How should I choose a concentrated sulfuric acid pump?

Sulfuric acid is widely used in industries such as the chemical sector. Carbon steel and cast iron materials generally exhibit good corrosion resistance to concentrated sulfuric acid; this is because iron forms a protective layer of ferric sulfate on its surface, which does not dissolve easily. Therefore, at room temperature, for concentrated sulfuric acid with a concentration of over 90%, manufacturers, considering economic factors, usually prefer to use cast iron materials. But strictly speaking, carbon steel and cast iron are not suitable for sulfuric acid flowing at high speeds; therefore, they cannot be used as materials for sulfuric acid pumps ； Stainless steels 304 (OCrl8Ni9), 316 (OCrl7Ni12Mo2), and 316L (OCrl8Ni12Mo2Ti) are also not ideal materials. In terms of material, nickel cast iron (STNiCr202), Hastelloy (a nickel-chromium-titanium-molybdenum alloy), and similar materials are suitable for transporting sulfuric acid. However, materials such as nickel cast iron are difficult to manufacture and process and come at high costs, which is why they are also excluded. Fluoroplastics exhibit excellent resistance to sulfuric acid; therefore, using fluorinated pump (F46) is an economical and reliable option. When transporting dilute sulfuric acid, high temperatures may occur. For such conditions, the material used in the pump was modified. Repeated tests have shown that PFA (soluble polytetrafluoroethylene) possesses excellent temperature resistance; using PFA instead of FEP (perfluoroethylene propylene) can increase the pump’s temperature tolerance by 15–20 degrees, allowing it to reach temperatures of up to 120 degrees. Therefore, users should also take into account the temperature of the medium when selecting a pump. Sulfuric acid of different concentrations has varying specific gravities; the specific gravity of 98% concentrated sulfuric acid is approximately 1.84 (T/m3). Therefore, the power required for its use also varies, and it can be calculated using the following formula: Required power = Current power × Specific gravity × 80%

If the pressure requirements are not high, a plastic pneumatic diaphragm pump can be used

The selection needs to be based on the specific requirements regarding flow rate and head.........For more details, contact me via QQ at 540992489 or by phone at 13636561438

For concentrated sulfuric acid, a regular corrosion-resistant pump is sufficient

It’s better to choose a fluorinated magnetic pump. Mechanical seals leak, and concentrated sulfuric acid absorbs moisture, causing severe corrosion. I’ll send you some information for reference.

Your question isn’t quite clear! For sulfuric acid pumps operating at temperatures below 120°, vertical pumps with the Lewis structure design from the United States are generally the preferred choice! If it’s over 120°, then a super-high-temperature concentrated sulfuric acid pump is required, and it too is vertical! Horizontal pumps are generally not chosen because sealing issues are difficult to resolve! And the problem with magnetic pumps is that their materials are of poor quality!

Based on my experience, it is recommended to use silicon cast iron pumps – they are economical, reliable, and resistant to corrosion.

When choosing an electric pump, there are concerns related to mechanical seals; therefore, if the flow rate is not high, a pneumatic diaphragm pump should be used. For dilute sulfuric acid, polypropylene is used as the material for the casing, while for concentrated sulfuric acid, Teflon or polyvinylidene fluoride is used as the material for the casing

In fact, transporting concentrated sulfuric acid is a very tricky problem. What is the specific value for concentrated sulfuric acid? 70%, 99%? 99% concentrated sulfuric acid is an excellent choice. 70% concentrated sulfuric acid is not a very good choice; it would be best if the poster could provide more details about the operating conditions, such as flow rate, head, etc. For low flow rates, I recommend using pneumatic diaphragm pumps – the WILDEN brand is a good option, with PVDF material enclosures

The main difficulty lies in temperature. Any pump can be used at room temperature. High temperatures require solutions from specialized pump manufacturers.

A magnetic pump is not necessary; it’s better to use a pump with a steel lining and PTFE coating. If a metal material is used, concentrated sulfuric acid can absorb moisture and turn into dilute sulfuric acid when the pump stops operating, thereby corroding the metal body of the pump

If possible, choose a vertical model – it won’t leak. Sulfuric acid is a hazardous substance, and vertical models have a longer service life. Jingjiang Yufeng

For our low-flow sulfuric acid pumps, we use F46 fluoropolymer alloy pumps; cast iron pumps are no longer used. However, it depends on whether the operation is continuous or intermittent, as 98% sulfuric acid tends to absorb moisture and causes severe corrosion of pipes, so continuous operation provides better reflux effects.