提高钛白三洗废水利用率的工艺实践

Utilization Rate Improvement of Third-Washed Wastewater for TiO2 Production

硫酸法钛白粉包膜工序后的三次水洗过程尤为关键。该工序要洗涤除去绝大部分的可溶性盐,因此对洗涤水的质量指标要求高,通常使用脱盐水作为三洗工序洗涤用水。洗后废水的含盐度高,除盐难度大,使得循环利用率低;采取变更三洗后水的工艺流程,采用增加分流管道、在线电导仪、控制阀门等技术改进措施,优化三洗压滤机PLC控制程序,根据三洗水电导率高低实现实时切换分离,在不影响产品质量的前提下,将低电导三洗废水回收利用至水洗工序,提高水的循环利用率,降低钛白粉用水消耗。

The key section in sulfuric acid method is the third-washing process for the coated TiO2.The process can remove most of the soluble salt.As the washing water shall be of high quality,the deironized water is usually used as the third-washing water.The washed wastewater contains high percentage of salt which is difficult to remove.Therefore,the cyclic utilization rate is low.Some innovative measures including incease of the diverting pipe,online conductometer,control valves,and optimization of the PLC controling procedure of the third-washing filter are used to realize the real-time separation of washed wastewater based on the conductivity.With no sacrifice of product quality,the third-washed wastewater with lower conductivity can be recycled for application of the washing process.Thus,It can improve the utilization of water and decrease the water consumption for TiO2 production.