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白钨精矿与黑白钨混合矿碱分解的方法与设备 总被引：5，自引：0，他引：5
引言NaOH分解法为钨冶金中分解黑钨精矿的常用方法,它具有工艺简单,分解率高等特点。但在通常条件下,由于NaOH与白钨矿(CaWO_4)难以反应,因此过去国内外学者都认为在工业条件下用NaOH法处理白钨精矿是不可能的,即使对黑钨精矿而言,也要求其中混杂的白钨矿相当少(Ca<1.0%),才能有好的分解效果,因而不得不要求选矿工作者将两者仔细分选,并要求用不同的工艺分别处理。我国过去主要是处理黑钨精矿,因此现有企业的流程和设备主要适用于黑钨精矿的碱分解法。 相似文献
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以硬脂酸和聚乙二醇为原料,经酯化后生成聚乙二醇双酯。再经磺化剂氯磺酸的磺化作用下得α-磺基硬脂酸聚乙二醇双酯,加NaOH中和后成盐,形成α-磺基硬脂酸聚乙二醇双酯钠盐。实验结果表明,在催化剂用量为2.0%(基于反应体系的质量分数),酸醇的量比为2.5∶1.0,反应时间为4小时,反应温度140~150℃时,聚乙二醇双酯收率达83%。磺化剂氯磺酸与双酯的量比为2.4∶1.0,反应时间为1小时,反应温度为60~70℃,α-磺基硬脂酸聚乙二醇双酯收率为96%。α-磺基硬脂酸聚乙二醇双酯钠盐的总收率为79.7%。 相似文献
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为了探索不同激发剂对固硫灰复合胶凝材料的化学激发效果,分别研究了NaOH、Na2SO4、Na2SiO3、Na2CO3单掺和复掺对固硫灰复合胶凝材料的力学性能的影响.结果表明:NaOH作为碱性激发剂单掺时对掺加固硫灰的复合胶凝材料具有比较明显的力学性能激发效果,复掺时NaOH与Na2CO3的复掺效果较其它含钠类碱性物质激发效果明显. 相似文献
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本文将微波技术与碱性助剂脱硫结合起来研究,选取试剂加入顺序,不同煤样,不同辐照时间,不同温度及微波辐照因素对脱硫效果的考察,建立了不同硫含量范围的工作曲线,结果表明微波脱硫速度快,不同煤种对脱硫影响大,反应条件温和,NaOH溶液在微波的辅助作用下具有较好的脱硫效果,并且对原煤质基本无影响。 相似文献
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<正>开学初,科学老师在课堂上演示NaOH溶液使无色酚酞试液变色时,她把无色酚酞试液滴入盛有NaOH溶液的试管内,我观察到溶液变红后又立即褪成无色。为什么氢氧化钠溶液使无色酚酞变红后又褪成无色? 相似文献
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采用改性的hummers法制备了氧化石墨,并与二水醋酸锌溶液、NaOH水溶液及水合肼反应制备出氧化锌—石墨烯(GZO)粉末。通过激光显微拉曼光谱仪、X射线衍射仪、场发射扫描电镜等,分析了所制备的GZO的结晶性能、微观形貌,并与氧化锌—铝(AZO)的电阻率、透光率进行了比较。结果表明:GZO的透光率在可见光波段与AZO相差不大,但在紫外光(200～380nm)波段,AZO的透光率为20%,而GZO的透光率达到了50%,透光效果明显优于AZO;AZO的电阻率一般在10-2～10-4Ω.cm,GZO的电阻率为1.03×10-5Ω.cm,导电性也优于AZO,所以理论上GZO更加适合作为TCO玻璃的材料。 相似文献
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本文在简介“行为引导型”教学法的基础上,以烧碱中NaOH和Na2CO3含量的测定为例,讲述了“行为引导型”教学法,在化学实验课中尝试过程及体会。 相似文献
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We describe a simple and cost-effective strategy for rapid fabrication of microfluidic paper-based analytical devices and valves by inkjet printing. NaOH aqueous solution was printed onto a hydrophobic filter paper, which was previously obtained by soaking in a trimethoxyoctadecylsilane-heptane solution, allowing selective wet etching of hydrophobic cellulose to create hydrophilic-hydrophobic contrast with a relatively good resolution. Hexadecyltrimethylammonium bromide (CTMAB)-ethanol solution was printed onto hydrophobic paper to fabricate temperature-controlled valves. At low temperature, CTMAB deposited on the paper is insoluble in aqueous fluid, thus the paper remains hydrophobic. At high temperature, CTMAB becomes soluble so the CTMAB-deposited channel becomes hydrophilic, allowing the wicking of aqueous solution through the valve. We believe that this strategy will be very attractive for the development of simple micro analytical devices for point-of-care applications, including diagnostic testing, food safety control, and environmental monitoring. 相似文献
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We developed a novel strategy for fabrication of microfluidic paper-based analytical devices (μPADs) by selective wet etching of hydrophobic filter paper using a paper mask having a specific design. The fabrication process consists of two steps. First, the hydrophilic filter paper was patterned hydrophobic by using trimethoxyoctadecylsilane (TMOS) solution as the patterning agent. Next, a paper mask penetrated with NaOH solution (containing 30% glycerol) was aligned onto the hydrophobic filter paper, allowing the etching of the silanized filter paper by the etching reagent. The masked region turned highly hydrophilic whereas the unmasked region remains highly hydrophobic. Thus, hydrophilic channels, reservoirs, and detection zones were generated and delimited by the hydrophobic barriers. The effects of some factors including TMOS concentration, etching temperature, etching time, and NaOH concentration on fabrication of μPAD were studied. Being free of any expensive equipment, metal mask and expensive reagents, this rapid, simple, and cost-effective method could be used to fabricate μPAD by untrained personnel with minimum cost. A flower-shaped μPAD fabricated by this presented method was applied to the glucose assay in artificial urine samples with good performance, indicating its feasibility as a quantitative analysis device. We believe that this method would be very attractive to the development of simple microfluidic devices for point-of-care applications in clinical diagnostics, food safety, and environmental protection. 相似文献
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Prabhat Kumar Nigam 《Indian journal of clinical biochemistry : IJCB》2016,31(2):237-239
The negative interference by bilirubin in serum creatinine estimation by Jaffe’s kinetic method is well known. Several approaches have been suggested to overcome this interference. In this article three different creatinine kits (Jaffe’s kinetic method) have been tested for bilirubin interference and its rectification using two simple approaches. The performance of three kits (A, B and C) supplied by three different manufacturers was tested using IQC and EQAS sera and pooled serum with added bilirubin. To overcome the bilirubin interference two approaches viz. NaOH preincubation and TCA precipitation were used. Bilirubin did interfere in creatinine estimation after a certain level (2.3 mg/dl). However, both NaOH preincubation and TCA precipitation approach rectified this interference. The performance of kit A was better than kit B and C. All the three kits showed bilirubin interference upon increasing the bilirubin concentration but kit A performed better than kit B and C. However, NaOH incubation and TCA precipitation methods overcame this interference to a great extent. 相似文献
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Charles A. Zittle 《Journal of The Franklin Institute》1947,243(4):334-336
Desoxyribonucleic acid prepared by a method which utilizes strong NaOH was not acted on by a speciflc nuclease but it was extensively hydrolyzed by phosphoesterase from calf intestinal mucosa. Experiments indicated that the adenine radical is concerned in the resistance of the nucleic acid to the nuclease. 相似文献
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John Frazer 《Journal of The Franklin Institute》1948,246(1):78-80
In contradiction to results previously reported, it has been found that DNA prepared by a method which utilizes strong NaOH is acted on by the specific nuclease, although at a rate only 20 per cent. of that of DNA prepared by a milder method. The nature of the changes responsible for the low rate of hydrolysis of the alkali-treated DNA are not known. 相似文献
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采用以氢氧化钠和高效表面活性剂煮炼原棉，再以过氧化氢和ＥＤＴＡ进行漂白的脱脂棉生产方法进行试验，与传统方法比较，煮炼液碱的浓度降低了２／３，煮炼时间缩短了１／２，获得满意的脱脂棉产品，药品费用有所降低，并减轻了废水对环境的污染。 相似文献
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在高浓度条件下,浆料直接被挤入快速加热器中,在10～20秒内快速升温到80～90度,同时加入0.5%H2O2、1%NaOH、3%Na2SiO3,使化学药剂与浆料充分混合。用搅拌机摩擦,再加入漂白剂H2O2（浓度为1%,2%,3%）进行漂白。漂白时间为2～4小时,终了时用造纸气浮澄清水把浆料稀释到3.5%左右,从塔底输出,加入硫酸中和,调pH为7.0左右,最后将干燥的再生纸进行白度、色度、回收率分析。 相似文献