The problem of difficult filtration when using sprayed metallic zinc powder
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Zinc powder is produced using the air atomization siphon method, with 80% of the particles having a particle size of less than 200 mesh. During the three-stage antimony removal purification process, difficulties arise in carrying out box filter pressing during the second stage of purification for cobalt removal – how can this problem be solved?
What exactly is the issue – is it a problem with penetration or poor filtering efficiency? The type of material, temperature, pH level, flow rate, as well as the material of the filter cloth and its weaving method are all important factors. By the way, everyone here can help analyze this for you
Apologies, let me add some details: The actual situation is as follows – the purified slag does not take a solid form; it is in a thin, paste-like state. This is the result of the second-stage high-temperature cobalt removal process using zinc purification liquid. The purification temperature is 80–90 degrees, with a pH level above 5. The filter cloth used is Zhejiang Sui Ta 621
The purified slag does not take a solid form; it is in a thin, paste-like state. This phenomenon indicates poor solid-liquid separation, as well as low permeability of the liquid – this may be due to high viscosity. It’s necessary to check whether the solid-liquid ratio is appropriate, and also whether certain ions undergo hydrolysis at this pH level. The PP filter fabric is likely to deform continuously when exposed to temperatures of 90 degrees Celsius
How about producing electrolytic zinc? What raw materials are used in its production? It could be a problem with the liquid; during purification, large amounts of hydrogen oxide colloidal substances are generated. I encountered this issue with a batch of raw materials from Vietnam as well, and it was resolved by adjusting the formula. Another cause could be crystallization on the filter plates – when the filtration outlet is blocked by crystals, it can also lead to residue formation.
It is electrolytic zinc; the raw materials remain unchanged. The only difference is that the zinc powder used has changed from that produced in electric furnaces to spray-dried zinc powder, which is what causes this phenomenon
It has nothing to do with zinc powder; it’s either the raw materials, the processing methods, or the control of technical parameters.