The invention relates to a method for producing a
high concentration composite water purifying agent with multi-ions of
aluminium,
zinc and magnesian. The method is characterized by comprising the following steps of: adding a circulation filtrate and a modifying agent into
aluminium alloy sludge containing multiple metals, mixing them fully, and conducting hydraulic
filtration through a filter plate hydraulic device so as to form a dry
sludge filter cake, which is then delivered to a
pulverizer for pulverizing, thus obtaining dry
sludge; adding an acid into the dry sludge; adjusting the pH value by controlling the adding amount of the sludge; conducting stirring for reaction continuously at a normal temperature to make the dry sludge dissolved completely, thus obtaining a composite water purifying agent (A) with multi-ions of
aluminium,
zinc and magnesian; adding a heavy
metal trapping agent into the obtained composite water purifying agent (A) with multi-ions of aluminium,
zinc and magnesian, continuing to stir the agent and pouring it to a
sedimentation basin, then carrying out
solid-liquid separation with a
filter press. Thus, the
liquid phase is a composite water purifying agent (B) with multi-ions of aluminium, zinc and magnesian, while the
solid phase is a residue of insoluble heavy
metal complexes and insoluble substances. The method of the invention effectively solves the problem of treating the sludge, creates remarkable
economic benefits, and eliminates the risk of environmental
pollution caused by the heavy
metal sludge.