Förfarande och system för att tillverka utfällt kalciumkarbonat

摘要

A method for manufacturing precipitated calcium carbonate (PCC) comprises the steps of increasing the pressure and temperature of a stream containing oxidizable material and water; causing the stream to flow in a first reaction chamber system; adding oxidant to the first reaction chamber system, oxidizing the oxidizable material of the stream through supercritical water oxidation (SCWO) to form carbon dioxide and water; causing the stream to leave the first reaction chamber system; causing the stream to flow in a second reaction chamber system; adding lime to the second reaction chamber system so that the carbon dioxide of the stream and the lime react to form PCC; and thereafter reducing the pressure of the stream. Preferably, the stream is a deinking sludge, wherein the method improves the brightness of paper filler recovered from the deinking sludge by means of precipitating PCC onto the paper filler.