Method and device for extraction and fractionation of small particles from solutions saturated with gas

摘要

In a novel process for the production of particles or powders, a substance or mixture of substances to be treated is provided in a pressure vessel. A highly compressible fluid is dissolved under pressure in the substance or mixture of substances provided until a solution containing 5% to 90% by weight of said highly compressible fluid has formed. The melting point of said highly compressible fluid is at least around 40 K lower than the melting point of the substance or mixture of substances to be treated. The solution obtained by dissolving said highly compressible fluid in the substance or mixture of substances provided is adjusted to a temperature of up to around 50 K above or below the melting point under atmospheric pressure of the substance or mixture of substances to be treated and is then rapidly decompressed by means of a decompression device in such a way that the temperature falls, downstream of the decompression device, below the solidification point of the substance or mixture of substances to be treated and essentially all of the highly compressible fluid turns gaseous, whereby particles of the substance or mixture of substances provided form. Subsequently, the particles which have formed are removed from the stream of decompressed highly compressible fluid.