硫酸法钛白废酸浓缩换热器堵塞成因分析

Analysis of causes of blockage of waste acid concentration heat exchanger in sulfuric acid process titanium dioxide

通过化学组成分析和XRD分析,明确了硫酸法钛白废酸换热器堵塞物为以硫酸钙、一水硫酸亚铁及偏钛酸为主的混合物,三者分别来源于20废酸中硫酸钙、硫酸亚铁及硫酸氧钛。在实验室研究了废酸温度及浓度对硫酸钙、硫酸亚铁及硫酸氧钛浓度的影响,研究结果表明:在废酸温度为107℃,废酸浓度由18.41%提升至49.93%时,硫酸钙、硫酸亚铁及硫酸氧钛的浓度分别由1.26、126.29、10.76 g/L降低至0.19、13.23、0.16 g/L。现场浓缩废酸各级的硫酸钙、硫酸亚铁及硫酸氧钛浓度变化规律及数据与实验室研究规律及数据基本一致。研究结果为后续解决换热器堵塞提供了重要的数据及理论支撑。

The blockage of the waste acid heat exchanger of sulfuric acid process titanium dioxide had been investigated through chemical composition analysis and XRD analysis,and caused by a mixture of calcium sulfate,ferrous sulfate monohydrate and meta-titanic acid.These mixture is derived from calcium sulfate,ferrous sulfate and titanyl sulfate in 20%waste acids.The influence of waste acid temperature and concentration on the concentration of calcium sulfate,ferrous sulfate and titanyl sulfate was studied in the laboratory.The results showed that when the waste acid temperature was 107℃and the waste acid concentration increased from 18.41%to 49.93%,the concentration of calcium sulfate,ferrous sulfate and titanyl sulfate decreased from 1.26 g/L,126.29 g/L and 10.76 g/L to 0.19 g/L,13.23 g/L and 0.16 g/L,respectively.The concentration changing rule and data of calcium sulfate,ferrous sulfate and titanium oxysulfate in concentrated waste acid at all levels are basically consistent with those of laboratory research.The research results provide important data and theoretical support for the solution of heat exchanger blockage.