拜耳法生产氧化铝过程脱锌技术研究

Study on dezincification technology of alumina production by Bayer process

通过在拜耳法溶出过程中添加硫化钠和高硫矿以及在溶出矿浆稀释过程添加硫化钠等不同方法开展脱锌试验。结果表明,溶出过程添加硫化钠脱锌,随着硫化钠添加量的增加和溶出温度的升高,脱锌率逐渐升高,当溶出温度270℃、硫化钠添加量0.9 g/L时,脱锌率可以达到81.15%;稀释脱硅过程添加硫化钠脱锌,脱锌效率明显升高,当硫化钠添加量0.5 g/L时,脱锌率达到90.23%;溶出过程添加高硫矿脱锌,随着高硫矿的配比增加,脱锌率逐渐升高,当混矿中S含量为0.4%时,脱锌率为36.92%。针对不同条件提出了氧化铝生产过程脱锌技术应用选择的建议。

Zinc removal tests are carried out by adding sodium sulfide and high-sulfur bauxite in Bayer digestion process and adding sodium sulfide in the digestion slurry dilution process.The results show that with respect to the zinc removal by adding sodium sulfide in the digestion process,the dezincification rate increases gradually with the increase of sodium sulfide content and digestion temperature.When the digestion temperature is 270℃and sodium sulfide content is 0.9 g/L,the dezincification rate can reach 81.15%.When sodium sulfide is added to dilute desilication process,the dezincification efficiency increases significantly.When sodium sulfide is added by 0.5 g/L,the dezincification rate reaches 90.23%.When the high-sulfur bauxite is added in digestion process to remove zinc,with the increased ratio of high-sulfur bauxite,the dezincification rate increases gradually.When the S content in the mixed bauxite is 0.4%,the dezincification rate is 36.92%.According to different conditions,some suggestions on the application and selection of dezincification technology in alumina production process are put forward.