| 摘要 |
The invention relates to aluminium-chloride compositions for water-purifying, sludge-dewatering and plant-dewatering purposes, comprising a clear, stable aqueous solution of aluminium chloride containing polynuclear complexes of the kind Alm(OH)n(3m-n)+ where m and n are positive integers. The composition is characterized in that it contains ions of alkali metal and/or alkaline earth metal in an amount which stoichiometrically substantially corresponds to the OH-content of the solution, and in that the total aluminium content is between about 0.3 and about 2 mole per liter. At least 40% of the total aluminium content of the solution may be present in the form of said polynuclear complexes. The invention also relates to a method for producing the composition, in which method a carbonate or hydrocarbonate, alkali metal or alkaline earth metal and an aluminium chloride are brought into aqueous solution. The amount of aluminium chloride is selected so as to obtain in the solution a total aluminium content of between about 0.3 and about 2 mole per liter, and the amount of carbonate or hydrocarbonate is selected so that, in relation to the amount of aluminium chloride, a given highest ratio is obtained between the number of moles of OH and the total number of moles of aluminium in the resultant solution at the desired given aluminium content of the solution.
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