The present invention relates to a process for producing sodium bicarbonate crystals. Sodium carbonate derived from TRONA ore is mixed with a treated mother liquor produced in a downstream process to form a sodium carbonate solution. The sodium carbonate solution is subjected to a crystallization process that produces sodium bicarbonate crystals. The sodium bicarbonate crystals are separated from the sodium carbonate solution to form a mother liquor that includes silica. To remove the silica in the mother liquor, the mother liquor is directed to a reactor where an aluminum salt is mixed with the mother liquor to precipitate hydrous aluminum oxide which adsorbs silica thereon. The hydrous aluminum oxide with adsorbed silica is removed from the mother liquor. This produces the treated mother liquor that is mixed with the sodium carbonate and which forms the sodium carbonate solutions.