硫对含草酸钠铝酸钠溶液蒸发排盐的影响

通过添加不同量的硫酸钠和硫化钠,研究硫对含一定浓度草酸钠(Ns)的铝酸钠溶液蒸发排盐的影响。结果表明,当Ns=6g/L时,硫酸钠对铝酸钠溶液中Na_2CO_3、硫盐、Na_2C_2O_4和NaAlO_2的结晶析出均有影响,随着添加量的增加,盐析出率均增大,排盐率也增大,当Ns=6g/L时,排盐率达到92.02%,排盐渣中存在Na_2CO_3、Na_2C_2 O4、NaAlO_2·1.25H_2O、Na_2SO_4以及Na_6CO_3(SO_4)_2、Na_4(SO_4)1.39(CO_3)0.61等结晶复盐;添加硫化钠也可以增加盐析出率与排盐率,但是效果不明显,在当Ns=6g/L时,排盐率仅为71.71%,结晶物相有Na_2CO_3、Na_2C_2O_4、NaAlO_2·1.25H_2O以及Na_2S,Na_2S2O_3,Na_2SO_3等,并不存在结晶复盐;随着硫化钠添加量的增加,抽滤时间增长,增加了排盐的难度,硫化钠滞留在溶液中,继续对生产产生危害,需要引入氧化剂将硫化钠充分氧化为硫酸钠,才能达到良好的强化排盐效果。

Effect of Sulfur on Salt Elimination from NaAlO2 Solution Bearing Na2C2O4

The effect of sulfur on evaporation salt discharge from sodium aluminate solution bearing Na2C2O4 was studied by adding different amount of Na2SO4 and Na2S respectively. The results show that when concentration of sodium oxalate is NS=6 g/L, sodium sulfate exerts effect on crystallization of Na2CO3, sulfur salt, Na2C2O4 and NaAlO2 in sodium aluminate solution. Salting-out rate and brine rate rises with increase of adding amount. With Ns=6 g/L, brine rate is 92.02%, and there are Na2CO3, Na2C2O4, NaAlO2?1.25H2O, Na2SO4, Na6CO3(SO4)2, and Na4(SO4)1.39(CO3)0.61 in evaporation residue. Adding sodium sulfide can also improve salting-out rate and brine rate with limited effect. With Ns=6 g/L, brine rate is as only as 71.71%, and crystal phase are Na2CO3, Na2C2O4, NaAlO2?1.25H2O, Na2S, Na2S2O3, and Na2SO3, etc, with no double salt crystallization. With increase of adding amount of sodium sulfide, suction filter time is growing, difficulty of row of salt enhances, and sodium sulphide remains in solution with continuing harm to production. It is necessary to apply oxidant to oxidize sodium sulphide to sodium sulfate to discharge more salts.