微波干燥闪锌矿试验研究

研究了利用微波加热干燥闪锌矿的新工艺,对影响闪锌矿相对脱水率的微波功率、微波辐射时间和物料质量等因素进行了研究,得出微波干燥闪锌矿优化试验条件为物料质量100g、干燥时间80s、微波功率700W,在此条件下微波干燥闪锌矿的相对脱水率为26.06%,并进一步对微波干燥闪锌矿的失水特性进行了分析和讨论;通过对试验数据的回归分析,获得了微波干燥闪锌矿的数学模型,采用Boltzmann模型最佳。     

微波辐射法干燥锡酸钠新工艺

研究了利用微波辐射干燥锡酸钠的新工艺，并对影响锡酸钠脱水率的微波功率、微波辐射时间、物料重量、物料厚度等各种因素进行了分析和讨论。实验结果表明利用微波辐射干燥锡酸钠新工艺是可行的，且微波干燥锡酸钠的脱水率与干燥的物料重量、辐射时间、微波功率和物料厚度等因素有关。     

响应曲面法优化微波干燥碳酸稀土的实验研究

采用中心组合设计(CCRD),三因素五水平响应曲面法(RSM),研究了微波功率、干燥时间和物料厚度间的交互作用对碳酸稀土脱除吸附水的影响,模拟得到二次多项式回归方程的预测模型。结果表明:物料厚度一定,脱水率随微波功率和干燥时间的增大而增加;微波功率一定,脱水率随物料厚度增加而降低,优化的最佳工艺参数为:微波功率800 W,干燥时间12 min,物料厚度2 cm,脱水率98.88%,实际测得97.69%,相对误差为1.31%。红外光谱(FT-IR)分析表明微波干燥后碳酸稀土不再含有吸附水;粒度分析表明微波干燥后的碳酸稀土具有粒度细和分布均匀的特点。     

响应曲面优化微波赤泥吸附废水中氟离子

为了优化微波赤泥吸附含氟废水的技术方法,基于响应面法（RSM）建立了3个影响因子（微波功率、吸附时间、废水温度）对赤泥吸附废水中氟离子吸附率的影响,并通过方差分析（ANOVA）研究了各个试验因子或交互作用对氟离子吸附的影响。结果表明,经过响应曲面优化后获得的最佳试验条件为：微波功率308 W、废水温度15 ℃、吸附时间22 min,预测值为96.83%,实际吸附效率为96.08%,通过响应曲面建立的回归模型可以预测微波赤泥吸附废水中氟离子的吸附率,且误差仅为0.77%。     

微波辅助硫酸浸出红土镍矿的研究

以红土镍矿为原料,研究了微波辅助硫酸浸出镍钴的工艺条件。考察了硫酸浓度、微波功率、微波温度、辐射时间、液固体积质量比对镍钴浸出率的影响。结果表明,在硫酸浓度3.0mol/L、微波功率700 W、微波温度90℃、辐射时间2.5 h、液固体积质量比4:1的最佳工艺条件下,镍浸出率达91%,钴浸出率65%以上。     

细粉煤微波加热除湿正交实验及SEM实验

采用正交试验设计方法,通过SEM分析,研究了微波加热比功率、试样初始水分质量分数、细粉煤粒径大小以及加热时间等因素对细粉煤微波加热除湿的影响。在本实验条件下,得出细粉煤微波加热的最优化除湿条件为:比功率8 kW/kg,初始水分质量分数10%,细粉煤粒径在1.25~2.5 mm,加热时间8 min。极差、方差分析表明:微波加热的比功率和加热时间是影响细粉煤微波除湿的主要因素,细粉煤粒径大小对除湿效果的影响不显著。经微波加热除湿后,试样小颗粒所占的比例有所增加,细粉煤颗粒表面微观形貌并未发生明显变化。     

微波加热预处理堆浸铀矿石

为了考察微波功率、辐射时间和物料质量对铀矿石浸出率和浸出周期的影响,采用频率为2.45 GHz微波对花岗岩铀矿石进行加热,然后配置了不同预处理条件下的铀矿样进行室内柱浸试验,并分析了不同微波功率预处理时铀矿石比表面积和孔隙率的变化。研究结果表明:微波预处理的温度应控制在600℃以下。当微波功率为40 k W,辐射时间为40 s,矿石质量为4 kg时,铀浸出率为85.27%,浸出周期为67 d,较原矿浸出率提高7.69%,浸出周期缩短25 d。4 kg矿石经40 k W微波辐射120 s后,比表面积较原矿增大39.9%,孔隙率增加71.8%。利用扫描电镜(SEM)观察微波预处理前后表面形貌,预处理后原有微裂隙扩展并加深,并出现新的裂缝。微波预处理改善了铀矿石渗透性,有利于浸出。     

微波辐射低聚壳聚糖磷钨酸盐催化合成丙烯酸十二酯

采用微波辐射技术,以低聚壳聚糖磷钨酸盐为酯化反应催化剂合成丙烯酸十二酯。利用正交设计实验优化了催化剂用量、微波辐射功率、微波辐射时间、反应物配比等因素对酯化反应的影响。实验结果表明,低聚壳聚糖磷钨酸盐催化剂在丙烯酸十二酯的合成中显示出较好的催化效果,微波辐射具有操作简单、反应速率快、节约能源等优点,优化的最佳条件为:微波输出功率260W、辐射时间12min、催化剂用量0.8%(质量分数)、十二醇与丙烯酸的摩尔比为1.0 ∶1.2。在此条件下,酯化产率达96%以上,反应速率提高了15倍以上。     

石煤微波浸出提钒工艺研究

考查浸出时间、硫酸浓度、液固比及微波功率等因素对石煤中钒浸出率的影响。研究表明,当浸出时间为60min、硫酸质量浓度为13%、液固比为2∶1、微波功率为800 W时,钒浸出率可达83.2%。     

响应曲面优化微波干燥铅渣的工艺研究

采用微波加热技术对铅渣进行脱水。通过响应曲面法中心组合设计分析了干燥温度、干燥时间、物料厚度对脱水率的影响,并建立了相关的数学模型。方差分析表明,二次方数学模型拟合较好,物料厚度、干燥温度对脱水率的影响较干燥时间更为显著。优化工艺参数为干燥温度93℃,干燥时间10min,物料厚度19mm,相对脱水率达到68.21%,实际值与模型预测值相差0.73个百分点,干燥后铅渣的含水量为8.12%,可以满足后序工艺要求。     

Preparation of V<Subscript>2</Subscript>O<Subscript>5</Subscript> from Ammonium Metavanadate via Microwave Intensification

Parameters of technique to prepare of V₂O₅ by microwave intensification from ammonium metavanadate were optimized using central composite design of response surface methodology. A quadratic equation model for decomposition rate was built and effects of main factors and their corresponding relationships were obtained. The microwave heating behavior indicated that ammonium metavanadate had weak capability to absorb microwave radiation, while V₂O₅ had good capability to absorb microwave radiation. The results of the statistical analysis showed that the decomposition rate of ammonium metavanadate was significantly affected by calcination temperature and calcination time in the range studied. The optimized conditions were as follows: calcination temperature 645.35 K, calcination time 9.66 min and 4.3 g, respectively. The decomposition rates of ammonium metavanadate were 99.13%, which coincided well with experiments values 99.33% under these conditions. These suggest that regressive equation fits the decomposition rates perfectly. XRD reveals that it is feasible to prepare the V₂O₅ by microwave intensification from ammonium metavanadate, which mixed with small amounts of V₂O₅.     

锍镍试金-高分辨率连续光源石墨炉原子吸收光谱法测定铬铁矿中铂族元素

针对难融铬铁矿样品中铂族元素的分析,提出了过氧化钠和氧化钙预烧结样品再进行锍镍试金富集的新方法,实验方法可完全分解铬铁矿,后续采用微波消解仪在优化的加热消解程序下以10mL王水(1+1)溶解Pt、Pd、Ru、Rh、Ir的硫化物沉淀连同滤纸,在微波消解密闭高温高压条件下,被测元素被完全溶解,然后应用高分辨率连续光源石墨炉原子吸收光谱法(HRCS-GFAAS)测定。实验优化了Pt、Pd、Ru、Rh和Ir的灰化和原子化温度、原子化读数时间和电感耦合器件(CCD)检测器有效像素点。在优化的实验条件下,Pt、Pd、Ru、Rh和Ir的吸光度与其对应的质量浓度运用二次方程最小二乘法拟合校准曲线,曲线拟合良好,校准曲线决定系数均不小于0.9994;特征浓度分别为1.56、1.98、0.45、1.27、3.06ng/mL。将实验方法应用于标准物质中5种铂族元素的测试,测定值与标准值吻合良好,5次平行分析实际铬铁矿样品中结果的相对标准偏差(RSD,n=5)介于5.0%~14%之间。所建立的方法满足铬铁矿样品中痕量、超痕量Pt、Pd、Ru、Rh和Ir的测定要求。     

Optimization of copper extraction from spent LTS catalyst (CuO–ZnO–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>) using chelating agent: Box-behnken experimental design methodology

The objective of the present work is to investigate the extraction of copper from spent low temperature Shift catalyst using EDTA, as chelating agent and optimization of the parameters that influence the extraction of copper. Response surface methodology was applied for designing the experiment and to determine the optimal experimental conditions. Most influencing parameters such as concentration of EDTA, solid to liquid ratio and particle size of catalyst were optimized based on 3 factors 3 levels box behnken design which requires 15 run of experiments for designing a response surface. The high value of regression coefficient R ² (0.981) indicates a good correlation between predicted and experimental response, which confirms the acceptability of the proposed model.The optimum conditions were found as—concentration of EDTA: 0.5889 M, solid to liquid ratio: 0.02 and particle size: 90 μm. Under these optimum conditions, the experimental value of extraction of copper was estimated as 94.5% which seems very close to predicted response.     

Heat and Mass Transfer during Microwave Steam Treatment of Contaminated Soils

A time-dependent mechanistic model has been developed to describe the coupled heat and mass transfer during microwave steam treatment of contaminated soils. The model consists of multiphase mass and energy conservation equations, along with various temperature-dependent parameterizations of important physical state properties. The coupled nonlinear equations were solved numerically by applying a macroscopic control volume method with the appropriate boundary and initial conditions and using a finite-difference scheme. Microwave heating experiments of soil samples were performed. The effects of microwave power, soil sample depth, and soil type on water evaporation rate and temperature were measured with time. The modeled results are in good agreement with the experimental data. The results revealed that microwave power density and soil sample depth significantly affect the microwave evaporation process of water from soils. Water evaporation rate and temperature variation are complex and associated with the dielectric properties of liquid water distributed within the soil. The deeper the soil sample, the more nonuniform the evaporation process, although nonuniformities diminish as the evaporation process approaches completion. Finally it was verified that soil types and their thermal properties play a minor role, provided that the soil minerals are microwave transparent.     

Preparation and evaluation of zidovudine-loaded sustained-release microspheres. 2. Optimization of multiple response variables

The formulation of zidovudine-loaded (AZT-loaded) sustained-release microspheres was prepared and optimized using response surface methodology. The objective was to use this statistical procedure to obtain a formulation with optimized overall properties. The effect of formulation variables (emulsifier concentration, drug to polymer ratio, and composition of the internal phase of the emulsion) on a number of response variables was systemically investigated. The response variables were t85, entrapment efficiency, yield, and percentage of loose surface crystals. A desirability function that combines these four response variables was constructed. A second-order polynomial equation was fitted to the data, and the resulting equation was used to predict the responses in the optimal region. All the investigated response variable were found to be highly dependent on the formulation variables, with strong interactions observed between the formulation variables. It was found that optimum overall desirability of AZT microspheres can be obtained at low levels of SDS and ethyl acetate concentrations and at intermediate levels of drug to polymer ratio. An optimized formulation was prepared under these experimental conditions and evaluated for individual responses and overall desirability. The experimental values of the response variables highly agreed with the predicted values.     

Intestinal lymph absorption of butter, corn oil, cod liver oil, menhaden oil, and eicosapentaenoic and docosahexaenoic acid ethyl esters in rats

The purpose of this work was to develop a computer program that assists optimization of controlled-release devices, both visually and mathematically, using response surface methodology (RSM). A Windows-based computer program, Optima, which interactively implemented a number of subroutines for the optimization procedure, was developed. Optima is an integrated, user-friendly, and graphically oriented program for pharmaceutical dosage form optimization. Central composite design is implemented in the program. First- and second-order models containing up to five variables can be fitted to the data. The user can also choose between linear and exponential individual desirability functions, and use them to construct an overall desirability function that combines all the response variables in a single response. The program can predict the optimum levels of experimental variables, with respect to individual responses and/or the overall desirability. Optima has been successfully used in the development of sustained-release AZT-loaded microspheres. During the optimization process, three experimental variables were investigated and four responses were measured. The experimental design was a central composite design that was generated by the program. The response values were used by the program to calculate the individual desirability functions, which were then combined into an overall desirability function. The individual responses as well as the overall desirability function were optimized by fitting to a second-order polynomial equation. The response surfaces were generated and optimum levels of the experimental variables were predicted. The observed responses of the optimized formulation were very close to those predicted by Optima. The program proved to be a very useful, integrated tool for optimization of the controlled-release microspheres.     

响应曲面法优化内配兰炭赤铁矿球团焙烧工艺

 为了有效解决赤铁矿球团焙烧能耗高的难题,对赤铁矿球团进行内配兰炭处理并利用响应曲面法对球团焙烧工艺进行了优化试验研究。通过单因素试验确定主要影响因素和水平,对内配兰炭赤铁矿球团各影响因素进行Box-Behnken设计,建立了用于球团抗压强度预测的多元回归模型,并对焙烧温度、焙烧时间、空气流量、兰炭配比以及它们之间的交互作用进行了研究和优化。得到最佳焙烧工艺,焙烧温度为1 292 ℃,焙烧时间为18.5 min,空气流量为3.2 L/min,兰炭配比为1.5%。最佳条件下的内配兰炭赤铁矿球团抗压强度为2 578.3 N,与响应目标值2 500 N相近,相对误差仅为3.13%,表明响应曲面法预测模型具有准确性和可靠性。     

高压微波消解-电感耦合等离子体质谱法测定地质样品中分散元素镓铟铊锗碲镉

建立灵敏度高、准确度高的分散元素分析方法一直是地质样品分析的重点。采用高压微波消解法以HF-HNO₃体系处理样品,选择²⁰⁵Tl、¹²⁵Te、⁶⁹Ga、⁷⁴Ge、¹¹⁵In、¹¹⁴Cd作为测量同位素,采用校正方程在线校正了⁷⁴Ge、¹¹⁵In 的同量异位素干扰,采用离线校正方式校正了¹¹⁴Sn对¹¹⁴Cd的同量异位素干扰,建立了电感耦合等离子体质谱法(ICP-MS)测定地质样品中分散元素Ga、In、Tl、Ge、Te、Cd的方法。对称样量、高压微波消解条件、浸取酸种类进行了优化。结果表明,在优化的实验条件下,校准曲线的相关系数均不小于0.9997,检出限为0.005~0.093μg/g,测定下限为0.017~0.31μg/g。按照实验方法对土壤成分分析标准物质、水系沉积物成分分析标准物质、安山岩岩石成分分析标准物质中Ga、In、Tl、Ge、Te、Cd平行测定12次,各元素测定值与认定值基本一致,相对标准偏差(RSD)均不大于8.5%,相对误差不大于9.1%。采用实验方法对土壤样品进行分析,测定结果与封闭酸溶-ICP-MS测定Ga、In和Tl,氢化物发生原子荧光光谱法测定Ge,乙醇增敏-ICP-MS测定Te,石墨炉原子吸收光谱法测定Cd的结果基本吻合。     

脉冲熔融-红外吸收/热导法测定高钴铸造高温合金中超低氧和氮

研究了脉冲熔融-红外吸收/热导法测定高钴铸造高温合金中超低氧和氮的取、制样和分析方法.将高钴铸造高温合金圆棒用互动切割机切割成厚度为15～25 mm的圆饼,将圆饼首先用水冷金相切割机切割出圆心角度数约90°的扇形块,再沿着扇形块的两个圆弧端点方向用水冷金相切割机切割出厚约5 mm的薄片,最后在薄片上切割出宽约5 mm的...