METHOD OF SELECTIVELY RECOVERING PHOSPHATES FROM SEWAGE SLUDGE ASH

摘要

There has been the need for a technology which can selectively isolate/purify and collect phosphates from sewage sludge ash containing toxic materials including heavy metals. The present invention relates to a method of recovering phosphates from sewage sludge ash, and more specifically, to a method of recovering phosphates in an efficient manner by sequentially performing acid pretreatment, alkali elution, and calcium salt treatment. According to the method of the present invention, when sewage sludge ash is subjected to an acid pretreatment, calcium is released first, and phosphates are bound to aluminum; in a phosphate release step, phosphates contained in solid matters are released in a liquid form; and in a phosphate recovery step, phosphates released in an overlying solution are recovered in an efficient manner in usable forms such as hydroxylapatite and calcium phosphate, and bioavailability of phosphates are increased. Additionally, unlike conventional time-consuming SESALPHOS process, the method of the present invention can release calcium first and recover phosphates in useful forms over a relatively short period of 30 minutes.;COPYRIGHT KIPO 2017