Preparation of Fine Carbonate Salts Using a Higee System
Date Issued
2007
Date
2007
Author(s)
Tai, Chia-Te
DOI
zh-TW
Abstract
The purpose of this study was to build a platform to apply the high-gravity (higee) technique in crystallization for producing fine particles. We used two types of higee equipment, rotating packed bed reactor (RPBR) and spinning disk reactor (SDR), to produce CaCO3 and BaCO3 particles via a gas-liquid-carbonation or a liquid-liquid-mixing reactive precipitation route. Fine CaCO3 particles can be used in polymers, paper industry etc., to enhance the performance of material. Small rod-like BaCO3 particles can also be used in optical and electronic industry.
First of all, an adequate particle-dispersing technique was developed and subsequently was used for PSD measurement. Through comparison of the results obtained from the PSD measurement, the effects of operation variables in a higee system on PSD of products, including rotating speed, flow rate, and solid-content of feed slurry, were investigated via a carbonation route; meanwhile comparison of the performance between RPBR and SDR was also included. As the CaCO3 system was concerned, RPBR was used to produce CaCO3 particles with volumetric mean size 0.39μm and calcite-polymorphism in a circulate carbonation process. The yield for this process was 85∼90 %. For the other system, we used types of reactors, i.e., RPBR and SDR, to produce BaCO3 particles in a continuous carbonation process. The volumetric mean size of BaCO3 was 0.39μm and 0.34μm for RPBR and SDR separately, and the prepared particles were rod-like and had a orthorhombic crystal morphology. The yield for the continuous carbonation process was about 75∼80 ％. Finally, we compared the products produced by a high-gravity reactor and a normal-gravity reactor.
Viewed in this light, the higee system fits the category of process intensification in the development of green processes, concerning the less space required, suitable for continuous operation, and much more improved efficiency in absorption and mixing to be able to produce fine particles with narrow distribution.
Subjects
超重力
微細粒子
旋轉填料床反應器
旋轉盤反應器
碳酸鈣
碳酸鋇
碳化法
反應沈澱
製程強化
high-gravity (higee)
fine particles
rotating packed bed reactor (RPBR)
spinning disk reactor (SDR)
CaCO3
BaCO3
carbonation
reactive precipitation
process intensification.
Type
thesis
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