| 摘要 |
A process for producing a cement binder composition comprising one or more magnesium carbonates having the general formula w MgCO3. x MgO. y Mg(OH)2 . z H2O in which w is a number equal to or greater than 1, at least one of x, y and z is a number greater than 0 and w, x, y and z may be (but need not be) integers is described. The process is characterised by the steps of (a) heating magnesite to liberate carbon dioxide gas and produce a solid product comprising magnesium oxide and (b) contacting an aqueous mixture comprising the magnesium oxide produced in step (a) with a source of carbonate ions at a temperature in the range 25 to 120°C to produce at least one of the magnesium carbonates, (c) optionally heating the magnesium carbonate product(s) of step (b) at a temperature from 45 to 500°C and (d) blending the magnesium carbonate(s) produced in step (b) or optional step (c) with at least magnesium oxide to produce a cement binder composition. The process is suitable for processing either naturally occurring magnesite ore or for magnesite produced by inter alia, mineral carbonation of magnesium silicate, carbonation of magnesium hydroxide or the treatment of sea water with carbon dioxide in the presence of inorganic base. |
