硫含量对铝酸钠种分母液盐蒸发结晶析出的影响  

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

作　　者：贾永真[1] 王家伟[1] 李军旗[1] 吕常胜[1] 

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025

出　　处：《过程工程学报》2013年第5期801-806,共6页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:51264006);贵州省科教青年英才培养工程基金资助项目(编号:黔省专合字[2012]149);贵州省教育厅"125"重大科技专项基金资助项目(编号:黔教合重大专项字[2012]002)

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300～310g／L时能有效析出Na2CO3且不导致NaAlO2析出过高．硫对NaAl（OH）。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．Na2S04对析出率影响最大，硫浓度6g／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6g／L时排盐率仅为68．49％．将硫浓度为4．5g／L的NaAl（OH）4溶液蒸发至苛碱浓度为310g／L时排盐渣中存在Na2CO3．H2O，NaAlO2．1．25H2O，Na2CO3．2Na2SOn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．The effect of sulfur on evaporation salt discharge in NaAI（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 NaAI（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 NaAI（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.

关 键 词：NaAl(OH)4种分母液 蒸发排盐 析出率 硫化合物 

分 类 号：TF821[冶金工程—有色金属冶金]