1. In metal and electronic technical industry more than 50 000 tons hydrochloric (HCI) used as mordant acid for cleaning metals before further surface treatment. Afterwards the waste Hydrochloric is discharged to public waters. Not the Hydrochloric in the aquatic environment but in particular the heavy metals which are dissolved in the hydrochloric are threatening the ecology of the public water. 2. In aluminium processing industry 35.000 tons of aluminiumtrihydroxyde (Al(OH)3) is released from mordant bathes. This Al(OH)3 is sold as dephosphatation and sedimentation aid for the purpose of waste water treatement. An overdoses of aluminium compounds in aquatic environment can be build up as environmental strange aluminates. 3. The reagent AlCl3 derived from the above mentioned problematical waste substances HCl and Al(OH)3 could be a valuable substance as coagulent and sedimentation aid. It can replace coagulants derived from raw materials like FeCl3 and virgin AlCl3. The reaction conditions of HCl with Al(OH)3 can be chosen at which the heavy metals contamination will be sedimentated and removed from the remaining AlCl3 solution. 4. The annual savings using waste aluminium solutions instead of ferro solutions for the purpose of dephosphatation and coagulation for sewage treatment counts only in the Benelux countries, 62.500 kECU and 430.000 m3 8% AlCl3. 5. After addition of AlCl3, waste Al(OH)3 can be dosed to sewage treatment plants as heavy metals sedimentation aid, and moreover as dephosphatation aid.
Funding SchemeEAW - Exploratory awards
6136 KN Sittard