金属离子在高温过氧化氢漂白中的影响与控制

研究了纸浆中通常存在的金属离子对硫酸盐法美国南方松氧脱木素浆高温过氧化氢漂白结果的影响以及对金属离子的控制方法。比较了锰,铜,铁、钙等离子对浆料白度,粘度及卡伯值的相关性和有关的变化规律。实验证明采用预处理方式和漂白中使用适量的螯合剂ＤＴＭＰＡ可以有效控制金属离子的负面影响,在过氧化氢用量４％时可使漂浆白度从２７．４％ＩＳＯ提高到８０％ＩＳＯ以上,漂浆质量得到明显改善。     

硫酸盐木浆含酶预处理的无元素氯和全无氯漂白

针叶木硫酸盐浆用木聚糖酶Ｉｒｇａｚｙｍｅ ４０－Ｘ４进行预处理,然后进行各种无元素氯和全无氯漂白。实验结果表明,酶预处理能提高后续漂白效果,提高白度,降低卡伯值,并改善纸浆的粘度,在不用元素氯的情况下,能将纸浆漂白到８８％ＩＳＯ以上的白度。     

氧化镁作亚硫酸镁盐浆氧漂的保护剂

进行亚硫酸镁盐法浆（下称镁盐浆）的氧气漂白（Ｏ）试验，氧漂浆的过氧乙酸（ＰＡ）预处理和Ｈ２Ｏ２漂白（Ｐ）试验，以及样品的傅立叶变换红外光谱、Ｘ－射线衍射研究．结果证明，添加ＭｇＯ的氧漂浆，在白度、粘度、结晶度等方面均优于添加ＭｇＳＯ４的氧漂浆；应用Ｏ′ＫＩ法红外结晶指数及Ｘ－射线衍射法结晶度均能较好地反映样品的结晶结构变化．Ｏ－ＰＡ－Ｐ漂白流程为实现镁盐浆全无氯、短序、高白度漂白提供一种有效途径．     

KRAFT WOOD PULP TCF AND ECF BLEACHING WITH ENZYME PRETREATMENT *

针叶木硫酸盐浆用木聚糖酶Ｉｒｇａｚｙｍｅ４０＿Ｘ４进行预处理,然后进行各种无元素氯（ＥＣＦ）和全无氯（ＴＣＦ）漂白．实验结果表明,酶预处理能提高后续漂白效果,提高白度,降低卡伯值,并改善纸浆的粘度,在不用元素氯的情况下,能将纸浆漂白到８８％ＩＳＯ以上的白度     

H_2O_2漂白蔗渣浆H_2SO_4预处理的研究

通过试验发现Ｈ２ＳＯ４预处理蔗渣浆能除去浆料中大量灰分，显著减少铁、锰离子含量，同时浆料高锰酸钾值有某些降低，可以为有少量木素溶解或结构发生变化，因而在相同漂白条件下，经Ｈ２ＳＯ４预处理后浆样白度提高６～８度。由于漂前酸的作用，漂白前后浆料多戊糖含量和漂白浆的得率略有减少。     

蔗渣浆ECF短序漂白流程的对比

对典型的蔗渣浆无元素氯(ECF)短序漂白流程D0EpD、OpDEp及OpD进行了对比,探讨了二氧化氯脱木素(D0)与过氧化氢强化氧脱木素(Op)的脱木素效率差异及对后续漂白的影响,并分析了漂白过程中可吸附有机卤化物(AOX)的产生量和各漂白流程的直接化学品成本.结果表明:D0段脱木素选择性好,ClO2用量为0.8%时脱木素率即达40%以上,且用量越高脱木素作用越强;Op段在脱出纸浆中残余木素的同时能大幅提升纸浆白度,纸浆白度明显高于D0浆;相同后续漂白化学品用量下,OpDEp漂后浆白度高于D0EpD漂后浆白度,且比OpD漂后浆白度约高12个百分点;相同纸浆白度下,OpDEp漂白过程中产生的可吸附有机卤化物总量约为D0EpD的50%,其直接化学品成本比后者低约40.00元/t,具有更好的环境、经济效益.     

LARGE PIEZORESISTANCE AND PRESSURE－INDUCED METAL－SEMICONDUCTOR TRANSISTION IN THE PEROVSKITE－LIKE La－Ar－Mn－O

ＬＡＲＧＥＰＩＥＺＯＲＥＳＩＳＴＡＮＣＥＡＮＤＰＲＥＳＳＵＲＥ┐ＩＮＤＵＣＥＤＭＥＴＡＬ┐ＳＥＭＩＣＯＮＤＵＣＴＯＲＴＲＡＮＳＩＳＴＩＯＮＩＮＴＨＥＰＥＲＯＶＳＫＩＴＥ┐ＬＩＫＥＬａ┐Ａｒ┐Ｍｎ┐ＯＺｈａｎｇＮｉｎｇ１），２）ＤｉｎｇＷｅｉｐｉｎｇ...     

烧碱-AQ法麦草浆全无氯漂白的研究

研究了烧碱-AQ法麦草浆全无氯漂白(OQP)流程中氧脱木素、整合处理和过氧化氢漂白的影响因素．结果表明;氧脱木素段NaOH用量2．5％,MgSO4用量0．5％,浆浓10％,温度105℃,氧压0．7MPa,时间75min时脱木素效果较好,对后续漂白有利．整合处理pH值为3时,浆料的自度最高,卡伯值最低．压力H2O2漂白的最佳工艺条件为;浆浓10％,H2O2 3．5％,NaOH1．5％,MgSO2 0．05％,EDTA 0．2％,氧压0．6MPa,温度105℃,时间2h．在优化条件下,漂终白度达82．2％ ISO．     

蔗渣浆的全无氯漂白工艺

对蔗渣浆采用过氧化氢强化的氧脱木素(OP)-螯合预处理(Q)-压力过氧化氢漂白(PO)的短序漂白,探讨了将蔗渣浆漂至82%ISO和用非硅过氧化氢漂白稳定剂代替硅酸钠用于过氧化氢漂白的可行性.研究表明,非硅过氧化氢稳定剂PP-1与PP-2耐高温、耐高压,可用于压力过氧化氢漂白.OP段氢氧化钠用量为2.0%(相对于绝干浆质量,下同)、过氧化氢用量为0.5%,PO段过氧化氢用量为3.0%、PP-1用量为0.1%、PP-2用量为0.5%时,蔗渣浆采用OPQPO流程漂白后,浆的白度可达到85%ISO.而且OPQPO从根本上消除了可吸附有机卤化物的产生;经测定,漂白废水属于可生物降解废水.     

废纸脱墨及H_2O_2漂白的研究

本试验分别以十二烷基苯磺酸钠、油酸钠等表面活性剂用于废纸脱墨,并对脱墨后的废纸浆进行了Ｈ２Ｏ２ 漂白。结果表明,在废纸浆中加入２％ ＮａＯＨ、３．５％ Ｎａ２ＳｉＯ３、１％ Ｎａ２ＣＯ３ 和１％ 的以油酸钠为主要成分的脱墨剂,废纸脱墨成本低、效果好。浆样在Ｈ２Ｏ２ 漂白后白度为８９．６％ ＳＢＤ,脱墨率可达到９２％ 。     

STUDY ON THE ELEMENTAL CHLORINE FREE BLEACHING OF BAMBOO KRAFT PULP

1INTRODUCTIONChina is a country using the most variety of non-wood fiber raw material and is the largest country producing non-wood fiber pulp and paper in the world[1]. Bamboo is one kind of the main non-wood species for papermaking in China. Although the structure of raw materials for papermaking has being adjusted through increasing the proportion of wood pulp and by effectively utilizing waste paper source, non-wood species will still remain an important fiber resource[1,2].At present…     

THE TCF BLEACHING OF NS-AQ ASPEN HIGH YIELD CHEMICAL PULP

INTRODUCTIONNowadays, under the pressure of energy crisis, Methods押The pulp was put in the high-density polyethylene plastic bag in the of thermostatic water bath where the pulp was treated with chelated environment pollution and market competition, the pulp industry has being developed in the direction of "Three Highness" and " Three Lowness". "Three Highness" means high yield, high strength and high brightness; on the other hand, " Three Lowness" means low energy consumption, low wa…     

STUDY OF COORDINATED PRETREATMENT OF XYLANASE AND LACCASE ON SODA-AQ WHEAT STRAW PULP BEFORE CEH BLEACHING

INTRODUCTIONXylanase pretreatment can produce many small holes on pulp surfaces and cross section by removing part xylose that may be sucked back or exists in style of LCC. Thus penetrability of following chemicals. Olsen [1] observed coordinated pretreatment of xylanase and lignin enzyme (compound of lignin peroxide enzyme and manganese peroxide enzyme) had better delignification than sole xylanase and sole laccase lignin enzyme. So we can forecast that coordinated pretreatment of xylan…     

ON THE BLACK LIQUOR AND RECYCLE COOKING OF AS-AQ STRAW PULP

1.INTRODUCTIONAs a kind of agriculture residues, straw occupies an important status in the non-wood papermaking material in China. Straw is herbaceous plant yearly, and composed with successive and organized cell groups that is similar with others plants. The construction of straw fiber has three obvious layers and the sequence is lamella, primary wall and second wall. Because the organization is loosen andporous, the lignin content is lower and the cooking liquor is easer to penetrate so…     

MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.     

微波辐射应用于麦草浆漂白工艺的研究

将微波辐射代替传统水浴加热应用于H2O2麦草浆漂白工艺中。研究了微波辐射时间、辐射功率、H2O2用量和NaOH用量等因素对纸浆漂白效果的影响。通过与传统水浴加热漂白对比发现,达到相应白度时微波辐射漂白时间大大缩短;微波辐射漂白纸浆粘度没有过多下降;微波辐射漂白废水中的残余过氧化物只有水浴漂白的10%。正交实验结果表明H2O2用量的影响最大,其次是微波辐射时间和NaOH用量,影响最小的是微波输出功率。最佳实验条件为微波辐射功率240?W、辐射时间25?min、H2O2用量5％和NaOH用量4％时纸浆白度约为59％ISO,纸浆粘度大于620?mL·g-1,纸浆硬度约为390。     

HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.     

THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

INTRODUCTIONHydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. IT is well known that hydrogen peroxide can be easily decomposed under alkaline conditions, especially in the presence of transition metal ions due to their catalyzing effect on the decomposition of hydrogen peroxide. Some recent reports show that the valence of transition metal ion can have a drastic effect on the decomposition of hydrogen peroxide.Generally, iron can exist in Fe2+ and Fe3+…