焙砂超浸强化硫脲浸金研究

以焙砂为原料,首先经过酸洗预处理去除砷等有害元素,并减少杂质含量,降低硫脲消耗,考察硫酸质量浓度对砷、铁、铜、锌浸出率的影响,并对酸洗后的矿相转化行为进行了分析;同时,开展超浸与常规酸性硫脲体系浸金效果的对比研究。结果表明:酸洗预处理可有效脱除有害元素砷,最优条件下,砷、铁、铜、锌浸出率分别为96.3%、0.5%、22.7%、7.6%;超浸可降低颗粒粒径,强化反应动力,实现包裹金的深度解离,有效提高金浸出率。常规酸性硫脲体系金浸出率仅为54.6%,采用超浸工艺反应10 min,金浸出率达到84.6%,可实现金的高效浸出。

湿法炼锌超浸渣的浮选研究

某铅锌冶炼厂湿法炼锌超浸渣组成复杂、酸度高、粒度细,存在部分硅胶,是一种难选物料。采用一粗、一扫、一次空白精选流程,添加硫化钠—丁铵黑药组合剂混合浮选铅、银,可获良好指标。

浸出制油技术开发动向

目前,植物油脂大多采用己烷溶剂浸出法,或预榨-己烷溶剂浸出法制取;然而,从安全及环境方面而言,人们对替代己烷浸出法技术日益寄予更多期待。完全压榨法和超临界二氧化碳流体浸出法已在小规模生产中得以利用,异丙醇浸出、酶法浸出研究也在进展之中;但这些替代技术在大豆油、菜籽油等一般油脂大量生产中仍尚未实用化,为此,有必要进一步研究提高收率,降低生产成本。

浸出制油技术研究进展

与压榨法制油技术相比,浸出制油法技术具有诸多优点,但现行油脂工业浸出制油技术的应用因健康及环保问题受到人们的不断质疑。为此,各国油脂科技工作者对新型浸出制油技术的新型替代溶剂筛选及其应用展开了大量的研究工作。其中,以饱和烃类溶剂、低碳链醇类溶剂、超临界二氧化碳及酶法浸出技术为目前的研究热点。就以上浸出技术的最新进展进行综述,重点介绍其工艺、装备及安全、环保等,以供业界参考。

米糠油浸出和精炼技术研究新进展

对米糠油浸出和精炼技术研究的最新进展进行了阐述。扼要介绍米糠油室温平衡浸出。超临界二氧化碳(SC-CO2)浸出、酶催化浸出技术和米糠油再酯化、膜技术、生物精炼,混合油精炼等脱酸技术的研究。

人参多糖提取工艺优化及其组成分析

以超临界脱脂、脱皂苷后的人参渣为原料,采用超临界辅助热水浸提法提取人参多糖,采用正交试验确定提取人参多糖的最佳工艺条件。结果表明:在萃取压力30 MPa、萃取温度80℃、萃取时间1.5 h、物料粒度0.20 mm、原料-夹带剂比例1∶2.5(g/m L)时,人参多糖提取率为(38.03±1.43)%,多糖纯度为(54.71±2.16)%,与热水浸提法相比,提取率和纯度分别提高了16.15%和13.44%。采用高效液相色谱法和高效凝胶渗透色谱法对人参多糖中的单糖组成和多糖平均分子质量进行分析,发现人参多糖含有较多的葡萄糖以及少量的半乳糖、阿拉伯糖,且超临界辅助热水浸提法中这3种单糖的含量均显著高于热水浸提法。超临界辅助热水浸提法与热水浸提法提取的人参多糖重均分子质量分别为123 847 u和127 016 u,但是超临界辅助热水浸提法的人参多糖中多糖种类多于热水浸提法。

Enrichment of ferric iron on mineral surface during bioleaching of chalcopyrite

In order to investigate the enrichment of ferric iron bound by extracellular polymeric substance （EPS） on the mineral surface during bioleaching of chalcopyrite, several methods including sonication, heating and vortexing were used and sonication at 48℃ was shown as a good way to extract ferric iron. Scanning electron microscope （SEM） and energy dispersive X-ray spectrometer （EDX） analysis showed that lots of cracks and pits can be found on the chalcopyrite surface after bioleaching and that iron oxide was filled in these cracks and pits. The variations of contents of ferric iron and EPS on the chalcopyrite surface were investigated. The results indicated that the content of EPS increased rapidly in the first 10 d and then maintained at a stable level, while ferric iron content increased all the time, especially in the later stage of bioleaching.

Intraluminal versus infiltrating gallbladder carcinoma:Clinical presentation,ultrasound and computed tomography

AIM： To compare clinical presentation and ultrasound （US） and computed tomography （CT） sensitivity between intraluminal and infiltrating gallbladder carcinoma （GBCA）. METHODS： This retrospective study evaluated 65 cases of GBCA that were categorized morphologically into the intraluminaI-GBCA （n = 37） and infiltrating-GBCA （n = 28） groups. The clinical and laboratory findings, presence of gallstones, gallbladder size, T-staging, nodal status, sensitivity of preoperative US and CT studies, and outcome were compared between the two groups. RESULTS： There were no significant differences between the two groups with respect to female predominance, presence of abdominal pain, serum aminotransferases level, T2-T4 staging, and regional metastatic nodes. Compared with the patients with intraluminaI-GBCA, those with infiltrating-GBCA were significantly older （65.49 ± 1.51 years vs 73.07 ± 1.90 years）, had a higher frequency of jaundice （3/37 patients vs 13/28 patients） and fever （3/37 patients vs 10/28 patients）, higher alkaline phosphatase （119.36 ± 87.80 IU/L vs 220.68 ± 164.84 IU/L） and total bilirubin （1.74 ± 2.87 mg/L vs 3.50 ± 3.51 mg/L） levels, higher frequency of gallstones （12/37 patients vs 22/28 patients）, smaller gallbladder size （length, 7.47± 1.70 cm vs 6.47 ± 1.83 cm; width, 4.21 ± 1.43 cm vs 2.67 ± 0.93 cm）, and greater proportion of patients with 〈 12 mo survival （16/37 patients vs 18/28 patients）. The sensitivity for diagnosing intraluminal- GBCA with and without gallstones was 63.6% and 91.3% by US, and 80% and 100% by CT, respectively. The sensitivity for diagnosing infiltrating-GBCA with and without gallstones was 12.5% and 25% by US, and 71.4% and 75% by c-r, respectively. CONCLUSION： In elderly women exhibiting small gallbladder and gallstones on US, especially those with jaundice, fever, high alkaline phosphatase and bilirubin levels, CT may reveal concurrent infiltrating-GBCA.

Ultrasonic-assisted Oxidation Leaching of Nickel Sulfide Concentrate

The feasibility of oxidation leaching process of nickel from nickel sulfide ore and the form of different components in the lixivium has been studied at first. The method of leaching nickel sulfide concentration directly by oxidants with existence of ultrasonic has been advanced. The process of leaching nickel from nickel sulfide concentration by using the system of persulfate and silver has been determined. The influence of different factors on the leaching rates of nickel,such as with and without ultrasonic,the concentration of Na2S2O8,liquid-solid ratio and the concentration of AgNO3 have been explored. The results show that:(1) in the oxidative leaching system,nickel can be leached completely as Ni2+ or NiSO4(aq.) from nickel sulfide concentration in theory;(2) the nicopyrite can not exist steadily in the persulfate acid leaching system,but Ni2+can. Meanwhile,sulfur may be existed steadily in the leaching process;(3) nicopyrite with much lower electrostatic potential may be leached earlier than chalcopyrite and sideropyrite;and(4) the overall reaction rate of the leaching process can be enhanced with ultrasonic radiation,but it does not change the mechanism of leaching. The more oxidant concentration or higher liquid-solid ratio is,the higher leaching percentage of nickel. The leaching percentage of nickel can be increased significantly by adding a small amount of AgNO3 during the leaching processes. Under the same conditions,the higher concentration of AgNO3 is,the higher leaching yields of nickel will be obtained.

Recovery of molybdenum from residues by simultaneous ultrafine milling and alkali leaching

A new technology of treating molybdenum residues by simultaneous ultrafine milling and alkali leaching was put forward to recover molybdenum from metallurgical residues. The effects of residue size, milling time, solid content, n (Na 2CO 3)/ n (Mo) and slurry pH value on molybdenum leaching rate were investigated. The results indicate that a simpler process, lower slurry temperature, 50% shorter treating time, 60% decrease of Na 2CO 3 content and 15% increase of molybdenum leaching rate can be obtained by the new technology compared with the traditional process. The leaching kinetic equation was determined, and calculation of active energy ( E =56.2 kJ/mol) shows that the leaching process of molybdenum residues by simultaneous ultrafine milling and alkali leaching is controlled by chemical reaction. Potential exists for the new process to form the basis for an economically viable, environmentally friendly process to recover valuable elements from residues.

Fabrication of Super Hydrophobic Surfaces on Copper by Solution-immersion

Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle measurements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu 7 S 4 . The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu 7 S 4 admirably, compared with Cu, which contributes to the stable super hydrophobic surface.

Mbius Homogeneous Hypersurfaces with Three Distinct Principal Curvatures in S^(n+1)

Let x ： M^n→S^n＋1 be an immersed hypersurface in the （n ＋1）-dimensional sphere S^n＋1. If, for any points p,q ∈ M^n, there exists a Mobius transformation Ф ： S^n＋l →S^n＋1 such that Ф o x（M^n） = x（M^n） and Ф o x（p） = x（q）, then the hypersurface is called a Mobius homogeneous hypersurface. In this paper, the Mobius homogeneous hypersurfaces with three distinct principal curvatures are classified completely up to a Mobius transformation.

Supramolecular PS-P4VP diblock copolymer thin films slowly dip-coated from chloroform solutions

This contribution shows the strong influence of using chloroform instead of THF on the characteristics of thin films of supramolecular block copolymers of poly(styrene-b-4-vinyl pyridine) dip-coated in the so-called "capillarity" regime from solutions containing 1-naphthol or 1-naphthoic acid.The small molecule content in the dip-coated films was investigated by infrared spectroscopy and the film morphology by atomic force microscopy.It was found that the small molecule content in the films is constant with dip-coating rate in the range investigated,but it is higher for 1-naphthoic acid than for 1-naphthol.The main morphology observed was in the form of "islands" and "holes",which is typical of flat-on lamellae.These findings are related to hydrogen-bonding between the small molecule and pyridine being conserved in chloroform and to the good solubility of both blocks in this solvent,with differences between the two small molecules related to their differing H-bond strengths.These findings contrast strongly with what was observed previously using THF as a solvent,for which the SM content increases with dip-coating rate and the morphologies are mainly spherical and cylindrical in the same parameter range.

The Extension of Infinitesimal Prolongation Theorem and Its Application

Infinitesimal prolongation theorem is extended from sequences to nets based on κ-saturated nonstandard model. As its an application, a main property about topology of uniform convergence is proved. The proof is much simpler than it was, meanwhile the nonstandard characteristics of convergence with respect to u.c. topology is given.

On the Conditions of Extending Mean Curvature Flow

The authors consider a family of smooth immersions F（., t） ：M^n→R^n＋1 of closed hypersurfaces in R^n＋1 moving by the mean curvature flow F（p,t）/ t=-H（p,t）.v（p,t） for t E [0, T）. They show that if the norm of the second fundamental form is bounded above by some power of mean curvature and the certain subcritical quantities concerning the mean curvature integral are bounded, then the flow can extend past time T. The result is similar to that in [6-9].