The invention provides a method for the combined production of (I) a sulfur oxide containing product and (II) a fertilizer selected from a group consisting of ammonium nitrate, ammonium phosphates and a combination thereof, through an indirect neutralization of ammonia with an acid selected from the group consisting of nitric acid, phosphoric acid and a combination thereof, the method comprising: a. contacting a precipitate containing calcium sulfite with a solution of nitric acid and a solution of ammonia in two separate steps, to form the fertilizer, the sulfur oxide containing product and a precipitate containing calcium hydroxide; and b. separating at least portion of the fertilizer, the sulfur oxide and the calcium hydroxide into three separated streams.