提高造纸用高岭土粘浓度及分散特性的研究

通过调节高岭土矿浆的pH值到8.5—9,使用6种分散剂单独或复配应用的方法,改变高岭土浆料的分散特性,提高粘浓度。结果表明:单独使用时,分散效果聚丙烯酸钠>萘磺酸钠>胶易素1>六偏磷酸钠>胶易素2>单宁酸;复配使用时,六偏磷酸钠与萘磺酸钠以质量比1∶1配合为最佳,可以将高岭土浆料粘浓度从69.7%提高至71.3%。

高岭石的结晶有序度及其对纸张涂布粘浓度的影响

粘浓度是纸张涂布的一项重要指标,测定的变化范围从46.4—72％。用Hinckley方法测定了高岭石的结晶度指数,从0.57变化至1.40。当粘浓度>67％时,结晶度指数>1。粘浓度<67％,结晶度指数<1,有序高岭石有利于粘浓度提高。随着结构无序化,晶粒变小,晶片变薄,比表面增加,晶体边缘和角易破损,使粘浓度降低。结构无序化破坏了颗粒的均匀性,使颗粒长/厚比增加,粘浓度降低。高岭石八面体中Fe^(3+)的存在一定程度上影响了有序度。

脲插层技术对茂名高岭土粘浓度的影响

对比美国、英国、巴西等国家高岭土近74%的高粘浓度,中国高岭土粘浓度不高,大多数在66%~70%之间。因而为满足造纸涂布工艺中,越来越高的刮刀速度的发展,各大造纸企业的优质高岭土都依赖于国外进口。为增强本国的造纸高岭土产品的竞争力,必须研究出高粘浓度的造纸涂布用高岭土。以脲插层技术提高茂名高岭土的粘浓度,使粘浓度自原来的68%提高至最大值74.05%。综合考察了反应时间、温度、水分及插层剂量的因素对高岭土粘浓度的影响。并通过粘浓度与插层率之间的对比,发现两者存在着相关关系。

洗涤对高岭土粘浓度的影响

介绍了茂名高岭土在精选过程中产生的电解质对产品粘度的影响机理 ,通过冲洗除去电解质后 ,可以提高茂名高岭土产品的粘浓度。

一种高粘浓度高岭土的生产工艺

本发明涉及一种高粘浓度高岭土的生产工艺，其特征在于它包括如下步骤：（1）用水力机械法开采高岭土矿，经制浆、分级、化学漂白、洗涤除铁、压滤脱水、分散制浆、剥片、振动筛分级，得高岭土矿浆料J；（2）喷雾干燥、插层。首先对喷雾干燥处生产线进行改进，喷雾干燥设备的绞龙、提升斗及料仓添加保温层，且在喷雾干燥设备的喷雾干燥口下方的绞龙处添置变频加料机，变频加料机由管道与尿素破碎机相连通；然后喷雾干燥，得高岭土粉；

响应面法提高神府煤制浆浓度的研究

针对神府煤丝质组含量高、高内水、高含氧量,难以制备出高浓度、低粘度的水煤浆的问题,以超细煤粉平均粒径d50=8μm煤粉百分含量,d50=6.5μm、4.5μm含量比和分散剂复配比为三因素,采用Box-Behnken设计试验,在粘度不变时,建立浓度的回归方程模型并进行方差分析。响应面分析三因素对水煤浆定粘浓度的影响,并进行优化。结果表明,最优配方为:8μm煤粉百分含量为70%,6.5μm:4.5μm为1.44,分散剂复配比为0.33,预测浓度为59.09%。按照最优配方进行试验验证,当粘度为580m Pa·s时,水煤浆浓度为60.29%,与理论预测值相近,且优化后的浆体稳定性和流变性也明显改善。

造纸高岭土粘度特性研究进展

粘度特性决定着高岭土在涂布造纸中的应用,作者通过对高岭土粘度特性及其影响因素的分析,对改善高岭土粘度特性方法和国内外研究现状进行了综述。

茂名高岭土漂白酸性废水的循环回用试验研究

为统筹协调经济发展和环境保护的问题,对茂名高岭土漂白工艺产生的酸性废水进行处理和循环回用研究。漂白酸性废水经中和—沉淀法处理后的外排水符合有关标准的要求,外排水与茂名山阁高岭土矿坑水以一定比例混合,混合水可进行循环回用。本文旨在探究混合水回用对造纸涂布用高岭土产品漂白工艺粘浓度的影响,评估混合水回用的可行性与经济环保价值。

Gravel Accumulation in Deposits of Viscous Debris Flows with Hyper-concentration

According to the observational data of viscous debris flows with hyper-concentration, debris flows can be classified into three types:high-viscous, viscous, and sub-viscous debris flows.Distinct formation mechanism of different graded bedding structures in deposits of viscous debris flows was analyzed in this paper by using their yield-stress ratio and flow plug ratio.This paper specially analyzed the effect of Weissenberg which the gravels in squirm condition of hyper-concentration viscous flows would tend to move vertically, and the formation mechanism of the gravels accumulated at surface was also studied.The analysis in this paper can establish a foundation for the studies on differentiation of bedding structures of debris flow deposits and studies on dynamic parameters of debris flows.

Influence of surfactants on bioleaching of arsenic-containing gold concentrate

To shorten the bioleaching cycle of arsenic-containing gold concentrate, surfactants were used to promote the interaction between bacteria and ore to increase the arsenic leaching rate. Three different kinds of surfactants were used to evaluate the effects of surfactants on the growth of bacteria and arsenic leaching rate of arsenic-containing gold concentrate. The mechanism underlying surfactant enhancement was also studied. Results show that when relatively low-concentration surfactants are added to the medium, no significant difference is observed in the growth and Fe2+ oxidation ability of the bacteria compared with no surfactant in the medium. However, only the anionic surfactant calcium lignosulfonate and the nonionic surfactant Tween 80 are found to improve the arsenic leaching rates. Their optimum mass concentrations are 30 and 80 mg/L, respectively. At such optimum mass concentrations, the arsenic leaching rates are approximately 13.7% and 9.1% higher than those without the addition of surfactant, respectively. Mechanism research reveals that adding the anionic surfactant calcium lignosulfonate improves the percentage of bacterial adhesion on the mineral surface and decreases the surface tension in the leaching solution.

Factors affecting phenol adsorption on clay-solidified grouting curtain

Batch experiments were conducted to study the adsorption of phenol on clay-solidified grouting curtain (CSGC) and the effects of contact time,pH and adsorbent concentration on the adsorption were investigated.Under the experimental conditions used,2 d was adequate to determine the equilibrium of phenol adsorption onto CSGC.The amount of phenol adsorbed by CSGC from an initial concentration of 100mg/L was found to be 8.4mg/g.The adsorption process includes particle diffusion and liquid film diffusion,and the latter is the predominating step of the adsorption process.The adsorption ability of CSGC decreased with pH but it increased non-linearly with the CSGC concentration.The optimized concentration for CSGC was found to be 20g/L for the adsorption of 100mg/L phenol.

Reducing Airborne Dust in a Loose-Housing System for Laying Hens

How different factors and techniques affect concentration and generation of dust in a floor housing system for laying hens was investigated in a climate chamber. The efficiencies of different dust reducing measures were investigated. A major part of the generated dust settled on different surfaces inside the building. The settling rate of dust was affected by the concentration of dust in the air. The settled amount of dust also stood in relation to the floor area of the stable. An increased ventilation rate had a limited effect on the concentration of total dust due to the importance of the settling of the dust. The generation of dust was also investigated when using six different bedding materials, namely： gravel, clay pellets, peat, wood shavings, chopped straw and chopped paper. Clay pellets and peat resulted in the lowest concentrations of dust. Automatic spraying of small droplets of water reduced the dust concentration in four trials with different bedding materials （chopped paper, clay pellets, peat and wood shavings）. Spraying a mixture of rapeseed oil in water was also effective with an automatic spraying system.

Effects of Alginate Gel on Rheological Properties of Hair-tail (Trichiurus lepturus) Surimi

Effects of alginate gel at different concentrations on rheological properties of hair-tail (Trichiurus lepturus) surimi were investigated. Alginate gel (1% - 3%) exhibited enhanced effects, especially when alginate gel concentration increased. The rheological properties of mixture samples were studied by the time sweep, frequency sweep and temperature sweep. The critical strain values of the mixture samples for the onset of non-linear viscoelasticity were about 5%. The storage modulus G' of the mixture samples increased with time for 4 h. The frequency sweep showed that G' was greater than G" for all the mixture gels with different alginate gel concentrations, and values of both n' and n" for all samples were low (<0.2), these constants corresponding to G' and G", and indicating the elasticity of mixture gels. The values of storage modulus G' decreased during heating process and increased with decreasing temperature.

Effect of starch particles on foam stability and dilational viscoelasticity of aqueous-foam

Surface dilational rheological behavior and foam stability of starch/surfactant mixed solutions were studied at different starch concentrations and constant surfactant concentration. The results show that dilational viscoelasticity modulus, dilational elasticity modulus and dilational viscosity modulus increase with the concentration of starch particles. Foam stability increases with dilational viscoelasticity. Foam strength also increases with starch concentration. Starch particles play a positive effect on foam stability and dilational viscoelasticity and the effect becomes more significant as drainage proceeds. Film pictures indicate that the film with 20%(by mass) starch particles is thicker than that without starch. Starch particles gather in Plateau border and resist drainage, making the foam more stable.

Membrane behavior of bentonite-amended Fukakusa clay in K, Na and Ca solutions

Bentonite has been proven to be effective in enhancing the membrane property of clay, by which landfill liners can have better barrier performance with regard to the migration of contaminants. In this work, 5% sodium bentonite amended with locally available Fukakusa clay was utilized to evaluate the membrane behavior toward different kinds of ions： K, Na and Ca. The chemico-osmotic efficiency coefficient, co, was obtained in electrolyte solution with different concentrations of 0.5, 1, 5, 10, and 50 mmol/L. According to the results, solute type and ion valence have a significant effect on membrane behaviors. Additionally, co continually decreased as the Na and Ca concentrations increased, which is consistent with the Gouy-Chapman theory. The membrane behavior toward Na was similar to that toward K, according to the chemico-osmotic efficiency coefficient co. In the case of the divalent ion Ca, the membrane behavior was lower compared to monovalent ions Na and K at the same concentration. The mechanisms of the membrane performance change were discussed with the assistance of XRD patterns, free-swelling results and SEM images.

Selenium in Soils of Moldova

Se （selenium） is an essential trace element for both animals and human beings, although it is considered to be conditionally required for plants. Se occurrence in the environment of Moldova is poorly understood. The objective of this study was to establish Se content and distribution in soils of this country. Se content in samples was detected using fluorometric method. Se concentration in soils ranged from 100 μg·kg^-1 to 668 og-kg-1 dry weight （mean 246 ± 73 μg·kg^-1）. Mainly, Se content in soils was optimal （more than 175 μg·kg^-1）, however, there were soil areas with Se deficiency （lower than 125/μg·kg^-1）. Maximum of Se in soils was observed at the depth of 0.4-0.7 m and then it decreased on going to parent rock. Se content typically increased with increasing of soil clay particles. Se washout from terraces and watershed slopes as well as Se accumulation in relief depressions was shown. High Se concentrations in local surface waters （0.2-6.1 μg·L^-1, mean 1.8 μg·L^-1） indicated the substantial presence of soluble Se forms, which were available to plants. Thus, geochemical conditions of Moldova are favorable for Se bioaccumulation by plants.

Clay Addition to Sandy Soil Influence of Clay Type and Size on Nutrient Availability in Sandy Soils Amended with Residues Differing in C/N ratio

Addition of clay-rich subsoil to sandy soil results in heterogeneous soil with clay peds （2-mm） or finely ground （〈 2 mm） clay soil （FG）, which may affect the nutrient availability. The aim of this study was to assess the effect of clay soil particle size （FG or peds） and properties on nutrient availability and organic C binding in sandy soil after addition of residues with low （young kikuyu grass, KG） or high （faba bean, FB） C/N ratio. Two clay soils with high and low smectite percentage, clay and exchangeable Fe and A1 were added to a sandy soil at a rate of 20% （weight/weight） either as FG or peds. Over 45 d, available N and P as well as microbial biomass N and P concentrations and cumulative respiration were greater in soils with residues of KG than FB. For soils with KG residues, clay addition increased available N and initial microbial biomass C and N concentrations, but decreased cumulative respiration and P availability compared to sandy soil without clay. Differences in measured parameters between clay type and size were inconsistent and varied with time except the increase in total organic C in the 〈 53 μm fraction during the experiment, which was greater for soils with FG than with peds. We concluded that the high exchangeable Fe and A1 concentrations in the low-smectite clay soil can compensate a lower clay concentration and proportion of smectite with respect to binding of organic matter and nutrients.