Patent ID: 6022406
Filing Date: 2000-02-08
Classification: C01P,C08K,C09C,C09D,C22B,Y02P

Abstract:
A method of preparing zinc ferrite containing inorganic pigments from foundry dust, the method comprising the following steps:a) separating the dust into two fractions, a fraction comprising magnetic elements and a fraction comprising non-magnetic elements;b) subjecting the non-magnetic fraction to a basic leaching reaction to dissolve a fraction of zinc that is not bound in the form of spinel, silica, lead, and a fraction of manganese;c) rinsing the resulting solid material to neutrality, and separating it out;d) calcining the resulting material at a temperature lying in the range of 450.degree. C. to 650.degree. C.;e) processing the calcined material in sulfuric acid in the presence of a catalyst, the catalyst dissolving iron oxides formed during the calcination step and heavy metals other than zinc; andf) recovering inorganic pigments.