Aluminum Chloride Hexahydrate Supplier South Africa

What Is Aluminum Chloride Hexahydrate?

Aluminum chloride hexahydrate (AlCl₃·6H₂O) is the hydrated form of anhydrous aluminium chloride — a white to pale yellow crystalline solid that is hygroscopic and highly soluble in water. On dissolving in water, it hydrolyses to produce aluminium hydroxide species (Al(OH)₂⁺, Al₂(OH)₂⁴⁺, Al₁₃O₄(OH)₂₄⁷⁺ — the Keggin ion) that carry high positive charge. These cationic species are highly effective at neutralising the negative surface charge on suspended particles, clay colloids, and natural organic matter (NOM) in water, causing rapid destabilisation (coagulation) and aggregation into settleable floc.

Coagulation Mechanism and Application

In water and wastewater treatment, coagulation is the first step in suspended solids, turbidity, and NOM removal before sedimentation and filtration. Aluminum chloride hexahydrate dissolves completely and immediately on addition to water, releasing Al³⁺ which hydrolyses to form polynuclear aluminium hydroxide complexes. These react with negatively charged colloids by charge neutralisation (at low dose, in the sweep-floc regime at higher dose where amorphous Al(OH)₃ precipitate enmeshes particles). The resulting floc settles rapidly under gravity and is removed in sedimentation basins or DAF (dissolved air flotation) units. Aluminum chloride is faster-acting than aluminum sulfate (alum) due to higher charge density and faster hydrolysis rate.

Industrial and Process Water Use

Aluminum chloride hexahydrate is used in municipal water treatment, industrial process water clarification, paper and pulp manufacturing (as a sizing precipitant and pitch control agent), and in textile processing. In the paper industry, AlCl₃ is used in rosin sizing to fix rosin size to pulp fibres. In municipal water treatment, it is an alternative to alum (aluminum sulfate) where rapid, higher-charge coagulation is beneficial. It also has applications in antiperspirant formulations (anhydrous AlCl₃ in ethanol-based roll-ons) and as a Lewis acid catalyst in organic synthesis (Friedel-Crafts chemistry). Terracore Chemicals supplies aluminum chloride hexahydrate in 25 kg bags.