PHOSPHATE RECOVERY FROM SLUDGE

摘要

The invention relates to a method for recovering reusable material, in particular phosphate, from sludge products, namely sludge, sludge ash or sludge scum, by extraction. In said method: the sludge product is suspended in water, alcohol, a water/alcohol mixture or an aqueous solution; gaseous carbon dioxide (CO2) or supercritical carbon dioxide (scCO2) is introduced into the suspension of the sludge product as an extracting agent; undissolved solids are isolated from the liquid suspension agent; carbon dioxide is removed from the suspension agent; and the reusable material dissolved in the suspension agent is precipitated and isolated from the suspension agent.