共查询到19条相似文献,搜索用时 109 毫秒
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纳米碳酸钙制备实验研究 总被引:2,自引:0,他引:2
取石灰石原料,经过煅烧、消化、过滤、碳化、改性、抽滤、干燥和磨粉制得纳米碳酸钙产品。探讨了消化和碳化反应温度随时间的变化、碳化反应pH值随时间的变化、不同氧化钙原料制得产品的产量和产率。 相似文献
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探索了以石灰石为原料制备轻质碳酸钙的工艺过程和具体参数。以河北省某市的石灰石为原料,通过煅烧、消化、碳化、干燥等步骤制备轻质碳酸钙。初步确定了以下工艺参数:石灰石煅烧过程,煅烧温度为900~950℃,煅烧时间为5 h,烧失率为42%;消化过程,用水量为粉料质量的6~8倍,消化温度为70~90℃;碳化过程,以溶液p H达到7.5为反应终点;最后通过过滤、干燥得到超细轻质碳酸钙产品。实验制得轻质碳酸钙一次粒径为10 nm,团聚颗粒粒度为2~3μm,粒度分布窄,白度由原料的42.86%提高到产品的76.47%,产品的综合性能有较大提高。 相似文献
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利用碳化法对白云石经煅烧,消化,碳化制得超细CaCO3粉体;利用络合滴定和原子吸收分光光度法测定各组分的含量;通过激光粒度分布测试仪,扫描电镜以及高倍偏反光显微镜对粉体的粒度和形态进行分析选择了最佳的反应温度,碳化时间及消化碳化的pH值,得到均匀的超细CaCO3粉体颗粒,其各项指标均符合要求。 相似文献
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研究了以白云石为原料经过煅烧、消化、二次碳化、过滤、洗涤、干燥制备碳酸钙纳米棒的工艺。用扫描电镜(SEM)、X射线衍射(XRD)对合成的样品进行表征。重点考查了二次碳化工序反应温度、氢氧化钙质量浓度、晶型控制剂用量及添加的分散剂种类对产品粒径的影响。结果表明,在二次碳化工序中,在碳化温度为20 ℃、氢氧化钙质量分数为6%条件下,加入2%(质量分数)晶型控制剂和聚乙烯醇分散剂,可以制得平均直径约150 nm、平均长度约1 μm、平均长径比为6~8的碳酸钙纳米棒。 相似文献
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石灰石经煅烧、消化、碳化可制取纳米碳酸钙产品,文章考察了碳化前的工艺条件对制备的纳米碳酸钙产品性能的影响,实验结果表明:采用电加热方式煅烧石灰石能过提高消化反应活性以及石灰乳的产率,并能提高碳化得到的纳米碳酸钙产品的比表面积,降低吸油值,提高产品的白度;采用高温消化以及增加石灰乳的陈化时间的方法,也能提高石灰乳的产率以及纳米碳酸钙产品的比表面积,并且在消化时加入药剂H能过缩短陈化时间。 相似文献
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碳化法制备高纯碳酸锂 总被引:3,自引:0,他引:3
以工业级碳酸锂为原料,采用碳化法进行提纯,对碳化温度、碳化时间、碳化压力等重要影响因素进行了实验研究及分析,并确定了最佳反应条件。最佳工艺参数:碳化压力为6×105~6.5×105 Pa,碳化时间为2~3 h,碳化温度为30~40 ℃,树脂牌号为D110,母液流出速度为120~140 g/h,分解搅拌速度为30 r/s以上,此工艺条件下制得的碳酸锂纯度为99.991%。 相似文献
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研究了聚丙烯(PP)/弹性体和PP/弹性体/纳米CaCO3两种复合体系。结果表明,弹性体的加入使体系的冲击强度有很大提高,而拉伸和弯曲强度明显下降;添加8 phr左右的纳米CaCO3,体系的拉伸强度和弯曲强度得到较大提高。通过扫描电子显微镜观察冲击试样断面的形貌,可以很好地解释力学性能的变化。 相似文献
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超声波强化钙基废渣碳酸化固定CO2的性能 总被引:1,自引:1,他引:0
钙基废渣碳酸化固定CO2可实现CO2的永久封存,并可实现CO2原位固定,但苛刻的反应条件、过慢的反应速率是困扰该技术发展的瓶颈。对超声波作用下的钙离子浸出及其碳酸化反应特性进行了实验研究,并与搅拌浸出过程进行了对比,考察了浸出条件的影响及其碳酸化反应过程中溶液pH值与电导率变化特性,对碳酸化反应产物进行了XRD、SEM和TGA分析。结果表明,超声波可有效促进Ca2+从钙基废渣中浸出,其促进效果与废渣种类、浸出时间、超声波功率、浸取剂pH值、浆液存放量和废渣粒度等有关,钢渣和电石渣的含钙量、浸出率和超声波强化效果都较其他废渣高;钙离子浸出浓度随超声波功率的增强而增多;浸取剂pH值越低,浸出浓度越高;废渣粒度越高,超声波作用越明显。超声波对碳酸化反应也有强化效果,与机械搅拌相比,在超声波作用下固碳率更高,碳酸化反应程度更高。 相似文献
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为改善聚氯化铝(PAC)生产中产品的过滤效果,从工艺、原料、产品 3个方面研究了反应时间、过滤温度、铝酸钙粉用量、硫酸根离子含量、三价铁离子含量、氧化铝含量、盐基度等多个因素对PAC过滤效果的影响。研究表明,反应时间、过滤温度、铝酸钙粉用量、原料中硫酸根离子含量对PAC的过滤效果均有显著影响。为确保PAC的可滤性,建议生产中反应时间为60 min,过滤温度为60~80 ℃,尽量少用铝酸钙粉,尽量选用不含硫酸根离子的原料酸。产品中氧化铝含量的变化对PAC的过滤效果有一定影响,但不会改变产品的可滤性。原料中三价铁离子含量、产品盐基度的变化对PAC的过滤效果无显著影响。 相似文献
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Effects of Steam Addition during Calcination on Carbonation Behavior in a Calcination/Carbonation Loop
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The effects of steam addition during calcination on the carbonation behavior of calcium‐based sorbents in cyclic calcination/carbonation experiments were investigated. Variations in the CaO conversion rate during carbonation were measured to evaluate the influence of operating conditions and particle size on the carbonation reaction in kinetic‐ and diffusion‐controlled reaction regimes. Surface sintering and particle aggregation during cyclic calcination/carbonation affected the sorbent surface area, pore volume, and possibly the pore size, resulting in less sorbent recyclability and a trigger time retard in the fast kinetic‐controlled carbonation. Steam addition during calcination positively affected the recyclability of the sorbents and altered the carbonation behavior. 相似文献
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C. J. GOODBRAKE J. F. YOUNG R. L. BERGER 《Journal of the American Ceramic Society》1979,62(9-10):488-491
The carbonation of wetted powders of beta-dicalcium silicate (β·2CaO·SiO2 =β-C2 S) and tricalcium silicate (3CaO·SiO2 = C3 S) was studied as a function of reaction conditions. The water/solids ratio is an important parameter and there is an optimum value for each silicate. Relative humidity and the partial pressure of CO2 also strongly affect the reaction. The rate of carbonation can be conveniently represented by plotting the degree of carbonation against the logarithm of time. C-S-H and calcite are the initial reaction products. Subsequently, carbonation of the C-S-H produces silica gel, whereas aragonite may form if the system is allowed to dry out. 相似文献
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This paper introduces a method for accelerating experiments to quantify gaseous carbonation of cementitious materials through a sheltered crack surface. To date the majority of measurements of carbonation have focused upon the determination of the carbonation reaction through an open material face with no restriction to gaseous exposure. Experiments to determine the extent of carbonation through a crack surface can verify the extent to which restrictions of gaseous exposure can alter rates of carbonation into the crack surface as well as the depth into the crack to which the reaction occurs.The paper demonstrates that with experimental data the accelerated protocol can produce differences in outcomes in time intervals that are short relative to those in which the reaction occurs naturally. The experiment conducted to demonstrate the viability of the accelerated protocol involved measuring differences in the penetration of carbonation into the crack surface that resulted from differences in crack width. A byproduct of this experiment was a measurement of the depth into the crack (from the material face) to which carbonation occurs. It is not the intent of the paper to develop a theory of rates of carbonation, but rather to demonstrate that statistical differences are obtainable with the accelerated protocol. 相似文献