Optimization of the technological properties of porcelain tile bodies containing rice straw ash using the design of experiments methodology

This study examines the effects of replacing fluxing and filler materials with rice straw ash (RSA) in manufacturing porcelain stoneware tile, using the design of experiments (DOE) methodology. The results of the characterization were used to obtain statistically significant, valid regression equations, relating the technological properties of the dried and fired test pieces to the raw materials content in the unfired mixtures. The regression models were analysed in relation to the X-ray diffraction and scanning electron microscopy results and used to determine the most appropriate combinations of traditional raw materials and RSA to produce porcelain stoneware tiles with specific technological properties. The studied range of tile body compositions: clay (40 wt%), feldspar (20–50 wt%), feldspathic sand (5–20 wt%), and RSA (0–25 wt%) was shown to be appropriate for porcelain stoneware tile manufacture.     

Purification of Biorefinery Lignin with Alcohols

After hydrothermal pretreatment and enzymatic hydrolysis of wheat straw, a slurry rich in lignin but with a high content of inorganic substances, especially silica, and residual carbohydrates is produced. This slurry was used to develop an ethanol organosolv separation method to produce silica-free lignin fractions. The addition of para toluene sulphonic acid (PTSA) and the use of two alternative long-chain alcohols, oleyl alcohol or nonylphenol, were tested. In every reaction, two lignin fractions were produced and their molecular size and elemental composition were characterized. The yield of each fraction and the change in MWD were studied as a function of temperature and solid to liquid ratio. At 100, 150, and 200°C and with the use of PTSA, high-purity lignin fractions were obtained. After lignin fractionation with nonylphenol, a liquid silica-free product with high lignin content was obtained in yields between 17 and 72%.     

玉米秸秆热解特性及动力学分析

以玉米秸秆为原料, 利用热重分析法研究其热解的特性及动力学。根据TG和DTG曲线, 研究玉米秸秆的热解特性, 采用Flynn-Wall-Ozawa(FWO)和Kissinger-Akahira-Sunose(KAS)两种等转化率法计算玉米秸秆热解的活化能, 并结合主曲线法和Coats-Redfern(C-R)法探讨了玉米秸秆热解遵循的机理方程。研究结果表明: 玉米秸秆热解过程可分为干燥脱水、过渡、主热解和炭化4个阶段, 随着热解升温速率增大, TG和DTG曲线向高温侧偏移; 利用FWO和KAS法计算得到的表观活化能分别为181.7和181.5 kJ/mol; 利用主曲线法和C-R法求解出玉米秸秆热解的机理方程遵循Avrami-Erofeev方程, 当α=0.1~0.5时, n=3, f(α)=1/3(1-α)[-ln(1-α)]^-2; 当α=0.5~0.7时, n=2, f(α)=1/2(1-α)[-ln(1-α)]^-1。     

^60Coγ辐照水稻秸秆制备阳离子吸附剂的研究

采用辐照法将二甲基二烯丙基氯化铵接枝共聚于预处理的水稻秸秆,考察了产物对于阴离子染料和COD的吸附性能,结果表明接枝后秸秆有吸附阴离子的效果.研究了溶液pH值、吸附时间和温度对吸附过程的影响,吸附剂对于阴离子染料与COD的最大吸附量分别为335 mg/g和73 mg/g.     

秸秆醋酸纤维素的制备

农作物秸秆是自然界中数量极大的可再生资源,本研究以农作物秸秆为反应原料,采用无污染蒸汽爆破技术活化预处理,然后进行乙酰化反应,通过溶剂萃取分离并制备出高附加值的醋酸纤维素。实验结果表明：秸秆汽爆后明显增加了反应活性,制备醋酸纤维素的适宜条件是123℃,2 h,催化剂用量为7％,汽爆秸秆中性洗涤剂处理后的乙酰化结果效果最好,不同汽爆秸秆中小麦秸秆乙酰化效果最佳,优化实验条件下,秸秆醋酸纤维素聚合度均在120以上,取代度2.80以上,并且用红外图谱、1H NMR进行了表征。与目前工业上采用α-纤维素含量较高的高级浆为反应原料相比,不仅原料和预处理成本大大降低,而且工艺流程简单。     

碱性条件下稻草NH4OH-KOH蒸煮黑液的絮凝处理

利用聚合氯化铝-聚丙烯酰胺处理稻草NH4OH-KOH蒸煮黑液。系统讨论了聚合氯化铝用量、聚丙烯酰胺用量、反应温度和黑液pH值等工艺参数对絮凝效果的影响,继而确定了适宜絮凝工艺条件。结果表明,该絮凝体系对黑液COD去除率为68%,木质素去除率为92%。仪器测试表明絮凝沉淀物中除含有大量木质素外,氮、钾等营养元素的含量分别为23. 73%、6. 24%(均为干基),为絮凝沉淀物制备固体有机肥料创造条件;上层清液pH 为9. 20,呈碱性,杂质含量低,补加NH4OH/KOH后可作为蒸煮液循环使用,使稻草制浆更易于实施清洁生产。     

圆网浓缩机在文化纸机打浆配料系统中的应用

介绍了圆网浓缩机在文化纸机打浆配料系统中对自制草浆进行二次洗浆中的应用。采用圆网浓缩机洗浆处理后,造纸机湿部系统Zeta电位趋于平衡,有效解决造纸机生产障碍,提高化工辅料使用效率。     

布袋除尘技术在干法备料的应用

介绍了营口造纸厂采用布袋除尘技术对芦苇制浆干法备料进行除尘及布袋除尘器在使用中应注意的问题。生产实践表明,采用布袋除尘器后,除尘效果很好,净化了生产车间的环境,从根本上改善了工人的劳动条件和厂区环境,彻底解决了造纸厂的灰尘污染问题,并取得了一定的经济效益。     

麦草碱木素基活性炭对苯酚吸附的研究

在无水碳酸钾与麦草碱木素质量比4∶1、活化温度800℃、活化时间1 h的条件下制备麦草碱木素基活性炭,探讨了麦草碱木素基活性炭对苯酚的吸附作用。结果表明,麦草碱木素基活性炭的得率为17.9%,碘吸附值为827.5 mg/g;用麦草碱木素基活性炭处理100 mL苯酚溶液时,当苯酚初始质量浓度250 mg/L、麦草碱木素基活性炭投加量0.1 g、吸附温度30℃、苯酚溶液pH值约7时,麦草碱木素基活性炭对苯酚的吸附于80 min时达到平衡。麦草碱木素基活性炭对苯酚的吸附行为可用Langmuir等温式描述。     

稻草常压酸水解工艺的研究

研究了稻草常压酸水解工艺,通过单因素实验确定了酸水解适宜的工艺条件,并以还原糖提取率为评价指标,评价了稻草的常压酸水解效果。结果表明,稻草适宜的酸水解工艺条件为:酸水解温度100℃、酸水解时间3 h、质量分数为3%的硫酸、固液比1∶4,在此工艺条件下稻草酸水解得率为73%,还原糖提取率约为17%,多戊糖去除率约为65%;酸水解后的稻草中多戊糖含量为12.2%,用酸水解后稻草生产的人纤浆基本能够达到人纤浆质量标准的要求。