Selection Guide for Chemical Pumps: Matching Materials, Environment, and Performance

1. Sulfuric acid: The key to corrosion resistance lies in material selection

For concentrated sulfuric acid with a concentration of over 80% and a temperature below 80 ℃, carbon steel and cast iron have good corrosion resistance, but they are not suitable for high-speed flowing sulfuric acid and are not suitable as materials for pumps and valves; Ordinary stainless steels such as 304 and 316 also have limited applications for sulfuric acid media.

Therefore, pumps and valves for transporting sulfuric acid are usually made of high silicon cast iron (difficult to cast and process) and high alloy stainless steel (alloy 20). Fluoroplastics have good sulfuric acid resistance, and using a fluorine lined pump (F46) is a more economical choice.

2. Hydrochloric acid: Advantages of non-metallic materials

Most metal materials, including stainless steel, do not have good corrosion resistance to hydrochloric acid.

Therefore, non-metallic materials such as lined rubber pumps and plastic pumps (such as polypropylene, fluoroplastics, etc.) have become better choices when transporting hydrochloric acid.

3. Nitric acid: Wide application of stainless steel

Most metals are rapidly corroded in nitric acid, but stainless steel exhibits good corrosion resistance to all concentrations of nitric acid at 80 ℃. Therefore, as long as the overcurrent component is a 304 stainless steel pump, it can meet the demand.

4. Phosphoric acid: the preferred choice for 316L material

Phosphoric acid has strong corrosiveness to metals, and the medium contains large particles. The overcurrent components are generally made of 316L material. Although 904 or 904L are expensive and difficult to process, 316L material has achieved a good balance between cost and performance.