Chemical
Phosphoric acid is a clear, odourless liquid, which is non-volatile. It is slightly viscous with a syrupy consistency when concentrated.
It is typically available in 85% concentration and in more dilute solutions for various commercial and laboratory uses.
Depending on the concentration, the S.G. ranges from 1.3-1.95. At 85% concentration, phosphoric acid is corrosive and extremely harmful to skin and eyes. When diluted the acid may become non-toxic and is suitable for consumption.
Applications
- The majority of phosphoric acid is used in the production of fertilizer where the acid is reacted with the minerals found in phosphate rock to produce phosphate salts.
- For use in rust treatment, phosphoric acid solutions are created as a dipping bath or gel to applied to rusted areas. Phosphoric acid also used for the etching of metal and the roughing of tooth enamel during dental treatments such as root canals and tooth whitening.
- For its sharp, tangy taste, phosphoric acid is used as a flavouring in many soft drinks, typically colas.
- Other uses include pharmaceuticals, cleaning products and as a chemical reagent.
Above Phosphoric acid is often used in the production of soft drinks, particularly colas. Below: A pump casing assembly with o-rings, which are featured throughout the pump to guarantee leak-free operation and protect the workforce and plant equipment.
Pumping considerations
It is strongly recommended using a sealless pump such as a mag drive pump, removing any risk of leakage. The absence of mechanical seals prevents the occurrence of abrasive wear on a seal between the fluid and atmosphere. All mechanical seals require regular inspection, require replacing. By replacing a mechanical seal arrangement with an o-ring assembly the inherent risk of a seal failing is removed.
It is very important to consider the S.G. as it can vary considerably. For specifying a mag drive pump the impeller will need to be trimmed accordingly to prevent the motor from overworking and decoupling.
Metals can be specified however some may incur a short working life. Hastelloy, specifically B-3, G-30 and G-35 are excellent for pumping even concentrated phosphoric acid. Some stainless steel grades are usable, however these may suffer a high rate of corrosion and incur a short working life. As the acid reacts with stainless steel, and vapours can be flammable. A non-metallic lining can be recommended for better chemical resistance.
PTFE, Viton and Kalrez elastomers can be used, though at higher concentrations Buna N and natural rubber should be avoided.
Verder UK supply pumps for virtually every chemical type and application. The Verder range includes leak-free mag drive pumps, chemically inert non-metallic AODD pumps, peristaltic dosing pumps for the accurate delivery of chemical including abrasive and solid-laden types.
For dosing of phosphoric acid, a peristaltic pump can be used with EPDM hose and non-metallic inserts at the flange ports.
