METHOD FOR THE PRECIPITATION OF ARSENIC AND HEAVY METALS FROM ACIDIC PROCESS WATER

The invention relates to a method for the precipitation of arsenic and heavy metals from acidic, in particular sulphuric acid, process water (12), containing both arsenic and heavy metals, comprising a precipitation method phase (II) with a precipitation stage (D) in which arsenic and at least one primary heavy metal are precipitated together, wherein a sulphide precipitating agent (20) is added to the process water (12) such that arsenic is precipitated as arsenic sulphide and the at least one primary heavy metal is precipitated as metal sulphide. The precipitation method phase (II) comprises a conditioning stage (C) which is carried out before the precipitation stage (D) and in which a conditioning agent (16) is added to the acidic process water (12), which has an effect on the character, in particular the filtering properties, at least of the precipitated arsenic sulphide.