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用甲醛滴定法研究了氨法脱碳产物NH_4HCO_3溶液的受热分解,测定了温度323~363 K、浓度3.0%~7.9%(w)时的NH_4HCO_3溶液分解过程中主要离子的浓度变化,并用动态法测定了288~313 K时NH_4HCO_3在Na_2CO_3-H_2O体系中的溶解度.结果表明,HCO_3~-浓度在前30 min内先快速下降再平缓下降,NH_4HCO_3分解速率随温度升高增大.同一温度下,浓度越高,达到分解平衡所需时间越短.NH_4HCO_3的分解过程符合Lageren吸附模型;NH_4HCO_3的溶解度随温度升高而增加,随Na2CO3浓度增加先上升后下降,在0.1 mol/kg时最大,此时平衡固相由NH_4HCO_3变为Na HCO3.
The titration of formaldehyde was used to study the thermal decomposition of the NH4HCO3 solution of ammonia decarburization. The concentration of main ions in the NH4HCO3 solution decomposition was measured at the temperature of 323-363 K and the concentration of 3.0% -7.9% (w) The solubility of NH_4HCO_3 in Na_2CO_3-H_2O was measured at 288 ~ 313 K. The results showed that the concentration of HCO_3 ~ decreased rapidly and then decreased slowly and the decomposition rate of NH_4HCO_3 increased with increasing temperature in the first 30 min.At the same temperature, The higher the concentration, the shorter the time needed to reach the decomposition equilibrium. The decomposition process of NH_4HCO_3 accords with the Lageren adsorption model. The solubility of NH_4HCO_3 increases with increasing temperature and then increases with the increase of Na2CO3 concentration and then decreases at 0.1 mol / kg, When the equilibrium solid phase changes from NH_4HCO_3 to Na HCO3.