Filtration and washing technology in preparing metal or non metal fine granular powder

Abstract

A filtering and washing process for preparing the metallic or non-metal fine particles includes filtering, washing, blow-drying of filtered cake, discharging and cleaning filter. Said filtering step features use of the precise millipore filter with at least two filter regions for respective filtering. Said washing step includes reversely blowing the washing liquid to drop the filtered cake onto filter plate, instantaneously reversely blowing compressed air several times, and stirring the mixture of filtered cake and washing liquid.

Description

technical field [0001] The invention relates to a filtration and washing process, in particular to a process for filtering and washing with a precision microporous filter in the preparation of metal or non-metallic fine particle powder. Background technique [0002] In the production of chemical industry, metallurgy and other industries, especially the production of new materials, it is necessary to prepare a large number of metal or non-metal powders with very fine particles, especially ultrafine powders. In the preparation process, liquid-solid filtration and washing of powder are indispensable unit operations. At present, there are two types of filtration and washing technologies in industrial production. One is the traditional technology, where the filtration and washing are carried out in two different devices. Generally, these filtering devices and washing devices are traditional devices; the slurry is filtered first, and then the filter cake i...

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Problems solved by technology

Disadvantages: First, the filter cloth is used as the filter medium, and the fine powder is easy to penetrate and filter, and the loss is large; the second is vertical installation, and the thickness of the upper and lower filter cake layers of the filter medium is uneven, making the washing uneven. In order to ensure the washing effect, it often takes a lot of detergent

The multi-layer horizontal leaf filter or multi-layer horizontal box filter has the advantages of high washing efficiency and less washing liquid, but the device is quite complicated to obtain a dry filter cake in the end.

There are also many enterprises that adopt simple horizontal vacuum suction filtration or horizontal pressure filtration process. Although the structure of the device is simple, there is only one horizontal filter plate with filter cloth as the filter medium. The filter area is small, the processing capacity is low, and the fine powder is easy to pass through. , and the filter cake is prone to cracking during washing, which causes the washing liquid to short circuit, resulting in a large amount of washing liquid waste, and it is difficult to guarantee product quality; moreover, the vacuum suction filter has a low pressure difference and a very slow filtration speed, so that the production efficiency is not high

In summary, so far, in the process of preparing fine particle powder, there are many defects in filtration and washing due to the unsatisfactory filtration and washing equipment used.

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