锯屑亚铵法制浆工艺条件探讨

在大力倡导节约原料,降低成本,减少污染的制浆方法下,本实验采用污染较小的亚铵法对锯屑进行蒸煮,找出了较佳的蒸煮工艺条件。其较佳蒸煮工艺条件为:最高蒸煮温度165℃,亚铵用量(18—20)%,液比1:2.5,尿素用量2%.AQ用量0.05%。在此条件下,所得浆耐破度165 kPa,裂断长4 768 m.撕裂指数8.7 mN·m2·g-1。     

用烧碱作亚铵蒸煮缓冲剂生产B级凸版纸

我厂用液体烧碱作亚铵蒸煮缓冲剂生产B级凸版纸效果很好。工艺技术条件是:装锅量2500kg(绝干,25m~3蒸球),亚铵用量17％,液体烧碱用量3％,液比1:2.4,蒸煮有效时间3:50h,粗浆     

亚铵法蒸煮的有关计算

我国的中小型纸厂中,亚铵法制浆厂不少。蒸煮工每天都要计算每球亚铵用量多少?每球应加游离铵多少?若亚铵母液中含亚氢铵时,中和氨需要多少?当液比一     

光叶楮白皮制浆方法的比较及亚铵制浆工艺的优化

采用4种方法对光叶楮白皮制化学浆进行了探讨,并且对光叶楮白皮亚硫酸铵法制浆工艺进行了优化,系统讨论了亚铵用量、尿素用量、蒽醌用量、液比、保温温度和时间对制浆效果的影响,确定出光叶楮白皮亚铵法制浆的最佳工艺条件为:亚铵用量18%,尿素用量5%,AQ用量0.15%,液比1:6,最高温度165℃,保温时间2h.最优化条件下纸浆的粗浆得率为50.3%,细浆得率为48.6%,高锰酸钾值为3.24,白度为51.0%ISO.     

氧化镁作亚铵法缓冲剂制取红麻浆的试验

目前,一些小草浆厂为了减轻蒸煮废液对土壤和水源的污染危害,采用了亚铵法制浆,并将蒸煮废液用作农肥。但亚铵法蒸煮对生产设备有一定腐蚀,为了防腐,一般在亚铵蒸煮液中添加过量氨水以提高pH值。由于氨的气味大,掌握也较难,有的企业在蒸煮液中添加烧碱或纯碱作为缓冲剂。这样虽较易控制,但给蒸煮废液中带入了大量钠离子,以此用作农肥是不利的。本文介绍的采用氧化镁作为亚铵法蒸煮液的缓冲剂蒸煮红麻浆,取得了较好效果。估计用于麦草等其他草类浆的蒸煮,也可以取得类似效果,希望能引起亚铵法草类浆厂的重视。     

麦草亚铵法用MgO作缓冲剂的生产试验

新疆和静7235厂生产主要品种为52克/米~22号凸版纸。原料为麦草,用亚硫酸铵法加氢氧化钠缓冲剂。所用蒸煮条件为:亚铵用量14.5％;氢氧化钠用量2.5％;最高蒸煮压力0.65MPa;保温4:00h;纸浆硬度15左右(高锰酸钾值)。从1991年10月至12月,试验了用氧化镁作亚铵蒸煮缓冲剂,蒸煮了30球,证明用MgO作亚铵蒸     

亚铵法蒸煮工艺改进的思考

亚铵法制浆、蒸煮设备被腐蚀的原因是多方面的，其中蒸煮终点的pH值下降为酸性是造成腐蚀的重要原因之一。蒸煮过程中产生的H 离子的逐渐积累最终导致pH下降的因果关系，为我们解决问题提供了基本的思路和方向。如何恒定蒸煮的pH值，提高蒸煮液的缓冲能力，这就需要对传统蒸煮工艺进行重大改进的原因。1确定蒸煮的初pH=9．26在亚铵法制浆的诸多理论与实践中都讲到了缓冲剂氨水的作用和用量问题，却少有对pH值确定的讨论，这是一个不可忽略的问题。本人在《纸和造纸》1997年第4期发表的《亚铰法蒸煮中亚按和氨水用量的计算》一文中提到了p…     

构皮过氧化氢草酸盐法制浆初探

本论文研究了蒸煮最高温度、蒸煮液的酸碱度、保温时间、草酸钠及过氧化氢用量对构皮过氧化氢草酸盐法制浆的影响。研究表明：蒸煮液的酸碱度对木素脱除影响较显著，中性偏弱酸性条件有利于木素的去除，较佳的构成过氧化氢草酸盐法蒸煮工艺条件为：草酸钠用量20％，碳酸钠0.5%，过氧化氢10％，最高温度90℃，保温时间1h，液比1∶10,pH值4.82-8.71。蒸煮结果为：粗浆得率71.22%，卡伯值36.12。     

低能耗亚铵法蒸煮制浆与废液回收利用消除污染

低能耗亚铵法蒸煮制浆与废液回收利用消除污染汪仲熙（四川宜宾造纸厂６４４００７）亚铵制浆在我国已有几十年经历，在非木材植物制浆领域用此法，制半化学浆，半漂白浆较为普遍，早有试验表明，亚铵蒸煮废液由氮、磷、钾含１０％左右和有机物组成，可作为农业肥料。但因...     

亚铵法玉米秆浆过氧化氢强化氧脱木素的研究

对亚铵法除髓玉米秆浆H2O2强化氧脱木素进行了研究,并通过正交实验得出H2O2强化氧脱木素的最佳工艺条件:浆浓9%,H2O2用量3%,用碱量4%,氧压0.6MPa,温度70℃,时间60min,MgSO4用量0.5%,Na2SiO3用量3%。在此条件下,漂白浆的白度可达72.5%,黏度为762mL/g。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status