ABSTRACT
The proposed process basically combines two decades old processes (Solvay and Dow Magnesium) for the manufacture of soda ash and magnesium, respectively into a single process that also produces “partially-desalinated” water. It does so by subjecting salt brines first, to ammonia causing two simultaneous actions: 1) the absorption of ammonia forming what is called “ammoniated brine”, and 2) the precipitation of magnesium ions, found in the brine, as magnesium hydroxide, Mg(OH)2, which is filtered and separated. Next, carbon dioxide is introduced through the bulk of ammoniated brine, brine saturated with ammonia, causing the chemical conversion of both Na+ and Cl﹣ into NaHCO3 and NH4Cl, respectively. Soda ash (Na2CO3) and ammonium chloride (NH4Cl) come as products, along with partially desalinated water. This process is identified as “brine desalting”, because of the drastic reduction of the salt content in brine. This part was experimentally tested before by the author and coworkers. Magnesium chloride (MgCl2) is obtained, next, by reacting ammonium chloride (NH4Cl) with Mg(OH)2. In this double reaction, ammonia will be regenerated and recycled back to the process: 2NH4Cl Mg(OH)2 à Mg(Cl)2 2NH3 2H2O. Magnesium chloride is the raw material for making magnesium metal. This makes an additional economic value to the proposed process. The present contribution offers this conceptual scheme as an amalgamation of both Solvay/Dow (Magnesium) processes.