Fluorosilicic Acid Supplier South Africa

What Is Fluorosilicic Acid?

Fluorosilicic acid (hexafluorosilicic acid, H₂SiF₆) is a strong inorganic acid — a clear to slightly yellow aqueous solution with a sharp, pungent odour, available commercially as a 20–25% solution. It is the most widely used and most cost-effective chemical for fluoridating municipal drinking water. In the water supply, fluorosilicic acid immediately dissociates and hydrolyses: H₂SiF₆ → 2H⁺ + SiF₆²⁻, and SiF₆²⁻ + 4H₂O → Si(OH)₄ + 6F⁻ + 4H⁺ (in dilute aqueous solution at the pH of treated drinking water). The fluoride ion (F⁻) is the active species providing the public dental health benefit. Fluorosilicic acid is preferred over sodium fluoride (NaF) and sodium fluorosilicate (Na₂SiF₆) for large-scale municipal fluoridation because it is a liquid — it is easy to pump and dose without the dissolution step required for solid fluoride chemicals.

Фторирование питьевой воды

Fluoridation of municipal drinking water at 0.7 mg/L F⁻ (the current WHO and SANS recommendation for South Africa and most international guidelines) prevents dental caries (tooth decay) — one of the most cost-effective public health interventions demonstrated by decades of epidemiological research. Fluorosilicic acid is the dominant fluoridation chemical globally (used in ~80% of fluoridated water systems in the USA) and is widely used in South African municipal water systems. It is dosed by chemical metering pump into the treated water downstream of all other treatment steps (post-chlorination) or into the treated water reservoir. Dosing is controlled to maintain 0.7–1.0 mg/L F⁻ in the distribution system, verified by continuous fluoride monitoring. Fluorosilicic acid is classified as a hazardous corrosive liquid — it requires chemical-resistant dosing equipment (HDPE or stainless steel tanks, Teflon-lined pumps and pipework) and appropriate handling and PPE protocols.

Industrial Fluoride Source Applications

Beyond drinking water fluoridation, fluorosilicic acid is used industrially as a fluoride source in cement manufacturing (to lower clinkering temperature), as a ceramic and enamel flux (glass etching), in the production of sodium fluoride and aluminium fluoride (by reaction with sodium carbonate or aluminium hydroxide respectively), in metal surface treatment (phosphating baths), and in the manufacture of magnesium fluorosilicate for concrete hardening. In wood preservation, fluorosilicate compounds have been used as timber preservatives. Terracore Chemicals supplies fluorosilicic acid in IBC containers and tanker deliveries, with full MSDS, handling documentation, and compliance information for South African drinking water standards. Bulk and contract supply to municipalities is available.