Process for the joint production of sodium carbonate and sodium bicarbonate

A process for producing sodium carbonate and sodium bicarbonate in a continuous mode from trona, comprising the following steps:

• c. feeding crushed trona, extraction water and an additive in a first leaching tank containing a dissolution solution comprising sodium carbonate and sodium bicarbonate, saturated or super-saturated in sodium bicarbonate, wherein the additive is selected from the group consisting of:
• anionic hexametaphosphate, anionic polyphosphate, anionic polyphosphonate, soja lecithine, anionic polycarboxylate polymer, anionic polyacrylate polymer, anionic polyacrylate-polyacrylamide co-polymer, anionic hydrolyzed polymaleic polymers, anionic maleic-acrylic acids copolymers, anionic acrylic acid-phosphonic acid copolymers, and combinations thereof;
• d. dissolving at least partially the crushed trona in the dissolution solution in order to produce a first suspension comprising solid particles comprising sodium bicarbonate and a first solution comprising sodium carbonate;
• e. removing continuously the first suspension from the first leaching tank to obtain a removed first suspension, and feeding the removed first suspension and an additive into a second leaching tank, wherein the additive fed to the second leaching tank is the same or different than the additive fed to the first leaching tank, and wherein the additive fed to the second leaching tank is selected from the group consisting of:
• anionic hexametaphosphate, anionic polyphosphate, anionic polyphosphonate, soja lecithine, anionic polycarboxylate polymer, anionic polyacrylate polymer, anionic polyacrylate-polyacrylamide co-polymer, anionic hydrolyzed polymaleic polymers, anionic maleic-acrylic acids copolymers, anionic acrylic acid-phosphonic acid copolymers, and combinations thereof;
• f. dissolving at least partially the crushed trona remaining in the removed first suspension from step e) in the dissolution solution present in the second leaching tank in order to produce a second suspension comprising second solid particles comprising sodium bicarbonate and a second solution comprising sodium carbonate;
• and
• g. separating the second solid particles from the second solution to produce a production solution comprising sodium carbonate and to produce a production solid comprising the second solid particles, said second solid particles comprising sodium bicarbonate.