摘要:
The invention is directed to a process for the production of sodium carbonate-anhydrate having a bulk density of at least 800 kg/m3, said process comprising: providing a suspension of solid sodium carbonate and/or solid sodium bicarbonate and/or solid double salts at least comprising one of sodium carbonate and sodium bicarbonate, in a mixture containing water and an organic, water miscible or partly water miscible solvent, which solvent influences the transition temperature below which sodium carbonate monohydrate is stable, whereby the type and the amount of solvent is selected in such way that the said transition temperature is below the boiling point of the said mixture of water and an organic, water miscible or partly water miscible solvent, in case sodium bicarbonate is present, converting the bicarbonate into carbonate, crystallising sodium carbonate anhydrate from said mixture at a temperature above the said transition temperature and below the said boiling point, and recovering the sodium carbonate anhydrate.
摘要翻译:本发明涉及生产体积密度为至少800kg / m 3的无水碳酸钠的方法,所述方法包括:提供固体碳酸钠和/或固体碳酸氢钠和/或固体双重盐的悬浮液 至少包含碳酸钠和碳酸氢钠之一,在含水和有机,水混溶或部分水混溶性溶剂的混合物中,该溶剂影响低于该转化温度的碳酸钠一水合物是稳定的,由此溶剂的类型和量 选择以使得所述转变温度低于所述水混合物和有机的,水混溶性的或部分水混溶性溶剂的沸点,在存在碳酸氢钠的情况下,将碳酸氢盐转化为碳酸盐,结晶的碳酸钠水合物 在高于所述转变温度并低于所述沸点的温度下从所述混合物中回收 e碳酸钠无水物。
摘要:
A thick suspension of sodium carbonate anhydride is obtained by countercurrent contacting of a high pressure steam and a suspension of sodium bicarbonate or sodium sesquicarbonate in a concentrated solution of sodium carbonate. The decomposition reaction is promoted to near completion by maintaining the reaction temperature above 150.degree. C. to realize a high HCO.sub.3.sup.- ion concentration in the solution. The sodium carbonate anhydride suspension is cooled to cause transition of the anhydride to the monohydrate, followed by the separation of the crystalline monohydrate from the mother liquor. Calcination of this monohydrate gives a dense soda ash featuring a high purity and a uniform particle size, while the mother liquor is recycled for the preparation of the sodium bicarbonate suspension.
摘要:
In the process of making sodium carbonate from trona by the method involving crushing the trona, calcining it and dissolving it in an aqueous medium for purification by crystallization, soluble silicate contamination of the crystallization liquor is reduced by an improvement which involves: (a) segregating the calcined trona into a coarse and a fine fraction; (b) separately dissolving the coarse and fine fractions to obtain aqueous solutions of sodium carbonate, sodium silicates and insoluble impurities; (c) optionally adding to the solution of the fine fraction insoluble impurities which have been separated from a solution of such fine fraction in a previous operation; followed by (d) digesting the solution of the fine fraction containing added insolubles at elevated temperature to insolubilize soluble silicates and separating the digested solution from insoluble impurities.