METHOD OF LEAD CROWN PRODUCING Russian patent published in 2003 - IPC

FIELD: technology of pigment production. SUBSTANCE: invention relates to production of lead crown used in paint and varnish industry. Method involves production of lead crown from the spent chrome-containing solution as chrome-containing waste from galvanic manufacture purified from metal impurities by passing gaseous hydrogen sulfide from it. Lead and its oxides obtained in utilization of depleted accumulator are used as Lead-containing component. Lead and its oxides are treated firstly with nitric acid and then with mixture of acetic acid and sodium acetate followed by addition of prepared chrome-containing solution and sodium carbonate to prepared solution at stirring, required temperature and with required exposition. Process is carried out up to the complete dissolving solid components. Obtained suspension is settled, filtered and precipitate is washed out with water and dried. Prepared crown exhibits the composition with indices corresponding to All-Union State Standard (AUSS) 478-80. Method provides decrease of energy consumption in parent solutions preparing. EFFECT: improved and simplified method. 7 cl