共查询到18条相似文献，搜索用时 140 毫秒
1.
以磐石膨润土原矿为原料,用挤压钠化法对钙基膨润土进行改型,本次实验钠化剂分别采用Na2CO3、NaCl,结果表明：以Na2CO3的用量为3%,土含水量30%-35%,挤压一次,陈化时间在3-7天进行钠化改型,效果显著。 相似文献
2.
通过改进滤失试验研究典型钠化改性钙基和天然钠基膨润土在重金属铅-镉以及铬作用下渗透系数的变化规律。研究发现,膨润土试样渗透系数在重金属铅-镉浓度小于6mmol/L时增幅较小,为2~3倍;当浓度超过10mmol/L时呈急剧增大的趋势。铬酸钾溶液作用下,钠化改性钙基膨润土的渗透系数低于未污染试样;天然钠基膨润土的渗透系数则增大2~8倍。两者差异归因于土-液相互作用下铬在不同pH-Eh环境中化学形态的不同。研究中钠化改性钙基膨润土浆液中铬以阴离子络合的六价铬形态存在,使得膨润土颗粒表面负电荷密度趋于增加,因而保持和促进膨润土的分散状态。天然钠基膨润土浆液中铬则出现以阳离子形态存在的三价铬,显著挤压膨润土颗粒双电层,导致膨润土颗粒团聚。综合国内外研究总结无机盐溶液作用下膨润土化学相容性随污染程度变化规律,发现渗透系数比与离子强度关系存在一临界值,当离子强度达到该临界值则渗透系数将呈数量级增大。 相似文献
3.
以溴化十六烷基三甲铵为改性剂，对天然钙基膨润土进行有机化改性，系统地研究了改性剂用量以及钠化，热活化和酸活化对有机膨润土吸附苯酚、苯胺、苯、甲苯和二甲苯的影响，并初步探讨了有机膨润土与有机物间的作用机理。实验结果表明，改进剂用量是影响有机膨润土对有机物吸附性能的主要因素；改性剂用量相同时，钠化土的吸附效果明显好于直接改性的6.0%土，而热活化和酸活化对于有机膨润土吸附不同的有机物时影响程度也不同。应用有机膨润土建造垃圾填埋场防渗衬层具有一定的可行性。 相似文献
4.
信阳上天梯矿区钙基膨润土可分为四个自然类型。根据矿石理化性能和蒙脱石晶体结构特征，选用第Ⅲ类矿石，运用对挤压钠化和最佳工艺进行实验研究，获得钻井泥浆用Ａ．Ｐ．Ｉ级膨润土。 相似文献
5.
针对甘肃平凉产钙基天然膨润土进行不同钠化试剂、反应时间,反应介质、温度等条件的钠化工艺研究,得出最佳钠化合成工艺,并制得十六烷基氯化吡啶(CPC)改性膨润土.研究该有机改性膨润土红外光谱、X射线衍射、热重分析及分散性结果表明,插层剂CPC已进入膨润土的片层同.使有机改性膨润土的层间距由1.04 nm增加到2.11nm,热失重率达17%,新型有机改性膨润土在有机介质中表现出很好的分散性. 相似文献
6.
利用钠盐对钙基膨润土进行人工钠化,在活化剂的催化作用下,使钠改性膨润土具有较高的膨胀性能,当尿素添加量达15%时,改性膨润土的膨胀指数、膨胀倍和胶质价可分别达到26 ml/2g,91 ml/g和420 ml/15g,此时效果最佳。 相似文献
7.
通过离子交换,使钠离子代替钙基膨润土中的钙离子,而使钙基膨润土钠化成为钠化膨润土,从而改善膨润土的铸造工艺性能。本文进一步探讨了连城膨润土钠化的原理;对新的钢化工艺和工厂里采用的钠化工艺做了比较;讨论了不同钠化工艺对连城膨润土铸造型砂强度的影响。采用新的工艺钠化连城膨润土,配制成的铸造型砂的湿压强度,干压程度和热湿拉强度都有明显地提高,同时具有理想的溃散性和可塑性。 相似文献
8.
安徽铜陵市蕴含地质储量达15 000万t的低品位钙基膨润土,蒙脱石平均含量50%～80%,现主要用于附加值较低的球团土和铸造土。将这种低品位钙基膨润土先通过悬浮和挤压综合钠化改型工艺,再添加一定量的超高分子量聚丙烯酸钠(PAA-Na)和轻烧氧化镁(MgO)组成的有机无机复合增黏剂,以及由小分子水解聚丙烯腈钠盐与腐植酸接枝聚合的专用流变性调节剂(HmPS),制备出了符合水平穿越钻井(HDD)使用要求的高造浆膨润土。分析了钠化工艺和增效添加剂对HDD造浆土的黏度(600)、动塑比(YP/PV)、综合流变性能以及成本等的影响,优化得到了具有较好性价比的工艺配方。优化工艺下的HDD造浆土性能600读数大于100 dia,YP/PV小于1.5,30 min的API滤失量小于15 mL。铜陵钙基膨润土改性制备成HDD高造浆膨润土,可将产品附加值提高到1 000元/t左右,利润率提高2~3倍,实现了低品位膨润土资源的高附加值利用。 相似文献
9.
以莱西的钙基膨润土为原料,研究了分散方法、分散时间、分散剂种类及分散剂用量对膨润土钠化的影响,确定了最好的分散设备,提出了以3％的碳酸钠为钠化剂,0．4％的焦磷酸钠为分散剂,制备超细钠基膨润土的新工艺,并制备出了平均粒径为0．496μm的超细钠基膨润土。 相似文献
10.
所谓改性处理，就是对膨润土进行人工钠化，即加入适量的Na~+用以尽可能地置换膨润土中的交换性Ca~(2+)·Mg~(2+)和可溶性Ca~(2+)、Mg~(2+)。改性处理工艺系指改性处理剂的种类及其加量的选择过程，以及必要时进行制浆的效果检验。 相似文献
11.
刘房子钠基膨润土矿床是我国膨润土矿石质量优异的矿区,经过三年的详查与勘探,探明钠基膨润土矿石2 300万t,钠蒙脱石含量高可达98%,平均含量达63.74%。本文通过X射线衍射、红外吸收光谱分析、矿物的粒度分析,并结合电子扫描对矿石质量进行了研究,应用热分析方法,确定刘房子钠基膨润土矿石具有的优良特征。 相似文献
12.
Measurements on plutonium diffusivity in water-saturated compacted bentonite were carried out. Representative specimens of sodium bentonite were taken from the Tsukinuno and Kuroishi mines situated in northeast Japan. Tsukinuno bentonite was divided into three types: raw type, purified Na-type, and H-type which was prepared by treating Na-type bentonite with hydrochloric acid. Kuroishi bentonite contained chlorite as impurity. H-type bentonite was used as reference for the convenience of profile measurement in bentonite, since plutonium diffusivity in H-type bentonite was considered to be larger than that in Na-type bentonite because of low pH and low swelling pressure of H-type bentonite. Sampled bentonite was compacted into pellets of 20 mm in diameter and 20 mm in height. Bulk densities of these specimens were 1200–1800 kg/m3 for purified Na-type and H-type bentonite and 1600 kg/m3 for raw type bentonite. Plutonium profiles obtained in H-type bentonite can be explained by diffusion equation with constant concentration source. Diffusivity ranges from 10-13 to 1012 m2/s for H-type and Kuroishi impure sodium bentonite. Diffusivity in both raw type and purified Tsukinuno bentonite was was estimated to less than 10-14 M2/s. Diffusivity in H-type bentonite showed a tendency to decrease with increasing density. Influence of in bentonite was also studied. Quartz content up to 50% or hematite content up to 1% did not influence diffusivity significantly in H-type bentonite. The chemical species of plutonium in pore water of Na-type and H-type were estimated Pu(OH)3-; and PuO2- , respectively. 相似文献
13.
This paper aims to prepare purified Na-bentonite with improved properties for its use in the pharmaceutical industry. Calcium bentonite from the Sohag region of Egypt was activated with various proportions of sodium carbonate (2, 3, 5 and 8 wt.%). Additionally, bentonite was purified by sedimentation to eliminate impurities, especially quartz. The results of X-ray diffraction (XRD) and swelling volume data confirmed that raw bentonite was converted to sodium bentonite using 5% Na 2CO 3. The sodium bentonite (M5) obtained by activation met the chemical and microbiological requirements set by the pharmacopoeias regarding toxic trace elemental contents (As, Pb and Cd), the absence of E. coli, the total contents of aerobic microbes and physicochemical properties such as swelling volume, pH and sedimentation volume. Therefore, (M5) bentonite can be designated as being potentially appropriate for pharmaceutical applications. The cation exchange capacity (CEC), surface area, porosity, pH, gel formation and swelling volume data indicated that M5 bentonite could be used to formulate oral suspensions and in topical application. 相似文献
14.
张家口地区膨润土以钙基土为主,其成因是处于侵蚀基准面以上的膨润土中钠离子往往被钙离子交换,而处于深部重碳酸钠型水中的膨润土却仍然保留了钠基土的原始特性。由于易采、易选的特殊条件,多年来该区膨润土开发一直旺而不衰,其原因之一就是随着工业化进程加快,膨润土开发利用已上升到重要地位。 相似文献
15.
对紫都台-于寺盆地内二道河、哈尔套、北窝棚及下扎兰波罗等膨润土矿床进行了系统采样、处理,开展与矿床相关的赋矿岩系岩石学及矿物学特征研究.通过基本分析、XRD、化学全分析、阳离子交换量等手段对样品进行测试,研究结果表明沉凝灰岩、流纹质熔结凝灰岩、砂砾质凝灰岩等富含火山玻璃的岩石更易于水解形成膨润土矿.膨润土总体呈碱性,矿... 相似文献
16.
This study was conducted to evaluate the efficiency of low-cost adsorbents including bentonite, kaolinite and zeolite saturated with calcium and potassium, potato and wheat residues, and three metal oxide nanoparticles functionalized with an acidic extract of potato residues in improving the quality of sodic waters. The optimization of factors such as pH, contact time, and adsorbent dosage was investigated using a solution containing sodium, calcium, magnesium, and potassium. The optimal pH and contact time were 7.0 and 24 h, respectively. The optimal dosage for using functionalized nanoparticles was 0.1 g and for using other adsorbents was 1.0 g. The sodium exchange isotherms were conducted in binary sodium–calcium and sodium–potassium and quaternary sodium–calcium–magnesium–potassium systems. Zeolite saturated with potassium was the most effective adsorbent in removing sodium from aqueous solutions with an average removal efficiency of 69.2 and 66.5 % in binary and quaternary systems, respectively. Freundlich and Langmuir equations fitted well to experimental data in both binary and quaternary systems. Cation selectivity coefficients calculated based on the Gaines–Thomas convention varied with changing pH and adsorbent dosage. Graphical and statistical evaluations confirmed that the mechanistic cation exchange model using average Gaines–Thomas selectivity coefficients in geochemical PHREEQC program was able to successfully simulate the sodium exchange on different adsorbents in both systems. The Gaines–Thomas selectivity coefficient values greater than unity and as a consequence, the negative values of the Gibbs free energy change of adsorption indicated that sodium exchange reactions in the presence of different adsorbents used is this study were exergonic and spontaneous. 相似文献
17.
以天然钠基膨润土为载体,利用四氯化钛水解法制备了掺铜TiO 2/膨润土复合光催化剂;比较了不同量Cu 2+对TiO 2/钠基膨润土的修饰作用及不同光照条件对光催化性能的影响。采用分光光度计、XRD、IR及TG-DTA等测试手段对试验结果进行表征。结果表明,铜的掺入对TiO 2/膨润土光催化活性有显著提高:当掺铜量为原土阳离子交换量的10.9%时,紫外光下催化效果最好;16.4%时太阳光下催化效果最好。复合后样品热处理温度为500 ℃,获得较理想的光催化活性。 相似文献
18.
Compacted bentonite has been considered as a candidate buffer material in the underground repository for the disposal of high-level radioactive waste. An erosion of bentonite particles caused by a groundwater flow at the interface of a compacted bentonite and a fractured granite was studied experimentally under various geochemical conditions. The experimental results showed that bentonite particles could be eroded from a compacted bentonite buffer by a flowing groundwater depending upon the contact time, the flow rate of the groundwater, and the geochemical parameters of the groundwater such as the pH and ionic strength. A gel formation of the bentonite was observed to be a dominant process in the erosion of bentonite particles although an intrusion of bentonite into a rock fracture also contributed to the erosion. The concentration of the eroded bentonite particles eroded by a flowing groundwater was increased with an increasing flow rate of the groundwater. It was observed from the experiments that the erosion of the bentonite particles was considerably affected by the ionic strength of a groundwater although the effect of the pH was not great within the studied pH range from 7 to 10. An erosion of the bentonite particles in a natural groundwater was also observed to be considerable and the eroded bentonite particles are expected to be stable at the given groundwater condition. The erosion of the bentonite particles by a flowing groundwater did not significantly reduce the physical stability and thus the performance of a compacted bentonite buffer. However, it is expected that an erosion of the bentonite particles due to a groundwater flow will generate bentonite particles in a given groundwater condition, which can serve as a source of the colloids facilitating radionuclide migration through rock fractures. 相似文献
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