Determination of potential migrants present in Nylon 'microwave and roasting bags' and migration into olive oil

Two groups of potential migrants were found in Nylon "microwave and roasting bags' (MRBs): volatile compounds were released at cooking temperatures and non-volatile compounds were extracted with methanol and/or water. A dynamic headspace system at 200 degrees C followed by gas chromatography (GC) coupled to mass spectrometry (MS) was used for determination of volatile compounds. Cyclopentanone (31.7 mg/bag), 2-cyclopentyl cyclopentanone (17.4 mg/bag), hexadecane (2.6 micrograms/bag), heptadecane (3.2 micrograms/bag), octadecane (3.0 micrograms/bag) and epsilon-caprolactam (5.0-35.5 mg/ bag) were the main volatile compounds present in the MRBs. High performance liquid chromatography (HPLC) and mass spectrometry were combined for identification and quantification of non-volatile compounds extracted with methanol (46.0 mg/bag). Nylon 6,6 cyclic monomer and cyclic oligomers up to the tetramer and Nylon 6 monomer and cyclic oligomers up to the octamer were identified and quantified, confirming that the plastic was made of Nylon 6,6 and Nylon 6 polymers. The same non-volatile compounds (except Nylon 6 heptamer and octamer) were found to migrate into olive oil at 175 degrees C for 1 h. A total of 0.916 mg/dm2 (19.2 mg/bag) of non-volatile compounds migrated into olive oil (41.8% of those quantified in the plastic material).     

球团矿氧化焙烧及还原过程中的强度变化

研究了球团矿在氧化焙烧和还原过程中抗压强度的变化规律.通过焙烧试验得到了球团矿必要的焙烧温度.通过还原反应后的高温抗压强度研究估算了球团矿焙烧中必要的强度.使用可调气氛高温抗压试验机研究了相应球团矿在氧化焙烧过程中的强度变化规律.球团矿在焙烧过程中有一个强度大幅下降的特定温度.如果该温度高于必要的焙烧温度,焙烧工艺是可行的.     

Arizona hazardous air pollutants monitoring program

In order to evaluate the existing risk to public health in Arizona related to hazardous air pollution, ambient air monitoring for selected hazardous air pollutants (HAPs) was carried out in 1994-1996 in several representative urban and rural areas of Arizona. A wide range of organic HAPs was monitored, requiring a variety of sampling and analysis methods. Stainless steel SUMMA canisters were used for collection of volatile hydrocarbons and halocarbons, which were analyzed by capillary gas chromatography with flame ionization and electron capture detection (GC-FID/ECD). Carbonyl compounds were collected using 2,4-dinitrophenylhydrazine-impregnated cartridges and analyzed by high performance liquid chromatography with ultraviolet detection. Semi-volatile and non-volatile polycyclic aromatic compounds were collected using a sampling train consisting of a filter followed by a PUF/XAD-4/PUF sandwich cartridge. Following extraction, samples were analyzed by capillary GC with mass spectrometric detection (GC-MS). Database software was developed for data processing and reporting functions. This paper describes the sampling strategy and the sampling and analysis methods employed in the monitoring program and presents a summary of all the results obtained during the duration of the sampling program.     

自热式回转窑钼精矿焙烧系统中铼走向研究

在钼精矿焙烧过程中,伴生的铼易挥发进入到烟气中,采用不同设备进行钼精矿焙烧,对应的铼挥发率也不尽相同。对自热式回转窑钼精矿焙烧系统产生物料中的铼含量进行了检测,包括焙砂、烟尘和废酸等,并对影响铼挥发率的关键性影响因素进行了分析。结果表明,焙烧过程铼平均挥发率为27.3%,布袋尘中铼含量142.4g/t,占总铼量的10.2%,废酸中铼含量7.7mg/L,占总铼量的5.0%。焙砂的氧化程度是影响铼挥发率的关键因素,较低的布袋收尘温度是铼无法大量进入废酸的原因。     

伊朗钼精矿氧化焙烧过程影响因素的探讨

通过回转管电炉焙烧伊朗钼精矿的工艺试验，发现该矿的一些理化指标对其氧化焙烧过程具有很大影响．结果表明，在焙烧工艺中采取适当措施，即可用伊朗钼精矿为原料生产出合符要求的氧化钼焙砂．     

处理火法炼锌焙烧烟尘的新方法

处理火法炼锌高温流态化焙烧过程所产的烟尘，采用回转窑二次焙烧流程。该流程存在着燃料消耗较高，劳动条件差和环境污染等严重问题。针对二次焙烧工艺的这些问题。本文提出用湿法冶金和浮选两种新方法处理火法炼锌焙烧烟尘，并从理论上对所采用方法进行初步可行行性探讨。     

Modulation of antennal scanning in the honeybee by sucrose stimuli, serotonin, and octopamine: behavior and electrophysiology

The objective of this publication is to present a new dynamic aerobic biodegradation test method simulating a river. A laboratory cascade test system and standardized batch shake flask tests were used for biodegradation studies with the non-volatile and non-sorbing model compounds 2,4-dinitrophenol, naphthalene-1-sulphonic acid and sulphanilic acid. To be closer to the often very low concentrations of substances in the environment the concentrations of the compounds used were standard test concentrations and lower. 14C labelled compounds were measured at 50 micrograms/l, capillary electrophoresis at 5000 micrograms/l and the removal of dissolved organic carbon at 50000 micrograms/l. The test results obtained confirmed the known ultimate biodegradability of the test compounds and showed that biodegradation degrees, rates and degradation durations depended on the test systems, the concentrations of test compounds and the inocula. The river model is a suitable simulation test for natural dynamic surface waters which can be used to perform biodegradability studies at low test concentrations if adequate analytical tools, preferably radioactive-labelled substances, are available.     

An application of acetonitrile leaching and disproportionation.: Refining segregated copper from roasted concentrates and ores

Pure copper with > 99% recovery has been obtained on a laboratory scale from a variety of copper sulfide concentrates by the following steps. An oxidative roast at 800–900°C to remove sulfur; reduction of the calcine, preferably but not necessarily under segregation roasting conditions at 650–750°C, to generate particulate copper; screening, in the case of segregation roasting, to partially separate from magnetite the over-size carbon which is coated with copper, gold and silver; selective dissolution in acetonitrile-water of the copper from both fractions; then thermal disproportionation of the copper(I) sulfate solution to remover pure copper powder. At least 80% of the silver and > 98% of the copper is recovered by this new concept. Cyanidation of leach residues recovers > 99% of the copper, > 90% of the silver and 80% of the gold, without interference from the iron in the residue. The method has been applied to the product of a segregation roast of refractory copper ores (TORCO process), to the product of a double roast of copper concentrates (Opie-Coffin process) and to the product of a non-segregation reductive roast of a dead roasted concentrate (USBM process). It is also applicable to calcines reduced in a blast furnace.Successful scale up could result in a low cost process for producing copper from copper concentrates. The energy requirements promise to be less than 6000 kJ as 25 psig steam per kg copper, if effective use of steam from the exothermic roasts can be achieved.     

Purification, physicochemical characterization and biological properties of a lectin from Erythrina velutina forma aurantiaca seeds

A lectin was purified from seeds of Erythrina velutina forma aurantiaca by affinity chromatography on cross-linked guar gum. The lectin is a potent agglutinin for human (minimal concentration of protein able to cause visible agglutination of a 2% erythrocyte suspension varying from 1 to 4 micrograms/ml), rabbit (4 micrograms/ml) and chicken erythrocytes (8 micrograms/ml) but presented low activity against cow (250 micrograms/ml) or sheep (333 micrograms/ml) blood cells. Hemagglutination of human O+ erythrocytes was inhibited by D-lactose (0.2 mM) > D-galactose (0.8 mM) > D-raffinose (2.1 mM). At pH 7.5, chromatography on a Superose 12 HR 10/30 column showed that the lectin was primarily a dimer (56.0 kDa) composed of two identical subunits (31.6 kDa each). A small amount of a tetrameric form was also apparently present. The lectin is a glycoprotein (7.3% carbohydrate), has a pI of 4.5, contains high levels of acidic (Asp and Glu, 64.2 and 51.6 residues/mol, respectively) and hydroxy amino acids (Ser and Thr, 42.9 and 38.5 residues/mol, respectively) but relatively low amounts of sulfur amino acids (Cys and Met, 1.0 and 5.0 residues/mol, respectively) and has an N-terminal sequence of Val-Glu-Thr-Ile/Leu-Pro-Phe-Ser. Its hemagglutinating activity was abolished by heating at 70 degrees C for 10 min. The activation energy (delta G') required for denaturation measured by loss of hemagglutination activity was 24.87 kcal/mol. In rats, the purified lectin (100 micrograms) induced neutrophil migration into the peritoneal cavity (3.7 +/- 0.6 x 10(6) neutrophils/ml) or into the air pouch (2.75 +/- 0.25 x 10(6) neutrophils/ml), 8 and 10 times greater than the negative control, respectively.     

Fluidized bed roasting of molybdenite-effect of operating variables

The results of an investigation on the fluidized bed roasting of molybdenite are reported. Molybdenite mixed with quartz was subjected to an oxidizing roast in a 22 mm diam stainless steel batch fluidized bed reactor. Enriched air (with O₂) or diluted air (with N₂) was used as the fluidizing and oxidizing gas. In addition to the MoS₂ content of the solids and the O₂ content of the gas, the effect of temperature and flow rate was also examined. For the range of variables investigated, it was found that the temperature influences the rate of the roasting reaction greatly. The gas flow rate affects the conversion favorably up to a certain fluidizing flow rate. An increase in the O₂ content of the gas and the MoS₂ of the solids results in higher conversion levels. The unreacted core kinetic model was applied to the results; and the energy of activation for the reaction was obtained from the Arrhenius plot as 31,100 cal/gmol of MoS₂. The data obtained should be useful in the design and operation of larger scale roasting reactors.     

中原黄金冶炼厂焙烧工艺浆式进料新技术

本文论述了中原黄金冶炼厂，焙烧－浸出－氰化提金工艺，采用浆式进料新技术，具有操作简单，炉况稳定，金属回收率高，投资省等优点。     

采用回转窑焙烧钼精矿

论述回转窑氧化焙烧钼精矿流程、焙烧温度和窑尾气体的处理方法。钼精矿在窑内的停留时间以及窑内尺寸的确定。     

氯化铵焙烧法从中品位氟碳铈矿精矿提取稀土的研究

采用氯化铵焙烧法分解中品位氟碳铈矿精矿(REO～30%),热水浸取焙砂后,浸取液采用环烷酸全捞制备氯化稀土产品。研究了氯化反应温度、氯化剂用量及氯化时间等因素对稀土氯化率的影响。将中品位氟碳铈矿精矿与2倍氯化铵混合并加入少量添加剂,在480℃焙烧1.5h,焙砂用90℃热水浸取得氯化稀土浸出液,稀土收率为82.8%,浸出液进一步用环烷酸全捞,浓缩结晶得相对纯度为99.2%的氯化稀土产品。     

The binding of ethyl carbamate to DNA of mouse liver in vivo: the nature of the bound molecule and the site of binding

Ethyl carbamate, labelled at C1 with 14C, bound in vivo to liver DNA of intact and partially hepatectomised mice. Isotope (18O) enrichment was not detected in the oxygen of liver DNA of mice injected with [18O] ethyl carbamate, C2H5--18O--CO--NH2. This suggests that it was the ethyl group and not the ethoxy group which bound to DNA. Chromatographic analysis of acid hydrolysates of liver DNA from mice treated with [1-14C] ethyl carbamate provided no evidence of alkylation or other form of binding to purine or pyrimidine bases. On relatively mild acid hydrolysis the alkyl group remained bound to the "apurinic acid" fraction, while more vigorous hydrolysis lead progressively first to its separation as highly ionisable hydrophilic non-volatile compounds and then to its loss as a volatile compound. DNAase I followed by phosphodiesterase hydrolysis also split off the 14C-containing group as a volatile compound. The volatile compound was identified as ethanol. These results suggest that the alkyl group was bound as an ester to a phosphate group in the DNA chain. Results with DNA from partially hepatectomised mice did not differ from those with DNA from intact mice.     

Roasting of the sulfide-zinc concentrate with predominant obtaining of sulfate roast for effective leaching

Roasting the sulfide-zinc concentrate with a high silver content is investigated by thermogravimetric and differential thermal analyses in the mode of polythermal heating. It is shown that roasting at 630 ± 10°C makes it possible to obtain mostly sulfate roast, which is most suitable for the effective recovery of zinc and other components.     

焙烧氰化渣氯化挥发提金的研究

对山东某焙烧氰化渣进行了氯化挥发提金的研究,将原料配入CaCl₂造球、烘干,将球团在不同条件下焙烧,分析焙烧前后的元素含量变化。结果表明：氰化渣中配入4%的CaCl₂造球烘干,在1 050 ℃下焙烧,金挥发率能达到85.93%,且在该温度下未发生熔融,证明使用氯化挥发法提取焙烧氰化渣中的金是可行的。实验中还发现,CaCl₂的分解温度远低于适宜的挥发温度,因此升温时间、中温停留时间过长会导致CaCl₂提前分解,影响金的挥发。     

Exposure to methyl tertiary-butyl ether from oxygenated gasoline in Stamford, Connecticut

In 1993, state health officials in Connecticut invited the Centers for Disease Control and Prevention (CDC) to assist in an investigation of exposure to methyl tertiary-butyl ether in oxygenated gasoline in Stamford, Connecticut. Venous blood samples were collected from 14 commuters and from 30 other persons who worked in the vicinity of traffic or automobiles, and the samples were analyzed for methyl tertiary-butyl ether, tertiary-butyl alcohol, benzene, m-/p-xylene, o-xylene, and toluene. The highest levels of methyl tertiary-butyl ether in blood were measured among gasoline service station attendants (median = 15 micrograms/l, range = 7.6-28.9 micrograms/l). Blood levels of methyl tertiary-butyl ether were highly variable among persons who worked in car-repair shops (median = 1.73 micrograms/l, range = 0.17-36.7 micrograms/l) and were generally lowest among commuters (median = 0.11 micrograms/l, range = < 0.05-2.60 micrograms/l). Blood levels of methyl tertiary-butyl ether were correlated strongly with personal-breathing-zone samples of methyl tertiary-butyl ether and blood levels of other volatile organic compounds. This exposure information should prove useful to a future risk analysis of this high-volume chemical.     

Comparison of extraction methods and detection systems in the gas chromatographic analysis of volatile carbonyl compounds

High-resolution gas chromatography (HRGC) with electron-capture detection (ECD), nitrogen-phosphorus detection (NPD), flame ionization detection (FID) or with mass spectrometry-selected ion monitoring (MS-SIM) was used in the analysis of volatile carbonyl compounds. Eighteen carbonyl compounds that are typically produced during lipid peroxidation were derivatized quantitatively with pentafluorophenylhydrazine (PFPH) at room temperature, to afford their corresponding water-insoluble hydrazones. These derivatives were extracted into non-polar phases by means of either liquid-liquid extraction (LLE) (hexane) or solid-phase extraction (SPE) on 3 ml C18 octadecyl-bonded phase cartridges. Detection limits of 10(-14) and 10(-12) mol/ml per aldehyde were achieved with the ECD and MS-SIM systems, respectively. The effects of extraction conditions on sensitivity and recovery were determined by performing parallel HRGC-ECD and HRGC-MS-SIM analyses of pentafluorophenylhydrazones of the eighteen compounds under study. Recoveries of 51.4-78.9 +/- 1.2-4.5 and 80.9-98.3 +/- 1.0-3.5% were obtained with LLE and SPE, respectively. The method was applied to the analysis of the volatile carbonyl compounds in various heated vegetable oils (corn, palm or sunflower) and to the analysis of volatile aldehydes in human urine.     

吹扫捕集与色谱—质谱联用分析宝钢水和废水中VOCs

吹扫捕集与色谱—质谱联用技术是一种较为成熟的有机物分析技术,结合实验室仪器条件采用此技术,开发出依据美国环保局(EPA)8260B方法分析水和废水中挥发性有机物(VOCs)的方法,并应用于宝钢实际水样的监测,取得了较好的分析结果。该方法可分析40种(类)挥发性有机物,每种物质分析的线性相关系数都能达到0.99以上,基体加标试剂的回收率为89.5%～102.7%,除四种物质为0.01mg/L外,其余物质的定量下限基本上为0.005mg/L,完全能够满足应用要求。     

旋涡炉布袋尘除氯

旋涡炉ＦＤ布袋尘中含锌２７．７％～３４．３１％,有待进一步回收利用。本工艺采用酸化焙烧脱氯。浸出得ＺｎＳＯ４溶液后,并入电锌系统的办法来回收布袋尘中的有价金属。