22537-22-0Relevant articles and documents
Dissolution Kinetics of MgO in Aqueous, Acidic Media
Bugajski, Jerzy,Gamsjaeger, Heinz
, p. 763 - 772 (1986)
The method of the rotating disc was used to study the kinetics of MgO dissolution.Single crystals of MgO with the orientation , , and were dissolved in N2-saturated HClO4-NaClO4 solutions of constant ionic strength (I=1.0 mol*kg-1).Chemical, mixed and diffusional control of the reaction leading to dissolution has been found between 25 to 90 deg C and 0.5/=3 occurred diffusionally controlled with respect to H+ ions.Independent measurements of the limiting current densities for the cathodic reduction of H+ ions were carried out in solutions of the same composition and confirmed this kind of control.In the chemical control region the dissolution rates were proportional to the Mg2+ ion densities of the single crystal surfaces investigated.The dissolution rates relative to , at 40 deg C and pH=1, were found to be: 1.0+/-0.1(1.0); 1.3+/-0.2(1.2) and 1.7+/-0.2(1.7).Figures in parentheses refer to the relative Mg2+ ion densities of the surface.Reproducible results of high quality can only be obtained when fresh dislocations are removed by chemical polishing.In a limited pH range these results were formally consistent with the complex formation model of metal oxide dissolution.For substances with large surfaces this model applies frequently.However, for single crystals no methods are known which allow the independent determination of the amount of surface OH-groups and the surface complex formation constants.Although the overall dissolution behaviour of MgO, which is relevant for industrial applications, is now rather well known, not enough information for unambiguous mechanistic conclusions is available. - Keywords: Dissolution kinetics; Magnesium oxide; Rotating disc
The state and stability of magnesium(II) complexes with azaporphyrins in the proton-donor medium
Khelevina,Ishutkina,Malyasova
, p. 1548 - 1555 (2013/10/22)
The state and stability of magnesium complexes with various azaporphyrins in the proton-donor media containing acetic acid have been studied. Kinetic parameters of the complexes dissociation have been determined, possible reactions mechanisms have been pr
Zum Einfluss mechanischer Aktivierung und thermischer Behandlung auf die Aufloesung des Magnesiumoxids in Saeuren.
Jost, K.,Kaestner, R
, p. 259 - 265 (2007/10/02)
MgO powder was solved with excess acid at a constant pH value.The concentration of Mg++ ions in time was determined complexometrically.The curves of dissolution could be described by U=k1+k3t-k1e-k2t, where U is the conversion and k1, k2, k3 are constants.Mechanical activation results in an increase of the rate constants k2 and k3.A subsequent heat treatment lowers the reaction rate.In the nechanically activated samples this effect is stronger the in the initial ones.REM images of the samples indicate the formation of smaller particles due to mechanical activation and sintering of these particles during heat treatment as the cause of the observed effects.
