拜耳法种分氢氧化铝周期性细化的原因及解决方法

针对对某氧化铝厂拜耳法种分过程氢氧化铝产品周期性细化的现象,分析认为,主要原因是晶种活性降低及过饱和度控制不好等。在种分流程进行了外加氢氧化铝作晶种试验、高温附聚试验和结晶助剂试验,结果表明,通过添加结晶助剂及改善晶种附聚条件等措施,可有效解决周期性细化问题,适宜的结晶助剂添加量为（10～30）×10-6,优化的晶种附聚的条件为固含150～200g/L,温度70℃以上,附聚时间6h以上。

Reason and Solution of Periodical Attenuation of Aluminum Hydroxide Particles in the Seed Precipitation of Bayer Process

In order to deal with the hydroxide periodical attenuation in the Bayer process of the alumina refinery,some factors were analyzed. The most important reasons are low seed activity and can’t control the solution supersaturation well. So several tests,involved seeds precipitation test through adding additional seeds in the precipitation section,high temperature agglomeration test and adding CGM in the seed precipitation section were done in the Bayer process. The test results showed that adding CGM and improving the seeds agglomeration condition can solve the periodic refined problem effectively. The modified CGM adding quantity was（10～30） × 10-6 and optimizing seed agglomeration conditions were as follows：the solid content was 150～200 g/L,the temperature was 70 ℃ above and the time was 6 h above.