Reactivity of Solids最新文献_第2页

Low- and high-temperature reoxidation of direct reduced iron: a relative assessment 直接还原铁的低温和高温再氧化:一个相对的评价

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80010-H

Amitava Bandopadhyay, Amit Ganguly, K.K. Prasad, S.B. Sarkar, H.S. Ray

引用次数: 4

Conversion of manganese-chromium spinel to sulphides in H2-H2O-H2S atmospheres 锰铬尖晶石在H2-H2O-H2S气氛下转化为硫化物

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80015-C

P. Papaiacovou, H.J. Grabke, M. Danielewski, H.P. Schmidt

{"title":"Conversion of manganese-chromium spinel to sulphides in H2-H2O-H2S atmospheres","authors":"P. Papaiacovou, H.J. Grabke, M. Danielewski, H.P. Schmidt","doi":"10.1016/0168-7336(90)80015-C","DOIUrl":"10.1016/0168-7336(90)80015-C","url":null,"abstract":"<div>The conversion of MnCr2O4 to sulphides was investigated at 1073 K, 1173 K and 1273 K in H2-H2O-H2S mixtures. From thermogravimetric studies on the sulphidation of the bulk spinel, the stability limit of MnCr2O4 was determined. When a certain sulphur pressure is exceeded corresponding to the reaction MnCr2O4 + 3/2S2 = MnS + 2CrS + 2O2, the spinel is converted to a porous layer of mixed sulphides (Mn,Cr)S and (Cr,Mn)S. The partial pressure dependences indicate that the reaction rate is controlled by a surface reaction, i.e. the sulphur transfer from H2S at the interface sulphide-spinel which is easily accessible through the large pores in the sulphide layer. Similar kinetics and morphology of the reaction products were observed when MnCr2O4 layers obtained by preoxidation of Fe-Cr-Mn alloys were sulphidized. The results provide information on the stability of oxide layers formed on Mn-containing high temperature alloys in oxidizing-sulphidizing atmospheres.</div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"8 1","pages":"Pages 147-158"},"PeriodicalIF":0.0,"publicationDate":"1990-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(90)80015-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86137469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Kinetic parameters for non-isothermal decomposition of cobalt(II), nickel(II) and palladium(II) complexes with 2-furaldehyde thiosemicarbazone 2-呋喃醛缩氨基脲非等温分解钴(II)、镍(II)和钯(II)配合物的动力学参数

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80011-8

K.K. Aravindakshan★, K. Muraleedharan

引用次数: 8

Effect of surface macrodefects on the mechanism of oxygen interaction with the boundary layer of Fe2O3 表面宏观缺陷对氧与Fe2O3边界层相互作用机理的影响

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80006-6

F. Adam , B. Dupré , C. Gleitzer , J. Janowski , J. Nowotny★ , M. Sloma

{"title":"Effect of surface macrodefects on the mechanism of oxygen interaction with the boundary layer of Fe2O3","authors":"F. Adam , B. Dupré , C. Gleitzer , J. Janowski , J. Nowotny★ , M. Sloma","doi":"10.1016/0168-7336(90)80006-6","DOIUrl":"10.1016/0168-7336(90)80006-6","url":null,"abstract":"<div>The interaction between gaseous oxygen and the surface of sintered polycrystalline Fe2O3 was studied by using “in situ” work function measurements at 1140 K (867°C). The treatment of the specimen (after preliminary sintering at 1673 K in air) involved polishing of the oxide surface with a diamond powder resulting in the formation of a high density of grooves of different orientations along the surface. Sorption of oxygen on the freshly polished surface resulted in the formation of a positive surface charge which has been considered in terms of the formation of subsurface microdipoles, induced either by specific active centres formed during the mechanical treatment, or by donors formed at the same centres. The centres were closely related to the presence of grooves. The charge decreased during the thermal treatment and finally changed in sign. It was also observed that the treatment led to disappearance of grooves except some with specific orientation. The time of the equilibration, whose rate is controlled by the surface diffusion, was about 300 h at 1140 K.</div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"8 1","pages":"Pages 41-50"},"PeriodicalIF":0.0,"publicationDate":"1990-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(90)80006-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82794388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Influence of particle size of α-Fe2O3 on the formation of ZnFe2O4 and the implications of a characteristic surface texture of the ferrite phase formed on α-Fe2O3 particles α-Fe2O3颗粒尺寸对ZnFe2O4形成的影响及α-Fe2O3颗粒形成的铁素体相特征表面织构的影响

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80007-7

S. Shimada, K. Soejima, T. Ishii

{"title":"Influence of particle size of α-Fe2O3 on the formation of ZnFe2O4 and the implications of a characteristic surface texture of the ferrite phase formed on α-Fe2O3 particles","authors":"S. Shimada, K. Soejima, T. Ishii","doi":"10.1016/0168-7336(90)80007-7","DOIUrl":"10.1016/0168-7336(90)80007-7","url":null,"abstract":"<div>The influence of particle size of α-Fe2O3 on the formation of ZnFe2O4, which proceeds by an initial rapid surface reaction followed by the diffusion process, was studied at 700–1000°C. Four kinds of α-Fe2O3 samples were used: a ball-milled and sieved sample with average particle size of d0 =1.2 μm (designated as M-1) and another with d0 = 16.8 (M-2), and an unmilled and sieved sample with d0 = 19.2 μm (I-1) and another with d0 = 73.5 μ (I-2). With sample M - 1, the initial surface reaction accounts for at least 35% of the reacted fraction at temperatures higher than 700 ° C and with the other samples, the surface reaction is of importance above 800°C.The M - 2, I - 1 and I - 2 samples had for the diffusion process almost the same activation energy (about 180 kJ mol−1), indicating the particle size had no influence on the diffusion process, whereas sample M - 1 showed a much lower activation energy, this reduction presumably due to the ball-milling. Scanning electron microscopy of the surfaces of α-Fe2O3 particles showed a characteristically textured ferrite surface with the wavy lines arising in the initial period from the rapid specific migration of the ZnO component leading to the surface reaction. This texture changed to an interwoven pattern as the reacted fraction increased.</div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"8 1","pages":"Pages 51-61"},"PeriodicalIF":0.0,"publicationDate":"1990-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(90)80007-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86725870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Effect of γ-irradiation on cationic and hydrogen zeolites reactivity: clinoptilolite and ferrierite γ辐照对阳离子和氢沸石反应性的影响:斜沸石和铁素体

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80018-F

A.K. Aboul-Gheit, A.M. Summan

{"title":"Effect of γ-irradiation on cationic and hydrogen zeolites reactivity: clinoptilolite and ferrierite","authors":"A.K. Aboul-Gheit, A.M. Summan","doi":"10.1016/0168-7336(90)80018-F","DOIUrl":"10.1016/0168-7336(90)80018-F","url":null,"abstract":"<div>Cationic and H-forms of clinoptilolite and ferrierite were irradiated with -γ-rays. Presorbed triethylamine (TEA) on the unirradiated and irradiated zeolites was subjected to oxidation in a differential scanning calorimetry (DSC) cell in flowing oxygen, making use of the programmed temperature increase of the DSC system. The sum of ΔH for all DSC effects obtained for TEA oxidation in a thermogram was taken as a measure for the zeolite chemisorptive capacity (acidity). The data given by DSC and the acidities determined thermogravimetrically (TG) for presorbed TEA as well as those determined from the IR spectra of presorbed pyridine (Bronsted pyridine “BPY” and Lewis pyridine “LPY”) show certain discrepancy due to evaluation of some high-temperature DSC effects by extrapolation beyond the DSC maximum temperature. Improvement of the DSC data is discussed. However, similar trends of the DSC ΔH values and the TG and IR values with irradiation dose are observed. The temperature at which the maximum of the principal oxidation DSC effect can be taken as a criterion for correlating the zeolite reactivity to oxidise TEA. In general, γ-irradiation was found to enhance the zeolite reactivity to chemisorb TEA (acidity) and to enhance the rate of oxidizing the presorbed base.</div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"8 1","pages":"Pages 179-188"},"PeriodicalIF":0.0,"publicationDate":"1990-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(90)80018-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85159905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Solid state thermal isomerisation of CoII-and CuII-metformin complexes coii -和cuii -二甲双胍配合物的固态热异构化

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80002-2

Ahmed M. Donia★, E. El-Shereafy, Mohamed A. El-Ries

引用次数: 5

Synthesis of zeolites from mechanically activated kaolin clays 机械活化高岭土合成沸石

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80017-E

E.I. Basaldella , A. Kikot, E. Pereira

引用次数: 18

The CsCl structure of the Raney nickel catalyst obtained from mechanically alloyed nickel aluminides 由机械合金镍铝化物制备的Raney镍催化剂的CsCl结构

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80009-9

E.Yu. Ivanov, G.V. Golybkova, T.F. Grigorieva

引用次数: 22

Thermal and spectroscopic study on the solid-solid interaction between CuO and Fe2O3 and the effect of sodium ions CuO与Fe2O3固-固相互作用及钠离子影响的热光谱研究

Reactivity of Solids Pub Date : 1990-06-01 DOI: 10.1016/0168-7336(90)80019-G

M.M. Selim, T.M.H. Saber, N.A. Youssef

{"title":"Thermal and spectroscopic study on the solid-solid interaction between CuO and Fe2O3 and the effect of sodium ions","authors":"M.M. Selim, T.M.H. Saber, N.A. Youssef","doi":"10.1016/0168-7336(90)80019-G","DOIUrl":"10.1016/0168-7336(90)80019-G","url":null,"abstract":"<div>CuO-Fe2O3 sample of equimolar ratio was prepared by coprecipitation. The mixed hydroxides were studied using differential thermal analysis. The thermal products at different temperatures up to 1000°C were characterized by means of X-ray diffraction analysis. The morphological changes were followed through scanning electron microscopy and complemented by X-ray photoelectron spectroscopy. The thermal treatment of the mixed hydroxides at temperatures between 200 and 1000°C produced almost a crystalline CuO-phase. Scanning electron microscopy showed two distinct types of species. The first (major) is microspheres and the second is needle-like type. Electron spectroscopy for chemical analysis revealed that this sample contained sodium ions which covered the surface of the CuO-Fe2O3 species in the form of sodium sulphate layer. This layer prevents the solid-solid interaction. Washing the sample thoroughly leads to the removal of sodium sulphate layer and increases the reactivity of solids to form a crystalline copper-ferrite phase.</div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"8 1","pages":"Pages 189-196"},"PeriodicalIF":0.0,"publicationDate":"1990-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(90)80019-G","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72559705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2