| This work shows the result obtained of studying the influence of synthesis variables, properties of delta and alpha crystalline phases, using two starting materials: amorphous solid silicate, with two different experimental processes used, a furnace (discontinuous process), and a pilot-plant rotary tubular oven (continuous process), and with a sodium silicate solution in a furnace. The aims of the present investigation work are: (1) Study and optimize the synthesis variables: crystallization temperature, crystallization time, particle size, percentage of seed, kinetics parameters and reaction times (in discontinuous process). (2) Characterization of samples obtained.; It should be emphasized that the delta silicates obtained in the present work have a Mg2+ binding capacity that is much higher than those found in other classical nonphosphated builders such as zeolite A. In addition, in an economic comparison between zeolite and layered silicates, one should consider the costs involved in the total zeolite builder system. Finally, ion exchange equilibrium between the ions Ca2+ and Mg2+ and the delta-Na2Si2O5 was studied. This silicate is more selective to the ion Mg2+ than ion Ca2+. Temperature favor the process of ion exchange increasing the equilibrium constant. As well, the thermodynamic parameters, DeltaG°, DeltaH°, and DeltaS° were calculated. |
