Patent ID: 7641801
Filing Date: 2010-01-05
Classification: C01G,C01P,C02F,Y10S

Abstract:
1. A method of removing manganese from waste liquor at least containing manganese and magnesium, comprising the steps of: (a) adding a first neutralizing agent to a first mixture of waste liquor and a recycled solution to precipitate a majority of the manganese as manganese-containing solids, without precipitating a substantial amount of the magnesium; (b) separating the manganese-containing solids to form a manganese-depleted solution; (c) oxidizing the manganese-depleted solution formed in step (b) in the presence of recycled seed with an oxidizing agent while adjusting the pH with a second neutralizing agent to form an aqueous solution containing manganese precipitate; (d) transferring the aqueous solution formed in step (c) to a thickener to produce an overflow solution containing a quantity of manganese which is below a predetermined environmental discharge criteria and an underflow solution containing manganese precipitate; (e) discharging the overflow and underflow solutions from the thickener; (f) separating the manganese precipitate from the underflow solution; (g) recycling a portion of the separated manganese precipitate to step (c) as the recycled seed; (h) dissolving a remaining portion of the separated manganese precipitate to form the recycled solution; and (i) transferring the recycled solution to step (a).