Abstract: A preparation method using micro-nano bubbles as crystal seeds to induce spherical or spherical-type silver power production, said method specifically comprising the steps of: pre-adding a prepared dispersing agent solution to a reaction vessel, within the reaction vessel, simultaneously adding a prepared oxidizing solution (an aqueous solution containing silver ions or a silver ammonia solution) and a reducing solution (an aqueous solution containing one or a plurality of hydroxylamine compounds, vitamin C, formaldehyde or hydrazine hydrate), performing a reduction reaction under vigorous stirring, and using the pre-generated micro-nano bubbles within the dispersing agent solution as crystal seeds, the micro-nano bubbles crystal seeds effectively controlling the particle size of reduced silver particles throughout the reduction reaction. The method effectively controls the particle size of the silver powder during production, and also controls the crystal nucleus growth rate and dispersibility.

Abstract: Provided is a method for preparing metal powder; a metal nitrate or metal sulfate is combined with ammonia water to produce an ammonia-containing complex metal salt solution; the said solution is then quantitatively jet-mixed with the solution containing the hydroxylamine compounds, and reacted under intense stirring; a dispersant solution is added during the reaction process, and after the reaction is complete, the solution is separated by centrifugation to yield the metal power. The method of the present invention can effectively control the reaction rate during the production process, and well control the nucleation rate and dispersity, with the produced metal powder having very good crystallinity, sphericity, tap property and dispersity.

Abstract: A preparation method using micro-nano bubbles as crystal seeds to induce spherical or spherical-type silver power production, said method specifically comprising the steps of: pre-adding a prepared dispersing agent solution to a reaction vessel, within the reaction vessel, simultaneously adding a prepared oxidizing solution (an aqueous solution containing silver ions or a silver ammonia solution) and a reducing solution (an aqueous solution containing one or a plurality of hydroxylamine compounds, vitamin C, formaldehyde or hydrazine hydrate), performing a reduction reaction under vigorous stirring, and using the pre-generated micro-nano bubbles within the dispersing agent solution as crystal seeds, the micro-nano bubbles crystal seeds effectively controlling the particle size of reduced silver particles throughout the reduction reaction. The method effectively controls the particle size of the silver powder during production, and also controls the crystal nucleus growth rate and dispersibility.