Calcium Hydroxide (Hydrated Lime) Supplier South Africa

What Is Calcium Hydroxide?

Calcium hydroxide (Ca(OH)₂, hydrated lime, slaked lime) is an inorganic base produced by hydrating quicklime (calcium oxide, CaO) with water. It is supplied as a fine white powder and is sparingly soluble in water (lime saturation: ~1.7 g/L at 20°C) but produces a strongly alkaline solution (pH ~12.4). Calcium hydroxide is the most widely used and most cost-effective alkaline chemical in water treatment — it is used to raise pH, precipitate heavy metals and phosphate, soften water, stabilise sludge, neutralise acid wastewater, and treat acid mine drainage (AMD).

Water Treatment and pH Adjustment

In municipal water treatment, lime softening uses calcium hydroxide to raise pH to ~10–11, precipitating calcium carbonate (from dissolved CO₂ and bicarbonate reaction) and magnesium hydroxide, reducing water hardness. In potable water treatment, lime is used to adjust the Langelier Saturation Index, balancing water so it is neither corrosive nor scale-forming in the distribution system. In wastewater neutralisation, lime is the preferred reagent for neutralising acidic wastewater from plating, semiconductor, chemical manufacturing, and mining operations due to its low cost and effectiveness across a wide acid neutralisation range.

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Acid mine drainage (AMD) treatment is the largest single application for hydrated lime in Southern Africa. AMD from sulphide ore mines and tailings is typically highly acidic (pH 2–4) and laden with dissolved iron, manganese, aluminum, zinc, copper, and other heavy metals. Lime dosing raises pH to 9–11, precipitating these metals as hydroxides and carbonates that settle in settling ponds or clarifiers and are removed as sludge. Terracore Chemicals supplies hydrated lime in 25 kg bags, 1 MT bags, and bulk tanker delivery for water treatment, wastewater, and mining operations across Southern Africa.