Experimental study on reactions between alkaline basaltic melt and orthopyroxenes: constraints on the evolution of lithospheric mantle in the North China Craton

The experimental results of the reactions between an alkaline basaltic melt and mantle orthopyroxenes under high-temperature and high-pressure conditions of 1300–1400℃ and 2.0–3.0 GPa using a six-anvil apparatus are reported in this paper.The reactions are proposed to simulate the interactions between melts from the asthenospheric mantle and the lithospheric mantle.The starting melt in the experiments was made from the alkaline basalt occurring in Fuxin,Liaoning Province,and the orthopyroxenes were separated from the mantle xenoliths in Damaping,Hebei Province.The results show that clinopyroxenes were formed in all the reactions between the alkaline basaltic melt and orthopyroxenes under the studied P–T conditions.The formation of clinopyroxene in the reaction zone is mainly controlled by dissolution–crystallization,and the chemical compositions of the reacted melt are primarily infl uenced by the diff usion eff ect.Temperature is the most important parameter controlling the reactions between the melt and orthopyroxenes,which has a direct impact on the melting of orthopyroxenes and the diff usion of chemical components in the melt.Temperature also directly controls the chemical compositions of the newly formed clinopyroxenes in the reaction zone and the reacted melt.The formation of clinopyroxenes from the reactions between the alkaline basaltic melt and orthopyroxenes can result in an increase of CaO and Al_(2)O_(3) contents in the rocks containing this mineral.Therefore,the reactions between the alkaline basaltic melt from the asthenospheric mantle and orthopyroxenes from the lithospheric mantle can lead to the evolution of lithospheric mantle in the North China Craton from refractory to fertile with relatively high CaO and Al 2 O 3 contents.In addition,the reacted melts in some runs were transformed from the starting alkaline basaltic into tholeiitic after reactions,indicating that tholeiitic magma could be generated from alkaline basaltic one via reactions between the latter and orthopyroxene.

Experimental study on the treatment of rabbit corneal melting after alkali burn with Collagen cross-linking

AIM: To evaluate the effect of Collagen cross-linking on the prevention of melting in rabbit corneas after alkali burn. METHODS: Twenty New Zealand white rabbits were randomly divided into model control group and collagen cross-linking treatment group. The second group of rabbits received collagen cross linked treatment. Both groups were applied with antibiotic eye drops to prevent infection. The corneas were evaluated for melting, opacity, pathological and immunohistochemistry, record the changes when 28 days after the animals were killed. RESULTS: In the control group, 6 out of 8 rabbits showed corneal melting after injury (14 +/- 4) days, while two corneal perforated. In collagen cross-linking treatment group, one rabbit showed corneal melting after injury 23 days, without corneal perforation; corneal dissolution rate between the two groups was significantly different (P <0.05). Pathological examination suggested that in the treatment group, mild corneal edema, mild damage to collagen fibers, inflammatory cell infiltration was significantly less than the control group. Immunohistochemistry showed that corneal collagen fibers arranged in neat rows in the control group. CONCLUSION: Collagen cross-linking treatment not only can prevent and delay the corneal melting after alkali burn, but also can reduce the destruction of corneal collagen fibers and infiltration of inflammatory cells in the corneal tissue.

High-precision nuclear magnetic resonance probe suitable for in situ studies of high-temperature metallic melts

High-temperature nuclear magnetic resonance(NMR)has proven to be very useful for detecting the temperatureinduced structural evolution and dynamics in melts.However,the sensitivity and precision of high-temperature NMR probes are limited.Here we report a sensitive and stable high-temperature NMR probe based on laser-heating,suitable for in situ studies of metallic melts,which can work stably at the temperature of up to 2000 K.In our design,a well-designed optical path and the use of a water-cooled copper radio-frequency(RF)coil significantly optimize the signal-to-noise ratio(S/NR)at high temperatures.Additionally,a precise temperature controlling system with an error of less than±1 K has been designed.After temperature calibration,the temperature measurement error is controlled within±2 K.As a performance testing,^(27)Al NMR spectra are measured in Zr-based metallic glass-forming liquid in situ.Results show that the S/NR reaches 45 within 90 s even when the sample's temperature is up to 1500 K and that the isothermal signal drift is better than0.001 ppm per hour.This high-temperature NMR probe can be used to clarify some highly debated issues about metallic liquids,such as glass transition and liquid-liquid transition.

Effect of La_2O_3 on microstructure and high-temperature wear property of hot-press sintering FeAl intermetallic compound

FeAl intermetallic compound with different contents of rare earth oxide La2O3 addition was prepared by hot pressing the mechanically alloyed powders.Effect of La2O3 on microstructure and high-temperature wear property of the sintered FeAl samples was investigated in this paper.The results showed that 1 wt.% La2O3 addition could refine the microstructure and increase the density of the FeAl intermetallic compound,and correspondingly improved the high-temperature wear resistance.SEM and EDS analyses of the wo...

High-temperature thermal stability of C/C−ZrC−SiC composites via region labeling method

To investigate the thermal stability of ceramic-matrix composites,three kinds of C/C−ZrC−SiC composites with different Zr/Si molar ratios were synthesized by reactive melt infiltration.Employing region labeling method,the high-temperature thermal stability of the composites was systematically studied by changing the temperature and holding time of thermal treatment.Results show that the mass loss rate of low Si composites has a growth trend with increasing temperature,and a crystal transformation from β-SiC toα-SiC occurs in the composites.In the calibrated area,SiC phase experiences Ostwald ripening and volume change with location migration,while ZrC phase experiences a re-sintering process with diffusion.Moreover,it is found that increasing temperature has a more obvious effect on the thermal stability than extending holding time,which is mainly attributed to the faster diffusion rate of atoms.

碱溶性聚酯/碳酸钙/聚酯(COPET/CaCO_(3)/PET)多孔纤维制备及性能研究

采用自制的碱溶性聚酯/碳酸钙(COPET/CaCO_(3))母粒与聚酯(PET)母粒,经熔融纺丝实现对传统PET纤维的改性,结合单因子控制变量法优选碱酸处理制备COPET/CaCO_(3)/PET多孔纤维的最佳工艺参数,并对纤维性能进行测试与表征。结果表明,当NaOH质量分数为4%、HCL质量分数为3%时,纤维具有较好的表观形态和孔隙结构。在最优处理条件下,纤维内部含有较多分布均匀的孔隙,孔径主要集中分布在15~54nm。此时,纤维的断裂强度、线密度、比表面积和熔融温度分别为1.29cN/dtex、4.84dtex、5.5273m^(2)/g和253.85℃。

碱熔-树脂分离-电感耦合等离子体质谱法测定黄铜矿单矿物中8种贵金属元素的含量

黄铜矿单矿物样品中常伴有金、银等贵金属元素,在冶炼铜时,还会综合回收贵金属等伴生元素,因此准确测定样品中各贵金属元素含量具有重要意义,但是相应方法未见报道。通过优化熔融、树脂分离条件以及校正共存元素干扰,提出了题示方法。取0.2000 g样品置于刚玉坩锅中,加入0.5 g氢氧化钠,于室温升温至700℃,熔融5 min。趁热加入1.5 g过氧化钠,于700℃熔融30 min,冷却后加入50 mL热水,于200℃煮沸3 min。用水洗涤坩埚,收集洗涤液并合并于样品溶液中,用体积比3∶1盐酸-硝酸溶液(王水)调节酸度至pH 1。加入由质量比2∶8的A21型阴离子交换树脂和R1S-82聚苯乙烯骨架硫脲螯合树脂混合制成的混合树脂1.0 g,于70℃吸附60 min。取出树脂,加入10 g·L^(-1)硫脲溶液20 mL和50%(体积分数)王水溶液20 mL,于90℃解吸60 min。用3%(体积分数)硝酸溶液将解吸溶液稀释至100 mL,分取1 mL,用3 mol·L^(-1)硝酸溶液稀释至10 mL,供电感耦合等离子体质谱仪分析。内标镥在线加入,用于补偿基体效应和灵敏度漂移;解吸溶液中含有微量铜、镍和铅,干扰低含量铑和钌测定,通过公式可校正相应干扰。结果显示:8种贵金属元素(铂、钯、铑、铱、钌、锇、金和银)的质量浓度均在一定范围内与质谱强度呈线性关系,7种元素的检出限(3s)为0.04~0.17 ng·g^(-1)(银的检出限为0.11μg·g^(-1))。对黄铜矿单矿物样品进行精密度和准确度考察,测定值的相对标准偏差(n=6)为0.47%~4.4%,加标回收率为97.2%~102%。

粉煤灰制备沸石分子筛及其吸附脱除氨氮性能

当前大量含氮废水的排入不仅使湖泊水体富营养化加剧,更对各类生物的生存和健康造成了很大威胁。由于沸石分子筛具有良好的吸附选择性和离子交换性,可以用来吸附脱除水中的氨氮,因此成为当前研究的热点。文章以粉煤灰为主要原料,采用碱熔融-水热法制备Na-X型沸石分子筛,通过正交试验得到沸石分子筛的最佳制备工艺条件,探索了氨氮溶液初始浓度、pH值、吸附时间、吸附温度以及阳离子对沸石分子筛吸附氨氮性能的影响。结果表明:Na-X型分子筛的最佳饱和氨氮吸附率为74.89%;Na-X型沸石分子筛吸附过程符合准二级动力学模型,吸附等温线符合Freundlich模型;其氨氮吸附量与初始浓度和吸附时间呈正相关,与温度呈负相关;强酸或强碱环境会使分子筛吸附性能下降。Na-X型分子筛氨氮吸附率较高、可多次循环使用,在废水治理方面有着广泛的应用前景。

A Comprehensive Review of Thermal Performance Improvement of High-Temperature Heat Pipes

Energy efficiency issues are being focused on the growing concern of global warming and environmental pollution.The high-temperature heat pipe(HTHP) is an effective and environmental-friendly heat transfer device employed in many industries,including solar power generation,high-temperature flue gas waste heat recovery,industrial furnaces,nuclear industries,and aviation.As a critical factor in HTHPs,thermal performance is mainly introduced in the entire paper.To date,most reviews have been published concerning one or several application scenarios.However,to the best of authors' knowledge,it is hard to find a review discussing how to improve the thermal performance of HTHPs comprehensively.First,the impact on the performance of three main components of HTHPs over the past 30 years is introduced:the working fluid,the HTHP structure,and the wick structure.Herein,it is a considerable review of the optimal operating conditions for each direction,and we expect this paper contribute to improving the thermal performance of HTHPs.Then,current numerical simulations and theoretical research on the heat transfer limit of HTHPs are recommended.The significant hypotheses used in numerical simulations and the present theoretical studies are compiled here.Finally,some potential future directions and tentative suggestions for HTHP research are put forward.

碱金属对氧化球团回转窑结圈的影响机制

回转窑结圈是制约回转窑生产氧化球团的主要因素,窑内结圈会影响温度场的分布并减小回转窑内径,导致成品矿强度及性能恶化,增加生产能耗。改善结圈问题有助于降低回转窑生产球团能耗,提高球团矿质量,推动铁前造块工艺节能减排。本文重点分析了碱金属(K/Na)对回转窑结圈的影响机制,即K_(2)O、Na_(2)O是以形成低熔点物相实现在微区液相富集,并随含量增加显著降低低熔点物质开始熔化温度和增加液相占比。

煤矸石制备NaX分子筛及其对Cu^(2+)的吸附性能研究

以云南曲靖地区煤矸石为研究对象,经硫酸除铁后采用碱熔法制备NaX分子筛,利用XRD、SEM等手段对其进行表征,并研究分子筛用量、吸附时间和吸附温度对NaX分子筛吸附废水中Cu^(2+)的影响,结果表明,以煤矸石酸浸渣为主要原料,不外加铝硅源合成NaX分子筛的最佳条件为:将酸浸渣和氢氧化钠混合(质量比1∶1.2)置于800℃下碱熔活化1.0 h,再在92℃水浴中晶化10 h,制得的NaX分子筛结构为四面体晶体形状;室温下在分子筛用量为2 g/L、吸附时间为24 min的条件下,分子筛对Cu^(2+)的吸附效果最好,去除率在98%以上;采用Langmuir等温吸附模型对分子筛吸附数据进行拟合,发现吸附过程是单层吸附。研究成果为煤矸石综合利用提供了一条有效途径。

碱高温熔融-乙二胺四乙酸滴定法测定铝灰中的总铝量

为了加强对铝灰中铝资源的回收利用,提出了碱高温熔融-乙二胺四乙酸(EDTA)滴定法测定铝灰中总铝量的方法。针对铝灰基质复杂以及钙、镁、氩含量高的特点,优化了前处理和滴定条件。0.1 g样品经干燥、乙醇润湿后,加入3 g氢氧化钠和2 g磷酸钠(与钙、镁形成沉淀分离除去,避免钙、镁氢氧化物吸附Al^(3+)),于400℃预熔融20 min。加入1 g过氧化钠,于750℃熔融15 min。加入沸水煮沸,使熔块全部溶解,再加入3 mL 6 mol·L^(-1)盐酸溶液煮沸除去过氧化氢。用水定容至100 mL,过滤,取滤液25 mL,加入10 mL 6 mol·L^(-1)盐酸溶液和5 mL高氯酸,加热至近干,以消除样品中高含量F^(-)对Al^(3+)的络合干扰。残渣用10 mL 6 mol·L^(-1)盐酸溶液溶解,再加入10 mL水、8 mL 40 g·L^(-1)EDTA溶液和二甲酚橙指示剂,用6 mol·L^(-1)盐酸溶液将溶液调至亮黄色,煮沸5 min,使EDTA充分络合Al^(3+)。加入15 mL乙酸-乙酸钠缓冲溶液(pH 5.8)和二甲酚橙指示剂,用1.00 mg·L^(-1)锌标准溶液将溶液滴定至橙红色。加入5 mL氟化钾溶液(100 g·L^(-1)),煮沸5 min,将Al^(3+)从EDTA络合物中完全置换出来。加入10 mL乙酸-乙酸钠缓冲溶液(pH 5.8)和二甲酚橙指示剂,用1.00 mg·L^(-1)锌标准溶液将溶液滴定至橙红色,记录滴定液消耗体积,并通过滴定度计算总铝量。结果显示:总铝回收率为96.8%~103%,测定值的相对标准偏差(n=6)小于1.0%,方法适用于试验条件有限的实验室进行矿山冶炼铝灰中总铝量的测定。

Na_(2)CO_(3)-Na_(2)SO_(4)复盐熔炼法从碱溶渣中高效分离钨的工艺研究

钨合金废料资源化利用过程中容易产生含钨碱溶渣,且该部分含钨碱溶渣中钨品位较高。本文开发了一种复盐(Na_(2)CO_(3)-Na_(2)SO_(4))熔炼工艺,以对含钨碱溶渣中的钨进行高效分离;探究Na_(2)CO_(3)和Na_(2)SO_(4)的添加量、复盐熔炼温度、熔炼时间以及水浸液固比、水浸温度对钨回收率的影响。结果表明:从含钨碱溶渣中高效分离钨的最优条件为n(W)∶n(Na_(2)CO_(3))∶n(Na_(2)SO_(4))=1∶1.25∶0.54,复盐熔炼温度为800℃,熔炼时间为3 h,水浸液固比为2.5,水浸温度为75℃,在该最优条件下可将含钨碱溶渣中99.93%的钨分离出来。同时,本文通过XRD分析以及热力学分析对复盐熔炼的反应机理进行了探讨,复盐体系的构建有助于降低体系共熔点,降低能耗,同时有助于促进碱溶渣与反应介质的充分接触,提高反应效率。

铱的溶解造液技术研究现状

随着我国科技和经济水平的不断进步,铱在高精尖领域的需求量逐年增长。然而,铱的原生矿产资源极为稀缺,从二次资源中高效回收铱具有重要意义。其中,铱的高效溶解造液是行业一大难题,严重制约铱回收行业的发展。本文综述铱的溶解造液技术,包括金属活化法、碱熔法、加压消解法和电化学溶解法,系统剖析和对比各种溶解技术的优缺点。现有技术存在溶解效率低、返料多、能耗高等问题,开发绿色、高效、节能的溶解造液技术是未来铱溶解技术的研究方向。

工业固体废物锂渣中二氧化硅的测定

以氢氧化钠-过氧化钠混合碱熔前处理,酸提取-等离子体发射光谱仪为测量手段,建立了快速准确测定工业固体废物锂渣中二氧化硅含量的方法。研究发现,该方法检出限为0.96%,精密度相对偏差小于5%,有证标准物质与其推荐值一致。此方法测定二氧化硅含量,不仅操作简便,效率高,可用于满足实际生产中锂渣中二氧化硅的测定。

电感耦合等离子体发射光谱法测定多金属矿石中钨的含量

本文利用过氧化钠碱融、酸化浸取、离心处理方法,利用电感耦合等离子体发射光谱法(ICP-OES)测定多金属矿石中钨元素的含量,试验过程对过氧化钠及酸度进行试验验证,排除元素之间对钨元素产生的干扰,测定结果与比色法、X荧光光谱法相比较,结果正确度及精密度较好,线性相关系数0.99992,检出限为0.001%,加标回收率为100.50%~102.00%,相对标准偏差为0.680%~1.760%,钨分析谱线为224.876nm,满足检测分析要求,该方法操作简单、高效,能有效指导选矿生产及其供配矿。

煤矸石碱熔—水热法制备NaX型分子筛及其对Pb^(2+)的吸附特性研究

为实现煤矸石中硅铝组分的高值利用,以煤矸石为原料,采用碱熔水热法合成NaX型分子筛,通过X射线衍射(XRD)、红外光谱(FT-IR)、扫描电镜(SEM)等对产物进行表征,同时采用静态饱和吸水量和钙离子交换量对所制备分子筛进行性能评价。结果表明:硅铝比为3,碱灰比1.2,陈化温度40℃,陈化30 min,水热温度100℃,水热时间5 h,NaOH浓度为2.73 mol/L时合成分子筛的钙离子交换量为283.37 mg/g。将所合成的NaX型分子筛用于吸附液相中的Pb^(2+)。在分子筛投加量1 g/L、吸附温度25℃、吸附时间2 h时,吸附容量(Q_(e))最高可达483.05 mg/g;分子筛的吸附等温线符合Langmuir模型,饱和吸附容量(Q_(m))可达528.31 mg/g。

碱熔-阳离子交换-HG-AFS测定多金属矿中的痕量硒

采用原子荧光光谱仪分析测试多金属矿中痕量硒的含量。通过过氧化钠高温碱熔样品,然后通过阳离子交换树脂去除铜、铅、钴、锌等过渡元素的干扰,酸化还原后经原子荧光光谱仪分析测试。硒检出限为0.0046μg/g,检出下限为0.0183μg/g;GBW07367、GBW07368、GBW07369三件多金属矿石成分分析标准物的测定值的相对标准偏差分别为4.70%、3.56%、2.86%,均小于10%;三件多金属矿物实际样品的相对标准偏差为1.55%,3.56%,2.20%,均小于10%。该方法结果准确性和精密度好,适合多金属矿物中的痕量硒的分析测定。

碱熔-电感耦合等离子体原子发射光谱(ICP-AES)法测定碳载钌催化剂中钌

钌作为一种酸难溶物质,在经过常规酸溶处理后,利用电感耦合等离子体原子发射光谱法(ICP-AES)进行测定时,其检测准确性较低。为了准确分析贵金属催化剂中钌的含量,本研究设计了一种碱熔-电感耦合等离子体原子发射光谱(ICP-AES)方法。实验过程中,采用氢氧化钾进行样品熔解,经盐酸酸化后定容,选择钌267.876 nm为分析谱线进行测定。经过一系列实验探索,确定了0.4 g样品加入2.0 g氢氧化钾,在400℃的马弗炉内加热反应5 min为最适宜的熔解条件。该元素的校准曲线线性相关系数可达0.999,检出限为0.019 mg/L。将该实验方法应用于样品中钌的测定,测定结果的标准偏差及加标回收率均在允许范围内,可满足碳载钌催化剂中钌含量测定需求。

Contribution to the Petrography, Geochemistry, and Petrogenesis of Zarqa-Ma’in Pleistocene Alkali Olivine Basalt Flow of Central Jordan

The Zarqa-Ma’in basalt (MB) occurs near a plateau basalt (wadi fills) covering about 15 km2 of Makawir, Ataruz, and Hammat um Hasana cone areas in central Jordan. The tectonic evolution occurred through intraplate volcanism and erupted through fissure systems along the Dead Sea, transforming the fault during Miocene to Pleistocene period. Three stages of eruption of MB have been recorded during Pleistocene from 6 to 0.6 Ma. The petrographic analyses data show that the MB rocks are composed of plagioclase, olivine, pyroxene, and magnetite, including secondary minerals calcite, iddingsite, serpentine, and zeolite. Furthermore, the MB rocks have narrow ranges of major and trace element concentrations, and are of under saturated silica type and belong to sodic alkaline magma series. The geochemical characteristics of MB indicate that MB was derived from a slightly fractionated magma as reflected by its high MgO (6.3 - 11.7 ppm) concentration with Mg number from 0.41 to 0.61, low silica content (40.83 - 47.55 wt%), and high Cr and Ni concentrations (115 - 475 and 105 - 553 ppm, respectively). This basalt exhibited low degree of partial melting (10%) for garnet peridotite mantle source. The model mineral fractionation showed that the MB could be fractionated to clinopyroxene, orthopyroxene, olivine, and plagioclase.