钠基膨润土新用途

在静态爆破中,过去使用的破碎剂常有破裂时间过长(10～20h)、膨胀力不够大、难于控制等问题.经试验证明,在破碎剂中加入18%的钠基膨润土,4.8h 就可达到38MPa的最大膨胀压力.最大膨胀压力提高,所需时间缩短,且时间控制准确,也不发生药喷.这种配有钠基膨润土的静态爆破剂配方,不仅适用于花岗岩、大理石的爆破,而且还能爆破混凝土砌块,为膨润土的应用开辟了新途径.     

我国锂基膨润土生产现状

锂基膨润土是采用天然膨润土经碳酸锂改性而成,既具有钠基膨润土浸水水化膨胀性能,又具有有机膨润土特性,在水和极性有机溶剂如乙醇中均能溶解成胶体或充分溶胀使涂料的粘度增强。适用于水基涂料、耐火基料涂料作增稠剂、悬浮稳定剂,使涂料粘度增大并在基料粒子表面形成溶剂化薄膜及立体网络结构以支撑和阻止颗粒下沉。这种涂料涂刷在冶金铸造砂型表面,由于溶剂乙醇易挥发能很快形成千的薄膜层,既可炼炉砂型又可使铸件更为光洁。     

钙基膨润土钠化工艺过程及其对矿浆黏度影响研究

为解决膨润土钠化过程中矿浆变黏的问题,系统研究了碳酸钠用量、矿浆浓度以及分散剂对钠化效果及矿浆黏度的影响,探讨了降低矿浆浓度和加分散剂的作用机理。结果表明:当采用降低矿浆浓度的方法时,“卡房”结构明显减少,矿浆变黏的问题得到改善,但同时会增大矿浆量,增加处理难度;当采用添加分散剂焦磷酸钠的方法时,磷酸根离子吸附在蒙脱石的正电性边缘,可以增加蒙脱石之间的排斥力,从而降低矿浆的黏度,有利于提高钠化效果。当焦磷酸钠用量为0.5%(质量分数)、矿浆浓度为5%(质量分数)、碳酸钠用量为5%(质量分数)时可制得高品质的钠基膨润土,与未钠化相比,在该条件下钠化1.5 h,得到的钠基膨润土胶质价由95 mL/15 g提高至975 mL/15 g,膨胀指数由8 mL/2 g提高至25 mL/2 g。     

均匀设计试验探讨制备钠基膨润土的最优条件

以钙基膨润土为原料,氯化钠作钠化剂,采用悬浮液法工艺制备钠基膨润土,通过均匀设计试验方法找到最优的制备条件,测定了产品的阳离子交换量、膨胀容、胶质价和吸蓝量,结果表明:钠基膨润土比钙基膨润土有更大的阳离子交换量、膨胀容和胶质价,当矿浆浓度为16%、钠化剂用量为6%、反应温度为65℃、反应时间为90 min时,钠化效果最好,此时产品的阳离子交换量达到0.992 mmol·g-1、膨胀容达到19.7 m L·g-1、胶质价达到5.98 m L·g-1,吸蓝量平均值为0.387 mmol·g-1、接近一级品标准。     

十六烷基溴化铵有机改性天然钠基膨润土的研究

本论文以吉林省刘房子天然钠基膨润土为原料,十六烷基溴化铵为改性剂对钠基膨润土进行有机改性。以灼失率为指标,获得了制备有机膨润土的最佳条件,反应温度为70℃,反应时间为1h,pH值为9,改性剂用量为阳离子交换容量CEC的150%,并通过X-射线衍射、红外光谱分析手段对有机膨润土的结构进行了表征。     

内蒙古高庙子钠基膨润土提纯试验研究

随着高水平放射性废物地质处置库缓冲/回填材料研究工作的深入,高庙子钠基膨润土的试验样品用量越来越大。露天浅层开采的高庙子钠基膨润土质量较差,需经提纯提高其蒙脱石质量分数和阳离子交换量。通过室内试验和室外扩大试验探索了湿法提纯高庙子钠基膨润土的工艺及效果,结果表明旋流器提纯可有效提高钠基膨润土的质量,经两次旋流后蒙脱石质量分数提高了约15%,因此该工艺可作为提纯缓冲/回填材料试验样品的方法。     

宁明膨润土制备有机包膜复合粘结剂中试研究

以宁明膨润土矿制备有机包膜复合粘结剂,通过钠化、挤压、有机促进剂、包膜等工艺的中试研究,生产出胶质价350mL／3g,膨胀倍90mL／g,膨胀指数22mL／g,吸水率640％的高效钠基复合膨润土。在精矿粒度-200目47％,水份10％条件下,控制膨润土粘结剂用量为0．6％,所造生球各项指标达到工业生产要求。此研究方法为生产铁矿球团高效复合粘结材料提供了可靠依据。     

铝柱撑膨润土对甲基橙的吸附性能研究

以铝的多聚羟基阳离子为柱撑剂对天然钠基膨润土进行柱撑改性,制备铝柱撑膨润土,并以其为吸附剂,通过静态吸附实验考察了其对废水中甲基橙的吸附性能。结果表明,膨润土经过铝柱撑改性后,其吸附性能得到了较大的提高。甲基橙在铝柱撑膨润土上的吸附过程可以通过伪一级动力学方程和Langmuir吸附等温线来描述。     

钠基膨润土对重金属离子的吸附特征

探讨了在不同振荡时间、不同溶液重金属离子浓度、不同矿物颗粒细度和不同pH值条件下,钠基膨润土对Cu2+、Zn2+和Cd2+的吸附效果,讨论了钠基膨润土对重金属离子吸附的影响因素。结果表明:重金属离子在钠基膨润土表面的吸附是个迅速的过程,钠基膨润土对重金属的吸附在10 min内即可达最大值。钠基膨润土不同颗粒细度对重金属离子的去除率有所不同,但并非颗粒越细吸附量越大。就试验的3种重金属离子而言,钠基膨润土对其吸附效果均很好。较高的pH值有助于钠基膨润土对溶液中重金属离子的吸附,但考虑到实际操作的其它因素,不能把pH值调得过高。     

微波法制备蒙脱石（膨润土）

因十数年来微波技术在分析化学和有机合成中应用的发展,微波辐射在蒙脱石(膨润土)中的应用也逐渐增多。通过微波技术可以将天然钙基蒙脱石(膨润土)转变为钠基蒙脱石(膨润土),进而转变成镍基蒙脱石(膨润土)、有机蒙脱石(膨润土)、插层型蒙脱石(膨润土)等等。同时,微波干燥、微波     

膨润土吸附处理甲基嘧啶磷废水的研究

以膨润土作为吸附剂处理甲基嘧啶磷废水,讨论了膨润土的种类、投加量、时间、pH值、温度等对甲基嘧啶磷某工段废水的处理效果的影响。结果表明,钠基膨润土的吸附效果较其它类型的膨润土效果好,其适宜吸附条件为:投加量5%,pH值3,反应温度20℃,搅拌60 min。反应结束后废水中2-二乙基氨基-6-甲基-4-羟基嘧啶的浓度从5 761 mg/L降至130 mg/L以下,COD浓度从12 500 mg/L降至4 233 mg/L以下。     

About the possible upgrade of bentonite with respect to iodide retention capacity

Compacted bentonites are currently investigated as geotechnical barrier in high level radioactive waste (HLRW) repositories due to their low permeability, high swelling pressure, and cation adsorption capacity. In contrast, anions are repelled by the negatively charged smectite surfaces due to electrostatic forces. Therefore anion diffusion through bentonites is particularly slow (‘anion exclusion’). However, in case of crack formation bentonites do not possess anion retention capacity. In this case anions, neutral or negatively charged molecules or colloidal particles can pass the technical barrier faster. One of the hazardous anions is ¹²⁹I⁻ which is particularly dangerous due to its long half life, mobility, and biological relevance. In this context several studies concerning iodide adsorption by a variety of solids are available.The selection of an applicable bentonite additive for the improvement of iodide retention capacity of HLRW technical barriers is still subject to discussion. The optimum bentonite additive should possess high selectivity towards iodide, thermal stability, should not affect bentonite properties, and should be inexpensive.In this study we compare different potential iodide adsorbents using standardized conditions since it is well known that experimental parameters (concentration, time, precursor material, solid liquid ratio…) significantly influence the results of adsorption experiments. Therefore, only the application of standardized conditions allow for the direct comparison of a set of potential I⁻ adsorber materials.Obtained results indicate that organoclays (bentonites modified by organic surfactants) are supposed to represent the most suitable bentonite additive with respect to the upgrade of iodide retention capacity. Additionally, we could show that the addition of 5 wt.% hexadecylpyridinium treated bentonite did not affect the swelling pressure of compacted MX80 bentonite. However, long term tests and/or natural analogue studies have to be performed in order to be able to answer the open questions.     

污泥型煤添加剂的研究

污泥具有一定的热值和黏结性。以污泥与粉煤为原料，采用膨润土与硅酸钠为热固剂，有机硅与聚乙烯醇为防水剂，制备工艺性能优良的型煤。实验考察了污泥量、热固剂与防水剂的种类及添加比例。结果表明，型煤的灰分和挥发分随污泥量的增加而升高，发热量降低；热固剂与防水剂的添加使型煤的热压强度与防水性明显提高；各因素优化的工艺参数为污泥质量分数20％、膨润土热固剂质量分数6％、有机硅防水剂质量分数1．8％时，型煤抗压强度1．4MPa，热稳定性92％，发热量20．24kJ／g，浸水复干强度1．4MPa。测试值均符合山西省型煤地方标准DB14／133—2005{太原市锅炉用洁净型煤》的各项指标要求。     

Mineralogy, chemistry and potential applications of a white bentonite in San Juan province, Argentina

A white bentonite deposit of Pleistocene age located in San Juan Province, Argentina, has very promising commercial applications because of its mineralogy and physical and chemical properties. The bentonite occurs in the Lower Member of the Las Trancas Formation which is a hydrothermally altered rhyolitic to rhyodacitic pumice and breccia.Analysis shows the major minerals present are smectite and opal-CT along with minor amounts of quartz, clinoptilolite, feldspar and biotite. The majority of the quartz, clinoptilolite, and biotite occurs in the >325 mesh fraction. The smectite is mainly a sodium montmorillonite along with some calcium and magnesium in the exchange positions. The <2 μm fraction consists of almost pure smectite and opal CT. Scanning electron micrographs show a typical “corn flakes” texture, which is characteristic of sodium montmorillonite.The physical and chemical properties including particle size, surface area, water and oil absorption, swelling index, cation exchange capacity, viscosity, and brightness indicate after wet beneficiation, that the processed white bentonite could be used in many industrial applications. These include paper coating and filling, paint, pharmaceuticals, cosmetics and filtering agents. Also the fine particle size fraction of <2 μm could be used to make an excellent quality organoclay.     

Simplified evaluation on hydraulic conductivities of sand–bentonite mixture backfill

Sand–bentonite mixtures are planned for use as backfill materials for high-level nuclear waste disposal in Japanese project. Sand–bentonite mixtures are attracting greater attention as backfill materials because they offer properties of very low permeability and high swelling. We must investigate the hydraulic properties by experiments and evaluate quantitatively the hydraulic-conductivities of sand–bentonite mixtures to design specifications, such as dry density and bentonite content, of backfill materials.For that purpose, this study investigated hydraulic conductivities at different bentonite contents and dry densities by experimentation. In addition, we discussed the relationship between hydraulic conductivity and bentonite content from the viewpoint of bentonite swelling in backfill voids. Furthermore, this study proposed simplified evaluation for hydraulic conductivity using a parameter proposed by the author: swelling volumetric strain of montmorillonite. This evaluation method can obtain hydraulic conductivity of backfill materials at various dry densities and bentonite contents. Therefore, this evaluation method can be used for designing bentonite content and compaction density to achieve very low permeability.     

The effect of different treatment conditions on biomass binder preparation for lignite briquette

The tests of treating rice straw with sodium hydroxide, lime and sulfuric acid were individually done and the possibility of using a binding agent based on rice straw as lignite briquette binder was studied. In this study, the lignite from Pingzhuang coal basin was selected as the coal for briquetting. It was found that the type of chemical agents and their concentration were the main factors influencing preparation of a binding agent based on rice straw. The binding mechanisms of a rice straw-based binder containing sodium hydroxide were quite different from that made with lime. The experiment showed that the rice straw treated with sulfuric acid could not be used as a briquette binding agent. Additionally, it made clear that comprehensive binders, which were prepared by adding bentonite, coal tar and/or polypropylene amide into rice straw-based binder, would have waterproof property and would benefit the quality of briquettes.     

聚丙烯酸盐防水材料合成工艺及其性能表征

以静态浸泡方式,研究了聚丙烯酸盐防水材料在含有Cl-、SO42-及碱性水环境介质的抗腐蚀性能。通过溶胀度的测定,研究了不同喷射距离及不同质量分数引发剂所形成的聚合物溶胀度变化与抗侵蚀性关系。研究表明,当喷射距离为50 cm,引发剂质量分数为10%时所合成的防水膜溶胀度最小,抗腐蚀能力较高。     

不同膨润土对模拟酒溶液中蛋白质的吸附

The adsorption of protein from model wine was investigated under different temperatures, pH values, contact times, and concentrations of ethanol, by certain bentonites. The results showed that ethanol molecules could broaden the protein molecules＇ channel to the interlayer of bentonite, and the maximum protein adsorption amount occurred under an ethanol concentration of 12% （by volume） and a pH value of 3.56. The increased single point Brunauer-Emmitt-Teller （BET） surface area （SBET） and adsorption pore volume （VAds） suggested a larger amount of active adsorption sites of the bentonite surface and a wider protein channel from the surface to the inner adsorption sites of bentonite, respectively. At the same time, higher methylene blue test （MBT） and swelling index （Sw） indicated that it was easy for the entrance of water and the absorbance of protein. Higher temperature was found favorable to eliminate more proteins and it took about 20 to 40min to arrive at the maximum adsorption.