陈家岭钒矿选矿工艺试验     

李麟  尹进喜  冯艳华 《陕西地质》2012,30(1):82-88

采用钙法氧化焙烧——酸浸的方法从钒矿石中浸出钒,克服了钠化焙烧过程中产生的H2S、Cl2,实验了矿石物料粒度、氧化钙添加量、焙烧温度、焙烧时间、漫出温度、浸出时间、酸的浓度、浸出液固比对浸出率的影响,获得了88％的浸出率。实验表明,焙烧温度、酸的浓度、浸出温度、浸出时间、液固比是影响钒浸出率的重要因素。  相似文献   

漂浮通量箱法和扩散模型法测定内陆水体CH_4和N_2O排放通量的初步比较研究   总被引：1，自引：0，他引：1       下载免费PDF全文

高洁  郑循华  王睿  廖婷婷  邹建文 《气候与环境研究》2014,19(3):290-302

采用漂浮通量箱法和扩散模型法同步地观测了模拟内陆水体在不同条件下的CH4和N2O的水-气交换通量,旨在比较两类方法取得结果的异同。结果显示:这两类方法所测得的绝大多数CH4排放通量都与水中溶解氧呈显著线性负相关(显著性系数P0.001)。同时N2O排放通量与表层水温及水中铵态氮、硝态氮、溶解碳和溶解氧的关系可用包含所有上述水环境因素的Arrhenius动力学方程来表达,这些因素可以共同解释86%~90%的N2O通量变化(P0.0001),且不同方法测定的N2O通量的表观活化能和对表层水温的敏感系数分别介于47~59 kJ mol-1和1.92~2.27之间;扩散模型法所获得的CH4和N2O通量分别是箱法测定值的13%~175%和15%~240%,差异程度因模型而异;不同模型取得通量间相差20%~1200%,平均相差2.3倍。上述结果表明:仅用一种模型方法来取得CH4或N2O排放通量易形成较大偏差;不同扩散模型法和箱法测定的通量在反映CH4和N2O排放的内在规律方面具有一致性,但它们对真实气体通量的测量是否都存在不同程度的系统误差,尚需进一步研究。  相似文献   

A role for nitrite in the production of nitrous oxide in the lower euphotic zone of the oligotrophic North Pacific Ocean     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

Understanding the role of the oceans in the Earth's changing climate requires comprehension of the relevant metabolic pathways which produce climatically important trace gases. The global ocean represents one of the largest natural sources of nitrous oxide (N₂O) that is produced by selected archaea and/or bacteria during nitrogen (N) metabolism. In this study, the role of nitrite (NO₂⁻) in the production of N₂O in the upper water column of the oligotrophic North Pacific Subtropical Gyre was investigated, focusing primarily on the lower euphotic zone where NO₂⁻ concentrations at the primary NO₂⁻ maximum reached 195 nmol L⁻¹. Free-drifting sediment trap arrays were deployed to measure N cycle processes in sinking particulate material and the addition of selected N substrates to unpreserved sediment traps provided an experimental framework to test hypotheses regarding N₂O production pathways and controls. Sinking particles collected using NO₂⁻-amended, unpreserved sediment traps exhibited significant production of N₂O at depths between 100 and 200 m. Subsequent stable isotope tracer measurements conducted on sediment trap material amended with ¹⁵NO₂⁻ yielded elevated δ¹⁵N values of N₂O, supporting N₂O production via a NO₂⁻ metabolism pathway. Experiments on seawater collected from 150 m showed N₂O production via NO₂⁻ metabolism also occurs in the water-column and indicated that the concentration of NO₂⁻ relative to NH₄⁺ availability may be an important control. These findings provide evidence for the production of N₂O via nitrifer-denitrification in the lower euphotic zone of the open ocean, whereby NO₂⁻ is reduced to N₂O by ammonia-oxidizing microorganisms.  相似文献   

Spatial heterogeneity of soil mineral oxide components in depression between karst hills,Southwest China   总被引：3，自引：0，他引：3  

Hu Du  Kelin Wang  Wanxia Peng  Fuping Zeng  Tongqing Song  Hao Zhang  Shiyang Lu 《中国地理科学(英文版)》2014,24(2):163-179

In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels.  相似文献   

广西德保县荣华锰矿床地质特征研究     

裴秋明  李社宏  苑鸿庆  刘建强  刘祥  曹华文 《岩石矿物学杂志》2014,33(2):343-354

荣华锰矿赋存于桂西三叠系百逢组中,为该层位首次发现的中型规模锰矿。笔者通过参与矿区锰矿勘查工作,采用室内外观测、测试、工程揭露和验证等手段,对研究区地层、构造、沉积演化、含矿层位、矿体及矿石矿物特征、矿床成因和找矿标志等方面进行了分析探讨。研究发现荣华锰矿为典型的沉积-锰帽型矿床,严格受地层和构造因素控制;矿石类型主要为氧化锰矿贫锰矿石;氧化锰矿物主要为水羟锰矿、硬锰矿及软锰矿;矿床成因与原始沉积作用、后期风化淋滤等有重要关系;百逢组浊积岩之下、罗楼组碳酸盐岩之上的狭窄范围是荣华锰矿的典型找矿标志,该标志对大量出露三叠系百逢组的桂西地区具有普遍意义,同时指出桂西地区该组地层内具有良好的找矿前景。  相似文献   

红柳沟北镁铁-超镁铁质岩体矿物学特征及矿石成因分析          下载免费PDF全文

周伟  姜常义  杜玮  宋艳芳  凌锦兰  夏明哲  王梦玺  赵彦锋 《岩石矿物学杂志》2014,33(4):671-680

红柳沟北镁铁-超镁铁质岩体位于柴达木陆块北部的欧龙布鲁克微陆块东北缘,呈岩墙状,出露面积约0.1km~2,由方辉橄榄岩、橄榄二辉岩、含长单辉橄榄岩、橄榄辉长苏长岩、暗色橄榄辉长岩、苏长岩、辉长岩等组成,各岩相带在空间上呈渐变过渡关系。电子探针分析结果显示,岩体的主要造岩矿物为贵橄榄石、古铜辉石、普通辉石和斜长石,并且各矿物的结晶温度为1 307~1 122℃。岩体钛铁矿化明显,主要金属矿物为钛铁矿、钛磁铁矿和磁铁矿。利用橄榄石Fo最高值反演出原生岩浆MgO含量为8.49%,FeO含量为10.03%,TiO_2含量为1.63%,为普通玄武质岩浆。通过综合研究各矿物形成的温度和氧逸度条件,认为岩浆从橄榄石结晶到普通辉石结晶,其氧逸度是缓慢升高的,并且氧逸度是控制红柳沟北岩体Ti-Fe氧化物结晶的主要因素。  相似文献   

Shock-induced temperatures of MgO     

Bob Svendsen  Thomas J. Ahrens 《Geophysical Journal International》1987,91(3):667-691

Shock-compressed MgO radiates thermally at temperatures between 2900 and 3700 K in the 170–200 GPa pressure range. A simple energy-transport model of the shocked-MgO-targets distinguishes between different shock-induced radiation sources in these targets and provides estimates of spectral absorption-coefficients, α _ΛMgO, for shocked MgO (e.g. at 203 GPa, α _ΛMgO˜ 630, 7500, 4200 and 3800 m⁻¹, at 450, 600, 750 and 900 nm, respectively). The experimentally inferred temperatures of the shock-compressed states of MgO are consistent with temperatures calculated for MgO assuming that (1) it deforms as an elastic fluid, (2) has a Dulong-Petit value for specific heat at constant volume in its shocked state, and (3) undergoes no phase transformation below 200 GPa.  相似文献   

广西都结氧化锑矿可选性试验研究     

李维天  陈柏泉 《南方国土资源》2002,15(3):67-70

都结锑矿的矿石矿物几乎均为黄锑矿 ,分布粒度微细 ,属难选的氧化矿石。经研究发现黄锑矿颗粒含3%的铁并具有弱磁性 ,采用分级强磁选与化学选矿相结合的试验流程 ,获得锑精矿品位 39.2 9% ,总回收率 >95 %的分选效果  相似文献   

洛川黄土-红粘土序列铁氧化物组成及其古气候指示   总被引：2，自引：0，他引：2  

谢巧勤  陈天虎  孙玉兵  李晓萱  徐晓春 《矿物学报》2008,28(4)

对洛川黄土、古土壤和红粘土中磁性矿物组成、成因和相关系进行了研究。结果表明:黄土磁性矿物以风尘磁铁矿为主,少量的成土赤铁矿和成土磁赤铁矿;古土壤磁性矿物以成土磁赤铁矿为主,成土赤铁矿次之,少量的风尘磁铁矿和赤铁矿;红粘土磁性矿物以成土赤铁矿为主,风尘磁铁矿和成土磁赤铁矿次之,少量风尘赤铁矿。黄土、古土壤和红粘土磁性矿物组成差异,反映了其形成期不同的古气候特性以及不同气候条件下生物地球化学作用强度的差异。干冷的冰期,黄土弱成土作用形成了以粗颗粒的风尘磁铁矿核 赤铁矿边的磁化率载体。间冰期的温暖湿润的古气候最有利于生物活动,强烈生物活动导致古土壤中大量纳米超细磁赤铁矿/磁铁矿产生,形成以磁赤铁矿为主,风尘磁铁矿核 赤铁矿边为辅的磁化率载体。红粘土成壤期,强降雨强蒸发的长干短湿的高温炎热的古气候使得红粘土化学风化强烈,生物地球化学活动较弱,形成以磁铁矿核 赤铁矿边和磁赤铁矿核 赤铁矿边的磁化率载体。黄土、古土壤和红粘土磁性矿物组成、磁性矿物相关系是其形成期独特的古气候指示。  相似文献   

Searching for ancient gold mines in Filippoi area,Macedonia, Greece,using Worldview-2 satellite imagery     

Dimitrios Oikonomidis  Michael Vavelidis  Vasilios Melfos  Mariam Artashova 《国际地球制图》2017,32(1):87-96

The study area is located near the town of Filippoi, north of the city of Kavala in northern Greece, known from ancient times for its rich gold mines, situated inside hydrothermal alteration zones (Fe–Mn oxide minerals). A Very High-Resolution (0.5 m pixel size) image of Worldview-2 satellite was digitally enhanced, yielding target areas of potential ore existence and lineaments. Ground-truth that followed digital image processing, revealed abandoned ancient mines, slags and ore occurrences. Also, a number of lineaments delineated on the satellite image were verified as faults.  相似文献