Phosphoric acid

Guichon manufactures valves specially adapted to the production of Phosphoric acid :

Check valve & Sight glasses & Strainers, Ball and plug valve, Globe valve, Tank bottom valve, Gate valve, Butterfly valve

Swing check valve
Type : 902

DN 1/2" to 24" Class 150 to 2500 Lbs

– Stainless and duplex steels, nickel alloys, special alloys (titanium, zirconium)

Sight glass
Type : 803

DN 1/2" to 8" Class 150 to 300 Lbs
– End connections : solid or screwed-on flanges
– Stainless steels or alloys

Ball valve
Type : 302N

DN 3/4"/1"1/2 Class 300 Lbs
– Reduced bore
– Titanium T40


  • Construction materials: Carbon Steel (CS), Stainless Steel (SS), Duplex & Super Duplex, Titanium, Zirconium, Uranus® B6, Tantalum, Nickel, Hastelloy®, Monel
  • Construction methods: Fabricated (Welded), Cast, Solid


  • Service conditions: High pressure, High temperature, Low temperature, Abrasion, Corrosion, High viscosity, Vacuum, Reliability, Low acoustic signature, Dead space free
  • Types of fluids: Liquids, Liquids with solid particles, Gas, Powder and powdery media, High viscosity fluids

FAQ - Phosphoric acid

Phosphoric acid – Uses of Phosphoric acid :

– Manufacture of fertilizers
– Surface treatment of metals
– E338 – acidity regulator / antioxidant / sequestering agent in the food industry
– Cleaning of surfaces (metal, tile, porcelain, …)
– Water treatment, petrochemical catalyst
– Coagulating the latex rubber
– Dyeing in textile industry
– Dental cement …

Posted in: FAQ - Phosphoric acid

Phosphoric acid – Manufacturing process for Phosphoric acid :

Phosphoric acid (H3PO4) can be produced by 3 main commercial methods: wet process, thermal process and dry kiln process. Wet process is by far the most common route and the acid can be used in phosphate fertilizers production (DAP, MAP, SPA). Thermal process phosphoric acid is of a much higher purity and is used in the manufacture of high grade chemicals, pharmaceuticals, detergents, food products, and other nonfertilizer products. The last method, using a rotary kiln, is a promising alternative because of its reduced environmental footprint and potential cost saving.

The concentration of phosphoric acid is normally expressed as % P2O5 (percent phosphoricanhydride) rather than % H3PO4 (percent phosphoric acid).
In a wet process facility (see figure 1), phosphoric acid is produced by reacting sulfuric acid (H2SO4) with naturally occurring phosphate rock. The reaction also forms calcium sulfate (CaSO4), commonly referred to as gypsum. The insoluble gypsum is separated from the reaction solution by filtration.

The operating conditions are generally selected so that the calcium sulfate will be precipitated in either the dihydrate or the hemihydrate form, thus producing 26-32% P2O5 at 70-80°C for dihydrate precipitation and 40-52% P2O5 at 90-110°C for hemihydrate precipitation. Further evaporation of the solvent can be performed for a high-concentration phosphoric acid.

Example of phosphoric acid process

Figure 1. Schematic flow diagram of a wet process plant (phosphoric acid process)

Posted in: FAQ - Phosphoric acid

Phosphoric acid – Recommended valves :

Industrial phosphoric acid solutions are very aggressive due to impurities coming from natural phosphate rocks. Pumps and valves must be made of corrosion resistant alloys such as super-austenitic stainless steel (AISI 904L or Uranus B6, Hastelloy, Incoloy, Inconel) or high chromium content.

Posted in: FAQ - Phosphoric acid