Preparation method of silver powder

Abstract

According to the scheme, a liquid phase reduction method is firstly adopted, silver nitrate and a reducing agent are adopted according to the main principle, and a certain amount of water-based dispersing agent or oil-based dispersing agent is added, so that the silver powder with certain dispersing performance is obtained, and in order to guarantee that the silver powder with high dispersity and uniform particle size can be obtained, the preparation method is simple, and the cost is low. The water-based dispersing agent is selected, meanwhile, the reducing agent is any one or more of ascorbic acid, formaldehyde, hydrazine hydrate and hydrogen peroxide, after the reduction reaction is finished, alkali liquor continues to be added, the pH of the suspension C is adjusted to be 8-14, hydroxyl ions are contained in the system in the process, the structure of the dispersing agent can be destroyed through strong alkalinity, and therefore the dispersing effect is improved. Therefore, the dissociation effect is achieved; the method can be applied to any preparation method of the silver powder using the water-based dispersing agent, complete sedimentation of the silver powder can be achieved, organic residues on the surface of the obtained silver powder are lower than those of the silver powder not using the method by 0.3% or above, and high practicability is achieved.

Description

technical field [0001] The invention relates to the technical field of silver powder preparation, in particular to a preparation method of silver powder. Background technique [0002] Now the preparation method of silver powder generally adopts the liquid phase reduction method. In order to improve the dispersion performance of silver powder, a certain amount of water-based or oil-based dispersant is generally added to it, because water-based dispersant can obtain high dispersion and uniform particle size compared with oil-based dispersant. The silver powder in the actual preparation process is mainly based on water-based dispersant. [0003] When using a water-based dispersant, in order to obtain a highly dispersible silver powder, the amount of the dispersant is often relatively large, but after the amount of the dispersant increases, the reaction liquid with water as the solvent will show a gel state, which will lead to silver powder After the reduction is completed, it ...

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Problems solved by technology

[0003] When using a water-based dispersant, in order to obtain a highly dispersible silver powder, the amount of the dispersant is often relatively large, but after the amount of the dispersant increases, the reaction liquid with water as the solvent will show a gel state, which will lead to silver powder After the reduction is completed, it floats in large quantities in the water and cannot settle

Even after using a certain type and a certain amount of flocculant to make it settle, the proportion of organic residues on the surface of the silver powder will be high, which will affect the performance of the silver powder in the slurry in the later stage

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