Particles with nano- or micron-structure such as metal oxide, organic compound, inorganic compound and medicine particles are widely used in fields of microelectronics, information technology, space technology, chemical industry, machinery, automotive technology, pharmaceutical technology, etc. Methods for preparing particles with nano- or micron-structure are generally classified as physical or chemical, wherein precipitation method is the most common method among both physical and chemical methods. However, conventional precipitation methods usually employs a stirring tank as a reactor or precipitation device, which can not guarantee the rapid mixing, mass transfer and heat transfer of the reacting material, and result in the producing of heterogeneous particles after precipitation, long precipitation or reaction time and low production efficiency. The main reason of the above-mentioned problems is uneven microcosmic mixing in the reactor or precipitation device.
To address the above-mentioned problems with stirring tank, Jianfeng Chen et al. disclosed a method for preparing ultrafine calcium carbonate (Chinese Patent No. ZL95105343.4) by improving the rotating packed bed (also known as high-gravity reactor, Chinese Patent No. ZL95215430.7) and using it as a reactor to enhance the mixing and mass-transfer involved in the precipitation method, based on a process for effecting gas-liquid mass transfer using rotating packed bed disclosed by Ramshaw et al. (U.S. Pat. No. 4,283,255). In the method disclosed by Jianfeng Chen et al., the time required for carbonation is reduced and nano-sized particles with a particle size of 10-40 nm and an evenly distributed particle size are produced. However, the rotator in the high-gravity reactor usually takes the form of a packing layer, and during the precipitation and crystallization of the material with a high viscosity, blocking will occur and cleaning must be done constantly, therefore it is not suitable for continuous operation.
Therefore there is a need to provide a device with enhanced liquid-liquid microcosmic mixing and reaction, which can prepare inorganic, organic or medicine particles with nano- or micron-structure in a continuous manner.
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