Étude de l'agglomération lors de la précipitation de carbonate de calcium par un procédé de carbonatation d'une suspension d'hydroxyde de calcium

Abstract : Precipitated calcium carbonate (PCC) is a mineral additive of various applications in paints, pharmacy, cosmetics, etc. It can be industrially synthesized through several ways but the most common one is the carbonation route. It consists in bubbling carbon dioxide in a suspension of calcium hydroxide to get particles of PCC. However, the challenge related to the synthesis and the use of this precipitate is the control of the agglomeration of the monoparticles. Indeed, they are agglomerated in micrometric "loose" structures. This agglomeration has consequences on the run of the process and the end use properties of the final product. Thus, the aim of this work is to understand the mechanisms of this phenomenon, to determine its kinetics and to study the impact of different process parameters under complex industrial conditions. The method to determine the agglomeration kernel is based on the resolution of a population balance using the moment approach. Provided that the kinetic rates of nucleation and growth are known, the agglomeration kernel can be obtained from a mathematical treatment of the experimental particle size distributions. Thanks to an agglomeration kernel model including the crystal growth, it is possible to determine the value of the agglomeration constant. Finally, by varying different process parameters, it also appears that the agglomeration constant increases with temperature whereas an optimum is observed for the shear rate. Regarding to this fact, we can also propose an expression of the agglomeration constant as a function of the shear rate, which can be used to control the agglomeration in the industrial reactor
Document type :
Theses
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01752062
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 1:31:59 PM
Last modification on : Tuesday, April 10, 2018 - 1:29:34 AM

File

DDOC_T_2015_0131_SCHNEBELEN.pd...
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01752062, version 1

Collections

Citation

Mathilde Schnebelen. Étude de l'agglomération lors de la précipitation de carbonate de calcium par un procédé de carbonatation d'une suspension d'hydroxyde de calcium. Alimentation et Nutrition. Université de Lorraine, 2015. Français. ⟨NNT : 2015LORR0131⟩. ⟨tel-01752062⟩

Share

Metrics

Record views

55

Files downloads

49