Polyaluminium Chloride Technology

Polyaluminium chloride (PAC) is increasingly used for water treatment. Against the conventional use of aluminium sulphate (alum) it is showing distinct advantages.
A polyaluminium chloride plant is an investment opportunity with attractive returns in a growing market.

ENCO ENGINEERING in co-operation with a European licensor is now in a position to offer plants for the production of polyaluminium chloride, with an up-to-date, efficient technology.


The production process for polyaluminium chloride is including the following reaction steps:




Depending on reaction conditions products with different characteristics are obtained. For the production of polyaluminium chloride 9% special auxiliaries and catalysts are used.


The proposed improved PAC process is giving the following advantages against a conventional process:

PAC with a concentration of 18 % Al2O3 (1-2 % higher)

PAC with a higher basicity

Low production cost

No by-products (no acidic calcium sulphates)


A typical plant capacity for a polyaluminium chloride production plant is 30'000 tons per annum.


Polyaluminium chlorides are synthetic polymers dissolved in water. They react to form insoluble aluminium poly-hydroxides which precipitate in big volumetric flocs.The flocs absorb suspended pollutants in the water which are precipitated with the PAC and can together be easily removed.

PAC can be used as a flocculant for all types of water treatment treatment, drinking water, industrial waste water, urban waste water and in the paper industry.

The possible slightly higher unit price of PAC is compensated by a

  • lower dosage requirement
  • no requirement for any neutralising agent (soda, lime)
  • shorter flocculation time
  • smaller amount of sludge
  • reduced number of back washing steps
  • higher quality of the treated water.

Polyaluminium chloride 18% Al2O3

Appearance liquid with yellow colour
Al2O3 content 17-19 %
Cl 21-22 %
Basicity 36-42 %
Specific Weight at 20 C 1.36-1.38 g/ml
pH 0.4 - 1.2
Solidification Point -10 C

Applications: PAC 18% Al2O3 can be used for most applications.

Polyaluminium chloride 9% Al2O3

Appearance liquid with yellow colour
Al2O3 content 8.8-9.2 %
Cl 9.8-11 %
Basicity 62-68 %
Specific Weight at 20 C 1.18-1.22 g/ml
Solidification Point -10 C

Applications: PAC 9% Al2Ohigh basicity is mostly used  for drinking water treatment. With its use no polyelectrolytes, fungicides etc. will be required for the treatment.


For more information send us an e-mail !

ENCO Engineering GmbH Switzerland enco@enco.ch

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