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Prediction of XRF analyzers error for elements on-line assaying using Kalman Filter

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International Journal of Mining Science and Technology 2012年第4期22卷 595-601页

作者： nakhaei F Sam A Mosavi MR nakhaei a Department of Mining Engineering Shahid Bahonar Kerman UniversityKerman 761886-8366Iran Department of Electrical Engineering Iran University of Science and TechnologyTehran 16846-13114Iran Department of Electrical Engineering Birjand UniversityBirjand 97175-376Iran

Determination of chemical elements assay plays an important role in mineral processing *** factor is used to control process accuracy,recovery calculation and plant *** new assaying methods including chemical methods,X-ray fluorescence and atomic absorption spectrometry are advanced and ***,in some applications,such as on-line assaying process,high accuracy is *** this paper,an algorithm based on Kalman Filter is presented to predict on-line XRF *** research has been carried out on the basis of based the industrial real data collection for evaluating the performance of the presented *** measurements and analysis for this study were conducted at the Sarcheshmeh Copper Concentrator Plant located in *** quality of the obtained results was very satisfied;so that the RMS errors of prediction obtained for Cu and Mo grade assaying errors in rougher feed were less than 0.039 and 0.002 and in final flotation concentration less than 0.58 and 0.074,*** results indicate that the mentioned method is quite accurate to reduce the on-line XRF errors measurement.

关键词：卡尔曼滤波误差预测 X射线荧光分析仪元素测定元素含量原子吸收光谱法 X射线荧光光谱化验方法

纳米微气泡存在下浮选机和浮选柱回收细粒磷酸盐矿物的比较

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Journal of Central South University 2022年第1期29卷 102-115页

作者： Fatemeh Taghavi Mohammad Noaparast Ziaeddin Pourkarimi Fardis nakhaei School of Mining Engineering College of EngineeringUniversity of TehranTehranIran Department of Mineral Processing and Applied Research Iran Mineral Processing Research Center(IMPRC)KarajIran School of Chemical and Minerals Engineering NorthWest UniversityPotchefstroomSouth Africa

细粒浮选一直是许多矿物加工厂面临的主要问题之一。由于细颗粒的气泡粒子碰撞概率很低,因此降低了浮选效率。细粒的存在通常不利于浮选过程,影响了浮选精矿的选择性和质量,而且增加了试剂的消耗量。因此,在大多数加工厂中,会将部分颗... 详细信息

细粒浮选一直是许多矿物加工厂面临的主要问题之一。由于细颗粒的气泡粒子碰撞概率很低,因此降低了浮选效率。细粒的存在通常不利于浮选过程,影响了浮选精矿的选择性和质量,而且增加了试剂的消耗量。因此,在大多数加工厂中,会将部分颗粒输送到尾矿池中,以减少这些问题的影响,并提高浮选过程的选择性。由于d80小于30μm的颗粒的存在,使伊朗的Esfordi磷酸盐厂损失了至少30%的处理能力。将这些P_(2)O_(5)含量为15.9%的细颗粒转移到尾矿坝,从经济和环境两方面来看,细颗粒的加工对磷酸盐工业具有重要意义。本文探讨了通过浮选工艺处理磷酸矿选矿厂的细尾矿的问题,尽管传统观点认为超细颗粒不可浮选。根据冶金工艺性能结果,比较了有无纳米气泡(NBs)时,浮选机和浮选柱两种处理工艺下磷酸盐矿物的浮选行为。由于NBs(由水动力空化作用产生)具有有趣的和独特的性能,如高稳定性、耐久性和高比表面积,提高了其在采矿、冶金和环境领域的应用。本研究结果表明,在没有NBs的情况下,使用浮选机工艺获得了P_(2)O_(5)含量为26.9%、回收率为29.13%的精矿,而使用浮选柱工艺,得到的P_(2)O_(5)含量为31.6%,回收率为32.74%的精矿。在NBs存在的情况下,通过浮选机和浮选柱获得精矿的回收率分别为40.49%和41.26%,P_(2)O_(5)含量分别为28.47%和30.43%。对比研究表明,在NBs存在的情况下,与浮选机相比,浮选柱工艺对磷矿的处理效率更高,泡沫层更厚。

关键词：浮选柱浮选机磷酸盐尾矿黏液纳米气泡 Venturi管水动力空化

Precipitation of hematite nanoparticles via reverse microemulsion process

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Journal of Natural Gas Chemistry 2011年第6期20卷 687-692页

作者： Mohammad Reza Housaindokht Ali nakhaei Pour Bimolecular Research Center Department of ChemistryFerdowsi University of MashhadP.O.Box:91775-1436MashhadIran

Hematite nanoparticles have been successfully synthesized via two processing routes：（i） conventional precipitation route and （ii） reverse microemulsion *** particle precipitation was carried out in a semibatch reactor.A microemulsion system consisting of water,chloroform,1-butanol and surfactant was loaded with iron nitrates to form iron nanoparticles *** precipitation was performed in the single-phase microemulsion operating *** technical surfactants,with different structure and HLB value are *** influence of surfactant characterization on the size of produced iron oxide particle has been studied to gain a deeper understanding of the important controlling mechanisms in the formation of nanoparticles in a *** electron microscopy （TEM）,surface area,pore volume,average pore diameter,pore size distribution and XRD were used to analyze the size,size distribution,shape and structure of precipitated iron nanoparticles.

关键词： iron nanoparticles microemulsion hematite

A new kinetic model for direct CO2 hydrogenation to higher hydrocarbons on a precipitated iron catalyst:Effect of catalyst particle size

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Journal of Energy Chemistry 2017年第3期26卷 359-367页

作者： Ali nakhaei Pour Mohammad Reza Housaindokht Department of Chemistry Faculty of ScienceFerdowsi University of MashhadP.O.Box:***MashhadIran

The kinetic of the direct COhydrogenation to higher hydrocarbons via Fischer–Tropsch synthesis（FTS）and reverse water-gas shift reaction（RWGS） mechanisms over a series of precipitated Fe/Cu/K catalysts with various particle sizes was studied in a well mixed, continuous spinning basket reactor. The iron catalysts promoted with copper and potassium were prepared via precipitation technique in various alcohol/water mixtures to achieve a series of catalyst particle sizes between 38 and 14 nm. A new kinetic model for direct COhydrogenation was developed with combination of kinetic model for FTS reaction and RWGS equilibrium condition. For estimate of structure sensitivity of indirect COhydrogenation to higher hydrocarbons, the kinetic parameters of developed model are evaluated for a series of iron catalysts with various particle sizes. For kinetic study a wide range of syngas conversions have been obtained by varying experimental conditions. The results show that the new developed model fits favorably with experimental data. The values of activation energies for indirect COhydrogenation reaction are fall within the narrow range of 23–16 kJ/mol.

关键词： Fischer–Tropsch synthesis Carbon dioxide hydrogenation Iron-based catalyst Kinetic parameters

Effect of Active Gas on Weld Shape and Microstructure of Advanced A-TIG-Welded Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 295-300页

作者： Reza nakhaei Alireza Khodabandeh Hamidreza Najafi Department of Materials Engineering Tehran Science and Research BranchIslamic Azad University

Advanced A-TIG method was conducted to increase the weld penetration and compared with the conventional TIG welding process.A two-pipeline setup was designed to apply Ar ＋ CO_2 mixed gas as the outer layer,while pure argon was applied as the inner layer to prevent any consumption of the tungsten *** results indicate that the presence of active gas in the molten pool led to the change in the temperature coefficient of surface tension so that the Marangoni convection turns inward and forms a deep weld *** increase in gas flow rate causes a decrease in the weld efficiency which is attributed to the increase in oxygen content in the weld pool and the formation o f a thicker oxide layer on the weld ***,the stir and the temperature fluctuation,led by double shielding gas,create more homogeneous nucleation sites in the molten pool so that a fine grain micros true ture was obtained.

关键词： Advanced A-TIG welding Weld metal Active gas Microstructure Marangoni convection

Application and comparison of RNN, RBFNN and MNLR approaches on prediction of flotation column performance

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International Journal of Mining Science and Technology 2015年第6期25卷 983-990页

作者： nakhaei Fardis Irannajad Mehdi Department of Mining & Metallurgical Engineering Amirkabir University of Technology

Evaluation of grade and recovery plays an important role in process control and plant profitability in mineral processing operations, especially flotation. The accurate measurement or estimation of these two parameters, based on the secondary variables, is a critical issue. Data-driven modeling techniques, which entail comprehensive data analysis and implementation of machine learning methods for system forecast, provide an attractive alternative. In this paper, two types of artificial neural networks(ANNs),namely radial basis function neural network(RBFNN) and layer recurrent neural network(RNN), and also a multivariate nonlinear regression(MNLR) model were employed to predict metallurgical performance of the flotation column. The training capacity and the accuracy of these three above mentioned types of models were compared. In order to acquire data for the simulation, a case study was conducted at Sarcheshmeh copper complex pilot plant. Based on the root mean squared error and correlation coefficient values, at training and testing stages, the RNN forecasted the metallurgical performance of the flotation column better than RBF and MNLR models. The RNN could predict Cu grade and recovery with correlation coefficients of 0.92 and 0.9, respectively in testing process.

关键词： RBF神经网络性能预测浮选柱网络应用 LR方法径向基函数神经网络多元非线性回归 MN

Ce-promoted Mn/Na_2 WO_4/SiO_2 catalyst for oxidative coupling of methane at atmospheric pressure

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Journal of Natural Gas Chemistry 2010年第1期19卷 47-53页

作者： Seyed Mehdi Kamali Shahri Ali nakhaei Pour Research Institute of Petroleum Industry (RIPI) National Iranian Oil Company P. O. Box 18745-4163 Tehran Iran

A series of Ce-promoted Mn-Na2WO4/SiO2 catalysts were prepared by incipient wetness impregnation method, and their catalytic performance for oxidative coupling of methane （OCM） was investigated at atmospheric pressure in a micro-quartz-tube reactor. The catalysts were characterized by X-ray diffraction （XRD）, temperature program reduction （TPR） and BET surface area. Ce promoter increased surface area and Na2WO4 species dispersion, which enriched the amount of the surface species. In addition, Ce promoter increased the Na/W species reduction, but the reduction peak shifted to higher temperature. Stability test of 5wt%Ce catalyst indicated suitable performance and stability. The selectivity and yield of C^2＋ hydrocarbons after 50 h operation reached 65.5% and 19.6%, respectively, at 840 ℃ over 5wt%Ce-2wt%Mn5wt%Na2WO4/SiO2 catalyst.

关键词： oxidative coupling of methane CeO2 promoter Mn/Na2WO4/SiO2

Kinetics and product distribution studies on ruthenium-promoted cobalt/alumina Fischer-Tropsch synthesis catalyst

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Journal of Natural Gas Chemistry 2010年第6期19卷 653-659页

作者： Ahmad Tavasoli Ali nakhaei Pour Masoumeh Ghalbi Ahangari School of chemistry College of scienceUniversity of Tehran Research Institute of Petroleum Industry

Hydrocarbon production rates and distributions on ruthenium promoted alumina supported cobalt Fischer-Tropsch synthesis （FTS） catalyst were studied by the concept of two superimposed Anderson-Schulz-Flory （ASF） *** results indicated that the characterizing growth probabilities α1 and α2 were strongly dependent on reaction *** increasing the H2 /CO partial pressure ratios and reaction temperatures,deviation from normal ASF distribution decreases and the double-α-ASF distribution changes into a straight *** on the concept of double-α-ASF distribution,a useful rate equation for the production of hydrocarbons under industrial reaction conditions is obtained.

关键词： Fischer-Tropsch synthesis cobalt catalyst ruthenium reaction rate products distribution

Numerical simulation of the Hall effect in magnetized accretion disks with the Pluto code

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Research in Astronomy and Astrophysics 2014年第1期14卷 93-103页

作者： Mohammad nakhaei Ghasem Safaei Shahram Abbassi School of Physics Damghan University School of Astronomy Institute for Research in Fundamental Sciences Department of Physics School of SciencesFerdowsi University of Mashhad

We investigate the Hall effect in a standard magnetized accretion disk which is accompanied by dissipation due to viscosity and magnetic resistivity. By consider- ing an initial magnetic field, using the PLUTO code, we perform a numerical magne- tohydrodynamic simulation in order to study the effect of Hall diffusion on the physi- cal structure of the disk. Current density and temperature of the disk are significantly modified by Hall diffusion, but the global structure of the disk is not substantially affected. The changes in the current densities and temperature of the disk lead to a modification in the disk luminosity and radiation.

关键词： Hall effect -- accretion disks