首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
铬渣NaCl浸出动力学   总被引:1,自引:0,他引:1  
通过研究铬渣NaCl浸出过程中Cr(Ⅵ)浓度随时间的变化,建立该反应的动力学方程,确定初始pH值、振荡速度对反应速率常数的影响,并计算相应的反应表观活化能。结果表明,铬渣NaCl浸出过程为0.26级反应,反应速率常数为3.38×10-7 mol/(L.s);pH值和振荡速度增大,反应速率常数不断增大,CaCrO4溶解率增加,溶解速率加快;该反应的表观活化能为34.24 kJ/mol,Cr(Ⅵ)浸出速率受温度影响较大。  相似文献   

2.
研究了D231树脂对铀(U)的吸附性能和机理。结果表明,树脂对铀的吸附酸度在pH2.0效果最佳,等温吸附服从Freundlich经验式;吸附过程基本符合Boyd液膜扩散模型;反应开始阶段吸附速率常数k为2.3×10-3s-1;反应的ΔH为18.57kJ/mol。吸附酸度在pH1.0~4.0,铀的吸附率可达98%以上;选用1mol/LNH4Cl-0.05mol/LH2SO4洗脱铀,其洗脱率可达98%以上;静态和动态饱和吸附容量分别为131mg/g和162mg/g干树脂。  相似文献   

3.
为回收废旧锂离子电池中的有价值金属,采用硫酸—甘蔗渣体系进行酸浸,将钴从废旧锂离子电池电极材料中浸出,并探讨了甘蔗渣对钴浸出效果的影响及反应机理。研究表明:甘蔗渣作为还原剂参与浸出反应,甘蔗渣中的醛基以及反应后的中间产物RCOO.H_2,都可与Co~(3+)反应,将其还原成Co~(2+),替代了价格昂贵且利用率低的H_2O_2,提高了钴的浸出率。钴的浸出反应符合有收缩的未反应核模型,反应前期,表观活化能为22.98 k J/mol;反应后期,表观活化能为38.31 k J/mol。在浸出温度90℃,浸出时间1 h,硫酸浓度2 mol/L,液固比150∶1,甘蔗渣粒径0.3 mm,甘蔗渣添加量0.5 g的最优条件下,钴的浸出率达95.38%。  相似文献   

4.
研究一种新型结构的双硫脲表面活性剂——N,N′-二异丙氧基丙基-N″,N′′′-氧二乙氧羰基硫脲(Di PODECTU)在黄铜矿表面的吸附动力学和热力学。研究结果表明:黄铜矿吸附Di PODECTU较佳的p H范围为5~10,吸附量随着温度的升高而减小。等温吸附模型符合Langmuir模型,其吸附焓变ΔH为-19.56 k J/mol,吸附自由能变ΔG为-28.70 k J/mol(298 K),说明Di PODECTU在黄铜矿表面为单层化学吸附。吸附过程符合二级动力学方程,吸附速率常数Ks为0.144 m-2/(mol·h),平衡吸附量Qe为5.72×10-5 mol/m2,与实测值5.41×10-5 mol/m2接近。Di PODECTU主要以化学作用方式吸附在黄铜矿表面。  相似文献   

5.
通过浸出率与浸出时间的关系曲线,推导出铀矿硫酸堆浸过程的控制模式和化学反应常数。实验结果表明浸出率在小于60%以内,与浸出时间呈直线关系,得出浸出过程控制模式为化学反应控制的结论。实验数据计算得出在该实验中化学反应浸出速率常数为1.5×10^-7s^-1,液固相化学反应速率系数为3.6×10^-8m/s。实验结果在未加氧化剂的酸堆浸铀矿石中,最多只有40%的四价铀能氧化成六价铀,要想进一步提高铀的浸出率,必须加入氧化剂,提高氧化能力。  相似文献   

6.
以山西朔州燃煤电厂高铝粉煤灰为对象,研究了煅烧温度为880℃,保温90 min条件下,粉煤灰纯碱煅烧后熟料在硫酸溶液中的铝浸出条件,揭示了铝浸出过程的动力学机制。研究结果表明,H2SO4溶液的浓度在7~9 mol/L之间,固液比(g/L)为1∶4、浸取时间在30~40 min之间、浸取温度在70~90℃之间时,可获得较高的氧化铝浸出率;H2SO4溶液浓度与浸取温度对氧化铝浸出率影响较大,浸取时间对浸出率影响不明显。煅烧熟料浸出过程符合液-固多相反应的内扩散控制模型,反应表观活化能为7.65 k J/mol.  相似文献   

7.
为研究松脂的氧化反应动力学,采用紫外分光光度法定量测定固态枞酸在聚乙烯膜上的吸光度变化,求出松脂参与氧化反应的反应量,进而研究松脂氧化反应动力学。实验结果表明,松脂的热氧化和光氧化反应动力学均呈现表观一级反应。热氧化反应温度为35、40、45℃时的表观速率常数分别为3.000×10-4、5.000×10-4、1.100×10-3 min-1,反应活化能Ea为105.8 kJ/mol。254 nm紫外灯辐照下,温度为35、40、45℃时,光强度与表观速率常数的关系分别k=1.162×10-4I+2.626×10-4、k=1.248×10-4I+4.588×10-4、k=1.298×10-4I+0.001 1。  相似文献   

8.
采用氧压酸浸的方法浸出低含铟浸出渣中的铟,研究铟的氧压酸浸过程及动力学;研究搅拌速率、浸出温度、初始硫酸浓度、氧分压、物料粒度对铟浸出率的影响。研究结果表明:在浸出温度为220℃,物料粒度为75~80μm,硫酸浓度为1.53 mol/L,转速为650 r/min,氧分压为0.60 MPa时,铟、锌和铜的浸出率分别为99.5%,95.36%和95.94%;铟的浸出过程符合未反应收缩核模型,前期受化学反应控制,然后转为混合控制,后期受固体产物层扩散控制;化学反应控制和固体产物层扩散控制过程的表观活化能分别为46.09 k J/mol和11.62 k J/mol。  相似文献   

9.
在pH 3.60的HCl-NaOAc缓冲介质中,考马斯亮蓝G250(CBBG)溶液与阳离子表面活性剂(CS)反应,形成离子缔合物,溶液颜色发生明显改变,最大褪色波长分别在584 nm(CBBG-CTMAB体系)和582 nm(CBBG-CPB体系)处,在此波长处阳离子表面活性剂的浓度与褪色程度呈良好线性关系,从而建立测定阳离子表面活性剂的光度法.在最大褪色波长处,CS的浓度在0~1.97×10-5mol/L(CTMAB体系)、0~2.31×10-5mol/L(CPB体系)范围内遵守比尔定律,表观摩尔吸光系数为1.64×104L/(mol.cm)(CTMAB体系)和1.31×104L/(mol.cm)(CPB体系),检出限为8.03×10-7mol/L(CTMAB体系)和1.02×10-6mol/L(CPB体系).方法具有较高的灵敏度和良好的选择性,用于水样中CS的测定,结果满意.  相似文献   

10.
高硅硫铁矿烧渣浸出过程动力学机理   总被引:2,自引:0,他引:2  
研究了高硅硫铁矿烧渣在硫酸浸出过程中的动力学机理,考察了液固比和温度对Fe浸出速率的影响.实验结果表明在液固比y<4.7时,y对浸出过程几乎没有影响;当y≥4.7时,增大γ,浸出率下降;硫酸浓度的反应级数为1.22;温度对Fe浸出速率的影响较大,提高温度有利于Fe的浸出;浸出1 h后浸出率能够很好地满足产物层扩散控制收缩核模型,即1+2(1一x)-3(1-x)2/3=kt;表观活化能为55.469 kJ/mol.此外,通过化学分析和EPMA分析,进一步证明了反应被产物层所控制.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

20.
Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号