膨润土提纯进展

介绍了膨润土提纯方法及原理,主要为化学提纯法、水力分级提纯法、离心分离法、重液法和电泳法,并分析各提纯方法的优缺点,对膨润土的提纯给出若干建议。     

工业碳酸钠提纯实验

对工业碳酸钠进行提纯研究,经溶解、过滤、蒸发结晶、灼烧等步骤,制备出纯度较高的碳酸钠,并对所得最终产品进行杂质含量分析。试验结果表明,经提纯后的碳酸钠其纯度和杂质含量要求均达到国标GB 210.1中Ⅱ类一等品指标要求。加入活性炭吸附剂提纯工业碳酸钠,所得提纯效果较好。使用滤布过滤进行提纯,可提高过滤速度且不影响提纯效果。提纯回收率可达94.4%。     

药用级蒙脱石的提纯研究与表征

对某钙基膨润土进行物理提纯试验,确定湿法提纯有利于得到高纯度蒙脱石。车间采用二次旋流分力分级法提纯得到了蒙脱石含量≥95%的提纯精矿,通过物理化学性能测试、XRD、电镜等表征,该提纯土达到了医药蒙脱石要求。     

N-苯基-β-萘胺的区域熔融提纯

防老剂N-苯基-β萘胺是一个老牌胺类防老剂,有必要使其高纯化。区域熔融提纯方法已广泛应用于多种有机物质的提纯。采用自制区域熔融仪对工业品防老剂N-苯基-β萘胺进行提纯,制定了提纯工艺,并用高效液相法(HPLC)检测其纯度。试验结果:区域熔融提纯可成功地分离N-苯基-β萘胺的杂质,生产出高纯物质。工业品防老剂N-苯基-β萘胺的纯度为96%,而提纯品的纯度为99%。讨论了区域熔融提纯技术的原理、影响因素和提纯技术。     

国内酒精提纯工艺进展

工业酒精、食用酒精、无水酒精是酒精生产的三大方面.根据三者对酒精质量要求的不同,应采用不同的提纯方法.其中,食用酒精GB10343-2000新标准要求普级95.5%(v/v)以上,因此,食用酒精提纯技术能较合适地反映酒精提纯技术水平.着重阐述了食用酒精提纯的提纯等技术,并简要介绍了无水酒精提纯的传统技术和非传统技术.     

石墨提纯对隐晶质石墨/炭黑/羧基丁腈橡胶 复合材料性能的影响

采用酸处理法提纯隐晶质石墨(CG)可将其固定碳质量分数提高到0.94,但仍残留少量难以除去的石英。采用乳液共混法制备CG/炭黑/羧基丁腈橡胶复合材料,研究CG提纯对复合材料性能的影响。结果表明:未提纯CG和提纯CG在橡胶基体中分散都较为均匀,但提纯CG具有更高的补强效率和更为优异的润滑性;添加提纯CG的复合材料摩擦因数和比磨损率均小于添加未提纯CG的复合材料,这可能是由于提纯CG中硬质杂质(如晶质石英)含量降低,在摩擦过程中更容易形成连续润滑膜和转移膜的缘故。     

广西钙基膨润土湿法提纯研究

采用自然沉降法、水力旋流器提纯法、超声波自然沉降法对广西宾阳膨润土进行提纯研究,主要考察了不同提纯方法及其提纯次数对膨润土提纯效果的影响,并通过测定吸蓝量换算得到蒙脱石质量分数及用XRD表征了原土与提纯产品的物相特征。研究结果表明,宾阳膨润土的d001基本分布在14.6～15.4nm之间,为钙基膨润土,杂质成分主要为石英、高岭土、方解石以及赤铁矿;超声波和水力旋流器均可使提纯效果得到提升,提纯后膨润土蒙脱石的质量分数可达85%以上,物化性质较原土均有提高。     

区域熔炼提纯超高纯锗

采用区域熔炼生长单晶的方法提纯超高纯锗,采用镀碳膜石英舟为容器,提纯后的锗锭在液氮温度下检测净杂质浓度。实验讨论了区熔次数和保护气氛对提纯效果的影响,结果表明区熔次数的增加可以明显提高提纯效果,在10～20次的范围内,最佳区熔次数为20次;在氢气氛围下提纯可避免微量氧对提纯的不利影响,有利于得到更高纯度的锗。实验提纯得到的锗锭净杂质浓度最低为5×10~(10)cm~(-3)。     

水冷磁体中去离子水提纯模式的改进

对稳态强磁场装置水冷磁体中去离子水提纯系统的各项指标和提纯模式进行了分析,并对以往提纯模式的不足进行了改进,提出了一种新的提纯模式。改进后,基本上可以做到切换磁体后无需等待即刻实验,提纯速度得到大幅提升。     

物化提纯法提纯SiC用高纯石墨制品技术研究

通过对现有石墨提纯技术梳理,提出物化提纯法的概念、反应机理及提纯流程,提出物化提纯法的3个重要技术指标,即工艺气体选择、工艺炉压选择和工艺温度选择,根据提纯流程对第3代半导体SiC用高纯石墨制品进行试验,通过试验证明,使用物化提纯法对第3代半导体碳化硅用石墨制品进行提纯,其纯度可以稳定在99.9995%～99.9999%,并且可以定向去除第3代半导体碳化硅用高纯石墨制品中B和Al元素,完全可以满足第3代半导体碳化硅用高纯石墨制品的纯度要求。     

我国高铝矾土的均化与提纯实践

通过重点介绍阳泉矾土矿30余年高铝矾土的设计、生产与技术开发的经验教训,提出了我国高铝矾土的发展方向应该是均化与提纯。     

不同粒度红柱石对矾土基喷涂料性能的影响

以矾土为主要原料,铝酸钙水泥、硅微粉为结合系统,分别研究了不同粒度的红柱石对矾土基喷涂料性能的影响。试样自然干燥24h脱模,再经110℃烘干24h,分别于1000℃、1300℃和1500℃热处理3h。检测各温度热处理后试样的线变化率、体积密度、常温抗折强度、常温耐压强度以及试样的热膨胀系数、耐磨性能和抗热震性能。结果表明,添加粗粒度的红柱石并不能有效弥补矾土基喷涂料经高温热处理产生的收缩。矾土基喷涂料的体积密度随着红柱石粒度的增大而增大。不同粒度的红柱石未对矾土基喷涂料的中温强度产生明显影响,粗粒度的红柱石可以提高矾土基喷涂料的高温强度。矾土基喷涂料的耐磨性能随着红柱石粒度的增大而提高。细粒度的红柱石有利于改善矾土基喷涂料的抗热震性能。     

Efficiency of adding very fine silica in high-silica and corundum ceramic concrete technology. Part 2

Results are provided for comparative evaluation of the properties of pressed specimens of a matrix system and ceramic concrete specimens prepared on the basis of bauxite with very fine quartz glass and quartz sand (VFQG and VFQS), and also the thermal expansion of castings based on a suspension of quartz sand, bauxite and bauxite ceramic concrete. It is established that high-silica molded and unmolded ceramic concretes prepared on a basis of bauxite VFQG (85%) and VFQS (15%) have improved physicomechanical properties. After firing at 1150 and 1420°C their open porosity is 16 – 18% and the ultimate strength in compression is 95 – 125 MPa. Their temperature for the onset of softening is above 1570°C and higher than 1650°C (for compositions containing SiC). Part 1 was published in Novye Ogneupory, No. 1 (2009). Translated from Novye Ogneupory, No. 3, pp. 34 – 40, March 2009.     

矾土基电熔锆刚玉粒度对Al2O3-MgO浇注料性能的影响

研究了不同粒度的矾土基电熔锆刚玉对Al2O3-MgO浇注料常规物理性能、高温机械性能及抗渣性的影响。结果表明：矾土基电熔锆刚玉细粉（〈0．074mm）或1-0mm颗粒的加入对Al2O3-MgO浇注料的常温性能和热震稳定性影响不大;而3～1mm锆刚玉颗粒的加入对浇注料的常温强度有负面影响,但明显提高了浇注料的抗热震性,浇注料的残余强度保持率显著提高。不同粒度矾土基锆刚玉的加入对浇注料的高温抗折强度和抗渣性能影响不大。     

Low Temperature Synthesis of High Alumina Cements by Novel Co‐Melt Precursors and Their Implementation as Castables with Some Micro Fine Additives

In the present investigations nano size high alumina cements (HAC) were prepared by very effective co‐melt precursor sintering technique from their metal nitrate precursors. The prime cementing phases observed were CA, CA₂, and C₁₂A₇. The addition of nano structured cements in refractory castables has improved the thermo‐chemical‐mechanical properties to a significant extent. Each batch of low cement castables (LCC) was prepared from calcined Chinese bauxite, HAC, and superfine additives. The effect of HAC in bauxite castable with the additives similar to Silicon Carbide, reactive alumina, and micro‐fine silica on the sinterability and properties of these castables was investigated. Physical properties such as apparent porosity and bulk density, mechanical properties such as hot modulus of rupture (HMOR), cold and hot modulus of rupture (CMOR), and cold crushing strength (CCS) of hydrated and sintered castables were studied. The sintered castables were also characterized for their solid phase compositions and microstructure using X‐ray diffraction (XRD) and FE‐SEM, respectively. In the castables new phases such as mullite, α‐alumina were formed at the expense of bauxite and silica. Solid solution of mullite formed at high temperature acts as a bonding phase and is accounted for high HMOR, CMOR, and CCS values. These excellent properties of such castables may enable their uses in various applications such as refractory lining for fabrication of steel, aluminium, copper, glass, cement, chemicals, and ceramics.     

新一代矾土基耐火材料

可以期望在新世纪我国根据丰富的高铝矾土资源特点,新一代矾土基耐火材料将会兴起--优质合成原料和高效耐火新产品.优质合成原料包括:(1)Al2O3含量为50%～90%的均质矾土熟料(均质类);(2)矾土基烧结和电熔锆刚玉莫来石和锆刚玉尖晶石系合成料(改性类);(3)矾土基Sialon和Alon(转型类).利用这些合成料开发的矾土基高效新产品为:(1)高温性能优良的高品位高铝砖和浇注料,(2)矾土基刚玉系材料,(3)矾土基Al2O3-Sialon(Alon)复合材料.     

Utilization of Bauxite Tailing

The characteristics of bauxite tailing in China were reviewed,and the current utilization methods and the actuality were discussed.It is found that the bauxite tailing is mainly used for production of building materials and chemical products,and extraction of useful component,etc.Meanwhile,the shortages of these utilization methods were analyzed.In order to enlarge the bauxite tailing application,some new utilization paths were proposed,such as preparing zeolite 4A and corundum-mullite composite materials,which are high value added materials.The utilization ways of bauxite tailing were widened,the utilization ratio of resources and the economic benefit were improved.     

多孔球形莫来石基浇注料的制备及性能研究

为制备保温性能及机械性能均较优异的高温窑炉用隔热耐火材料,以多孔球形莫来石、矾土细粉、α-Al₂O₃微粉、硅微粉和Secar71水泥为主要原料,制备了多孔球形莫来石基浇注料,研究了矾土细粉掺量对多孔球形莫来石基浇注料机械性能、导热系数、抗侵蚀性能及热震稳定性的影响。结果表明,改变矾土细粉的掺量,可使多孔球形莫来石基浇注料在保持较高机械性能的基础上提高保温性、热震稳定性和抗侵蚀性能。随着矾土细粉掺量的增加,多孔球形莫来石基浇注料的机械性能变化不大,但导热系数小幅降低,抗侵蚀性能出现较大差异,热震稳定性先提高后降低。当矾土细粉掺量为28%(质量分数)时,多孔球形莫来石基浇注料的机械性能、热震稳定性及抗侵蚀性能良好,在1 000 ℃时导热系数为0.905 W·m^-1·K^-1。多孔球形莫来石基浇注料的导热系数低于中间包和钢包永久层用高铝浇注料,可替代中间包、钢包永久层用高铝浇注料以减少热损失。     

铝钒土含量对低膨胀高远红外瓷质卫生陶瓷性能的影响

采用煤矸石废料、劣质原料黑滑石和铝钒土为主要原料,通过原位生长法制备了堇青石质低膨胀高远红外瓷质卫生陶瓷。利用XRD、SEM和性能测试研究铝钒土含量对堇青石卫生陶瓷性能的影响。实验结果表明:铝钒土含量对吸水率、抗折强度和膨胀系数具有较明显的影响,而对远红外辐射率并未带来不利的影响,所有样品的远红外率均保持在0.93以上。当铝钒土含量为27%,煤矸石33wt.%,黑滑石37%时,陶瓷性能达到最优:吸水率为0.04%,热膨胀系数为2.74×10-6/℃,抗折强度为87.4 MPa。这主要是由于样品的主晶相堇青石含量最高,并且烧结致密化程度高,其中气孔分布更加均匀所致。相关研究结果对环境保护和工业废物的资源化利用有着积极意义。     

改性铝土矿负载Ni-Mn-K一氧化碳高温变换催化剂的研究

以改性后铝土矿石为载体,采用两步浸渍法,制备Ni-Mn-K一氧化碳高温变换催化剂。采用活性评价、低温N₂吸附、XRD和TPR等表征方法,考察催化剂的结构和性能。结果表明,改性后的铝土矿本身具有一定的变换活性,用该载体负载多组分制得的催化剂具有较好的变换活性。XRD和TPR结果表明,催化剂中具有明显的晶相NiO和K₂CO₃的特征衍射峰, MnO₂与铝土矿载体中的Fe₃O₂和SiO₂形成非晶态复合氧化物。比表面积和孔容减小主要因负载引起,负载活性组分后使耗氢量增大,还原峰温降低。