ALUMINA PRODUCTION PROCESS Russian patent published in 2003 - IPC

FIELD: mining industry. SUBSTANCE: invention relates to technology of production of alumina-containing raw material via processing of man-caused wastes, in particular mineral part of brown coal combustion products and can be used in alumina and building industries. Process comprises preparing blend by mixing ash-slag heating-and-power plant waste with limestone, adjusting blend, caking at 1320-1400 C (initial caking temperature does nor exceed 500 C and heating rate is 15 C/min), cooling resulting cake, leaching it with recycling soda solution, lime- milk-mediated single-stage desiliconization of heterophase leaching product and isolation of aluminate solution and sludge, washing the latter, carbonizing aluminate solution to form aluminum hydroxide and recycling soda solution, which is then used to leach cake. Ash-slag waste comes in the form of electrofilter ash and limestone is taken in 28-75% excess to its stoichiometric amount. Aluminum recovery degree achieves 84-87%. EFFECT: enabled environmentally safe conversion of ash-slag waste to yield high-quality alumina at minimum expenses and considerably simplified process. 4 cl, 3 ex