SILVER FINE PARTICLES AND PROCESSES AND EQUIPMENT FOR THE PRODUCTION THEREOF

摘要

A process for production of silver fine particles which is characterized by making an aqueous silver ammine complex solution and a reducing agent solution meet each other in an open space to reduce the silver ammine complex and deposit silver fine particles, either in which the meeting is conducted by (i) a method of spraying an aqueous silver ammine complex solution and a reducing agent solution through nozzles or (ii) a method of ejecting an aqueous silver ammine complex solution and a reducing agent solution from obliquely downward nozzles opposite to each other to thereby produce silver fine particles which are free form coarse particles having particle sizes of 5µm or above and have a mean particle size of primary particles of 0.08 to 1.0µm and crystallite sizes of 20 to 150nm or in which an aqueous silver ammine complex solution having a silver concentration of 20 to 180g/L and an organic reducing agent solution having a reducing agent concentration of about 0.6 to about 1.4 times the silver concentration by reaction equivalent are used to thereby stably produce silver fine particles having a mean particle size of primary particles of 0.05 to 1.0µm and crystallite sizes of 20 to 150nm.