木质素磺酸镁的改性及其对水泥的减水性能研究

以木质素磺酸镁溶液为原料，通过化学方法，分别引入了羟甲基、羧基、酰氨基、磺酸基等基因，以期增大木质素磺酸镁对水泥的分散作用和提高对混凝土的减水率。结果显示：引入羟甲基可提高木质素磺酸镁对水泥的分散效果，减水率为9．5％；而同时引入羟甲基和磺酸基的效果最好，减水离最高达19．0％。     

木质素磺酸钠接枝改性脂肪族高减水剂的研究

针对脂肪族减水剂原材料价格上涨与纸浆废液的资源化利用,在传统脂肪族减水剂中引入草本木质素磺酸钠(木钠)进行接枝共聚,设计合成了木钠接枝改性脂肪族高效减水剂HLC-RS(M).采用单因素法研究影响HLC-RS(M)分散性的主要参数,得出接枝共聚的最佳参数,并与传统脂肪族减水剂及脂肪族减水剂-木钠物理复配的性能进行比较表明,HLC-RS (M)的综合性能优于传统脂肪族减水剂.     

木质素磺酸钠改性Ca-LDH对水泥基材料性能的影响

水滑石材料(LDHs)是一种新型多功能二维纳米材料,水泥的水化产物(AFm相)属于钙铝型水滑石系列,因LDHs优异的性能在建筑材料领域其应用前景广阔。本文以木质素磺酸钠作为改性剂,采用水热法合成了木质素磺酸盐改性LDHs(Ca-SLS-LDH),对比了改性前后Ca-LDH的表面形貌、平均颗粒尺寸和比表面积的差异,研究了不同掺量Ca-LDH对水泥凝结时间、砂浆流动性和力学性能的影响,并采用SEM、XRD和压汞仪(MIP)等方法对水泥水化产物组成和微观结构进行了分析。结果表明:Ca-SLS-LDH的平均颗粒尺寸更小,比表面积是未改性Ca-LDH的60多倍;当LDHs掺量不超过4%(质量分数)时,能够有效改善水泥石孔结构,促进水泥砂浆强度发展,掺量为6%(质量分数)时会导致孔隙率增大,强度降低。     

木质素磺酸钠和木质素磺酸钙对煤的成浆性研究

以陕西某地区煤样为对象,进行木质素磺酸钠和木质素磺酸钙的成浆实验。研究发现,2种添加剂的分散性能较差,其中木质素磺酸钠的分散性能明显优于木质素磺酸钙;而2种添加剂的稳定性较好,且差异较小;在成浆浓度仅为60%和61%、添加剂量0.6%～1.4%的条件下,成浆粘度均在800 mPa.s以上。     

MnO2 reduction by calcium lignosulfonate: the kinetics and mechanism studies

ABSTRACT

The kinetics and mechanism of the reduction of manganese dioxide ore by calcium lignosulfonate (CLS) in acid solution were investigated. The results showed that the reducing process mainly occurred after the adsorption and then decomposition of CLS by ore and the concentration of sulphuric acid exerted an enhancing effect on both CLS adsorption and manganese extraction. The effects of leaching temperature, the mass ratio of CLS to MnO₂ in ore, concentration of sulphuric acid as well as leaching time on per cent leached of Mn were also discussed. The experimental data were well interpreted with a shrinking core model of internal diffusion, and an overall kinetic model was established. The reaction rate constant was found to be proportional to the mass ratio of CLS to MnO₂ in ore and concentration of sulphuric acid, and the apparent activation energy was determined to be 69.4?kJ?mol^?1 by using Arrhenius expression.     

木质素磺酸盐的膜法提纯及分级

研究利用微滤除杂+陶瓷膜酸化除盐+多级超滤工艺提纯分级木质素磺酸钠,该工艺离子去除率高,Ca~(2+)含量由90.41 mg/L降至15.53mg/L, Mg~(2+)含量由96.24mg/L降至11.77mg/L, SO_4~(2-)含量由6667.9mg/L降至224.07mg/L,离子去除率分别为82.82%, 87.77%, 96.64%,木质素磺酸钠纯度由53.42%提高到95.10%。分子量测试证实了膜法分级木质素磺酸钠的有效性,各级分产品红外光谱存在差异。该提纯分级工艺满足了高端应用中对纯度、活性、分散度的要求,工业上可因应用需求选择不同级别的级分,提升了其工业实用价值。     

Study of sodium lignosulfonate prepare low-rank coal-water slurry: Experiments and simulations

The effect of sodium lignosulfonate (SL) as additive on the preparation of low-rank coal-water slurry (LCWS) was studied by experiments and molecular dynamics (MD) simulations. The experimental results show that the appropriate amount of additives is beneficial to reduce the viscosity of LCWS and increase the slurry concentration. Adsorption isotherm studies showed that SL conforms to single-layer adsorption on the coal surface, and △G_ads⁰ was negative, proving that the reaction was spontaneous. Zeta potential measurements showed that SL increased the negative charge on coal. FTIR scanning and XPS wide-range scanning were performed on the coal before and after adsorption, and it was found that the content of oxygen functional groups on coal increased after adsorption. Simulation results show that when a large number of SL molecules exist in the solution, some SL molecules will bind to hydrophobic hydrocarbon groups on coal. The rest of the SL molecules, their hydrophobic alkyl tails, come into contact with each other and aggregate in solution. The agglomeration of SL molecules and the surface of coal with static electricity will also produce electrostatic interaction, which is conducive to the even dispersion of coal particles. The results of mean square displacement (MSD) and self-diffusion coefficient (D) show that the addition of SL reduces the diffusion rate of water molecules. Simulation results correspond to experimental results, indicating that MD simulation is accurate and feasible.     

木质素磺酸钙接枝改性制备高效减水剂的研究

以(NH4)2S2O8为引发剂,通过自由基溶液共聚反应,在木质素磺酸钙表面接枝丙烯酸、马来酸酐等单体,合成了接枝改性木质素磺酸盐减水剂.以净浆流动度为考察指标,通过正交试验确定最佳工艺条件:引发剂用量为0.2%,丙烯酸用量为10%,反应时间为2 h,反应温度为80℃;对于改性前后的起泡性进行了对比,研究了改性木质素磺酸盐减水剂对水泥净浆流动度、凝结时间和减水率的影响,并进行了对比试验.结果表明:改性后的起泡性有了明显的减弱,并有效缩短了凝结时间,具有较好的减水性能,减水率达20.85%.     

麦草木质素磺酸钠制备缓释氮肥的研究

通过对尿素改性后木质素磺酸钠产品中总氮和铵态氮含量的分析测定,研究了改性反应pH值、反应时间、温度、尿素用量等工艺条件对尿素改性麦草木质素磺酸钠制备缓释有机氮肥的影响。结果表明：pH4、温度70℃、时间4h、尿素／木质素（w／w）为1．6时,是较为理想的反应条件,改性木质素磺酸钠产品的总氮含量为5．85％,铵态氮含量为0．48％。     

木素磺酸盐添加剂对水煤浆流变行为影响研究

为了工业应用上的需要，实验通过流变测量的方法研究了木质素磺酸钠(简称木钠)对水煤浆的流变行为影响，包括木钠浓度、分子量、浆体温度、pH值及木钠与NDF在预剪切条件下的流变性能比较。结果表明：木钠的添加量超过煤重的0．8％时，过量的木钠会引起水煤浆黏度的增加。煤浆的流动性并不随着木钠分子量的增加而增加。相对分子量在10000～50000的级分对流变性较为有利。掺加木钠的煤浆温度只有在60℃时达到最佳的降粘效果。远离此温度点时黏度将增加。煤浆溶液在pH=9的弱碱性环境时最能发挥木钠的分散作用。预剪切实验表明掺加木钠的煤浆溶液的黏度会随着预剪切时间的增加而增加。