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Sulfuric acid storage tanks, as specialized equipment for storing highly corrosive chemicals, play an important role in the industrial sector. Its material selection and anti-corrosion measures are key factors in ensuring safe production. During the long-term storage of sulfuric acid, the materials used for storage tanks are faced with significant challenges; they must not only withstand the strong corrosive effects of sulfuric acid but also resist external factors such as pressure and temperature. Research on the material selection and anti-corrosion measures for sulfuric acid storage tanks is crucial. 1. Carbon steel – Suitable for concentrations of concentrated sulfuric acid above 70%. - Temperature range: room temperature to about 50°C. - Basis: Concentrated sulfuric acid forms a dense layer of ferric sulfate (Fe₃O₄) passivation film on the surface of carbon steel, preventing further corrosion. The reaction equation is: concentrated It is generally assumed in middle school that this is formed after iron passivation. But in reality, the product formed has an extremely complex composition, which is related not only to the ratio of x and y but also closely tied to the crystal structure. These factors can all vary depending on conditions such as the type and concentration of acid, as well as temperature, which in turn causes the values of x and y to differ as well. At concentrations of over 70%, the corrosion rate is usually below 0.1 mm/year. - Usage restrictions: Dilute sulfuric acid (with a concentration of less than 70%) can destroy the passivation film, leading to rapid corrosion; the corrosion rate may exceed 1 mm/year. When the temperature is above 50°C, the stability of the passivation film decreases, and the corrosion rate increases significantly. 2. Stainless steel – Suitable concentrations: dilute sulfuric acid (concentration below 10%) or certain moderate-concentration sulfuric acids. - Temperature range: room temperature to about 80°C. - Common grades: 304 stainless steel: Suitable for use in low-concentration sulfuric acid (50%) or at high temperatures (>80°C), where the passivation film is damaged and the corrosion rate increases significantly. - Usage restrictions: Not suitable for high-concentration sulfuric acid or high-temperature environments. 3. Plastic – Suitable concentration: dilute sulfuric acid or medium-concentration sulfuric acid. - Temperature range: room temperature to about 60°C (depending on the material). - Common materials: Polypropylene (PP): Suitable for sulfuric acid with concentrations below 50%; the corrosion rate is extremely low. At 70%, it may cause corrosion in certain plastics. 4. Fiberglass Reinforced Plastic (FRP) – Suitable concentration: dilute sulfuric acid or medium-concentration sulfuric acid. - Temperature range: room temperature to about 80°C. - Basis: Fiberglass-reinforced plastic is composed of resins (such as epoxy resin and vinyl ester resin) and glass fibers, and its corrosion resistance depends on the type of resin. Vinyl ester resins are suitable for sulfuric acid at concentrations below 50%, with an extremely low corrosion rate