EFFECT OF SURFACE POTENTIAL AND DISPERSITY ON THE TOTAL INTERACTION POTENTIAL ENERGY BETWEEN MINERALS AND HYDROCARBON OIL

The effect ofψ-potentials anddispersities on the total interaction potentialenergy between natural hydrophobic minerals-molybdenite,graphite,talc and hydrocarbon oilis investigated based on the colloid and surfacescience.     

Properties of Highly-Dense Iron‐Base Powder Metallurgy Materials Pressed without Zinc Stearate

The possibility of obtaining highlydense compacts by single pressing and sintering and the use of heatresistant solid lubricants (graphite, talc) instead of conventional lubricant was studied. It was shown that the addition of graphite is most effective to obtain highly-dense powder metallurgy materials since it substantially facilitates ejection of the part from the die and improves the mechanical properties.     

滑石粉原位聚合改性聚酯热熔胶的结晶性能

采用差示扫描量热仪研究了滑石粉原位聚合对聚酯热熔胶非等温结晶性能的影响,并用Takhor方程和莫志深非等温结晶动力学新方程处理所得数据。结果表明:滑石粉原位聚合显著促进了聚酯热熔胶的结晶,提高了结晶速率,表现在结晶温度和结晶活化能大幅提高,当降温速率分别为5,10℃/min时,半结晶时间缩短50%以上。动力学分析表明:莫志深方程适合描述聚酯热熔胶的非等温结晶过程,在达到相同相对结晶度时,加入滑石粉的聚酯热熔胶所需降温速率更小,缩短了热熔胶涂覆后的冷却固化时间。     

添加剂对滑石质瓷坯料料浆性能影响研究

通过X射线衍射、流动度、厚化度分析等检测手段,研究了不同种类添加剂对滑石质瓷坯料料浆流动性、稳定性、触变性的影响。结果表明:六偏磷酸钠、硅酸钠、碳酸钠、萘磺酸甲醛缩合物、复合添加剂均可以降低滑石质瓷坯料料浆的黏度,提高料浆流动性;六偏磷酸钠与硅酸钠对料浆流动性的改善作用都优于碳酸钠;萘磺酸甲醛缩合物对滑石质瓷坯料料浆黏度降低效果比无机添加剂更加明显,其最佳添加量为0.06%,但添加之后坯料料浆的触变性严重,悬浮稳定性变差;复合添加剂最佳添加量为0.08%,复合添加剂对滑石质瓷坯料料浆性能的改善作用优于以上单一种类的添加剂。     

电子探针在中药滑石质量检验中的应用

滑石是一种十分重要的中药矿物药,其质量检验对于人体健康和环境至关重要。本文提出的以电子探针为主、并辅以X光衍射分析等方法的滑石质量检验途径,是一次新的探索。正是由于电子探针可以同时进行高倍图像观察和定性定量分析,对滑石中的杂质分析灵敏度更好,其检测结果也更直观易懂。     

Asymmetric alumina-based ultrathin composite ceramic membranes with interfacial modification of black talc nanosheets

In this work, ultrathin planar alumina-based ceramic membranes with asymmetric structure and thickness less than 0.85 mm were successfully prepared by one-step molding phase transformation/sintering method using low-cost black talc (BT) nanosheets for the first time. The microstructure, pore structure, mechanical strength and permeability of novel ceramic membranes were systematically investigated with different BT amount and sintering temperatures. The doping of BT nanosheets effectively modulated the interfacial bonding area and strength between the grains, achieving significant increase in flexural strength through the evolution of the dense layer structure. The asymmetric structural features formed by the phase transformation/sintering process in combination with polymer substrate significantly reduced the thickness of effective separation layer, thus weakening the loss of flux caused by the densification of the film layer due to the interfacial modification process. Moreover, the organic carbon layers between BT layers were oxidized during the sintering process, forming fine pores and increasing the porosity, which showed to be unique characteristic different from other clay mineral materials. The prepared composite membrane had the pure water flux up to 16335 L m⁻² h⁻¹/bar at 1350 °C sintering, which achieved stable permeation of ∼5200 L m⁻² h⁻¹/bar and high retention over 90% for O/W emulsions.     

Improving 2‐phenylethanol and 6‐pentyl‐α‐pyrone production with fungi by microparticle‐enhanced cultivation (MPEC)

Trichoderma atroviride IMI 206040 synthesizes the coconut lactone 6‐pentyl‐α‐pyrone (6‐PAP) de novo and Aspergillus niger DSM 821 produces the rose‐like flavour compound 2‐phenylethanol (2‐PE) from the precursor l ‐phenylalanine. Here, microparticles of different chemical composition and nominal particle diameter in the range 5–250 µm were added to shake‐flask cultures of both fungi to investigate the particles' effect on product formation. Maximum 2‐PE concentration increased by a factor of 1.3 to 1430 mg/l with the addition of 2% w/v talc (40 µm diameter). Maximum 6‐PAP concentration increased by a factor of 2 to 40 mg/l with the addition of 2% w/v iron (II, III) oxide. The influence of ions leaching out of the particles was investigated by cultivating the fungi in leached particle medium. For the first time, the positive effect of the microparticle‐enhanced cultivation (MPEC) technique on the microbial production of volatile metabolites, here flavour compounds from submerged fungal cultures, is demonstrated. The effect is strain‐ and particle‐specific. Copyright © 2014 John Wiley & Sons, Ltd.     

Adsorption and Flotation Characteristics of the Different Types of Frothers

This article investigates the adsorption of different frothers onto talc particles. The adsorption and flotation characteristisc of tallow amine acetate (TAA) + frothers (MIBC and pine oil) was studied for talc mineral. In this study, we analyzed some parameters affecting froth flotation performance and it was determined that adsorption capacity in particular, had an important role in froth flotation enrichment. The effect of pH and adsorption time on adsorption capacity was also studied. Analyses were carried out using ultraviolet spectrometry. The results showed that MIBC had the lowest frother adsorption capacity and it improved recovery during froth flotation of on the talc. It can be said that MIBC was adsorbed on the talc surface less and provided the best conditions to generate bubbles in flotation cell.     

羧甲基纤维素的应激反应规律及对滑石表面疏水性的影响

通过浮选实验、接触角测试、动电位测量及红外光谱试验研究不同的溶液条件对吸附在滑石表面的羧甲基纤维素(CMC)作用效果的影响,并考察其作用机理。结果表明,滑石具有较好的天然可浮性,CMC能够吸附在滑石表面,降低滑石的表面疏水性。吸附后的CMC对滑石的抑制作用效果受溶液pH及溶液中离子的浓度影响较大。当吸附有CMC的滑石位于pH=9的溶液中,CMC的羧甲基之间存在较强的静电排斥作用,吸附的CMC分子呈伸展状态存在,形成的吸附层较薄,造成的亲水性较弱;当矿浆pH变为酸性或溶液中有离子存在时,CMC羧甲基之间的静电排斥作用减弱,CMC分子在滑石表面呈蜷缩状态,所形成的吸附层较厚,造成的亲水性较强,这种变化是可逆的。     

白云岩型滑石矿的化学提纯及性能表征

本试验以白云石型滑石矿为原料,采用盐酸酸浸法除去其中的碳酸盐矿物,继而采用过筛、连二亚硫酸钠漂白等方法提纯滑石。漂白过程中,试验因素影响最大的是反应时间,其次是搅拌条件、加水量、Na2S2O4加入量。其最佳漂白条件为:Na2S2O4加入量为1%、用水量为原矿的3倍、时间1h,不搅拌。运用差热—热重分析(DTA-TGA)分析得知滑石在1 000℃时发生脱羟反应;X-射线粉末衍射(XRD)分析表明:提纯后白云石及方解石全部除去,只有少许石英残留在滑石中;通过分析其扫描电镜(SEM)分析得知,滑石形貌呈片状,尺寸在5～40μm之间。经测定滑石白度在90%以上,其各项指标均符合橡胶和化妆品优等品标准。