Preparation method of silver powder or doped silver powder

Abstract

The invention discloses a preparation method of silver powder or doped silver powder. The preparation method comprises the steps of firstly, preparing silver salt solution, and then carrying out ultrasonic atomization on the silver salt solution to obtain atomized matter, wherein the ultrasonic atomization power is 0.2-10kw, the ultrasonic atomization frequency is 1.7-2.4MHz, and the atomization speed is 0.5-500kg / h; mixing the atomized matter with carrier airflow, carrying out thermal decomposition, and collecting to obtain the silver powder or doped silver powder, wherein the silver salt solution has the silver ion molar concentration of 0.0001-4mol / L or contains doped metal ions, and microwave heating is preferentially adopted by the thermal decomposition. After the preparation method is adopted, the silver powder or doped silver powder with the particle sizes of 0.01-5 mu m can be prepared, and power bonding agglomeration can be prevented; the microwave thermal decomposition is short in heating time and high in efficiency, and dopant in the doped silver powder can be evenly distributed; continuous production is realized, the cost is low, and the product quality is stable.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation method of silver powder or doped silver powder. Background technique [0002] Silver powder has high electrical conductivity, thermal conductivity, anti-oxidation and other properties, and is widely used in the electronics industry and environmental protection fields. Its preparation technology has always been a key and difficult point in domestic research, and high-end silver powder has been monopolized by foreign countries. There are many ways to prepare silver powder, mainly including electron beam irradiation method, DC arc thermal plasma method, microwave plasma method, mechanochemical synthesis method, electrolysis method, etc., but these methods have high energy consumption, special equipment and harsh environmental requirements. Shortcomings. [0003] The liquid-phase reduction method is a widely used method for large-scale industrial production o...

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Problems solved by technology

There are many ways to prepare silver powder, mainly including electron beam irradiation method, DC arc thermal plasma method, microwave plasma method, mechanochemical synthesis method, electrolysis method, etc., but these methods have high energy consumption, special equipment and harsh environmental requirements. Shortcomings

[0003] The liquid-phase reduction method is a widely used method for large-scale industrial production of silver powder. By changing the silver content of the precursor, the type and amount of reducing agent and dispersant, adjusting the reaction concentration, temperature, stirring rate and intensity, etc., control The shape and particle size of silver powder, but the silver powder prepared by direct pyrolysis of silver nitrate is easy to agglomerate, and the shape and particle size are not easy to control, it is difficult to meet the increasingly high quality requirements of silver powder

[0004] Among them, in the prior art, there is a public pyrolysis method to prepare silver powder. Put the silver nitrate solid powder into a crucible and place it in a tube furnace for heating, heat it to 550°C at a heating rate of 5-50°C / min, and pass it into the relative humidity It is 80-100% air, the air flow rate is 200-800mL / min, after calcination for 2-8h, stop heating and pass in cold air to cool to room temperature, collect the solids in the crucible, and obtain ultra-fine particles with an average particle size of 0.5-2μm Silver powder, the process is simple, and the obtained silver powder has a regular spherical shape, but the product has a coarse particle size, unstable performance, high energy consumption, and low cost performance for industrialization

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