, pulp concentration 20%, 100 ℃, 40 min, formula(0.5% divinyl three amine five methylene phosphine acids DTPMPA and ethylenediamine 0.5% two adjacent phenyl acetic acid natrium EDDHA-Na) whose whiteness of bleaching pulp is 79.42% ISO is almost the same as formula(2.5%Na2SiO3 and 0.5%DTPA) which is 79.41% ISO. The whiteness of pulp by using EDDHA-Na and DTPA indicate that the effect of EDDHA-Na in the process of bleaching effect is better than DTPA.0.5%DTPMPA /0.5%EDDHA-Na were compared with 2.5%Na2SiO3 /0.5%DTPA and as stabilizer,which were used for three kinds of Eucalyptus TMP alkaline hydrogen peroxide bleaching process at different hydrogen peroxide levels, the results show that:at the same level of H2O2, the stability is similar, and they can get the similar brightness with same dosageof NaOH.DTPMPA /EDDHA-Na were compared with Na2SiO3 /DTPADTPA as stabilizer, which were used for Eucalyptus CTMP alkaline hydrogen peroxide bleaching process, the results show that : at the same total dosage of H2O2 and NaOH, and the same freeness of 200 mL,two kinds of stabilizer consume similar energy and get nearly tensile strength while the former stabilizer increased thickness by 5.1%, increased burst strength by 13.8%, increased tear strength by 79.45%, increased brightness by 1.3% ISO, opacity and light scattering coefficient also increased slightly. For eucalyptus CTMP, the amount of NaOH in the chemical pretreatment stage influenced pulping performance. At the same total dosage of NaOH, when the usage of NaOH was increased by 0.5% at chemical pretreatment stage, energy consumption is lower, thickness decreased by 9.5%, while burst strength increased by 53.1%,the tear strength increased by 118.3%, the tensile strength increased by 36.4%, brightness increased by 3%ISO. The bleaching stability of NG2 was better than that of NG1 and SA. The pollution load from three pretreatment methods were different, the highest pollution load was SA which is 140.7 kg/t, the second was NG1 which is about 126.9 kg/t, the lowest was NG2 which is about 97.24 kg/t, about 33% lower than SA. So the non-silicon stabilizer NG in bleaching process can reduce the pollution load, and it is more possible to realize cleaner production.