The choice of material for the reaction tank depends on the chemical nature of the material, the reaction conditions (temperature, pressure), the need for corrosion resistance and cost. The following is a categorised description of common materials and the materials they are suitable for:
metal materials
Stainless Steel
- 304 Stainless Steel
- Properties: general-purpose austenitic stainless steel, resistant to general acid, alkali, salt corrosion.
- Applicable materials: weak corrosive media (such as dilute sulfuric acid, acetic acid), aqueous solutions, organic solvents (ethanol, acetone).
- Industry: food, pharmaceuticals, dyes.
- 316L stainless steel
- Properties: Containing molybdenum (Mo), resistant to corrosion by chlorides and reducing acids.
- Applicable materials: chloride-containing solutions (seawater, brine), dilute sulfuric acid, phosphoric acid, organic acids (such as citric acid).
- Industry: pharmaceuticals, fine chemicals, marine engineering.
- Duplex stainless steel (2205, 2507)
- Characteristics: High strength and resistance to stress corrosion cracking.
- Applicable materials: high chloride ion, high temperature acidic environment (such as oil refining, seawater treatment).
Carbon Steel
- Characteristics: low cost, high mechanical strength, but easy to be corroded.
- Applicable scenes: need to be lined with anti-corrosion coating (such as epoxy resin, rubber) or for non-corrosive media (lubricating oil, non-acidic materials).
- Industry: petroleum, storage and transport.
Titanium and titanium alloy
- Characteristics: resistant to strong oxidising acids (concentrated nitric acid, concentrated sulphuric acid), seawater, wet chlorine gas.
- Not applicable: reducing acid (dilute sulfuric acid, hydrochloric acid).
- Industry: chlor-alkali chemical industry, metallurgy, seawater desalination.
Nickel-based alloys (e.g. Hastelloy, Monel)
- Hastelloy C-276
- Characteristics: high temperature resistant strong acid (concentrated sulfuric acid, hydrochloric acid), chlorine-containing media.
- Applicable materials: strong corrosive acids, mixed acids (such as aqua regia).
- Industry: petrochemical, nuclear industry.
- Monel alloy (Monel)
- Characteristics: Hydrofluoric acid, high temperature alkali.
- Applicable materials: hydrofluoric acid, molten alkali.
Zirconium
- Characteristics: Resistant to concentrated sulphuric acid, hydrochloric acid, organic acid, but expensive.
- Industry: special chemical (such as concentrated sulfuric acid reaction).
non-metallic materials
Enamel
- Characteristics: glass layer acid (except hydrofluoric acid), temperature (-20 ~ 200 ℃), not resistant to strong alkali and sudden temperature changes.
- Applicable materials: hydrochloric acid, nitric acid, organic acids (such as acetic acid).
- Industry: pesticide, dye intermediates.
Ceramic
- Characteristics: high temperature resistance, corrosion resistance, but brittle.
- Applicable materials: high temperature strong acid, molten salt.
- Industry: metallurgy, speciality chemicals.
Plastic (PP/PVC/PTFE)
- Polypropylene (PP): Resistant to room temperature acid and alkali, used for dilute acid and alkali storage tanks.
- Polytetrafluoroethylene (PTFE): Resistant to almost all chemicals, often used as a liner (e.g., strong acids, strong alkalis, organic solvents).
Graphite
- Characteristics: Resistant to hydrochloric acid and phosphoric acid, good thermal conductivity.
- Applicable materials: Strong acid reactions (scenes requiring heat transfer).
Glass fibre reinforced plastic (FRP)
- Characteristics: Lightweight, acid-resistant, but poor temperature resistance (generally <80℃).
- Applicable materials: dilute acid, waste water treatment.
Composite Materials
- Lining material: such as rubber lining, PTFE lining, lead lining, extend the corrosion resistance of the base material (such as carbon steel).
- Applicable scene: strong corrosive but not high pressure environment (such as sulfuric acid storage tanks lined with lead).
the main points of material selection
- Corrosivity: according to the material pH, oxidising/reducing selection (such as titanium or Hastelloy for hydrochloric acid).
- Temperature/pressure: high temperature and pressure need metal materials (such as nickel-based alloys), atmospheric pressure and low temperature can be plastic.
- Cleanliness: 316L stainless steel or glass-lined is preferred for pharmaceutical/food industry.
- Cost: Carbon steel + coatings for economy, Titanium/Hastelloy for extreme conditions.