强韧包装纸板用落叶松半化学浆的研究

主要研究一种可以替代传统硫酸盐化学木浆，来生产强韧包装纸板或瓦楞纸箱箱板纸的落叶松碱性亚硫酸盐－蒽醌半化学浆。这种采用碱性亚硫酸盐添加蒽醌助剂的制浆方法研制的落叶松半化学浆，当纸浆得率为５６．９％时，在低打浆度情况下纸浆强度性能可以达到我国２号未漂硫酸盐化学木浆的标准，而且有可能达到１号未漂硫酸盐化学木浆的标准，纸浆得率比落叶松硫酸盐木浆得率实际指标（４３％）绝对值提高１３％以上。用于制作强韧包装纸板或瓦楞纸箱箱板纸的落叶松碱性亚硫酸盐－蒽醌半化学浆，蒸煮终点宜于控制在得率约６２％、卡伯值１００左右。     

在矿浆过滤预处理中表面活性剂的应用

针对钼矿的基本物性,筛选合适的表面活性剂,进行钼矿浆过滤条件的试验研究。结果表明,钼矿浆中加入合适的表面活性剂后,增加了滤饼厚度,降低了滤饼湿含量,提高了对矿浆的处理能力。     

Optimising the dewatering behaviour of clay tailings through interfacial chemistry, orthokinetic flocculation and controlled shear

The effect of shear on dewatering behaviour and particle interactions of Na-exchanged smectite and kaolinite clay dispersions has been investigated at pH 7.5, using hydrolysable Ca(II) and Mn(II) ions as coagulants and high molecular weight anionic and non-ionic polyacrylamide (PAM A and PAM N, respectively) and polyethylene oxide (PEO) flocculants. Metal ion addition enhanced the flocculation performance by dramatically reducing the magnitude of the particle zeta potential and, in the case of smectite pulp, suppressing osmotic swelling. Under optimum orthokinetic flocculation conditions of controlled agitation rate and duration, PAM A and PEO-based flocs settled faster than those of PAM N whilst kaolinite pulps produced higher sedimentation rates than smectite pulps. The settling rates are nearly an order of magnitude greater than those observed under standard flocculant-pulp mixing/flocculation methods of inversion and plunging. The difference in the flocculant behaviour is attributed to the more expanded conformation of PAM A and PEO polymer chains in contrast to PAM N, whilst the lower yield stresses, reflecting inter-particle bridging and floc network structure strength that are conducive to faster clarification, were displayed by kaolinite pulps. Following shear, similar consolidation enhancement of ≈ 5-7 wt.% solid for both pulps was achieved at an optimum agitation range of 100-200 rpm. This was accompanied by decreased yield stress in the case of PAM A-based pulps, indicating non-reversible disruption of polymer mediated particle and floc network structure. In contrast, the yield stresses of PAM N and PEO flocculated dispersions indicated similar and stronger particle interactions, respectively, upon consolidation following shear. The findings show clear links between effect of shear, interfacial chemistry and polymer structure on pulp particle interactions and dewaterability.     

GC/MS characterization of effluents front the ozone bleaching of eucalypt kraft pulps

Concerns regarding the possible environmental effects of organochlorine by‐products from bleaching of pulp with chlorine‐based compounds have led to the pulp and paper industry developing new bleaching sequences. Ozone, oxygen and hydrogen peroxide are the main reagents in these Totally Chlorine Free (TCF) bleaching processes.

In this study, eucalypt kraft pulps from a variety of Australian wood sources were subjected to bleaching sequences comprising oxygen, ozone and hydrogen peroxide/alkali extraction stages. The aqueous liquid effluents from each stage were analyzed by GC/MS for aldehydes, ketones, alcohols, carboxylic acids and other by‐products. Pentafluorobenzyl oxime derivatives of the aldehydes and ketones were analyzed by electron impact GC/MS. The major carbonyl compounds detected were formaldehyde, glyoxal, dimethylglyoxal and acetone. An homologous series of n‐aldehydes corresponding to cleavage of ω‐3, 6, 9 and 12 unsaturated fatty acids also was detected. Aromatic aldehydes were identified in the oxygen stage and high consistency ozone stages, but not in any medium consistency ozone or post‐ozone bleach stages. In all stages a series of saturated alkyl carboxylic acids from formic to octacosanoic acid was detected. Formic and acetic acids were present in the highest yield. Only trace quantities of unsaturated fatty acids were detected. Details of these and other compounds detected are discussed.     

未脱墨废人民币纸浆配抄瓦楞原纸

为增加造纸工业的纤维原料来源并充分利用废人民币纸,本文对未脱墨废人民币纸浆配抄瓦楞原纸进行了初步的研究。采用5%氢氧化钠和硫酸溶液对废人民币纸进行化学预处理,再经PFI磨机械疏解后得到未脱墨的废人民币纸浆。采用纤维形态分析仪对未脱墨废人民币纸浆的纤维长度、宽度及其分布进行了分析检测。通过在废新闻纸浆中配加不同比例的未脱墨废人民币纸浆考查瓦楞原纸的质量指标,并对不同的纸浆配比进行分析。结果表明,废人民币纸浆的纤维长度在机械疏解过程中损失较多,只相当于草类原料化学浆的纤维长度。抄造定量为120 g/m2的瓦楞原纸,当废人民币纸浆配比增加时,瓦楞原纸的裂断长和环压指数均下降,废人民币纸浆的配抄比例控制在40%左右时,可以满足D级瓦楞原纸对裂断长和环压指数的要求。虽然废人民币纸浆的成纸强度较低而导致瓦楞原纸的强度指标下降,然而由于其原料价格较低,有利于降低瓦楞原纸的生产成本。     

Neural networks in process life cycle profit modelling

Changes in operational environment of the process industry such as decreasing selling prices, increased competition between companies and new legislation, set requirements for performance and effectiveness of the industrial production lines and processes. For the basis of this study, a life cycle profit (LCP) model of a pulp process was constructed using different kind of process information including chemical consumptions and production levels of material and energy flows in unit processes. However, all the information needed in the creation of relevant LCP model was not directly provided by information systems of the plant. In this study, neural networks was used to model pulp bleaching process and fill out missing information and furthermore to create estimators for the alkaline chemical consumption. A data-based modelling approach was applied using an example, where factors affecting the sodium hydroxide consumption in the bleaching stage were solved. The results showed that raw process data can be refined into new valuable information using computational methods and moreover to improve the accuracy of life cycle profit models.     

基于神经网络的统计优化方法及其在纸浆漂白工艺中的应用

应用三层前向网络作为预测纸浆漂白效果的分类模型。在网络能正常识别漂白效果所属类别的基础上，通过模拟计算和统计分析，确定了漂白工艺参数的优化操作区域。这为难以建立精确数学模型又是多约束的漂白工艺过程的优化提供了一种有效方法。     

基于支持向量机的蒸煮过程卡伯值软测量

卡伯值是制浆蒸煮过程表征纸浆质量的一个重要质量指标，卡伯值软测量是实现蒸煮过程质量控制的重要途径。支持向量机是一种新型的机器学习方法。该方法采用了结构风险最小化原则，与传统机器学习方法相比，在最小化学习误差的同时可以保证有较小的泛化误差。将支持向量机应用于制浆蒸煮过程卡伯值的软测量建模，取得了比经验模型更好的预测效果。     

A pulp mill benchmark problem for control: application of plantwide control design

A heuristic for design of plantwide control strategies is introduced and applied to the millwide control of a previously presented pulp mill benchmark. Two control strategies (decentralized control and unit-based model predictive control) are compared according to their capacity to reduce the total error and maximize the operating profits. The control strategies are studied through closed-loop simulations of the process including several disturbances and setpoint changes in the digester, oxygen reactor, bleach plant, recausticizing plant and lime kiln.     

The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS₂) and pyrite (FeS₂) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.