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PP Filter press application for caustic soda (NaOH)
Apr 13, 2018

PP Filter press are widely used for chemical engineering. Because filter part is pp material, which has very stable chemical performance. Besides that, pp filter press also has outstanding cost advantages and it's easy to operate and maintain. For example, while caustic soda (NaOH) manufacturing, pp filter press is the necessary dewatering equipment.

Caustic soda, namely NaOH, is a strong alkali with causticity. Commonly it's a state of piece or lump and easily dissolve in water to form alkaline solution. It has wide usage, such as, making soap, refined petroleum, paper making, water treatment, textile and dyeing field etc... For industry, it has three methods to get NaOH: causticization, membrane electrolysis and ion exchange membrane. Causticization is the most popular method. Why use our pp filter press in the NaOH process? Let's take causticization as example.

What's causticizing? The product is caustic soda, so it's named causticizing. It's a process to get NaOH from the reaction of Na2CO3 and Ca(OH)2. After clarification, evaporation and concentration, the final causticizing liquid will be made into liquid NaOH and solid NaOH. The chemical formula likes this, Na2CO3+Ca(OH)2= 2NaOH+CaCO3↓. While the reaction, CaCO3 will precipitate. In order to get pure NaOH, so it uses our pp filter press to remove calcium carbonate.

While pp filter press operation, following points should be attended. First, solid percentage. For final causticizing liquid (the mixture of NaOH and CaCO3), normally it has lower solid content at 2-4%. As a pp filter press manufacturer, we suggest customer to improve the solid percentage, thus it can save cost and improve filter efficiency and effect. Second, temperature. Caustic soda solution has high temperature, so if the condition allows, it will be better after cooling. Third, for NaOH, we know, it's a strong alkali, which has corrosion, so it needs to notice the corrosion resistance when pp filter press recommended. Additionally, if you want to know more information about chemical filter press, please contact us now. 

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