POLY ALUMINIUM CHLORIDE process card 103 - 1/2 1 - The product - Poly Aluminium Chloride (PAC) solution.

The poly aluminium chloride is a polymeric compound of aluminium hydrate variously chlorinated as indicated by the generic formula:

(Aln(OH)mCl3n-m)x

where x is approximately equal to 15. It is produced and marketed as solution with concentration up to 18% of Al2O3.

2 - Production method - The poly aluminium chloride production process lies in the

batch etching reaction of alumina with an acqueous solution of hydrochloric acid.

The reaction takes place in a reactor equipped with internal agitator. During reaction the reactor temperature is controlled and at end of reaction the reaction product is discharged into an holding tank. The discharged product is maintained in agitation and non reacted alumina and insolubles are separated by filtration. The clarified product is transferred into vessels where the product is taken to standard specification. To this scope water, hydrochloric acid, aluminium sulphate can be mixed into the product according to market specifications. A venting system assures the collection of vent discharges for storage tanks and safety valves. The liquid effluents, mainly acid waters, are collected into a holding tank from which they are recycled to the production plant. Using sulphuric acid instead of hydrochloric acid Aluminium sulphate solution can be produced with the same process.

3 - Quality The basic product from the plant will be according the following specifications.

Specifications Poly-aluminium aluminium Chloride( 18%) sulphate - Appearance - clear liquid liquid - Density at 20°C kg/dm3 1.35 - - Viscosity at 20°C Cst 21.6 - - Freezing point °C -20 - - PH at 20°C N° 0,8÷1,2 - - Al2O3 content % 18 8 - Al2O3/Cl ratio max 3.3÷ 3.5 -

Formulations, according to end use requirements, will be obtained by blending the basic product with other formula components.

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POLY ALUMINIUM CHLORIDE process card 103 - 2/2

4 - Consumptions - Referred to one m. ton of finished product. Feedstocks Poly-aluminium aluminium & utilities chloride (18%) sulphate (8%) - Alumina (Al2O3 - 58/62%) kg 300 ÷ 325 145 - Hydrochloric acid (31 ÷33%) kg 680 ÷ 700 - - Sulphuric acid (98%) kg - 242 - Steam (7 bar) kg 250 170 - Cooling water m3 15 16 - Electric power Kwh 35 38 - Compressed air Nm3 16 16

5 - Investment - U.S. Dollars : (quoted on request) - Required area (m. 50x50) : m2 2500 - Type of process : BATCH - Capacity – PAC 18% sol : t/yr 25.000 - Operation (24 hr/day) : 330 days/yr 6 - Use pattern

Water treatment - The poly aluminium chloride (PAC) is used for settling of solid particles present into drinkable waters and for the flocculation of civil and industrial effluents. It has also a high antibactericide effect, due to the presence of chlorine into the product formula, and can be utilized for large range of pH and with higher turbidity. Paper manufacture - The main features of PAC are its high Al2O3 content and polymeric nature, which give rise to products of hydrolysis characterized by a high molecular weight and a large number of positive electric charges able to interact with the cellulose fibres and size, optimizing the sizing phase and the retention of fibres.

7 –Basicity - Simple dilution of PAC 18% allows to obtain a PAC 10% solution showing a

basicity up to 40%. By blending some components to PAC 18% it is possible to produce PAC 9% H.B. a solution with a basicity of 64 ÷ 68% without formation of solid residues as common for other commercial processes which require a filtration. The stability to storage is very good and PH range is 2.6÷3.0. PAC 9% H.B. is recommended for treatment of potable waters whilst PAC 18% is used for waste waters of civil and industrial effluents.