Zinc Sulfate

Zinc sulphate (ZnSO4; heptahydrate CAS 7446-20-0, monohydrate CAS 7446-19-7) is supplied by Global Chemicals LLC in two hydrates from stock in Muscat: the heptahydrate (ZnSO4·7H2O, 21–23% zinc, 98% minimum purity, the agricultural standard) and the monohydrate (about 33% zinc, used where a more concentrated, free-flowing granule is wanted), in 25 kg and 50 kg bags and big bags. Both are white crystalline powders or granules, highly soluble in water, with a 5% solution at pH 4–6.

Agriculture is the main market. Zinc deficiency is widespread in Oman's alkaline, calcareous, low-organic-matter soils, where the available zinc is locked up at high pH, and it shows as small, narrow, chlorotic leaves and short internodes on date palm, citrus, mango, vegetables and wheat. Zinc sulphate corrects it three ways: a soil application of about 5–10 kg of zinc per hectare (roughly 25–45 kg of heptahydrate or 15–30 kg of monohydrate), worked in or banded, which lasts two to three seasons; a foliar spray of 0.2–0.5% with a little hydrated lime or a wetting agent to prevent leaf scorch, which acts within days; or fertigation, where it dissolves cleanly and can be injected with other sulphate fertilizers but not with phosphate or calcium concentrates. Feed mills use it as the zinc source in animal mineral premixes.

Industrial uses: a cathodic corrosion inhibitor in cooling-water programmes, where 1–3 mg/L of zinc forms a protective film on steel; a component of zinc phosphating baths and electroplating electrolytes; the coagulating bath of rayon fibre; wood preservation; a mordant in textile dyeing; and an intermediate for other zinc chemicals. Pharmaceutical zinc sulphate is a separate grade and is not what this page describes.

Handling: zinc sulphate is harmful if swallowed, irritates eyes, and is toxic to aquatic life, so keep spills out of drains and watercourses. Store bags closed and dry; the heptahydrate loses water and cakes in heat, and the solution is mildly acidic to mild steel, so use plastic or stainless tanks. Every lot carries a certificate of analysis giving zinc content, purity and insolubles, and a GHS safety data sheet.

Delivery is same day within Muscat, next day to Sohar, Nizwa, Salalah and Duqm, and by road across the GCC with a certificate of origin. Request a quote with the hydrate, grade, tonnage and delivery point.