Prepn process of micro silver powder

A technology of silver micropowder and silver nitrate, applied in the field of preparing silver substances, can solve the problems of high cost, large equipment investment, poor operating environment and the like, and achieve the effects of controllable average particle size, improved operating environment and low production cost

Active Publication Date: 2007-12-19
CHINA BANKNOTE PRINTING & MINTING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

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. The silver precipitates out, but the application of ammonia makes the operating environment worse, the conditions are harsh, and it is easy to produce explosive silver.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Embodiment 1: adding 40 kilograms of silver nitrate to 200 liters of deionized water to make concentration is the silver nitrate solution of 200 grams per liter, and 15 kilograms of Na 2 CO 3 Add 60 liters of deionized water to make a Na concentration of 250 g / l 2 CO 3 solution.

[0021] Then under the temperature condition of 20~45℃, the Na 2 CO 3 The solution is completely added dropwise to the silver nitrate solution within 20 to 30 minutes, and the above solution is stirred at a low speed at a speed of 50 rpm, and 15 liters of analytically pure formaldehyde is poured into the above solution to react until the temperature does not rise any more. The temperature dropped by 0.1°C, the reaction was complete, filtered, washed, and dried at 60°C to obtain silver micropowder with an average particle size of 5.21 microns.

Embodiment 2

[0022] Embodiment 2: adding 40 kilograms of silver nitrate to 200 liters of deionized water to make concentration is the silver nitrate solution of 200 grams per liter, and 15 kilograms of Na 2 CO 3 Add 60 liters of deionized water to make a Na concentration of 250 g / l 2 CO 3 solution.

[0023] Then under the temperature condition of 20~45℃, the Na 2 CO 3 90% of the solution is completely added dropwise to the silver nitrate solution within 20 to 30 minutes, and the above solution is stirred at a low speed at a speed of 60 rpm, and 15 liters of analytically pure formaldehyde is poured into the above solution to react until the temperature is no longer Rising, when the temperature drops by 0.1°C, the reaction is complete, filtered, washed, and dried at 70°C to obtain silver powder with an average particle size of 6.54 microns.

Embodiment 3

[0024] Embodiment 3: adding 40 kilograms of silver nitrate to 200 liters of deionized water to make concentration is the silver nitrate solution of 200 grams per liter, and 15 kilograms of Na 2 CO 3 Add 60 liters of deionized water to make a Na concentration of 250 g / l 2 CO 3 solution.

[0025] Then under the temperature condition of 20~45℃, the Na 2 CO 3 Add 80% of the solution dropwise into the silver nitrate solution within 20-30 minutes, stir the above solution at a low speed at 70 rpm, measure 15 liters of analytical pure formaldehyde and pour it into the above solution for reaction until the temperature does not rise any more , when the temperature dropped by 0.1°C, the Na 2 CO 3 The remaining 20% ​​of the solution is poured into the above solution until the temperature no longer rises. When the temperature drops by 0.1°C, the reaction is complete, filtered, washed, and dried at 80°C to obtain silver powder with an average particle size of 7.48 microns.

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 王自森杨玉祥汪云林詹刚王刚
Owner CHINA BANKNOTE PRINTING & MINTING
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