PAC (Polyaluminum Chloride) Supplier South Africa

What Is Polyaluminium Chloride?

Polyaluminium chloride (PAC) is a pre-hydrolysed inorganic polymer coagulant of general formula Aln(OH)mCl(3n−m). Unlike alum (Al₂(SO₄)₃), which hydrolyses in-situ on addition to water, PAC is manufactured as a pre-polymerised product containing high-charge polynuclear aluminium hydroxide clusters — principally the Keggin-ion Al₁₃O₄(OH)₂₄⁷⁺ — already formed at the factory. This pre-hydrolysis means PAC delivers a high-charge, high-molecular-weight aluminium coagulant species immediately on contact with raw water, without the need for the slow hydrolysis reaction that limits alum performance at low temperatures (< 5°C). PAC produces compact, rapidly settling floc with lower sludge volume than alum, and is effective across a wider pH range (5–9).

Advantages Over Conventional Alum

PAC offers several performance advantages over alum (aluminum sulfate): lower effective dose (typically 30–50% less Al by weight for equivalent turbidity removal), better floc formation at low water temperatures, lower sludge volume (less Al(OH)₃ sludge per unit Al dosed), reduced alkalinity depression of treated water (PAC is pre-hydrolysed and consumes less alkalinity than alum), and faster floc formation that can increase clarifier throughput. The higher basicity of PAC reduces pH depression and alkalinity consumption — an important advantage in low-alkalinity waters where alum addition drives pH below the effective coagulation range without lime supplementation. PAC liquid is also easy to dose as a solution without the dissolution step required for dry alum.

Application in Water and Wastewater Treatment

PAC is used in municipal drinking water treatment (turbidity, NOM/DOC, colour removal), industrial process water clarification, and wastewater treatment. In drinking water, PAC is particularly preferred for treating cold, low-turbidity, high-NOM surface waters in winter conditions where alum performs poorly. In paper manufacturing, PAC is used for paper sizing retention, pitch control, and fibre flocculant applications. In textile effluent treatment, PAC removes dye, colour, and suspended solids. PAC powder (28–30% Al₂O₃) is used where dry chemical dosing systems are in place. Terracore Chemicals supplies PAC liquid and PAC powder in various pack sizes for water treatment applications across Southern Africa.