Prepn process of micro silver powder

Abstract

The chemical reaction process for preparing silver micropowder includes the following steps: dissolving silver nitrate in deionized water and diluting to 200 g / l concentration, adding 200-300 g / l concentration alkaline solution of NaOH, KOH, Na2CO3 or K2CO3 at 20-45 deg.c, adding organic reductant formic acid, formaldehyde, ethylene glycol or glycerin under low speed stirring at 50-85 rpm to produce silver micropowder of 5-10 micron size, filtering, washing, and stoving to obtain the silver micropowder product. The process has the advantages of simplicity, low production cost and controllability of the average silver micropowder size.

Description

technical field

[0001] The invention belongs to a method for preparing silver substances by chemical reaction, in particular to a method for preparing silver micropowder. Background technique

[0002] At present, the preparation methods of nano-silver powder mainly include physical methods and chemical methods. The physical method generally adopts vacuum evaporation-condensation method, vacuum sputtering method and plasma sputtering method, which have the disadvantages of large equipment investment, low yield, large energy consumption and high cost. The chemical method generally uses silver nitrate as the raw material, adding ammonia water to complex the silver ions to form silver ammonia complex ions to reduce the concentration of silver ions in the solution, and then use hydrogen peroxide, hydrazine hydrate, triethanolamine, sodium citrate, ascorbic acid, etc. However, the application of ammonia water makes the operating environment worse, the conditions are harsh, and it...