Patent ID: 8388916
Filing Date: 2013-03-05
Classification: C05C,C22B,Y02P

Abstract:
1. A continuous method for producing KNO 3 from raw polyhalite, said method comprising steps of: washing raw polyhalite; heating said washed polyhalite; contacting said washed and heated polyhalite with water to produce decomposition products comprising K separating at least one solid product from said first solution; contacting at least a portion of said at least one solid product separated from said first solution with a quantity of HNO contacting said slurry with an alkaline Ca compound to precipitate sulfate as gypsum; filtering said contacted slurry to obtain a filtrate; washing gypsum obtained in the preceding steps; concentrating the filtrate obtained in said step of filtering the product of said step of contacted said slurry with an alkaline Ca compound; separating at least part of any CaSO separating KNO adding an alkaline Ca compound to the third solution; and, separating at least part of any Mg(OH)