Method for increasing production volume of fine particles using forced thin film fluid treatment apparatus

A method comprising the steps of:

• preparing at least two fluids, including a first fluid and a second fluid, the first fluid being a raw material fluid which contains at least one kind of the fine particle raw material, the second fluid being a fluid to process the fine particle raw material;
• introducing the at least two fluids into a processing device, the processing device comprising at least two processing surfaces facing each other, the at least two processing surfaces being operable to approach to and separate from each other, wherein at least one of the at least two processing surfaces is in the form of a ring and rotates relative to the other;
• mixing the at least two fluids in a space formed between the at least two processing surfaces, thereby forming a thin film fluid between the at least two processing surfaces;
• and
• obtaining fine particles from the thin film fluid,
• wherein the raw material fluid is introduced from a center of the at least two processing surfaces into the space between the at least two processing surfaces via a first introduction path, the processing device includes a second introduction path independent of the first introduction path, the second introduction path forming at least one opening, which is formed on at least one of the at least two processing surfaces and leading to the space between the at least two processing surfaces, and wherein the second fluid is introduced into the space between the at least two processing surfaces via the second introduction path and the at least one opening,
• and
• wherein a ratio of a total open area (a) to a total open area (b) is no more than 5, wherein:
• the total open area (a) is obtained by multiplying a circumference of a circle having a radius which is a distance from a center of the ring to a point from which the first fluid and the second fluid start joining together, by a distance between the at least two processing surfaces in a direction along a rotation axis of the at least one processing surface;
• and
• the total open area (b) is a sum of introduction opening areas of the at least one opening formed on the at least one processing surface.