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›› 2013, Vol. 13 ›› Issue (5): 801-806.

• 反应与分离 • 上一篇    下一篇

硫含量对铝酸钠种分母液盐蒸发结晶析出的影响

贾永真 王家伟 李军旗 吕常胜   

  1. 贵州大学材料与冶金学院 贵州大学材料与冶金学院 贵州大学材料科学与冶金工程学院 贵州大学材料科学与冶金工程学院
  • 收稿日期:2013-05-27 修回日期:2013-07-25 出版日期:2013-10-20 发布日期:2013-10-20
  • 通讯作者: 王家伟

Effect of Sulfur Content on Evaporation Crystallization Precipitation of Salts in Sodium Aluminate Seeded Precipitation Mother Solution

JIA Yong-zhen WAMG Jia-wei LI Jun-qi LV Chang-sheng   

  1. School of materials and metallurgy institute，Guizhou university School of materials and metallurgy institute，Guizhou university School of Material and Metallurgy,Guizhou university School of Material and Metallurgy,Guizhou university
  • Received:2013-05-27 Revised:2013-07-25 Online:2013-10-20 Published:2013-10-20
  • Contact: WAMG Jia-wei

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被引次数

19

摘要： 研究了高硫铝土矿中硫对拜耳法NaAl(OH)4种分母液蒸发排盐的影响. 结果表明，NaAl(OH)4溶液深度蒸发排盐渣中主要存在Na2CO3×H2O和NaAlO2×1.25H2O，苛碱浓度300~310 g/L时能有效析出Na2CO3且不导致NaAlO2析出过高. 硫对NaAl(OH)4溶液中Na2CO3、硫盐和NaAlO2析出影响很大，析出率均随硫含量增加而增加，且排盐率均在60%以上. Na2SO4对析出率影响最大，硫浓度6 g/L时排盐率可达91.33%；Na2SO3的影响稍低；Na2S对析出率影响较小，硫浓度6 g/L时排盐率仅为68.49%. 将硫浓度为4.5 g/L的NaAl(OH)4溶液蒸发至苛碱浓度为310 g/L时排盐渣中存在Na2CO3×H2O, NaAlO2×1.25H2O, Na2CO3×2Na2SO4和其他形式复盐. 蒸发过程中有部分低价硫被氧化，约有7%和4%的S2-氧化为S2+和S4+，7%~11% S4+氧化为S6+. Na2CO3和各价态硫化合物交互作用，影响蒸发排盐效果.

关键词: NaAl(OH)4种分母液, 蒸发排盐, 析出率, 硫化合物

Abstract: The effect of sulfur on evaporation salt discharge in NaAl(OH)4 seeded precipitation mother solution of high sulfur bauxite in Bayer process was studied. The results showed that Na2CO3×H2O and NaAlO2×1.25H2O mainly existed in the discharged salt slag after deep evaporation of NaAl(OH)4 solution. Sodium carbonate was precipitated effectively without too much NaAlO2 when the elemental sulfur concentration was 300~310 g/L. In the evaporation process the sulfur content had a great influence on the precipitation of Na2CO3, sulfosalt and NaAlO2. Their precipitation rates increased with increasing of sulfur content, and the salt discharge rates were all above 60%. The effect of sodium sulfate was the largest, and the salt discharge rate reached 91.33% at the elemental sulfur concentration of 6 g/L. And sodium sulfite followed. The effect of sodium sulphide on the precipitation rate was the smallest, the salt discharge rate was only 68.49% at the elemental sulfur concentration of 6 g/L. Na2CO3×H2O, NaAlO2×1.25H2O, Na2CO3×Na2SO4 and other forms of double salts existed in the slag when the NaAl(OH)4 solution of elemental sulfur concentration 4.5 g/L was evaporated to the sodium hydroxide concentration of 310 g/L. There were some sulfocompounds in lower valence state oxidized in the evaporation. About 7% and 4% of sodium sulphide were oxidized to sodium thiosulfate and sodium sulfite, and about 7%~11% of sodium sulfite to sodium sulfate. So the salt discharge effect was influenced by the interaction of sodium carbonate and each valence state sulfocompounds.

Key words: sodium aluminate seeded precipitation mother solution, evaporation salt discharge, precipitation rate, sulfocompound

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