Soda ash and sodium bicarbonate production method

A soda ash and sodium bicarbonate production method, comprising:

• (S1) solution mining
• injecting water into trona ore to dissolve sodium carbonate and/or sodium bicarbonate to obtain a raw brine 1;
• (S2) pretreatment
• removing solid particles and/or total organic carbon (TOC) in the raw brine 1 to obtain a brine 2;
• (S3) stripping and concentration
• subjecting the brine 2 to stripping to convert most of sodium bicarbonate in the brine 2 to sodium carbonate and concentration to obtain a concentrated brine 3;
• (S4) decahydrate crystallization and separation
• subjecting the concentrated brine 3 to neutralization with a concentrated sodium hydroxide solution, crystallize at low-temperature in a sodium carbonate decahydrate crystallizer and separation to obtain a low liquid residual sodium carbonate decahydrate crystal and a discharge liquid 1;
• (S5) dissolution of sodium carbonate decahydrate
• dissolving the low liquid residual sodium carbonate decahydrate crystal to obtain a dissolved sodium carbonate decahydrate solution;
• and dividing the dissolved sodium carbonate decahydrate solution into two parts, respectively a brine 4 and a brine 5;
• (S6) sodium carbonate monohydrate crystallization, separation and drying
• subjecting the brine 4 to evaporation, concentration, crystallization in a sodium carbonate monohydrate crystallizer and separation to obtain a low liquid residual sodium carbonate monohydrate crystal and a discharge liquid 2;
• drying the low liquid residual sodium carbonate monohydrate crystal to obtain dense soda ash;
• mixing the discharge liquid 2 with the concentrated brine 3 to obtain a mixed solution;
• neutralizing the mixed solution;
• and feeding the mixed solution to the sodium carbonate decahydrate crystallizer followed by crystallization and separation;
• (S7) sodium bicarbonate crystallization, separation and drying
• subjecting the brine 5 to carbonation reaction with carbon dioxide in a sodium bicarbonate crystallizer, cooling, crystallization and separation to obtain a low liquid residual sodium bicarbonate crystal and a discharge liquid 3, wherein the discharge liquid 3 is collected to be used in step (S3) and/or step (S1);
• and drying the sodium bicarbonate crystal to obtain sodium bicarbonate;
• (S8) causticization
• subjecting the discharge liquid 1 and lime milk to causticization, followed by clarification and separation to obtain a low NaOH content solution and causticized sludge;
• and subjecting the causticized sludge to washing and calcination to obtain quick lime to be reused for causticization;
• and
• (S9) evaporation
• subjecting the NaOH solution to evaporation and concentration to remove impurities to obtain a concentrated NaOH solution, wherein the concentrated NaOH solution is used for neutralization of residual sodium bicarbonate in the concentrated brine 3 and discharge liquid 2.