Reaktionen im festen Zustande bei höheren Temperaturen. XI. Mitteilung. Die Reaktion zwischen Calciumoxyd und Siliciumdioxyd

Study of reaction of finely-divided silica with barium carbonate by TG and DTA

“…5; this is similar to the reaction scheme for CaO-SiO2 proposed by Jander et al [8]. The first step is the formation of BaSiO3 at the interface between SiO2 and BaCOz by reaction (A) (AG ~ = -23 kcal/mole at 800~ The second step is the diffusion of BaO through the BaSiO 3 layer towards the SiO2-BaSiOa interface to form BaSiO3 by reaction with SiO2, and the formation of Ba2SiO4 at the BaSiO3-BaCO3 interface by reaction (B) (AG ~ = -13 kcal/mole at 800~ Estimated by using data from the literature [9].…”

High-Temperature Studies of Metallurgical Processes: Part I. The Thermal Reduction of Magnesium Oxide With Silicon

“…As this orthosilicate layer builds up around the silicon, diffusion of the oxygen anion outward to the silicon or diffusio~l of silicon to the magnesiunl oxide is necessary. Jander (1,11) has indicated the rapidity a t which alkaline earth oxides cliffuse through the orthosilicate structure and this fact may also account for the diffusion process in the present reaction. According to equation (VII) any SiO n~olecules that react with MgO produce free silicon, which can act as a nucleus for further reaction.…”

“…(11) In general, the reaction ceases when a dibasic silicate 2h/IO.Si02 has been formed. Jander (1) has shown that in a system of alkaline earth oxide -silica, the dibasic silicate is preferably formed.…”

Burnability and Clinkerization of Cement Raw Mixes

“…The solid-state reactions between lime and silica or lime and alumina are diffusion-controlled. Originally it was regarded that the diffusion-controlled reaction in solid phase followed the Jander's equation [85] ( In the diffusion process the Ca 2+ ions are the diffusing species.…”