碱法提高铝硅矿物的铝硅比

采用NaOH溶液时铝硅矿物进行预脱硅处理,测出溶渣中SiO2和Al1O3的含量,计算得出渣中的铝硅比.考察液固比、溶出温度、溶出时间、碱浓度等因素对铝硅矿物溶出后渣中铝硅比的影响.实验表明,在液固比为40∶1、温度95℃、溶出时间3 h、40%碱浓度条件下,矿物的脱硅率可达55%以上.预脱硅后渣中铝硅比由0.89提高到...     

由高炉渣酸解废液制备镁铝尖晶石粉体

以含Mg2+和Al3+等有价元素的高炉渣酸解提硅废液为原料、尿素为沉淀剂,采用均匀沉淀法制备镁铝尖晶石粉体,研究了其产率及性能. 结果表明,最佳工艺条件为：反应温度100℃,尿素用量为理论用量的10倍,煅烧温度1100℃,保温时间2 h. 加入5%(w) Na2S2O4后,样品中Fe2O3含量从1.70%(w)降到0.49%(w),除铁率达71.2%,白度增加11度. 产品为富铝型镁铝尖晶石,且杂质含量远低于国家标准.     

不同硅含量多级孔SAPO-5分子筛的制备及表征

以N-甲基二环己基胺(MCHA)为结构导向剂、正硅酸乙酯(TEOS)为硅源、氢氧化铝为铝源、85%的磷酸为磷源,采用水热法制备了不同硅含量的多级孔SAPO-5分子筛。采用X-射线粉末衍射(XRD)、氮气物理吸附、傅立叶变换红外光谱(FTIR)和氨程序升温脱附(NH3-TPD)等方法分别对样品的晶体结构、比表面积、骨架结构和酸性等进行表征。结果表明:随着硅含量的增加,多级孔SAPO-5分子筛的结晶度降低;孔径无明显变化,孔容增大;当硅含量为0.33时,样品不再具有AFI结构;总酸量随着硅含量的增加先升高后降低,当硅含量为0.20时,总酸量最大。     

NaX型分子筛硅铝比的简易测定

分子筛样品以1+1硫酸溶样处理,固体残渣经高温恒重后直接得出样品SiO_2含量;滤液以络合—锌盐返滴定测定出样品中Al_2O_3含量,从而求出样品的硅铝比。本法简便、快捷,还可适用于NaA、NaY及氢型分子筛的硅铝比测定。     

绞胎瓷水晶釉的研究

主要从配方、工艺方面着手,用普通陶瓷原料生产绞胎瓷水晶釉研究。拟定样品的铝硅比为0.09、0.10、0.11,并调节各种碱金属氧化物的含量,采用生料釉和一次烧成的方法。实验结果显示,配方中铝硅比对釉面的光泽度影响比较大,铝硅比控制在0.09时样品的光泽度好。对其酸度系数的分析显示,在铝硅比相同的情况下,样品的光泽度随其酸度系数的增加而呈下降趋势,除此之外还研究了多种金属氧化物对水晶釉光泽度的影响。     

微波消解-ICP-AES法测定布洛芬注射液包材相容性研究中微量元素含量

建立了中性硼硅酸玻璃安瓿相容性试验后的布洛芬注射液中微量元素硼、铝、钡和硅含量测定的方法。采用微波辅助酸消解样品,电感耦合等离子发射光谱法(ICP-AES)测定。以硼249.772nm、铝396.152nm、钡493.408nm和硅288.158nm为检测波长,线性范围:硼和铝0.1~1.0mg·L~(-1),钡0.01~0.1mg·L~(-1),硅0.5~5.0mg·L~(-1),线性关系良好,相关系数:硼0.9999、铝0.9998、钡0.9998和硅0.9997;检出限:硼0.006mg·L~(-1)、铝0.02mg·L~(-1)、钡0.0005mg·L~(-1)和硅0.0mg·L~(-1);加标回收率:硼95.1%~102.0%,铝104.8%~106.8%,钡101.5%~104.2%,硅101.2%~105.1%。该测定方法快速、准确、灵敏度高,适用于药品内包装材料加速试验后的药品中金属元素含量变化的研究。     

酸碱联合法从煤矸石中提取铝硅资源初步研究

我国的能源结构以煤为主,煤炭无论是在一次能源的生产或消费结构中均占到75%,每生产1吨煤炭约产生0.1～0.3吨煤矸石,而煤矸石中主要化学成分为铝、硅、铁,其中铝和硅的赋存物相成分主要为高岭土等铝硅矿物。化学分析结果表明,其中氧化铝含量在27%～36%,平均含量在30%左右。二氧化硅含量在50%～61%,因此理论上具有可利用的可能性。基于此,本文通过实验,对这一课题进行了初步研究,试图探究通过酸碱联合法从煤矸石中提取铝硅资源。     

亚熔盐法粉煤灰脱铝渣水热处理后碱含量的影响因素

以亚熔盐法处理粉煤灰的脱铝渣为原料,采用动态水热法分解脱碱,研究了不同A/S(Al2O3/SiO2质量比)、C/S(CaO/SiO2质量比)和不同脱铝溶出工艺对硅渣碱含量的影响. 结果表明,随脱铝渣A/S增加,碱含量先降低后升高,脱铝渣A/S为0.11,硅渣Na2O含量降至1.18%,适当的A/S有利于提高硅渣中含铝托贝莫来石的晶化程度;脱铝渣C/S为0.98,硅渣Na2O含量仅有1.31%,随脱铝渣C/S增加,硅渣碱含量增加,C/S过高会降低硅酸钠钙(NaCaHSiO4)的分解率,不利于生成含铝托贝莫来石相;溶出时间和停留时间较长的脱铝渣在脱碱过程中不易生成含铝托贝莫来石.     

L型沸石的离子交换与脱铝改性研究

为了改善L型沸石的催化性能,优化其在FCC中的应用,对L沸石进行离子交换和脱铝的改性研究。考察离子交换时间和离子交换方式对降低L沸石中氧化钾含量的影响及水热焙烧和化学脱铝对提高L沸石硅铝物质的量比的影响。结果表明,L型沸石离子交换时间不易过长,较适宜的时间为3 h。离子交换和水蒸汽处理相结合对降低L型沸石的钾含量更有效,离子交换和水蒸汽处理交替进行3次的样品氧化钾质量分数可降至0.82%。水热焙烧和化学脱铝能使L型沸石显著脱铝,其中,经过700 ℃水蒸汽处理1 h,再进行盐酸处理而制得改性L型沸石样品的硅铝物质的量比可达21.91,相对结晶度高于80％。     

EDTA直接滴定硅酸盐样品中镁的研究

研究了EDTA(乙二胺四乙酸)直接滴定硅酸盐样品中镁含量的方法,并用于实际样品的分析测定.其中硅、铁、铝等元素按国际方法掩蔽,钙用EGTA(乙二醇双-N,N,N＇,N＇一四乙酸)掩蔽.     

Improvement of piezoresistance properties of silicon carbide ceramics through co-doping of aluminum nitride and nitrogen

The piezoresistance coefficient was measured on co-doped silicon carbide ceramics. Evaluation samples of -silicon carbide ceramics were first fabricated by glass capsule HIP method using powder mixture of silicon carbide and aluminum nitride with various ratios. The resultant aluminum nitride added silicon carbide ceramics were doped with nitrogen by changing the post-HIP nitrogen gas pressure. The lattice parameter increased with the amount of adding aluminum nitride indicating that the incorporated aluminum substituted smaller silicon atoms. After post-HIP treatment, lattice parameter then decreased with nitrogen gas pressure. The piezoresistive coefficient increased with the addition of aluminum nitride, it further increased with the nitrogen doping pressure.     

Determination of In-Shell Peanut Oil and Fatty Acid Composition Using Near-Infrared Reflectance Spectroscopy

NIR reflectance spectroscopy was used to analyze the total oil and fatty acid concentration of Virginia and Valencia types of in-shell peanuts rapidly and nondestructively. NIR absorbance spectra were collected in the wavelength range from 400 to 2,500 nm using a NIR instrument. Average total oil concentrations of all samples were determined by a standard Soxtec extraction method. Fatty acids were converted to the corresponding methyl esters and measured using gas chromatography. Partial least squares analysis was performed on the calibration set, and models were developed for predicting total oil and fatty acids. The best model was selected based on coefficient of determination (R ²), standard error of prediction, and residual percent deviation (RPD) values. Virginia-type in-shell peanuts had RPD values of >5.0 for both absorbance and reflectance models, indicating that the method could be used for quality control and analysis. Valencia peanuts had an RPD value of 3.01, which indicates that the model is good for initial screening purposes. For both types of peanuts, fatty acid prediction gave RPD values of <5 for all the models, indicating they could be used for initial screening purposes.     

工业硅中铁铝成分分析中乙二胺四乙酸二钠和硫酸铜标准溶液配制方法的改进

介绍了对工业硅中铁铝成分分析中乙二胺四乙酸二钠(以下简称EDTA)和硫酸铜标准溶液配制方法的改进,改进后的方法缩短了标准溶液配制时间,减少了分析步骤,准确度不受影响。     

云南省水稻增施硅肥肥效及优化施肥量研究

通过全省近１０ａ（１９８８ ～１９９９）硅肥在水稻上施用的结果及土壤化验资料分析,研究了土壤有效硅、硅肥用量与硅肥肥效的相关性,提出了水稻增施硅肥的土壤硅素的丰缺指标及优化施肥量。     

中压微波消解——冷原子荧光法测定大米中的汞

利用中压微波消解,不赶酸,20%~25%HNO3介质,冷原子荧光法测定大米中的汞,样品加标回收率91.9%~104.5%,国家标准物质相对误差小于5%,标准溶液相对标准偏差小于3%,样品相对标准偏差小于4%。此法快速有效、简洁环保,适合测定大米以及其它农作物样品中的汞。     

蔬菜中农残分析方法及残留农药去除率的研究

建立了一种气相色谱法检测蔬菜中农药残留的测定方法,考察了自制果蔬洗涤盐对蔬菜农药残留的去除率。采用基质固相分散法处理蔬菜样品,弗洛里硅土为固相吸附剂,丙酮/正己烷为洗脱液,各农药回收率在78%~107%,检出限0.003~0.006 mg/kg,定量限0.02~0.03 mg/kg,相对标准偏差小于8%。此方法简单、易操作,可用于评价各类洗涤剂去除农药的效果。为有效去除蔬菜表面残留的农药,以食盐为基本原料,通过复配表面活性剂制备出高效的果蔬洗涤盐,其对有机磷农药敌敌畏、乐果、毒死蜱的去除率在70%~94%,蔬菜中农药残留量均低于国家最高残留限量。     

ICP—AES法测定金属钙中铁、镍、铜、锰、镁、硅、铝

研究了ICP-AES法测定金属钙中铁、镍、铜、锰、镁、硅、铝的样品处理和分析条件。金属钙线经表面处理和制样后,马上用（1＋1）硝酸溶解、定容,工作曲线不需作基体匹配。在选定的分析谱线和仪器条件下测量,相对标准偏差为1．3％～13．1％,回收率92．2％～107％。本方法简便、快速、准确,可以满足生产需求。     

硅改性拟薄水铝石合成SAPO-34分子筛的研究

SAPO-34分子筛常用于甲醇制烯烃（MTO）反应中。以硅酸钠、硝酸铝和氨水为原料采用碱滴酸加料方式制备一种硅改性拟薄水铝石,再以硅改性拟薄水铝石为硅源和铝源、磷酸（H₃PO₄）为磷源、四乙基氢氧化铵（TEAOH）为模板剂采用水热合成法制备SAPO-34分子筛。采用XRD、SEM、FT-IR、NH₃-TPD等表征手段对合成的硅改性拟薄水铝石及SAPO-34分子筛进行表征并对其MTO催化性能进行评价。结果表明,在硅铝物质的量比为0.08~0.5时,硅的引入对合成纯相拟薄水铝石无影响,但硅的引入量对拟薄水铝石的结晶度及形貌有一定影响;在硅铝物质的量比为0.2~0.5时,以硅改性拟薄水铝石为硅源和铝源可以合成纯相SAPO-34分子筛,MTO催化反应甲醇转化率可达99%以上,双烯选择性最高达87%以上,并拥有较高的乙烯选择性。     

An investigation of oven methods for determining the moisture content of shelled peanuts

Air-oven methods, using ground, sliced, and whele shelled peanuts, were investigated. The use of ground samples was found to be unsatisfactory. Slightly more accurate results were obtained with whole nuts than with sliced nuts. The method of heating 50-g. samples of whole shelled peanuts for 3 hrs. at 130°C. in a foreed-draft oven gave results agreeing closely with those obtained by the Karl Fischer method for samples of low moisture content.     

A method for determining kernel moisture content and aflatoxin concentrations in peanuts

A method was developed to determine kernel moisture content (KMC) and aflatoxin concentration in discrete peanut samples. Shelled peanuts were weighed to the nearest 0.01 g, and a water slurry was made by blending the peanuts for 2 min with 2.2 ml of water per g of peanuts. The slurry (10 g) was withdrawn and dried at 130°C for 3 h to determine KMC. Methanol was added to the remaining slurry and blended for an additional 1 min, and aflatoxins were quantitated with high-performance liquid chromatography. Comparison of the slurry method with an official peanut moisture method showed good agreement between the two over a range of moisture levels. Recovery of aflatoxin B₁ from spiked samples averaged 97% with an average coefficient of variation of 3.6%. The method enables determination of both KMC and aflatoxin content in peanut samples without degradation of aflatoxin that would occur when using the official moisture method.