Method for preparing low apparent density copper powder by reduction of water atomized dry powder

Abstract

The invention relates to a method which uses water atomized dry powder to reduce and prepare copper powder with lower loosen rate. Present method which directly process reduction without oxidation has longer reduction time, higher furnace temperature, larger energy consumption, high cost, bigger labor strength, lower producing efficiency and higher transfer cost; therefore, it can not apply the production of high-property powder metallurgical product. Said invention is characterize in that using annular multi-focus injection water to atomize the copper liquid, then directly drying the atomized copper powder into dry powder, processing reduction sintering, breaking and filtration to attain fine-grained grouped irregular copper powder. Since the invention processes reduction sintering directly on the dry powder after multi-focus water atomization, the reduction time can be shortened, and via lower temperature, the reduction sintering can be realized to reduce energy consumption and producing cost. And the invention has lower labor strength, high producing efficiency, and the application of high-property powder metallurgical product.

Description

technical field [0001] The invention relates to a method for preparing copper powder in the technical field of metallurgy, in particular to a method for preparing copper powder with a low loose ratio through water atomization dry powder reduction. Background technique [0002] Copper powder is widely used in powder metallurgy industry, diamond tool industry and electric carbon industry. The lower the bulk density (hereinafter referred to as loose ratio) of copper powder, the better the compressibility, forming filling and sintering activity. There are three main production methods of copper powder in China: electrolysis method, oxidation reduction method after water atomization (AOR method), and method of direct reduction without oxidation by water atomization. [0003] The particles of copper powder obtained by electrolysis are dendritic, with developed specific surface, so the compressibility and sintering activity are excellent, but the fluidity i...

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Problems solved by technology

The advantage of this method is that the loose ratio of copper powder is lower than 2.9g / cm 3 , but the process is long and complicated. Due to the serious sintering during high temperature oxidation, it needs to be processed in a crushing process, which consumes a lot of energy and high production costs.

[0005] The method of direct reduction without oxidation can be taken as an example of the technical scheme of Chinese patent application No. 03136699.6, which has the characteristics of "shortened process flow and simple post-treatment process", but because the method uses dehydrated wet powder according to the chemical treatment method To reduce the loose ratio of copper powder, the following disadvantages still exist: 1) in the description of the application, the dehydrated wet powder after atomization is said to "do not need to go through the drying and oxidation process", which means that this method eliminates the existing technology that will be destroyed. The process of atomizing copper powder for drying, and using the dehydrated wet powder after centrifugal dehydration for direct reduction

Since the water content of the dehydrated wet powder is 3-5%, the reduction time required for the copper powder is long, the furnace temperature is high (450-620°C), the required energy consumption is large, and the cost is still high; 2) Dehydration The physical state of the wet powder prevents it from being directly transported to the reduction furnace. It usually takes steps such as removing the upper layer of water, putting the copper powder into a container such as a cloth bag, and then moving the copper powder in the container to the reduction furnace, which is labor-intensive. Large, low process efficiency and high transportation costs; 3) The atomized water flow is a single focus, and there is only one intersection, and the copper liquid particles can only be hit once

The loose ratio of copper powder is 2.5~2.7g / cm 3 Between, the loose ratio is still high, the sintering activity is poor, and it cannot be used to produce high-performance powder metallurgy products

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