盐湖卤水硼镁分离工艺及高纯氧化镁的制备

于培峰，杨喜云，徐 徽，石西昌，陈 亚，颜果春

(中南大学 冶金科学与工程学院，长沙 410083)

摘 要：以富含硼、镁、锂的盐湖卤水为原料，采用硫酸和离子交换法联合提硼，实现硼与镁、锂分离；采用氨法沉淀镁实现镁与锂的分离。分别用静态法和动态法研究卤水pH值、吸附温度、吸附时间、树脂用量、卤水流速、交换柱高径比对硼提取率的影响，确定提硼最佳工艺条件，硼提取率达95%以上。研究卤水硼浓度对氢氧化镁中硼含量的影响。结果表明：当卤水中的硼浓度由4.54 mg/L增加到1 200 mg/L时，氢氧化镁中硼含量由0.04 mg/g增加到8.82 mg/g。对硼浓度4.54 mg/L的卤水用氨法沉淀制备氢氧化镁，在1 500 ℃下煅烧得到氧化镁，其纯度为99.8%。

关键词：卤水；氢氧化镁；氧化镁；分离；提硼

Separation technique for boron and magnesium from salt lake brine and preparation of high-purity magnesium oxide

YU Pei-feng, YANG Xi-yun, XU Hui, SHI Xi-chang, CHEN Ya, YAN Guo-chun

(School of metallurgical Science and Engineering, Central South University, Changsha 410083, China)

Abstract:Using salt lake brine with high boron, magnesium and lithium as raw material, the boron was separated from magnesium and lithium with sulfate acid and ion exchange resin, and the magnesium was separated by precipitation with ammonia. The effects of pH value, temperature, time, resin amount, flowing rate of brine and ratio of height to diameter (H/D) of the column on boron removal were investigated under static and dynamic conditions. The optimum process conditions of boron removal are obtained. The results show that the boron removal ratio reaches 95% under the optimum process conditions. The boron concentration of brine has a significant effect on the content of boron in magnesium hydroxide. The content of boron in magnesium hydroxide increases from 0.04 mg/g to 8.82 mg/L with boron increasing from 4.54 mg/L to 1 200 mg/L. Using brine containing 4.54 mg/L boron as raw material to prepare magnesium hydroxide followed by calcination at 1 500 ℃ for 2 h, 99.8% magnesium oxide is obtained.

Key words:brine; magnesium hydroxide; magnesium oxide; separation; boron adsorption