Tannic Acid Powder

Tannic acid is a natural polyphenol (C76H52O46) supplied by RXSOL as a reddish-brown, non-dusting powder with 50–60% tannin content, moisture 10–12%, ash 4–6%, bulk density 0.71 g/ml and very high cold-water solubility (800 g/L). On steel it reacts with rust to form a stable blue-black iron tannate — the chemistry behind rust-converter primers — so it is used both as a rust converter and as a corrosion inhibitor before painting. It is also a vegetable tanning and dyeing agent for leather and textiles, and an astringent in veterinary and feed products.