The adsorption of dyes from aqueous solution using diatomite

Raw diatomite was calcined at 450 °C for dyes removal from aqueous solution. SEM and FTIR analysis show that the raw diatomite contains organic impurities, which are removed after the calcination. The impurities removal decreases the specific surface area and increases the average pore diameter of raw diatomite, while improves its adsorption capability of dyes. The adsorption isotherm and kinetics experiments of methylene blue onto calcined diatomite were then carried out to investigate the adsorption property. It shows that the adsorption capacity of methylene blue is about 50 mg/g. The adsorption isotherm was fitted by the Langmuir, Freundlich and Redlich-Peterson models, which reveals that the Redlich-Peterson isotherm is the best one. Two kinetic models, pseudo-first order and pseudo-second order, were rearranged for expediently investigating the adsortpion mechanisms. Fitting results show that the pseudo-first-order model is better in describing the adsorption process.     

硅藻土纯化处理工艺研究进展

硅藻土具有良好的物理、化学特性,被广泛的应用于填料、建材、农业、化工等多个领域。我国硅藻土虽然储量多,分布广,但是多数矿床杂质含量高,不能直接利用。合理的选择纯化工艺以及新的纯化工艺的开发已经成为该领域未来研究的热点。从物理纯化法、化学纯化法和物理-化学联合纯化法三个方面对目前硅藻土的提纯方法进行了归纳整理,在此基础上,提出了获得高品位、高比表面积硅藻土的纯化方案新构想,以期能在具体工业生产中具有一定的指导意义。     

CFD Process Modeling of the Industrial Calcination of Diatomite

Calcination of diatomite is an expensive process frequently resulting in products with unpredictable structure. Alternatively, calcination in swirling flow is an energy‐saving option. Computational fluid dynamics modeling of an experimental calcination process unit is presented. Experimental results and systematic collection of process data were used to define boundary condition for steady‐state and transient simulation runs. The comparison of experimental and simulation results shows the complexity of the calcination process. The results can be used for further process optimization.     

Effect of boric acid on the porosity of clay and diatomite monoliths

Porous silica ceramics were obtained at low forming pressure (40–80 MPa) and low sintering temperature (850–1300 °C) for 4 h in air. Boric acid was used as a low-cost additive, in the amount of 2 wt%. Relatively high porosities of nearly 40% and 65% are obtained for the samples of clay and diatomite pressed at 40 MPa, and sintered at 1000 °C, respectively. The samples sintered at 1150 °C and 1300 °C have the average pore size diameters in the range of macroporous for clay 0.2–10 μm and for diatomite 0.2–5 μm. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and mercury porosimetry measurements were employed to characterize of the obtained samples. Measurements of densities and open porosities by immersion technique were used, according to the Archimedes principle. The relations between mechanical characteristics of the samples formed by using different pressures and sintered at different temperature, were discussed.     

硅藻土的扩容处理及其在复合保温材料中的应用研究

硅藻土除去泥砂杂质后,经酸溶及焙烧扩容处理,比表面积、孔体积增加,孔体积增加,堆密度下降。用硫酸进行处理的合适浓度为４０％￣４２％,处理时间为８￣１０ｈ;焙烧的温度为７５０℃,时间为２ｈ。扩容后的硅藻土制备复合保温材料,其性能比传统硅藻土保温材料性能有较大提高,扩大了硅藻土保温材料的使用范围。     

硅藻土矿分布区斜坡稳定性分析与评价

在嵊县丘陵地区范围内,广泛发育有交替分布的玄武岩和硅藻土层,岩层倾角平缓。在丘陵区此独特的层序地层近年来随着人类工程活动强度的增大,滑体后缘建筑,前缘切坡,造成下滑力增加,抗滑力减弱;另一方面在降雨的作用下,地表水体沿着卸荷裂隙通道浸入到下伏硅藻土层界面,硅藻土吸水软化,抗剪强度减弱,同时地下水水位上升,动水压力和扬压力加大,抗滑力进一步降低,于是产生了低倾角滑面滑坡。通过滑坡形成机理的分析,达到了为滑坡的治理提供依据的目的。     

硅藻土涂料在热模法离心铸造球铁管中的应用

采用硅藻土为骨料配制的悬浊液作为涂料涂覆于管模内壁生产球铁管,论述了涂料原材料选择、涂料配制、性能及合适的施涂方式。试验表明,膨润土浆持续搅拌2h,再静止10h后配制涂料;硅藻土是涂料热模法中最合适的骨料;对于小管径的管模涂料,膨润土含量高一些,硅藻土与膨润土的质量比为(8～15):1;对于大口径管模涂料,膨润土含量稍低,硅藻土与膨润土质量比为(12～20):1,另外,有气喷涂是最佳的喷涂方式。     

硅藻土吸附法去除糖化酶中的转苷酶

探讨了利用硅藻土作吸会剂去除液体曲糖化酶中转苷酶的方法。结果表明：硅藻土具有吸附转苷酶的作用并使糖化酶活力有所损失。发酵液ｐＨ值和硅藻土添加量对转苷酶去除率和糖化酶活力影响较大，而处理时间的影响较小。     

MG-1型硅藻土过滤机

当前在我国啤酒过滤技术中,采用硅藻土过滤机取代落后的棉饼过滤机的趋势已经形成。但引进或国产硅藻土过滤机价格昂贵,中、小型啤酒厂难以采用。本文介绍的新型MG-1硅藻土过滤机是在原有棉饼过滤机的基础上,经加工改造而成。投资少,滤酒效果好,符合我国国情,对中、小型啤酒厂有十分可观的经济效益。