| 摘要 |
The invention concerns a method for obtaining inactive lanthanum carbonate of higher purity, applying the method consisting in saturating the solution of lanthanum salts with carbon dioxide, characterised in that the solution of lanthanum salt of concentration not lesser than 0.5 M and temperature 15-40 degrees Celsius or 55-85 degrees Celsius, is saturated simultaneously with gaseous ammonia, preferably with thinned air or another inactive gas and with carbon dioxide of pH 3.5-6.0 till releasing not more than 95 percent of lanthanum, and then the sediment so formed is filtered, washed with demineralised water saturated with carbon dioxide of temperature equal to the temperature of saturation, that is 15-40 degrees Celsius or 55-85 degrees Celsius, and dried at temperature of 30-50 degrees Celsius till obtaining a solid mass, whereas filtrates, washings and other diluted solutions of lanthanum salts of concentration not exceeding 0.5 M are saturated at temperature of 55-85 degrees Celsius and pH 4.0-6.0 simultaneously with gaseous ammonium and gaseous carbon dioxide till releasing a maximum of 95 percent of lanthanum, and then the sediment so formed is filtered, washed with demineralised water saturated with carbon dioxide at temperature of 55-85 degrees Celsius, and then diluted in the stoichiometric amount of mineral or organic acid, the solution so obtained is fed with the initial solution of lanthanum salt till obtaining the starting volume, and then generating of the next batch of inactive lanthanum carbonate commences applying the aforesaid method at temperature of 15-40 degrees Celsius or 55-85 degrees Celsius, whereas lies and washings after the sediment separation are acidified with oxalic acid, and then the lanthanum oxalate so obtained is oxidized.
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