摘要:

AbstractDifferent theories are proposed in the literature to explain passivation mechanisms of iron by means of the use of lead compounds. In some cases the protective action is related to the formation of lead soaps with vegetable oils or oleoresinous binders. These soaps are partially dissolved from the film, acting at the interface metallic substrate/paint film. In the case of inert binders (those corresponding to vinyl resins), red lead acts as a passivating agent. The protection of iron plates in the presence of suspensions of red lead, lead monoxide and lead dioxide in a 0.5M sodium perchlorate solution as electrolyte is studied in this paper. Polarisation curves were traced and measurements of voltage at open circuits were made. Only two of the lead oxides tested (red lead and lead monoxide) have corrosion inhibiting action, both showing a similar behaviour.

ISSN:0264-3413    

DOI:10.1002/jctb.5040350302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe polymetal complex ore Umm‐Gheig considered in Egypt as a rather rich source of lead and zinc is subjected to mineralogical, chemical, spectral, X‐ray and differential thermal analyses. Hydrometallurgical treatments based on leaching, precipitation and electrodeposition of metal from the ore are established. The influences of current density, temperature and metal ion concentration on the Faradic current efficiency are discussed. Advantages and disadvantages of flowsheets and various approaches depending on convenient baths for the electro‐deposition of metals are investigated. The results of electron microscopic investigation confirmed by metal value data given in the A.S.T.M. cards coincide well with those given by chemical ana

ISSN:0264-3413    

DOI:10.1002/jctb.5040350303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe adsorption of C2H4, C2H6and CO has been studied on Zn2+‐exchanged A‐zeolites. Partial exchange with Zn2+or Cd2+increases the adsorption capacity for C2H4and CO. Complete Zn2+exchange leads to a decrease, indicating a complicated variation of cation positions with exchange level. N.m.r. measurements are consistent with adsorption of C2H4as weak π‐complexes on the divalent cations. Weak specific adsorption complexes are also demonstrated

ISSN:0264-3413    

DOI:10.1002/jctb.5040350304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe iso‐electric points (i.e.p.) and the points of zero charge (p.z.c.) of alumina coated rutile pigments have been determined using potentiometric titrations and electrophoresis techniques. The alumina coated rutiles all had a p.z.c. close to pH9. The i.e.p. of coatings precipitated in an alkaline medium were close to pH7, while those of coatings precipitated in acid media were around pH5. The discrepancy between the values of the i.e.p. and the p.z.c. is thought to have arisen because the electrophoresis technique measures only the charge on the outer alumina coating, while the i.e.p. (found by titration) is a combination of charge properties of both the alumina and the underlying rutile (i.e.p. 3.7). It is suggested that the pigments whose coatings were precipitated in an alkaline medium have the higher i.e.p. because the alumina shields the rutile more effectively than does alumina that was precipitated in acid medi

ISSN:0264-3413    

DOI:10.1002/jctb.5040350305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA kinetic study of the reaction between chloroform and 2,5‐dimethylpyrrole in a continuous flow vapour phase system at 733 K showed the rate to be first order with respect to chlorofor

ISSN:0264-3413    

DOI:10.1002/jctb.5040350306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractRecent studies have suggested the possibility of spontaneous emulsification as a mechanism for enhanced oil recovery (EOR). The discussions have, however, remained essentially qualitative. A study was therefore undertaken to estimate quantitatively the contribution of spontaneous emulsification as an EOR mechanism. The tests were conducted on several bulk liquid/liquid systems as well as by displacement experiments in unconsolidated synthetic sand packs. Spontaneous emulsification was found to be a mechanism for EOR: the estimated extra contribution to EOR due to this mechanism was found to be significant in laboratory scale displacement experiments. Tertiary recovery was always greater when spontaneous emulsification was evident than otherwise. Results of tests on bulk liquid/liquid systems indicate that the occurrence or absence of spontaneous emulsification can be correlated with the values of ‘partition parameter’. It may be concluded that higher oil recoveries may be achieved in chemical EOR processes where interface mass transfer (and the accompanying spontaneous emulsification) occurs. The evaluation of efficiency of residual oil mobilisation through the capillary number theory (with and without spontaneous emulsification) is also discussed. Displacement tests with spontaneously emulsifying systems showed that residual oil left behind a conventional waterflood was mobilised in a range of capillary numbers much less than that which applies to low‐tension waterf

ISSN:0264-3413    

DOI:10.1002/jctb.5040350307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractOrganic matter from North Carolina and Idaho phosphorites has been extracted and characterised using humic acid, kerogen and bitumen fractions. Extracts from thermally treated rock showed that the organic matter from the two source rocks responds quite differently to the heat treatment. With current commercial calcination of both North Carolina and Idaho phosphate rock at about 800°C, problems with acid‐evolvable sulphide formation have arisen. From the findings made on the thermal behaviour of the organic matter and the associated sulphur redistribution, alternative processing strategies have been suggested for both North Carolina and Idaho phosphorites. Since these two rocks represent extremes in maturity for the contained organic matter, the results should be of relevance to other organic‐rich unweathered and low‐grade phosphorite or phosphatic shale de

ISSN:0264-3413    

DOI:10.1002/jctb.5040350308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0264-3413    

DOI:10.1002/jctb.5040350301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY